Form 485BPOS Calamos ETF Trust

As filed with the U.S. Securities and Exchange Commission on June 18, 2026

Securities Act File No. 333-191151
Investment Company Act File No. 811-22887

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

and/or

REGISTRATION STATEMENT

(Check appropriate box or boxes)

Calamos ETF Trust

(Exact Name of Registrant as Specified in Charter)

2020 Calamos Court
Naperville, Illinois
(Address of Principal Executive Offices)

60563
(Zip Code)

Registrant’s Telephone Number, including Area Code: (630) 245-7200

Erik D. Ojala

2020 Calamos Court

Naperville, Illinois 60563

(Name and Address of Agent for Service)

With Copies to:

Paulita A. Pike and Rita Rubin
Ropes & Gray LLP
191 North Wacker Drive, 32nd Floor
Chicago, Illinois 60606

Approximate Date of Proposed Public Offering: As soon as practicable following the effectiveness of the Registration Statement.

If appropriate, check the following box:

CALAMOS ETF TRUST

CONTENTS OF POST EFFECTIVE AMENDMENT NO. 87

This Registration Statement consists of the following papers and documents:

Cover Sheet

Part A – Calamos Timpani Active SMID Growth ETF

Part B – Statement of Additional Information

Part C – Other Information

Signature Page

Exhibits

STATEMENT OF ADDITIONAL INFORMATION

Dated June 22, 2026

2020 Calamos Court
Naperville, Illinois 60563
866.363.9219

This Statement of Additional Information ("SAI") relates to Calamos Timpani Active SMID Growth ETF (the "Fund"), a series of the Calamos ETF Trust (the "Trust"). This is not a prospectus, but provides information that should be read in conjunction with the prospectus for the Fund, dated June 22, 2026 and any supplements thereto, which are incorporated herein by reference. Capitalized terms used herein that are not defined have the same meanings as in the Prospectus, unless otherwise noted. A copy of the Prospectus may be obtained without charge by calling the Fund at (866) 363-9219, visiting the Fund's website at www.calamos.com or through your financial advisor.

References to the Investment Company Act of 1940, as amended (the "1940 Act"), or other applicable law, will include any rules promulgated thereunder and any guidance, interpretations or modifications by the Securities and Exchange Commission (the "SEC"), SEC staff or other authority with appropriate jurisdiction, including court interpretations, and exemptive, no action or other relief or permission from the SEC, SEC staff or other authority.

TABLE OF CONTENTS

THE TRUST AND THE FUND

The Trust was organized as a Delaware statutory trust on June 17, 2013. The Trust is an open-end, registered management investment company. The Trust currently offers Fund Shares in forty-six series of the Trust. Series other than the Fund are offered through separate prospectuses and statements of additional information and are not further discussed herein. The offering of the Fund's shares ("Fund Shares") is registered under the Securities Act of 1933, as amended (the "Securities Act").

The Fund is a diversified, actively managed exchange-traded fund. The Fund offers and issues Fund Shares at net asset value ("NAV") only in aggregations of a specified number of Fund Shares, generally in exchange for a basket of securities constituting the portfolio holdings of the Fund, together with the deposit of a specified cash payment, or, in certain circumstances, for an all-cash payment. Fund Shares will be listed and principally traded on Texas Stock Exchange LLC (“TXSE” or the "Exchange"). Fund Shares will trade on the Exchange at market prices that may be below, at, or above NAV.

Unlike mutual funds, Fund Shares are not individually redeemable securities. Rather, the Fund issues and redeems Fund Shares on a continuous basis at NAV, in aggregations of a specified number of Fund Shares (each, a "Creation Unit"). In the event of the liquidation of the Fund, the Trust may lower the number of Fund Shares in a Creation Unit. Financial entities known as "authorized participants" (which are discussed in greater detail below) have contractual arrangements with the Fund or the Distributor to purchase and redeem Fund Shares directly with the Fund in Creation Units in exchange for the securities comprising the Fund and/or cash, or some combination thereof. Fund Shares are traded in the secondary market and elsewhere at market prices that may be at, above, or below the Fund's NAV. Fund Shares are only redeemable in Creation Units by authorized participants. An authorized participant that purchases a Creation Unit of Fund Shares deposits with the Fund a "basket" of securities and/or other assets identified by the Fund that day, and then receives the Creation Unit of Fund Shares in return for those assets. The redemption process is the reverse of the purchase process: the authorized participant redeems a Creation Unit of Fund Shares for a basket of securities and other assets. The basket is generally representative of the Fund's portfolio, and together with a cash balancing amount, it is equal to the NAV of the Fund Shares comprising the Creation Unit. Pursuant to Rule 6c-11 of the 1940 Act ("Rule 6c-11"), the Fund may utilize baskets that are not representative of the Fund's portfolio. Such "custom baskets" are discussed in the section entitled "Creations and Redemptions of Creation Units." Transaction fees and other costs associated with creations or redemptions that include cash may be higher than the transaction fees and other costs associated with in-kind creations or redemptions. In all cases, conditions with respect to creations and redemptions of Fund Shares and fees will be limited in accordance with the requirements of SEC rules and regulations applicable to management investment companies offering redeemable securities.

Unlike index-based ETFs, the Fund is "actively managed" and does not seek to replicate the performance of a specified index.

The Board of Trustees of the Trust (the "Board of Trustees" or the "Trustees") has the right to establish additional series in the future, to determine the preferences, voting powers, rights and privileges thereof and to modify such preferences, voting powers, rights and privileges without shareholder approval. Fund Shares of any series may also be divided into one or more classes at the discretion of the Trustees. The Trust or any series or class thereof may be terminated at any time by the Board of Trustees upon written notice to the shareholders.

EXCHANGE LISTING AND TRADING

Fund Shares are listed and traded on the TXSE. Fund Shares trade on the Exchange or in secondary markets at prices that may differ from their NAV or Intraday Indicative Value ("IIV") because such prices may be affected by market forces (such as supply and demand for Fund Shares). As is the case of other securities traded on an exchange, when you buy or sell Fund Shares on the Exchange or in the secondary markets your broker will normally charge you a commission or other transaction charges. Further, the Trust reserves the right to adjust the price of Fund Shares in the future to maintain convenient trading ranges for investors (namely, to maintain a price per Share that is attractive to investors) by share splits or reverse share splits, which would have no effect on the NAV.

There can be no assurance that the requirements of the Exchange necessary to maintain the listing of Fund Shares of the Fund will continue to be met. TXSE will consider the suspension of trading in, and will initiate delisting proceedings under the TXSE Rule Series 16.500 of, a series of Exchange Traded Fund Shares under any of the following circumstances: (A) if TXSE becomes aware that the series of Exchange Traded Fund Shares is no longer eligible to operate in reliance on Rule 6c-11 under the Investment Company Act of 1940; (B) if, following the initial twelve-month period after commencement of trading on TXSE of a series of Exchange Traded Fund Shares, there are fewer than 50 beneficial holders of such series of Exchange Traded Fund Shares; (C) if any of the other requirements set forth in this TXSE Rule 17.104 are not continuously maintained; or (D) if such other event shall occur or condition exists which in the opinion of TXSE, makes further dealings on TXSE inadvisable.

The Fund is not sponsored, endorsed, sold or promoted by the Exchange. The Exchange makes no representation or warranty, express or implied, to the owners of Fund Shares or any member of the public regarding the advisability of investing in securities generally or in the Fund particularly or the ability of the Fund to achieve its objectives. The Exchange has no obligation or liability in connection with the administration, marketing or trading of the Fund.

DISCLOSURE OF PORTFOLIO HOLDINGS

The Board has adopted a policy regarding the disclosure of information about the Fund's portfolio securities. Under the policy, portfolio holdings of the Fund, which will form the basis for the calculation of NAV on any day on which the Trust is open for business ("Business Day"), are publicly disseminated prior to the opening of trading on the Exchange that Business Day through financial reporting or news services, including the website www.calamos.com. In addition, each Business Day a portfolio composition file, which displays the basket of securities to be deposited to purchase Creation Units of the Fund ("In-Kind Creation Basket") and the amount of cash necessary to equal the difference between the NAV of a Creation Unit and the market value of the In-Kind Creation Basket ("Cash Component"), is publicly disseminated prior to the opening of the Exchange via the National Securities Clearing Corporation ("NSCC").

INVESTMENT OBJECTIVES

The Fund's investment objective is capital appreciation.

Under normal circumstances, the Fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in growth equity securities of small and mid-capitalization companies of issuers primarily located in the United States. The Fund defines a small and mid-capitalization company as any company with a market capitalization less than or equal to that of the company with the largest market capitalization of either the Russell 2500^® Index or the MSCI USA SMID Cap Index as measured on a rolling 24-month basis over the most recent period. The market capitalization of a security is measured at the time of purchase. Calamos Advisors LLC ("Calamos Advisors") defines "growth" to include any company, security or instrument if any of the following characteristics rank better than average when compared to the Fund's broad-based equity index (long-term projected earnings growth, book value growth, sales growth, cash flow growth and historical earnings growth) or if the company is included as a constituent in any of the growth indices published by third-party index providers or if the security or instrument tracks the performance of a growth index. Calamos Advisors uses fundamental research to evaluate investment opportunities, focusing on companies that it believes have superior management and whose business models have a high potential for earnings upside.

Equity securities in which the Fund invests as a part of its principal investment strategy consist of common stocks and American Depositary Receipts ("ADRs"). The Fund may invest up to 25% of its net assets in foreign securities. Foreign securities are securities issued by issuers that are organized under the laws of a foreign country, that have a substantial portion of their operations or assets in a foreign country or countries, or that derive a substantial portion of their revenue or profits from businesses, investments or sales outside of the United States. The Fund may also invest in foreign securities that are represented in the United States securities markets by ADRs or similar depositary arrangements. The Fund's foreign investments can be denominated in U.S. dollars or in foreign currencies. Calamos Advisors may actively trade portfolio securities. From time to time, the Fund may have significant investments in certain sectors due to Calamos Advisors' investment process yielding opportunities for sound growth potential within those sectors. The Fund's sector exposure may vary.

The Fund's investment objective is non-fundamental and may be changed by a vote of the Fund's Board, without shareholder approval.

INVESTMENT PRACTICES

The prospectus contains information concerning the Fund's investment objective and principal investment strategies and risks. This Statement of Additional Information provides additional information concerning certain securities and strategies used by the Fund and their associated risks.

In pursuing its investment objective, the Fund expects to invest as described below and in the Fund's prospectus. The table below indicates whether the Fund invests in the securities and instruments listed as part of its principal (P) or non-principal (N) investment strategies.

Unless otherwise noted, all investment policies and restrictions described in the Prospectus and Statement of Additional Information are measured at the time of the transaction in the security. If market action affecting Fund securities (including, but not limited to, appreciation, depreciation, or a credit rating event) causes the Fund to exceed an investment policy or restriction, Calamos Advisors LLC ("Calamos Advisors" or the "Adviser") is not required to take immediate action. Under normal market conditions, however, Calamos Advisors will not make any acquisitions that will make the Fund further outside the investment restriction.

CURRENCY EXCHANGE TRANSACTIONS

Currency exchange transactions may be conducted either on a spot (i.e., cash) basis at the spot rate for purchasing or selling currency prevailing in the foreign exchange market or through forward currency exchange contracts (“forward contracts”). Forward contracts are contractual agreements to purchase or sell a specified currency at a specified future date (or within a specified time period) and price set at the time of the contract.

Forward contracts are usually entered into with banks, foreign exchange dealers and broker-dealers, are not exchange traded, and are usually for less than one year, but may be renewed.

EQUITY SECURITIES

Equity securities include common and preferred stocks, warrants, rights, and depositary receipts. An investment in the equity securities of a company represents a proportionate ownership interest in that company. Therefore, the Fund participates in the financial success or failure of any company in which it has an equity interest.

Equity investments are subject to greater fluctuations in market value than other asset classes as a result of such factors as the issuer's business performance, investor perceptions, stock market trends and general economic conditions. Equity securities are subordinated to bonds and other debt instruments in a company's capital structure in terms of priority to corporate income and liquidation payments. See the prospectus for additional information regarding equity investments and their risks.

FOREIGN SECURITIES

A foreign security is a security issued by a foreign government or a company whose country of incorporation is a foreign country. For this purpose, foreign securities include American Depositary Receipts (ADRs) or securities guaranteed by a U.S. person but which represent underlying shares of foreign issuers. ADRs are receipts typically issued by an American bank or trust company evidencing ownership of the underlying securities. Generally, ADRs, in registered form, are designed for the U.S. securities markets. The Fund may invest in sponsored or unsponsored ADRs. In the case of an unsponsored ADR, the Fund is likely to bear its proportionate share of the expenses of the depository and it may have greater difficulty in receiving shareholder communications than it would have with a sponsored ADR.

To the extent positions in portfolio securities are denominated in foreign currencies, the Fund’s investment performance is affected by the relative strength or weakness of the U.S. dollar against those currencies. For example, if the dollar falls in value relative to the Japanese yen, the dollar value of a Japanese stock held in the portfolio will rise even though the price of the stock remains unchanged. Conversely, if the dollar rises in value relative to the yen, the dollar value of the Japanese stock will fall. (See discussion of transaction hedging and portfolio hedging below under “Currency Exchange Transactions.”)

Investors should understand and consider carefully the risks involved in foreign investing. Investing in foreign securities, which are generally denominated in foreign currencies, and utilization of forward foreign currency exchange contracts involve certain considerations comprising both risks and opportunities not typically associated with investing in U.S. securities. These considerations include: fluctuations in exchange rates of foreign currencies; possible imposition of exchange control regulation or currency restrictions that would prevent cash from being brought back to the U.S.; less public information with respect to issuers of securities; less governmental supervision of stock exchanges, securities brokers, and issuers of securities; lack of uniform accounting, auditing and financial reporting standards; lack of uniform settlement periods and trading practices; less liquidity and frequently greater price volatility in foreign markets than in the U.S.; greater costs of buying, holding and selling securities, including brokerage, tax and custody costs; and sometimes less advantageous legal, operational and financial protections applicable to foreign sub-custodial arrangements.

Although the Fund that invests in foreign securities intends to invest in companies and government securities of countries having stable political environments, there is the possibility of expropriation or confiscatory taxation, seizure or nationalization of foreign bank deposits or other assets, establishment of exchange controls, the adoption of foreign government restrictions, or other adverse political, social or diplomatic developments that could affect investment in these nations.

The Fund that invests in foreign securities may invest in the securities of emerging countries. The securities markets of emerging countries are substantially smaller, less developed, less liquid and more volatile than the securities markets of the U.S. and other more developed countries. Disclosure and regulatory standards in many respects are less stringent than in the U.S. and other major markets. There also may be a lower level of monitoring and regulation of emerging markets and the activities of investors in such markets, and enforcement of existing regulations has been extremely limited. The Public Company Accounting Oversight Board, which regulates auditors of U.S. public companies, is unable to inspect audit work papers in certain foreign countries. Investors in foreign countries often have limited rights and few practical remedies to pursue shareholder claims, including class actions or fraud claims, and the ability of the SEC, the U.S. Department of Justice and other authorities to bring and enforce actions against foreign issuers or foreign persons is limited. Economies in individual emerging markets may differ favorably or unfavorably from the U.S. economy in such respects as growth of gross domestic product, rates of inflation, currency depreciation, capital reinvestment, resource self-sufficiency and balance of payments positions. Many emerging market countries have experienced high rates of inflation for many years, which has had and may continue to have very negative effects on the economies and securities markets of those countries. Certain emerging markets are sometimes referred to as “frontier markets.” Frontier markets, the least advanced capital markets in the developing world, are among the riskiest markets in the world in which to invest. Frontier markets have the fewest number of investors and investment holdings and may not even have stock markets on which to trade. Investments in this sector are typically illiquid, nontransparent and subject to very low regulation levels as well as high transaction fees, and may also have substantial political and currency risk. Emerging and frontier markets both offer the prospect of higher returns with higher risk. However, emerging markets are more stable and developed than frontier markets. The economies of emerging market countries have achieved a rudimentary level of development, while frontier markets represent the least economically developed nations in the global marketplace. Emerging and frontier markets also carry several types of investment risk, including market, political and currency risk, as well as the risk of nationalization.

A portion of the Fund’s investments may be in Russian securities and instruments. The United States and the European Union have imposed sanctions on certain Russian persons and issuers. The United States and other nations or international organizations may impose additional, broader economic sanctions or take other actions that may adversely affect Russian-related issuers in the future. These sanctions, any future sanctions or other actions, or even the threat of further sanctions or other actions, may negatively affect the value and liquidity of the Fund’s investments. For example, the Fund may be prohibited from investing in securities issued by companies subject to such sanctions. In addition, the sanctions may require the Fund to freeze its existing investments in Russian companies, prohibiting the Fund from buying, selling or otherwise transacting in these investments. Russia may undertake countermeasures or retaliatory actions which may further impair the value and liquidity of the Fund’s portfolio and potentially disrupt its operations. For these or other reasons, the Fund could seek to suspend redemptions of shares, including in the event that an emergency exists in which it is not reasonably practicable for the Fund to dispose of its securities or to determine its net asset value. During the period that redemptions are affected, shares could trade at a significant premium or discount to their net asset value.

FUTURES CONTRACTS AND OPTIONS ON FUTURES CONTRACTS

The Fund may enter into interest rate futures contracts, index futures contracts, volatility index futures contracts and foreign currency futures contracts. An interest rate, index, volatility index or foreign currency futures contract provides for the future sale by one party and purchase by another party of a specified quantity of a financial instrument or the cash value of an index¹ at a specified price and time. A public market exists in futures contracts covering a number of indexes (including, but not limited to, the S&P 500 Index, the Russell 2000 Index, the Value Line Composite Index, and the New York Stock Exchange Composite Index) as well as financial instruments (including, but not limited to, U.S. Treasury bonds, U.S. Treasury notes, Eurodollar certificates of deposit and foreign currencies). Other index and financial instrument futures contracts are available and it is expected that additional futures contracts will be developed and traded. The Fund may enter into such contract if, in Calamos Advisors’ opinion, such contract meets the Fund’s investment parameters.

The Fund may purchase and write call and put futures options. Futures options possess many of the same characteristics as options on securities, indexes and foreign currencies (discussed in this Statement of Additional Information). A futures option gives the holder the right, in return for the premium paid, to assume a long position (call) or short position (put) in a futures contract at a specified exercise price at any time during the period of the option. Upon exercise of a call option, the holder acquires a long position in the futures contract and the writer is assigned the opposite short position. In the case of a put option, the opposite is true. The Fund might, for example, use futures contracts to hedge against or gain exposure to fluctuations in the general level of stock prices, anticipated changes in interest rates or currency fluctuations that might adversely affect either the value of the Fund’s securities or the price of the securities that the Fund intends to purchase. Although other techniques could be used to reduce or increase the Fund’s exposure to stock price, interest rate and currency fluctuations, the Fund may be able to achieve its desired exposure more effectively and perhaps at a lower cost by using futures contracts and futures options.

The Fund will only enter into futures contracts and futures options that are standardized and traded on an exchange, board of trade or similar entity, or quoted on an automated quotation system.

The success of any futures transaction by the Fund depends on Calamos Advisors’ correctly predicting changes in the level and direction of stock prices, interest rates, currency exchange rates and other factors. Should those predictions be incorrect, the Fund’s return might have been better had the transaction not been attempted; however, in the absence of the ability to use futures contracts, Calamos Advisors might have taken portfolio actions in anticipation of the same market movements with similar investment results, but, presumably, at greater transaction costs.

When the Fund makes a purchase or sale of a futures contract, the Fund is required to deposit with its custodian (or broker, if legally permitted) a specified amount of cash or U.S. Government securities or other securities acceptable to the broker (“initial margin”). The margin required for a futures contract is set by the exchange on which the contract is traded and may be modified during the term of the contract, although the Fund’s broker may require margin deposits in excess of the minimum required by the exchange. The initial margin is in the nature of a performance bond or good faith deposit on the futures contract, which is returned to the Fund upon termination of the contract, assuming all contractual obligations have been satisfied. The Fund expects to earn interest income on its initial margin deposits. A futures contract held by the Fund is valued daily at the official settlement price of the exchange on which it is traded. Each day the Fund pays or receives cash, called “variation margin,” equal to the daily change in value of the futures contract. This process is known as “marking-to-market.” Variation margin paid or received by the Fund does not represent a borrowing or loan by the Fund but is instead settlement between the Fund and the broker of the amount one would owe the other if the futures contract had expired at the close of the previous day. In computing daily net asset value, the Fund will mark-to-market its open futures positions.

The Fund is also required to deposit and maintain margin with respect to put and call options on futures contracts written by it. Such margin deposits will vary depending on the nature of the underlying futures contract (and the related initial margin requirements), the current market value of the option and other futures positions held by the Fund.

Although some futures contracts call for making or taking delivery of the underlying reference asset, usually these obligations are closed out prior to delivery by offsetting purchases or sales of matching futures contracts (same exchange, underlying reference asset, and delivery month). If an offsetting purchase price is less than the original sale price, the Fund engaging in the transaction realizes a capital gain, or if it is more, the Fund realizes a capital loss. Conversely, if an offsetting sale price is more than the original purchase price, the Fund engaging in the transaction realizes a capital gain, or if it is less, the Fund realizes a capital loss. The transaction costs must also be included in these calculations.

¹ A futures contract on an index is an agreement pursuant to which two parties agree to take or make delivery of an amount of cash equal to the difference between the value of the index at the close of the last trading day of the contract and the price at which the index contract was originally written. Although the value of a securities index is a function of the value of certain specified securities, no physical delivery of those securities is made.

RISKS ASSOCIATED WITH FUTURES. There are several risks associated with the use of futures contracts and futures options. A purchase or sale of a futures contract or option may result in losses in excess of the amount invested in the futures contract or option. In trying to increase or reduce market exposure, there can be no guarantee that there will be a correlation between price movements in the futures contract or option and in the portfolio exposure sought. In addition, there are significant differences between the securities and futures markets that could result in an imperfect correlation between the markets, causing a given transaction not to achieve its objectives. The degree of imperfection of correlation depends on circumstances such as: variations in speculative market demand for futures, futures options and the related securities, including technical influences in futures and futures options trading and differences between the securities markets and the securities underlying the standard contracts available for trading. For example, in the case of index futures contracts, the composition of the index, including the issuers and the weighing of each issue, may differ from the composition of the Fund’s portfolio, and, in the case of interest rate futures contracts, the interest rate levels, maturities and creditworthiness of the issues underlying the futures contract may differ from the financial instruments held in the Fund’s portfolio. Futures prices are highly volatile at times and are influenced by many external economic, governmental, and world events. The low margin deposits normally required in futures trading permits an extremely high degree of leverage, which can result in the Fund experiencing substantial gains or losses due to relatively small price movements or other factors. A decision as to whether, when and how to use futures contracts involves the exercise of skill and judgment, and even a well-conceived transaction may be unsuccessful to some degree because of market behavior or unexpected stock price or interest rate trends.

Futures exchanges may limit the amount of fluctuation permitted in certain futures contract prices during a single trading day. The daily limit establishes the maximum amount that the price of a futures contract may vary either up or down from the previous day’s settlement price at the end of the current trading session. Once the daily limit has been reached in a futures contract subject to the limit, no more trades may be made on that day at a price beyond that limit. The daily limit governs only price movements during a particular trading day and therefore does not limit potential losses because the limit may work to prevent the liquidation of unfavorable positions. For example, futures prices have occasionally moved to the daily limit for several consecutive trading days with little or no trading, thereby preventing prompt liquidation of positions and subjecting some holders of futures contracts to substantial losses. Stock index futures contracts are not normally subject to such daily price change limitations.

The markets for futures positions may be thinly traded from time to time. In addition, futures positions may become illiquid due to daily price limits taking effect or due to market disruptions. There can be no assurance that a liquid market will exist at a time when the Fund seeks to close out a futures or futures option position. The Fund would be exposed to possible loss on the position during the interval of inability to close, and would continue to be required to meet margin requirements until the position is closed. In addition, many of the contracts discussed above are relatively new instruments without a significant trading history. As a result, there can be no assurance that an active secondary market will develop or continue to exist.

LIMITATIONS ON OPTIONS AND FUTURES. If options, futures contracts or futures options of types other than those described herein are traded in the future, the Fund may also use those investment vehicles, provided the board of trustees determines that their use is consistent with the Fund’s investment objectives.

The Fund may not maintain open short positions in futures contracts, call options written on futures contracts or call options written on indexes if, in the aggregate, the market value of all such open positions exceeds the current value of the securities in its portfolio, plus or minus unrealized gains and losses on the open positions, adjusted for the historical relative volatility of the relationship between the portfolio and the positions. For this purpose, to the extent the Fund has written call options on specific securities in its portfolio, the value of those securities will be deducted from the current market value of the securities portfolio.

The use of options and futures is subject to applicable regulations of the Securities and Exchange Commission (“SEC”), the several exchanges upon which they are traded and the Commodity Futures Trading Commission (“CFTC”). For example, the CFTC, certain foreign regulators, and many futures exchanges have established (and continue to evaluate and monitor) speculative position limits (“position limits”) on the maximum speculative position which any person, or group of persons acting in concert, may hold or control in particular contracts. In addition, U.S. federal position limits apply to swaps that are economically equivalent to futures contracts on certain agricultural, metals, and energy commodities. All positions owned or controlled by the same person or entity, even if in different accounts, must be aggregated for purposes of complying with the speculative limits. Thus, even if the Fund does not intend to exceed applicable position limits, it is possible that different clients managed by the Adviser and its affiliates may be aggregated for this purpose. Therefore, the trading decisions of the Adviser may have to be modified and positions held by the Fund liquidated in order to avoid exceeding such limits. The modification of investment decisions or the elimination of open positions, if it occurs, may adversely affect the profitability of the Fund. A violation of position limits could also lead to regulatory action materially adverse to the Fund’s investment strategy. The Fund may also be affected by regimes of the European Union and United Kingdom that impose position limits on its trade of commodity derivative contracts.

Calamos Advisors has registered with the CFTC as a commodity pool operator (“CPO”) and is a member of the National Futures Association in such capacity. However, because of each Fund’s limited exposure to commodity interests, Calamos Advisors has claimed an exclusion from the definition of CPO, with respect to each Fund, pursuant to Rule 4.5 under the Commodity Exchange Act (“CEA”). Consequently, Calamos Advisors is not subject to registration or regulation as a CPO under the CEA with respect to each Fund.

Under Rule 4.5, if the Fund uses commodity interests (such as futures contracts, options on futures contracts and swaps) other than for bona fide hedging purposes (as defined by the CFTC) the aggregate initial margin and premiums required to establish these positions (after taking into account unrealized profits and unrealized losses on any such positions and excluding the amount by which options that are “in-the-money”² at the time of purchase) may not exceed 5% of the Fund’s NAV, or alternatively, the aggregate net notional value of those positions, as determined at the time the most recent position was established, may not exceed 100% of the fund’s NAV (after taking into account unrealized profits and unrealized losses on any such positions). The Fund is subject to the risk that a change in U.S. law and related regulations will impact the way the Fund operates, increase the particular costs of the Fund’s operation and/or change the competitive landscape. In this regard, any further amendments to the CEA or its related regulations that subject the Fund to additional regulation may have adverse impacts on the Fund’s operations and expenses.

In addition, the Fund’s ability to use options and futures will be limited by tax considerations. See “Taxation — Options, Futures and Forward Contracts, and Swap Agreements or Derivatives” below.

ILLIQUID SECURITIES

The Fund may invest up to 15% of its net assets under regulatory rules, taken at market value, in illiquid investments that are assets, including any securities that are not readily marketable either because they are restricted securities or for other reasons. Restricted securities are securities that are subject to restrictions on resale because they have not been registered for sale under the Securities Act of 1933, as amended (“Securities Act”). A position in restricted securities might adversely affect the liquidity and marketability of a portion of the Fund’s portfolio, and the Fund might not be able to sell or dispose of its holdings in such securities promptly or at reasonable prices. In those instances where the Fund is required to have restricted securities held by it registered prior to sale by the Fund and the Fund does not have a contractual commitment from the issuer or seller to pay the costs of such registration, the gross proceeds from the sale of securities would be reduced by the registration costs and underwriting discounts. Any such registration costs are not included in the percentage limitation on the Fund’s investment in restricted securities.

INITIAL PUBLIC OFFERINGS

The Fund may purchase stock in an initial public offering (“IPO”). An IPO is a company’s first offering of stock to the public, typically to raise additional capital. Shares are given a market value reflecting expectations for the company’s future growth. The market for these securities may be more volatile and entail greater risk of loss than investments in larger companies due to the absence of a prior public market, unseasoned trading, a limited number of shares available for trading, lack of information about the issuer and limited operating history.

The purchase of IPO shares may involve high transaction costs. Because of the price volatility of IPO shares, the Fund may choose to hold IPO shares for a very short period of time. This may increase the turnover of the Fund’s portfolio and may lead to increased expenses to the Fund, such as commissions and transaction costs. Calamos Advisors cannot guarantee continued access to IPOs.

LENDING OF PORTFOLIO SECURITIES

In seeking to earn additional income, the Fund may lend its portfolio securities to qualified parties (typically broker-dealers and banks) who need to borrow securities in order to cover transactions into which they have entered. Any such loan must be continuously secured by collateral in cash or cash equivalents maintained on a current basis in an amount at least equal to the market value of the securities loaned by the Fund. The Fund would continue to receive the equivalent of the interest or dividends paid by the issuer on the securities loaned, and would also receive an additional return that may be in the form of a fixed fee or a percentage of income earned on the collateral. The Fund may experience losses as a result of a diminution in value of its cash collateral investments. The Fund may pay reasonable fees to persons unaffiliated with the Fund for services in arranging these loans. The Fund would have the right to call the loan and obtain the securities loaned at any time on notice of not less than five business days. The Fund would not have the right to vote the securities during the existence of the loan; however, the Fund may attempt to call back the loan and vote the proxy if time permits prior to the record date. In the event of bankruptcy or other default of the borrower, the Fund could experience both delays in liquidating the loan collateral or recovering the loaned securities and losses, including (a) possible decline in the value of the collateral or in the value of the securities loaned during the period while the Fund seeks to enforce its rights thereto, (b) possible subnormal levels of income and lack of access to income during this period, and (c) expenses of enforcing its rights. In an effort to reduce these risks, the Fund’s securities lending agent will monitor, and report to Calamos Advisors on, the creditworthiness of the firms to which the Fund lends securities.

OPTIONS ON SECURITIES, INDEXES AND CURRENCIES

The Fund may purchase and sell (write) put options and call options on securities, indexes or foreign currencies. The Fund may purchase agreements, sometimes called cash puts, that may accompany the purchase of a new issue of bonds from a dealer.

A put option gives the purchaser of the option, upon payment of a premium, the right to sell, and the writer the obligation to buy, the underlying security, commodity, index, currency or other instrument at the exercise price. For instance, the Fund’s purchase of a put option on a security might be designed to protect its holdings in the underlying instrument (or, in some cases, a similar instrument) against a substantial decline in the market value by giving the Fund the right to sell such instrument at the option exercise price. A call option, upon payment of a premium, gives the purchaser of the option the right to buy, and the seller the obligation to sell, the underlying instrument at the exercise price. The Fund’s purchase of a call option on a security, financial future, index, currency or other instrument might be intended to protect it against an increase in the price of the underlying instrument that it intends to purchase in the future by fixing the price at which it may purchase such instrument.

The Fund may purchase and sell (write) exchange listed options and over-the-counter (“OTC”) options. Exchange listed options are issued by a regulated intermediary such as the Options Clearing Corporation (“OCC”), which guarantees the performance of the obligations of the parties to such options. The discussion below uses the OCC as an example, but is also applicable to other financial intermediaries.

With certain exceptions, OCC issued and exchange listed options generally settle by physical delivery of the underlying security or currency, although in the future cash settlement may become available. Index options and Eurodollar instruments are cash settled for the net amount, if any, by which the option is “in-the-money” (i.e., where the value of the underlying instrument exceeds, in the case of a call option, or is less than, in the case of a put option, the exercise price of the option) at the time the option is exercised. Frequently, rather than taking or making delivery of the underlying instrument through the process of exercising the option, listed options are closed by entering into offsetting purchase or sale transactions that do not result in ownership of the new option.

OTC options are purchased from or sold to sellers or purchasers (“Counterparties”) through direct bilateral agreement with the Counterparties. In contrast to exchange listed options, which generally have standardized terms and performance mechanics, all the terms of an OTC option, including such terms as method of settlement, term, exercise price, premium, guarantees and security, are set by negotiation of the parties. The Fund will only sell (write) OTC options (other than OTC currency options) that are subject to a buy-back provision permitting the Fund to require the Counterparty to sell the option back to the Fund at a formula price within seven days. The Fund generally is expected to enter into OTC options that have cash settlement provisions, although it is not required to do so. The staff of the SEC currently takes the position that OTC options purchased by the Fund, and portfolio securities “covering” the amount of the Fund’s obligation pursuant to an OTC option sold by it (or the amount of assets equal to the formula price for the repurchase of the option, if any, less the amount by which the option is “in the money”) are illiquid, and are subject the Fund’s limitation on investing no more than 15% in illiquid securities.

The Fund may also purchase and sell (write) options on securities indexes and other financial indexes. Options on securities indexes and other financial indexes are similar to options on a security or other instrument except that, rather than settling by physical delivery of the underlying instrument, they settle by cash settlement, i.e., an option or an index gives the holder the right to receive, upon exercise of the option, an amount of cash if the closing level of the index upon which the option is based exceeds, in the case of a call, or is less than, in the case of a put, the exercise price of the option (except if, in the case of an OTC option, physical delivery is specified). This amount of cash is equal to the excess of the closing price of the index over the exercise price of the option, which also may be multiplied by a formula value. The seller of the option is obligated, in return for the premium received, to make delivery of this amount. The gain or loss on an option on an index depends on price movements in the instruments making up the market, market segment, industry or other composite on which the underlying index is based, rather than price movements in individual securities, as is the case with respect to options on securities.

The Fund will sell (write) call options and put options only if they are “covered.” A written option will be considered “covered” to the extent it has entered into an offsetting transaction or otherwise has segregated or earmarked cash or liquid assets equal to its uncovered obligations under the written option. For example, a call option written by the Fund could be covered by purchasing an offsetting call option, by purchasing or holding the underlying reference security or asset (or a security convertible into the underlying reference security or asset), or by segregating or earmarking cash or liquid assets equal to the exercise price of the written option (or such amount as is not otherwise covered by an offsetting transaction). The Fund writing a call option on an index would be considered as holding an offsetting position to the extent the Fund owned portfolio securities substantially correlating with the movement of the underlying reference index.

If an option written by the Fund expires, the Fund realizes a capital gain equal to the premium received at the time the option was written. If an option purchased by the Fund expires, the Fund realizes a capital loss equal to the premium paid.

The Fund will realize a capital gain from a closing purchase transaction if the cost of the closing option is less than the premium received from writing the option, or, if it is more, the Fund will realize a capital loss. If the premium received from a closing sale transaction is more than the premium paid to purchase the option, the Fund will realize a capital gain or, if it is less, the Fund will realize a capital loss. The principal factors affecting the market value of a put or a call option include supply and demand, interest rates, the current market price of the underlying security, asset or index in relation to the exercise price of the option, the volatility of the underlying security, asset or index, and the time remaining until the expiration date.

A put or call option purchased by the Fund is an asset of the Fund, valued initially at the premium paid for the option. The premium received for an option written by the Fund is recorded as a deferred credit. The value of an option purchased or written is marked-to-market daily and is valued at the closing price on the exchange on which it is traded or, if not traded on an exchange or no closing price is available, at the mean between the last bid and asked prices.

RISKS ASSOCIATED WITH OPTIONS. There are several risks associated with transactions in options. For example, there are significant differences between the securities markets, the currency markets and the options markets that could result in an imperfect correlation among these markets, causing a given transaction not to achieve Calamos Advisors’ objective. A decision as to whether, when and how to use options involves the exercise of skill and judgment, and even a well-conceived transaction may be unsuccessful to some degree because of market behavior or unexpected events. The Fund’s ability to utilize options successfully will depend on Calamos Advisors’ ability to predict pertinent market investments, which cannot be assured.

The Fund’s ability to close out its position as a purchaser or seller (writer) of an OCC or exchange listed put or call option is dependent, in part, upon the liquidity of the option market. Among the possible reasons for the absence of a liquid option market on an exchange are: (i) insufficient trading interest in certain options; (ii) restrictions on transactions imposed by an exchange; (iii) trading halts, suspensions or other restrictions imposed with respect to particular classes or series of options or underlying securities including reaching daily price limits; (iv) interruption of the normal operations of the OCC or an exchange; (v) inadequacy of the facilities of an exchange or OCC to handle current trading volume; or (vi) a decision by one or more exchanges to discontinue the trading of options (or a particular class or series of options), in which event the relevant market for that option on that exchange would cease to exist, although outstanding options on that exchange would generally continue to be exercisable in accordance with their terms. If the Fund were unable to close out an option that it has purchased on a security, it would have to exercise the option in order to realize any profit or the option would expire and become worthless. If the Fund were unable to close out a covered call option that it had written on a security, it would not be able to sell the underlying security until the option expired. As the writer of a covered call option on a security, the Fund foregoes, during the option’s life, the opportunity to profit from increases in the market value of the security covering the call option above the sum of the premium and the exercise price of the call. As the writer of a covered call option on a foreign currency, the Fund foregoes, during the option’s life, the opportunity to profit from any currency appreciation.

The hours of trading for listed options may not coincide with the hours during which the underlying financial instruments are traded. To the extent that the option markets close before the markets for the underlying financial instruments, significant price and rate movements can take place in the underlying markets that cannot be reflected in the option markets.

Unless the parties provide for it, there is no central clearing or guaranty function in an OTC option. As a result, if the Counterparty (as described above under “Options on Securities, Indexes and Currencies”) fails to make or take delivery of the security, currency or other instrument underlying an OTC option it has entered into with the Fund or fails to make a cash settlement payment due in accordance with the terms of that option, the Fund will lose any premium it paid for the option as well as any anticipated benefit of the transaction. Accordingly, Calamos Advisors must assess the creditworthiness of each such Counterparty or any guarantor or credit enhancement of the Counterparty’s credit to determine the likelihood that the terms of the OTC option will be satisfied.

The Fund may purchase and sell (write) call options on securities indexes and currencies. Even though the Fund will receive the option premium to help protect it against loss, a call sold by the Fund exposes the Fund during the term of the option to possible loss of opportunity to realize appreciation in the market price of the underlying security or instrument and may require the Fund to hold the security or instrument that it might otherwise have sold. In addition, a loss on a call option sold may be greater than the premium received. The Fund may purchase and sell (write) put options on securities indexes and currencies. In selling (writing) put options, there is a risk that the Fund may be required to buy the underlying index or currency at a disadvantageous price above the market price.

OTHER INVESTMENT COMPANIES

The Fund may invest in the securities of other investment companies to the extent that such investments are consistent with the Fund's investment objectives and permissible under the 1940 Act. Under one provision of the 1940 Act, the Fund may not acquire the securities of other investment companies if, as a result, (i) more than 10% of the Fund's total assets would be invested in securities of other investment companies, (ii) such purchase would result in more than 3% of the total outstanding voting securities of any one investment company being held by the Fund or (iii) more than 5% of the Fund's total assets would be invested in any one investment company. In some instances, the Fund may invest in an investment company in excess of these limits. For example, the Fund may invest in other registered investment companies, such as mutual funds, closed-end funds and ETFs, including affiliated funds, and in BDCs in excess of the statutory limits imposed by the 1940 Act in reliance on Rule 12d1-4 under the 1940 Act. These investments would be subject to the applicable conditions of Rule 12d1-4, which in part would affect or otherwise impose certain limits on the investments and operations of the underlying fund. Accordingly, if the Fund serves as an "underlying fund" to another investment company, the Fund's ability to invest in other investment companies, private funds and other investment vehicles may be limited and, under these circumstances, the Fund's investments in other investment companies, private funds and other investment vehicles will be consistent with applicable law and/or exemptive relief obtained from the SEC. The Fund, as a holder of the securities of other investment companies, will bear its pro rata portion of the other investment companies' expenses, including advisory fees. These expenses will be in addition to the direct expenses incurred by the Fund. In the event the Fund invests in another affiliated fund (the "Acquired Fund"), the portion of the Fund's Investment Management Fee equal to the advisory fee payable to the Acquired Fund (based on average daily net assets invested) is waived.

PORTFOLIO TURNOVER

Although the Fund does not purchase securities with a view to rapid turnover, there are no limitations on the length of time that a portfolio security must be held. Portfolio turnover can occur for a number of reasons, including calls for redemption, general conditions in the securities markets, more favorable investment opportunities in other securities, or other factors relating to the desirability of holding or changing a portfolio investment. The portfolio turnover rates may vary greatly from year to year. A high rate of portfolio turnover in the Fund would result in increased transaction expense, which must be borne by the Fund. High portfolio turnover may also result in the realization of capital gains or losses and, to the extent net short-term capital gains are realized, any distributions resulting from such gains will be considered ordinary income for federal income tax purposes. Portfolio turnover for each Fund is shown under “Financial Highlights” in the prospectus. A portfolio turnover rate of 100% would mean that the Fund had sold and purchased securities valued at 100% of its net assets within a one-year period.

SWAPS, CAPS, FLOORS AND COLLARS

The Fund may enter into interest rate, currency, index, credit default, total return and other swaps and the purchase or sale of related caps, floors and collars. The Fund expects to enter into these transactions primarily to preserve a return or spread on a particular investment or portion of its portfolio, to protect against currency fluctuations, as a duration management technique or to protect against any increase in the price of securities the Fund anticipates purchasing at a later date. The Fund will not sell interest rate caps or floors where it does not own securities or other instruments providing the income stream the Fund may be obligated to pay. Interest rate swaps involve the exchange by the Fund with another party of their respective commitments to pay or receive interest, e.g., an exchange of floating rate payments for fixed rate payments with respect to a notional amount of principal. A currency swap is an agreement to exchange cash flows on a notional amount of two or more currencies based on the relative value differential among them and an index swap is an agreement to swap cash flows on a notional amount based on changes in the values of the reference indexes. A credit default swap is an agreement to transfer the credit exposure of fixed-income products between parties. The purchase of a cap entitles the purchaser to receive payments on a notional principal amount from the party selling such cap to the extent that a specified benchmark exceeds a predetermined interest rate or amount. The purchase of a floor entitles the purchaser to receive payments on a notional principal amount from the party selling such floor to the extent that a specified benchmark falls below a predetermined interest rate or amount. A collar is a combination of a cap and a floor that preserves a certain return within a predetermined range of interest rates or values.

The Fund will usually enter into swaps on a net basis, i.e., the two payment streams are netted out in a cash settlement on the payment date or dates specified in the instrument, with the Fund receiving or paying, as the case may be, only the net amount of the two payments. The Fund will not enter into any swap, cap, floor or collar transaction unless, at the time of entering into such transaction, the unsecured long-term debt of the securities dealers, financial institutions or other parties with whom the Fund has entered into such a transaction (“Counterparties”), combined with any credit enhancements, is rated at least A by S&P or Moody’s or has an equivalent rating from an NRSRO or is determined to be of equivalent credit quality by Calamos Advisors. If there is a default by the Counterparty, the Fund may have contractual remedies pursuant to the agreements related to the transaction. Although the swap market has grown substantially over the years, increasing liquidity, some swaps, including caps, floors, and collars, may be considered illiquid.

In addition, some swaps are, and more in the future may be, centrally cleared. Swaps that are centrally-cleared are subject to the creditworthiness of the clearing organizations involved in the transaction. For example, the Fund could lose margin payments deposited with the clearing organization, as well as the net amount of gains not yet paid by the clearing organization, if the clearing organization breaches the swap agreement with the Fund or becomes insolvent or goes into bankruptcy. Also, the Fund will be exposed to the credit risk of the futures commission merchant who acts as the Fund’s clearing member on the clearinghouse for a centrally cleared swap. If the Fund’s futures commission merchant becomes bankrupt or insolvent, or otherwise defaults on its obligations to the Fund, the Fund may not receive all amounts owed to it in respect of its trading, even if the clearinghouse fully discharges all of its obligations. In the event of bankruptcy of the Fund’s futures commission merchant, the Fund may be entitled to the net amount of gains the Fund is entitled to receive, plus the return of margin owed to it, only in proportion to the amount received by the futures commission merchant’s other customers for the relevant account class, potentially resulting in losses to the Fund. Credit risk of market participants with respect to derivatives that are centrally cleared is concentrated in a few clearing organizations and clearing members, and it is not clear how an insolvency proceeding of a clearing organization or clearing member would be conducted, what effect the insolvency proceeding would have on any recovery by the Fund, and what impact an insolvency of a clearing organization or clearing member would have on the financial system more generally.

TEMPORARY INVESTMENTS

The Fund may make temporary investments without limitation when Calamos Advisors determines that a defensive position is warranted, or as a reserve for possible cash needs. Such investments may be in money market instruments, consisting of obligations of, or guaranteed as to principal and interest by, the U.S. Government or its agencies or instrumentalities; certificates of deposit, bankers’ acceptances and other obligations of domestic banks having total assets of at least $500 million and that are regulated by the U.S. Government, its agencies or instrumentalities; commercial paper rated in the highest category by a recognized rating agency; cash; and repurchase agreements.

U.S. GOVERNMENT OBLIGATIONS

U.S. Government Obligations include securities that are issued or guaranteed by the U.S. Treasury or by various U.S. Government agencies and instrumentalities. U.S. Treasury obligations (“U.S. Treasuries”) include Treasury bills, Treasury notes, and Treasury bonds. U.S. Treasuries also include the separate principal and interest components of U.S. Treasuries that are traded under the Separate Trading of Registered Interest and Principal of Securities (“STRIPS”) program. U.S. Treasury obligations are backed by the full faith and credit of the U.S.

Obligations issued or guaranteed by U.S. Government agencies and instrumentalities may be supported by any of the following: (a) the full faith and credit of the U.S., (b) the right of the issuer to borrow an amount limited to a specific line of credit from the U.S. Treasury, (c) the discretionary authority of the U.S. Treasury to lend to such Government agency or instrumentality, or (d) the credit of the agency or instrumentality.

Government agencies that issue or guarantee securities backed by the full faith and credit of the U.S. include the GNMA and the Small Business Administration. Government agencies and instrumentalities that issue or guarantee securities not backed by the full faith and credit of the U.S. include the Federal Farm Credit Banks, the Federal Home Loan Banks, the Federal Home Loan Mortgage Corporation (“FHLMC”), the Federal National Mortgage Association (“FNMA”), the Federal Land Bank, the Bank for Cooperatives, the Federal Intermediate Credit Bank, the Federal Financing Bank, the Resolution Funding Corporation, the Financing Corporation of America and the Tennessee Valley Authority. In the case of securities not backed by the full faith and credit of the U.S., the investor must look principally to the agency issuing or guaranteeing the obligation for ultimate repayment and may not be able to assert a claim against the U.S. in the event the agency or instrumentality does not meet its commitment.

In September 2008, the U.S. Treasury and the Federal Housing Finance Agency (“FHFA”) announced that FNMA and FHLMC had been placed in conservatorship. The conservatorship is still in effect as of the date of this SAI and has no specified termination date. There can be no assurance as to when or how the conservatorship will be terminated or whether FNMA or FHLMC will continue to exist following the conservatorship or what their respective business structures will be during or following the conservatorship. Since that time, FNMA and FHLMC have received significant capital support through U.S. Treasury preferred stock purchases, as well as Treasury and Federal Reserve purchases of their mortgage backed securities (“MBS”). The FHFA and the U.S. Treasury (through its agreement to purchase FNMA and FHLMC preferred stock) have imposed strict limits on the size of their mortgage portfolios. The FHFA, as conservator, has the power to repudiate any contract entered into by FNMA or FHLMC prior to its appointment if it determines that performance of the contract is burdensome and repudiation of the contract promotes the orderly administration of FNMA’s or FHLMC’s affairs. Further, the FHFA has the right to transfer or sell any asset or liability of FNMA or FHLMC without any approval, assignment or consent. If FHFA were to transfer any such guaranty obligation to another party, holders of FNMA or FHLMC MBS would have to rely on that party for satisfaction of the guaranty obligation and would be exposed to the credit risk of that party. No assurance can be given that the Federal Reserve or the U.S. Treasury will ensure that FNMA and FHLMC remain successful in meeting their obligations with respect to the debt and mortgage-backed securities that they issue.

In addition, the problems faced by FNMA and FHLMC, resulting in their being placed into federal conservatorship and receiving significant U.S. Government support, have sparked serious debate among federal policy makers regarding the continued role of the U.S. Government in providing liquidity for mortgage loans. In December 2011, Congress enacted the Temporary Payroll Tax Cut Continuation Act (“TCCA”) of 2011 which, among other provisions, requires that FNMA and FHLMC increase their single-family guaranty fees by at least 10 basis points and remit this increase to Treasury with respect to all loans acquired by FNMA and FHLMC on or after April 1, 2012 and before January 1, 2022. Serious discussions among policymakers continue, however, as to whether FNMA and FHLMC should be nationalized, privatized, restructured, or eliminated altogether. FNMA reported in the second quarter of 2014 that there was “significant uncertainty regarding the future of our company, including how long the company will continue to exist in its current form, the extent of our role in the market, what form we will have, and what ownership interest, if any, our current common and preferred stockholders will hold in us after the conservatorship is terminated and whether we will continue to exist following conservatorship.” FHLMC faces similar uncertainty about its future role. FNMA and FHLMC also are the subject of several continuing legal actions and investigations over certain accounting, disclosure or corporate governance matters, which (along with any resulting financial restatements) may continue to have an adverse effect on the guaranteeing entities.

The Fund may invest in securities issued or guaranteed by any of the entities listed above or by any other agency established or sponsored by the U.S. Government, provided that the securities are otherwise permissible investments of the Fund. Certain U.S. Government Obligations that have a variable rate of interest readjusted no less frequently than annually will be deemed to have a maturity equal to the period remaining until the next readjustment of the interest rate.

The Fund’s yield will fluctuate due to changes in interest rates, economic conditions, quality ratings and other factors. The prepayment experience of the mortgages underlying mortgage-related securities, such as obligations issued by GNMA, may affect the value of, and return on, an investment in such securities.

RECENT MARKET CONDITIONS

In the past decade, financial markets throughout the world have experienced increased volatility, depressed valuations, decreased liquidity and heightened uncertainty and turmoil. This turmoil resulted in unusual and extreme volatility in the equity and debt markets, in the prices of individual securities and in the world economy. Events that have contributed to these market conditions include, but are not limited to, major cybersecurity events, geopolitical events (including wars, terror attacks and public health emergencies), measures to address budget deficits, downgrading of sovereign debt, declines in oil and commodity prices, dramatic changes in currency exchange rates, and public sentiment. In addition, many governments and quasi-governmental entities throughout the world have responded to the turmoil with a variety of significant fiscal and monetary policy changes, including, but not limited to, direct capital infusions into companies, and new monetary programs.

Federal, state, and other governments, their regulatory agencies, or self-regulatory organizations may take actions that affect the regulation of the instruments in which the Fund invests, or affect the issuers of such instruments, in ways that are unforeseeable. There is a possibility of future regulatory changes altering, perhaps to a material extent, the nature of an investment in the Fund or the ability of the Fund to continue to implement its investment strategies. The U.S. government has enacted and is continuing to implement legislation that provides for regulation of the derivatives market, including clearing, margin, reporting and registration requirements. The CFTC, SEC, and other federal regulators have adopted and continue to develop rules and regulations enacting the provisions of the Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Dodd-Frank Act”). The Dodd-Frank Act has and will continue to change the way in which the U.S. financial system is supervised and regulated.

Governments or their regulatory agencies may also acquire distressed assets from financial institutions and acquire ownership interests in those institutions. The implications of government ownership and disposition of these assets are unclear, and such ownership or disposition may have positive or negative effects on the liquidity, valuation and performance of the Fund’s portfolio holdings.

Following financial crises, such as the global financial crisis fueled by the COVID-19 pandemic, the Federal Reserve generally attempted to stabilize the U.S. economy and support the U.S. economic recovery by keeping the federal funds rate low. Following such periods, the Federal Reserve terminated certain of its market support activities and raised interest rates. With continued economic recovery and the cessation of certain market support activities, the Fund may face a heightened level of interest rate risk as a result of a rise or increased volatility in interest rates. These policy changes may reduce liquidity for certain of the Fund’s investments, causing the value of the Fund’s investments and share price to decline.

Global regulation of the derivatives market in particular has undergone substantial change in the past decade, including clearing, margin, trade execution, reporting and registration requirements. Because these requirements continue to evolve, their impact on the Fund remains unclear. These and other new rules and regulations could, among other things, restrict the Fund’s ability to engage in derivatives transactions (for example, by making certain types of derivatives transactions no longer available to the Fund) and/or increase the costs of such derivatives transactions, and the Fund may be unable to execute its investment strategy as a result. Global requirements may also result in increased uncertainty about counterparty credit risk, and they may also limit the flexibility of the Fund to protect its interests in the event of an insolvency of a derivatives counterparty. In the event of a counterparty’s (or its affiliate’s) insolvency, the Fund’s ability to exercise remedies, such as the termination of transactions, netting of obligations and realization on collateral, could be stayed or eliminated under special resolution regimes adopted in the United States, the European Union, the United Kingdom and various other jurisdictions. Such regimes provide government authorities with broad authority to intervene when a financial institution is experiencing financial difficulty. In particular, with respect to counterparties who are subject to such proceedings in the European Union or the United Kingdom, the liabilities of such counterparties to the Fund could be reduced, eliminated, or converted to equity in such counterparties (sometimes referred to as a “bail in”).

As economies and financial markets throughout the world are increasingly interconnected, the likelihood increases that geopolitical conflicts in one country or region will adversely impact markets or issuers in other countries or regions, including in ways that are difficult to predict or foresee. Economic, financial or political events, trading and tariff arrangements, terrorism, natural disasters, rapid technological developments, such as artificial intelligence, and other circumstances in one country or region could have profound impacts on global economies or markets. Widespread disease and virus epidemics, such as the recent coronavirus outbreak, could likewise be highly disruptive, adversely affecting individual companies, sectors, industries, markets, currencies, interest and inflation rates, credit ratings, investor sentiment, and other factors affecting the value of the Funds’ investments. The impacts of these conflicts or events can be exacerbated by failures of governments and societies to respond adequately to a geopolitical conflict and subsequent emerging events or threats. As a result, whether or not the Fund invest in securities of issuers located in or with significant exposure to the countries directly affected, the value and liquidity of the Fund’ investments may be negatively affected.

Trade disputes may affect investor and consumer confidence and adversely affect financial markets and the broader economy, perhaps suddenly and to a significant degree. The U.S. government has indicated its intent to alter its approach to international trade policy and, in some cases, to renegotiate or potentially terminate certain existing bilateral or multilateral trade agreements and treaties with foreign countries and has made proposals and taken actions related thereto. In addition, the U.S. government has recently imposed tariffs on certain foreign goods and has indicated a willingness to impose tariffs on imports of other products. Some foreign governments, including China, have instituted retaliatory tariffs on certain U.S. goods and have indicated a willingness to impose additional tariffs on U.S. products. Other countries, including Mexico, have threatened retaliatory tariffs on certain U.S. products. Global trade disruption, significant introductions of trade barriers, and bilateral trade frictions, together with any future downturns in the global economy resulting therefrom, could adversely affect the financial performance of the Fund and its investments. U.S. trade policy has changed rapidly in the past, and may do so in the future, and it may be an ongoing source of instability, potentially resulting in significant currency fluctuations and/or having other adverse effects on international markets, international trade agreements, and/or other existing cross-border cooperation arrangements (whether economic, tax, fiscal, legal, regulatory, or otherwise). To the extent trade disputes escalate globally, there could be additional significant impacts on the sectors or industries in which the Fund invests and other adverse impacts on the Fund’s overall performance.

Inflation may reduce the intrinsic value of increases in the value of the Fund. Inflation risk is the risk that the value of assets or income from investments will be less in the future as inflation decreases the value of money. As inflation increases, the value of the Fund’s assets can decline.

Recent technological developments in, and the increasingly widespread use of, artificial intelligence, including machine learning technology and generative artificial intelligence (“AI”), may pose risks to the Portfolio. For instance, the economy may be significantly impacted by the advanced development and increased regulation of AI. As AI is used more widely, the profitability and growth of Portfolio holdings may be impacted, which could significantly impact the overall performance of the Portfolio. The legal and regulatory frameworks within which AI operates continue to rapidly evolve, and it is not possible to predict the full extent of current or future risks related thereto.

TAX RISK

The Fund intends to elect and to qualify each year to be treated as a regulated investment company ("RIC") under Subchapter M of the Code. As a RIC, the Fund is generally not subject to corporate-level U.S. federal income tax on any net ordinary income or capital gains that are timely distributed to shareholders. If the Fund does not qualify as a RIC for any taxable year and certain relief provisions are not available, the Fund's taxable income will be subject to tax at the Fund level and to a further tax at the shareholder level when such income is distributed.

INVESTMENT RESTRICTIONS

The Fund is classified as a diversified, open-end management investment company. Except as noted below, the Fund operates under the following investment restrictions and may not:

(i)   as to 75% of its assets, invest more than 5% of its total assets, taken at market value at the time of a particular purchase, in the securities of any one issuer or acquire more than 10%, taken at the time of a particular purchase, of the outstanding voting securities of any one issuer except that this restriction does not apply to securities issued or guaranteed by the U.S. Government or its agencies or instrumentalities;

(ii) act as an underwriter of securities, except insofar as it may be deemed an underwriter for purposes of the Securities Act on disposition of securities acquired subject to legal or contractual restrictions on resale;

(iii)  purchase or sell real estate (although it may purchase securities secured by real estate or interests therein, or securities issued by companies that invest in real estate or interests therein), commodities or commodity contracts, except that the Fund may enter into (a) futures, options and options on futures, (b) forward contracts and (c) other financial transactions not requiring the delivery of physical commodities;

(iv)  make loans, but this restriction shall not prevent the Fund from (a) investing in debt obligations, (b) investing in repurchase agreements or (c) lending portfolio securities, provided, however, that it may not lend securities if, as a result, the aggregate value of all securities loaned would exceed 33% of its total assets (taken at market value at the time of such loan);

(v)  borrow, except from banks, other affiliated funds and other entities to the extent permitted under the 1940 Act;^1,2,3

(vi)  invest in a security if more than 25% of the Fund's total assets (taken at market value at the time of a particular purchase) would be invested in the securities of issuers in any particular industry or group of industries, except that this restriction does not apply to securities issued or guaranteed by the U.S. Government or its agencies or instrumentalities;

(vii)  issue any senior security, except to the extent permitted under the 1940 Act;⁴

The above restrictions are fundamental policies and may not be changed with respect to the Fund without the approval of a "majority" of the outstanding shares of the Fund, which for this purpose means the approval of the lesser of

(a) more than 50% of the outstanding voting securities of the Fund or

(b) 67% or more of the outstanding shares if the holders of more than 50% of the outstanding shares of the Fund are present or represented at the meeting by proxy.

In addition to the fundamental restrictions listed above, the Fund has adopted the following as non-fundamental policies:

(a)  To the extent other Calamos Funds invest in the Fund in reliance on section 12(d)(1)(G), the Fund may not acquire any securities of registered open-end investment companies or unit investment trusts in reliance on section 12(d)(1)(F) or (G) of the 1940 Act;⁵

¹ The Fund does not intend to purchase securities when its borrowings exceed 5% of total assets.

² The Fund's borrowing practices are limited by the 1940 Act. Currently, under the 1940 Act, the Fund may borrow in an aggregate amount not exceeding 33 1/3% of its total assets, including the proceeds of borrowings, for any purpose, but borrowings from entities other than banks may not exceed 5% of its total assets and may be only as a temporary measure for extraordinary or emergency purposes, unless the Fund has received an exemptive order from the SEC permitting it to borrow from other affiliated funds in excess of 5% of its total assets.

³ Certain trading practices and investments, such as reverse repurchase agreements, may be considered to be borrowings or involve leverage and thus are subject to the Investment Company Act restrictions. In accordance with Rule 18f-4 under the Investment Company Act, when the Fund engages in reverse repurchase agreements and similar financing transactions, the Fund may either (i) maintain asset coverage of at least 300% with respect to such transactions and any other borrowings in the aggregate, or (ii) treat such transactions as "derivatives transactions" and comply with Rule 18f-4 with respect to such transactions. Short-term credits necessary for the settlement of securities transactions and arrangements with respect to securities lending will not be considered to be borrowings under the policy. Practices and investments that may involve leverage but are not considered to be borrowings are not subject to the policy.

⁴ Currently, under the 1940 Act, a "senior security" does not include any promissory note or evidence of indebtedness where the indebtedness is for temporary purposes only and in an amount not exceeding 5% of the value of the total assets of the issuer at the time the loan is made. A loan is presumed to be for temporary purposes if it is repaid within 60 days and is not extended or renewed.

⁵ Under Section 12(d)(1)(A) of the 1940 Act, the Fund generally must limit its investment in other investment companies so that, as determined immediately after the Fund invests in another investment company: (i) not more than 3% of the outstanding voting shares of any one investment company will be owned by the Fund; (ii) not more than 5% of the value of its total assets will be invested in the securities of any one investment company; and (iii) not more than 10% of the value of its total assets will be invested in the aggregate in securities of investment companies as a group, except as permitted under the 1940 Act, the rules thereunder or SEC exemptive relief. Currently, under the 1940 Act, the rules thereunder and SEC exemptive relief, the Fund may invest in other investment companies in excess of the above limitations if certain requirements are met, including (i) that the Fund complies with Rule 12d1-4 under the 1940 Act or (ii) that any Fund whose shares are acquired by another Fund in accordance with Section 12(d)(1)(G) of the 1940 Act shall not purchase securities of a registered open-end investment company or registered unit investment trust in reliance on either Section 12(d)(1) (F) or Section 12(d)(1)(G) of the 1940 Act. The Fund may also invest without limitation in money market funds, provided the Fund complies with Rule 12d1-1 under the 1940 Act. These limitations do not apply in connection with a merger, consolidation, reorganization or acquisition of substantially all the assets of another investment company.

(b)  The Fund may not invest in companies for the purpose of exercising control or management;

(c)  The Fund may not purchase securities on margin (except for use of such short-term credits as are necessary for the clearance of transactions, including transactions in options, futures and options on futures), or participate on a joint or a joint and several basis in any trading account in securities, except in connection with transactions in options, futures and options on futures;

(d)  The Fund may not make short sales of securities, except that the Fund may make short sales of securities (i) if the Fund owns an equal amount of such securities, or owns securities that are convertible or exchangeable, without payment of further consideration, into an equal amount of such securities, (ii) other than those described in clause (i), provided that no more than 20% of its net assets would be deposited with brokers as collateral or allocated to segregated accounts in connection with all outstanding short sales other than those described in clause (i).

The non-fundamental investment restrictions above may be changed by the Board of Trustees without shareholder approval. Notwithstanding the foregoing investment restrictions, the Fund may purchase securities pursuant to the exercise of subscription rights. Far Eastern and European corporations frequently issue additional capital stock by means of subscription rights offerings to existing shareholders at a price substantially below the market price of the shares. The failure to exercise such rights would result in the Fund's interest in the issuing company being diluted. The market for such rights is not well developed in all cases and, accordingly, the Fund may not always realize full value on the sale of rights. The exception applies in cases where the limits set forth in the investment restrictions would otherwise be exceeded by exercising rights or would have already been exceeded as a result of fluctuations in the market value of the Fund's portfolio securities with the result that the Fund would be forced either to sell securities at a time when it might not otherwise have done so, or to forego exercising the rights.

MANAGEMENT

TRUSTEES AND OFFICERS

The management of the Trust, including general supervision of the duties performed for the Funds under the investment management agreement between the Trust and Calamos Advisors, is the responsibility of its Board of Trustees. Each trustee elected will hold office for the lifetime of the Trust or until such trustee's earlier resignation, death or removal; however, each trustee who is not an interested person of the Trust shall retire as a trustee at the end of the calendar year in which the trustee attains the age of 75 years.

The following table sets forth each trustee's name, year of birth, position(s) with the Trust, number of portfolios in the Calamos Fund Complex overseen, principal occupation(s) during the past five years and other directorships held, and date first elected or appointed. Each trustee oversees each series of the Trust, including the Fund.

TRUSTEES WHO ARE INTERESTED PERSONS OF THE TRUST:

TRUSTEES WHO ARE NOT INTERESTED PERSONS OF THE TRUST:

^ The Fund Complex consists of Calamos Investment Trust, Calamos Advisors Trust, Calamos Convertible Opportunities and Income Fund, Calamos Convertible and High Income Fund, Calamos Strategic Total Return Fund, Calamos Global Total Return Fund, Calamos Global Dynamic Income Fund, Calamos Dynamic Convertible and Income Fund, Calamos Long/Short Equity & Dynamic Income Trust, Calamos ETF Trust, Calamos Antetokounmpo Sustainable Equities Trust and Calamos Aksia Alternative Credit and Income Fund, Calamos Aksia Private Equity and Alternatives Fund, and Calamos Aksia Hedged Strategies Fund.

^^ Messrs. Koudounis and Toub are the only Trustees of the Trust who oversee Calamos Aksia Alternative Credit and Income Fund, Calamos Aksia Private Equity and Alternatives Fund, and Calamos Aksia Hedged Strategies Fund.

* Messrs. Calamos and Koudounis are trustees who are each an "interested person" of the Trust as defined in the 1940 Act because each is an officer of the Trust and is an affiliated person of Calamos Advisors and CFS.

** Overseeing forty-one portfolios in fund complex.

*** Overseeing nineteen portfolios in fund complex.

**** Overseeing four portfolios in fund complex.

***** Overseeing 134 portfolios in fund complex.

****** Overseeing eleven portfolios in fund complex.

The address of each trustee is 2020 Calamos Court, Naperville, Illinois 60563.

OFFICERS. The preceding table gives information about John P. Calamos, Sr., who is Chairman, Trustee, and President of the Trust and John S. Koudounis, who is Trustee and Vice President of the Trust. The following table sets forth each other officer’s name, year of birth, position with the Trust and date first appointed to that position, and principal occupation(s) during the past five years. Each officer serves until his or her successor is chosen and qualified or until his or her resignation or removal by the Board of Trustees.

The address of each officer is 2020 Calamos Court, Naperville, Illinois 60563.

COMMITTEES OF THE BOARD OF TRUSTEES. The Trust’s Board of Trustees has established five standing committees: the Executive Committee, the Dividend Committee, the Audit Committee, the Valuation Committee and the Governance Committee.

Executive Committee. Messrs. John Calamos and Christopher Toub are members of the executive committee, which has authority during intervals between meetings of the Board of Trustees to exercise the powers of the board, with certain exceptions. John Calamos is an interested trustee of the Trust.

Dividend Committee. Mr. John Calamos serves as the sole member of the dividend committee. The dividend committee is authorized, subject to Board review, to declare distributions on the Fund Shares of the Trust’s series in accordance with such series’ distribution policies, including, but not limited to, regular dividends, special dividends and short- and long-term capital gains distributions.

Audit Committee. Messrs. Armstrong, Phlegar, Rybak (Chair), Toub and Wennlund and Mses. Breen and Stuckey serve on the audit committee. The audit committee operates under a written charter adopted and approved by the board. The audit committee selects independent auditors, approves services to be rendered by the auditors, monitors the auditors’ performance, reviews the results of the Trust’s audit and responds to other matters deemed appropriate by the board. All members of the audit committee are independent trustees of the Trust.

Valuation Committee. Messrs. Armstrong, Phlegar, Rybak, Toub, and Wennlund (Chair) and Mses. Breen and Stuckey serve on the valuation committee. The valuation committee operates under a written charter approved by the board. The valuation committee oversees valuation matters of the Trust delegated to the valuation designee, including the fair valuation determinations and methodologies proposed and utilized by the valuation designee, reviews the Trust’s valuation procedures and their application by the valuation designee, reviews pricing errors and procedures for calculation of net asset value of each series of the Trust and responds to other matters deemed appropriate by the board.

Governance Committee. Messrs. Armstrong, Phlegar, Rybak, Toub and Wennlund and Mses. Breen (Chair) and Stuckey serve on the governance committee. The governance committee operates under a written charter adopted and approved by the board. The governance committee oversees the independence and effective functioning of the Board of Trustees and endeavors to be informed about good practices for fund boards. It also makes recommendations to the board regarding compensation of independent trustees. The governance committee also functions as a nominating committee by making recommendations to the Board of Trustees regarding candidates for election as non- interested trustees. The governance committee looks to many sources for recommendations of qualified trustees, including current trustees, employees of Calamos Advisors, current shareholders of the Fund, search firms that are compensated for their services and other third-party sources. Any such search firm identifies and evaluates potential candidates, conducts screening interviews and provides information to the governance committee with respect to the individual candidates and the market for available candidates. In making trustee recommendations, the governance committee considers a number of factors, including a candidate’s background, integrity, knowledge and relevant experience. These factors are set forth in an appendix to the committee’s charter. Any prospective candidate is interviewed by the trustees and officers, and references are checked. The governance committee will consider shareholder recommendations regarding potential trustee candidates that are properly submitted to the governance committee for its consideration.

The Fund shareholder who wishes to propose a trustee candidate must submit any such recommendation in writing via regular mail to the attention of the Trust’s Secretary, at the address of the Trust’s principal executive offices. The shareholder recommendation must include:

●  the number and class of all shares of the Trust’s series owned beneficially or of record by the nominating shareholder at the time the recommendation is submitted and the dates on which such shares were acquired, specifying the number of shares owned beneficially;

●  a full listing of the proposed candidate’s education, experience (including knowledge of the investment company industry, experience as a director or senior officer of public or private companies, and directorships on other boards of other registered investment companies), current employment, date of birth, business and residence address, and the names and addresses of at least three professional references;

●  information as to whether the candidate is, has been or may be an “interested person” (as such term is defined in the 1940 Act) of the Trust, Calamos Advisors or any of its affiliates, and, if believed not to be or have been an “interested person,” information regarding the candidate that will be sufficient for the committee to make such determination;

●  the written and signed consent of the candidate to be named as a nominee and to serve as a trustee of the Trust, if elected;

●  a description of all arrangements or understandings between the nominating shareholder, the candidate and/or any other person or persons (including their names) pursuant to which the shareholder recommendation is being made, and if none, so specify;

●  the class or series and number of all shares of the Trust’s series owned of record or beneficially by the candidate, as reported by the candidate; and

●  such other information that would be helpful to the governance committee in evaluating the candidate.

The governance committee may require the nominating shareholder to furnish other information it may reasonably require or deem necessary to verify any information furnished pursuant to the procedures delineated above or to determine the qualifications and eligibility of the candidate proposed by the nominating shareholder to serve as a trustee. If the nominating shareholder fails to provide such additional information in writing within seven days of receipt of written request from the governance committee, the recommendation of such candidate will be deemed not properly submitted for consideration, and the governance committee is not required to consider such candidate.

Unless otherwise specified by the governance committee’s chairman or by legal counsel to the non-interested trustees, the Trust’s Secretary will promptly forward all shareholder recommendations to the governance committee’s chairman and the legal counsel to the non-interested trustees, indicating whether the shareholder recommendation has been properly submitted pursuant to the procedures adopted by the governance committee for the consideration of trustee candidates nominated by shareholders.

Recommendations for candidates as trustees will be evaluated, among other things, in light of whether the number of trustees is expected to change and whether the trustees expect any vacancies. During periods when the governance committee is not actively recruiting new trustees, shareholder recommendations will be kept on file until active recruitment is under way. After consideration of a shareholder recommendation, the governance committee may dispose of the shareholder recommendation.

In addition to the above committees, there is a valuation designee, appointed by the Board of Trustees, comprised of officers of the Trust and employees of Calamos Advisors.

The following table identifies the number of meetings the Board of Trustees and each committee held during the fiscal period ended July 31, 2025:

LEADERSHIP STRUCTURE AND QUALIFICATIONS OF THE BOARD OF TRUSTEES. The Board of Trustees is responsible for oversight of the Trust. The Trust has engaged Calamos Advisors to manage the Fund on a day-to-day basis. The Board of Trustees oversees Calamos Advisors and certain other principal service providers in the operations of the Fund. The Board of Trustees is currently composed of ten members, eight of whom are non-interested trustees. The Board of Trustees meets in-person at regularly scheduled meetings four times throughout the year. In addition, the board may meet in-person or by telephone at special meetings or on an informal basis at other times. As described above, the Board of Trustees has established five standing committees — Audit, Dividend, Executive, Governance and Valuation — and may establish ad hoc committees or working groups from time to time to assist the Board of Trustees in fulfilling its oversight responsibilities. The non-interested trustees also have engaged independent legal counsel to assist them in fulfilling their responsibilities. Such independent legal counsel also serves as counsel to the Trust.

The chairman of the Board of Trustees is an “interested person” of the Trust (as such term is defined in the 1940 Act). The non-interested trustees have appointed a lead independent trustee. The lead independent trustee serves as a liaison between Calamos Advisors and the non-interested trustees and leads the non-interested trustees in all aspects of their oversight of the Fund. Among other things, the lead independent trustee reviews and approves, with the chairman, the agenda for each board and committee meeting and facilitates communication among the Trust’s non-interested trustees. The trustees believe that the board’s leadership structure is appropriate given the characteristics and circumstances of the Trust. The trustees also believe that this structure facilitates the exercise of the board’s independent judgment in fulfilling its oversight function and efficiently allocates responsibility among committees.

The Board of Trustees has concluded that, based on each trustee’s experience, qualifications, attributes or skills on an individual basis and in combination with those of the other trustees, each trustee should serve as a member of the board. In making this determination, the board has taken into account the actual service of the trustees during their tenure in concluding that each should continue to serve. The board also has considered each trustee’s background and experience. Set forth below is a brief discussion of the specific experience qualifications, attributes or skills of each trustee that led the board to conclude that he or she should serve as a trustee.

Each of Mses. Breen and Stuckey and Messrs. Calamos, Rybak, Toub, and Wennlund has served for multiple years as a trustee of the Trust. In addition, each of Mses. Breen and Stuckey and Messrs. Armstrong, Calamos, Koudounis, Rybak, Toub, and Wennlund has more than 25 years of experience in the financial services industry. Each of Mses. Breen and Stuckey and Messrs. Calamos, Koudounis, Phlegar, Rybak, Toub, and Wennlund has experience serving on boards of other entities, including other investment companies. Each of Ms. Breen and Messrs. Calamos, Phlegar, Rybak Toub, and Wennlund has earned a Masters of Business Administration degree.

RISK OVERSIGHT. The operation of an ETF, including its investment activities, generally involves a variety of risks. As part of its oversight of the Fund, the Board of Trustees oversees risk through various regular board and committee activities. The Board of Trustees, directly or through its committees, reviews reports from, among others, Calamos Advisors, the Trust’s Compliance Officer, the Trust’s independent registered public accounting firm, outside legal counsel, and internal auditors of Calamos Advisors or its affiliates, as appropriate, regarding risks faced by the Fund and the risk management programs Calamos Advisors and certain service providers. The actual day-to-day risk management with respect to the Fund resides with Calamos Advisors and other service providers to the Fund. Although the risk management policies of Calamos Advisors and the service providers are designed to be effective, there is no guarantee that they will anticipate or mitigate all risks. Not all risks that may affect the Fund can be identified, eliminated or mitigated and some risks simply may not be anticipated or may be beyond the control of the Board of Trustees or Calamos Advisors, its affiliates or other service providers.

TRUSTEE AND OFFICER COMPENSATION. John P. Calamos, Sr. and John Koudounis, the trustees who are an “interested person” of the Trust, do not receive compensation from the Trust. Although they are compensated, the non-interested trustees do not receive any pension or retirement benefits from the Trust. Mr. Kelly is the only Trust officer who receives compensation from the Trust. The following table sets forth the total compensation (including any amounts deferred, as described below) paid by the Trust during the periods indicated to each of the current trustees and officers compensated by the Trust. As the Fund was not in operation as of the date of this SAI, no Trustee received any compensation from the Fund during that time.

The Trustees also serve as Trustees of the Calamos Timpani SMID Growth Fund (the "Predecessor Fund"). For the Predecessor Fund's fiscal year ended October 31, 2025, the Predecessor Fund paid the following amounts to the Trustees:

(1) Compensation paid to the Independent Trustees for the Fund’s initial fiscal year ending July 31, 2026.

(2)  Calamos Funds Complex consisted of 49 portfolios as of the end of the period indicated.

* Messrs. Armstrong, Koudounis, and Phlegar were elected to the Board effective September 1, 2025.

** Mr. Kelly was designated as Chief Compliance Officer effective July 29, 2025.

The compensation paid to the non-interested trustees of Calamos Funds for their services as such consists of an annual retainer fee in the amount of $230,000 (increased on January 1, 2026 from $210,000), with annual supplemental retainers of $40,000 to the lead independent trustee, $20,000 to the chair of the audit committee and $10,000 to the chair of any other committee. Each non-interested trustee receives a meeting attendance fee of $7,000 for any special board meeting attended in person or $3,500 for any special board meeting attended by telephone.

Compensation paid to the non-interested trustees is allocated among the series of the Calamos Funds in accordance with a procedure determined from time to time by the board.

The Trust has adopted a deferred compensation plan for non-interested trustees (the “Plan”). Under the Plan, a trustee who is not an “interested person” of Calamos Advisors and has elected to participate in the Plan (a “participating trustee”) may defer receipt of all or a portion of his or her compensation from the Trust in order to defer payment of income taxes or for other reasons. The deferred compensation payable to the participating trustee is credited to the trustee’s deferred compensation account as of the business day such compensation otherwise would have been paid to the trustee. The value of a trustee’s deferred compensation account at any time is equal to what the value would be if the amounts credited to the account had instead been invested in shares of one or more of the Funds as designated by the trustee. Thus, the value of the account increases with contributions to the account or with increases in the value of the measuring shares, and the value of the account decreases with withdrawals from the account or with declines in the value of the measuring shares. If a participating trustee retires, the trustee may elect to receive payments under the plan in a lump sum or in equal annual installments over a period of five years. If a participating trustee dies, any amount payable under the Plan will be paid to the trustee’s beneficiaries. The Fund’s obligation to make payments under the Plan is a general obligation of that Fund. No Fund is liable for any other Fund’s obligations to make payments under the Plan.

The Fund had not yet publicly offered any Fund Shares for sale as of December 31, 2025. Accordingly, no trustee owned “beneficially” (within the meaning of that term as defined in Rule 16a-1(a)(2) under the 1934 Act) any Fund Shares of the Fund as of December 31, 2025. As of December 31, 2025, each trustee beneficially owned (as determined pursuant to Rule 16a-1(a)(2) under the Securities Exchange Act of 1934, as amended (“1934 Act”)) Fund Shares of all funds in the Fund Complex having values within the indicated dollar ranges.* Mr. Armstrong and Mr. Phlegar, who were elected trustees of the Trusts effective September 1, 2025, did not beneficially own shares of any Fund as of December 31, 2025.

(1)  Pursuant to Rule 16a-1(a)(2) of the 1934 Act, John P. Calamos, Sr. may be deemed to have indirect beneficial ownership of Fund shares held by Calamos Investments LLC, its subsidiaries, and its parent companies (Calamos Asset Management, Inc. and Calamos Partners LLC, and its parent company Calamos Family Partners, Inc.) due to his direct or indirect ownership interest in those entities. As a result, these amounts reflect any holdings of those entities in addition to the individual, personal accounts of John P. Calamos, Sr.

(2) Messrs. Armstrong, Koudounis, and Phlegar were elected to the Board effective September 1, 2025.

*  Valuation as of December 31, 2025.

CODE OF ETHICS. Personnel of Calamos Advisors and Calamos Financial Services LLC (“CFS”), the Fund’s distributor, are permitted to make personal securities transactions, including transactions in securities that the Trust may purchase, sell or hold, subject to requirements and restrictions set forth in the Code of Ethics of the Trust and the Code of Ethics of Calamos Advisors and CFS. The Codes of Ethics adopted pursuant to Rule 17j-1 under the 1940 Act contain provisions and requirements designed to identify and address certain conflicts of interest between personal investment activities of Calamos Advisors and CFS personnel and the interests of investment advisory clients such as the Trust. Among other things, the Codes of Ethics prohibit certain types of transactions absent prior approval, impose time periods during which personal transactions may not be made in certain securities, and require the submission of duplicate broker confirmations and statements and quarterly reporting of securities transactions. Additional restrictions apply to portfolio managers, traders, research analysts and others involved in the investment advisory process. Exceptions to these and other provisions of the Codes of Ethics may be granted in particular circumstances after review by appropriate personnel.

Affiliates of Calamos Advisors and CFS, CAM, CILLC, Calamos Partners LLC (“CPL”), Calamos Family Partners, Inc. (“CFP”) and the owners of these affiliates, which include John P. Calamos, Sr. and members of his family (“Calamos Family”), may invest in products managed by Calamos Advisors to support the continued growth of our investment products and strategies, including investments to seed new products. Notwithstanding any provision to the contrary in the Code of Ethics, investments and corresponding hedging transactions made by Calamos Advisors, CFS, CAM, CILLC, CPL, CFP and the Calamos Family in Calamos products (excluding Closed-End Funds and ETFs) are not subject to restrictions of the Code of Ethics, such as the short-term trading ban. However, these hedging transactions are subject to pre-clearance by the Corporate Investment Committee. Calamos Advisors’ CCO and Funds’ CCO are copied in the approval process. In addition, these entities do not receive preferential treatment over clients. (They may, however, be traded together with discretionary client transactions.)

The General Counsel may approve additional strategies or instruments based on unusual market circumstances and on the determination that the transactions would not impact the broader market or conflict with any customer activity.

PROXY VOTING PROCEDURES. The Fund has delegated proxy voting responsibilities to Calamos Advisors, subject to the board of trustees’ general oversight. The Fund expects Calamos Advisors to vote proxies related to that Fund’s portfolio securities for which the Fund has voting authority consistent with the Fund’s best interests. Calamos Advisors has adopted its own Proxy Voting Policies and Procedures (the “Policies”). The Policies address, among other things, conflicts of interest that may arise between the Funds’ interests, and the interests of Calamos Advisors and its affiliates.

The following is a summary of the Policies used by Calamos Advisors in voting proxies.

To assist it in voting proxies, Calamos Advisors has established a Proxy Review Committee (“committee”) comprised of representatives of its Portfolio Management (which may include portfolio managers and/or research analysts), Operations, and advisory, non-voting members from the Legal and Compliance Departments. The committee and/or its members will vote proxies using the following guidelines.

In general, if Calamos Advisors believes that a company’s management and board have interests sufficiently aligned with the Fund’s interest, Calamos Advisors will vote in favor of proposals recommended by the company’s management, including, but not by way of limitation, management’s recommendations on the election of directors but will consider both meeting attendance and number of boards each board member sits on when determining its vote.

Because of the enormous variety and complexity of transactions that are presented to shareholders, such as mergers, acquisitions, reincorporations, reorganizations, shareholder rights plans, “poison pills”, severance compensation packages, golden parachutes, that occur in a variety of industries, companies and market cycles, it is extremely difficult to foresee exactly what would be in the best interests of the Fund in all circumstances. Moreover, voting on such proposals involves considerations unique to each transaction. Accordingly, Calamos Advisors will vote on a case-by-case basis on proposals presenting these transactions.

Calamos Advisors has assigned its administrative duties with respect to the proxy analysis and voting decisions to the “Proxy Group” (the Investment team - research analysts and portfolio management), and administrative processing to its Corporate Actions Group within the Operations Department. To assist it in analyzing proxies, Calamos subscribes to Glass Lewis, an unaffiliated third-party corporate governance research service that provides in-depth analyses of shareholder meeting agendas and voting recommendations. Glass Lewis facilitates the voting of each proxy by applying Calamos’ custom proxy voting rules (“proxy voting policy”) to the proposal(s). Any proxy proposal that is not covered by the proxy voting guidelines is reviewed and considered by Calamos’ Proxy Group and voted in accordance with that review.

Finally, Calamos Advisors has established procedures to help identify and resolve conflicts of interest that might arise when voting proxies for the Funds. Calamos will generally apply its proxy voting policy to proxy proposals regardless of whether a conflict has been identified. However, in these situations, the Proxy Group will refer the proxy proposal, along with the recommended course of action, if any, to the Proxy Review Committee or a subcommittee thereof (each, a “committee”) for evaluation. The committee will independently review the proposals and determine the appropriate action to be taken. The Corporate Actions Group will then memorialize the conflict(s) and the procedures used to address the conflict.

The Trust is required to file with the SEC on Form N-PX its complete proxy voting record for the 12-month period ending June 30, by no later than August 31 of each year. The Trust’s proxy voting record for the most recent 12-month period ending June 30 will be available by August 31 of each year (1) on the SEC’s website at www.sec.gov, (2) on the Calamos Funds’ website at www.calamos.com, and (3) without charge, upon request, by calling 866.363.9219 or emailing [email protected].

You may obtain a copy of Calamos Advisors’ Policies by calling 866.363.9219, by emailing [email protected], or by writing Calamos Advisors at: Calamos Investments, Attn: Client Services, 2020 Calamos Court, Naperville, IL 60563, and on the SEC’s website at www.sec.gov.

DISCLOSURE OF PORTFOLIO HOLDINGS. The Trust has adopted a policy regarding the disclosure of information about the Trust’s portfolio holdings. The Board must approve all material amendments to this policy. The Fund’s portfolio holdings are publicly disseminated each day the Fund is open for business through financial reporting and news services including publicly accessible Internet web sites. In addition, a basket composition file, which includes the security names and share quantities to deliver in exchange for Fund Shares, together with estimates and actual cash components, is publicly disseminated daily prior to the opening of the Exchange via the National Securities Clearing Corporation (“NSCC”). The basket represents one Creation Unit of the Fund. The Trust and Calamos Advisors will not disseminate non-public information concerning the Trust.

Calamos Advisors and CFS carry out the policies and procedures governing disclosure of portfolio security holdings, and as such have access to information regarding portfolio security holdings on a daily basis and may disclose that information to the Fund’s service providers and other third parties only in accordance with the policies and procedures adopted by the Board of Trustees.

NON-PUBLIC DISCLOSURE

Disclosures required by Applicable Law. The Fund, Calamos Advisors and CFS may disclose portfolio security holdings information of the Fund as may be required by applicable law, rule, regulation or court order. Any officer of the Fund, Calamos Advisors or CFS is authorized to disclose portfolio security holdings pursuant to these policies and procedures.

As part of the Fund’s compliance program under Rule 38a-1 under the 1940 Act, the Trust’s Chief Compliance Officer periodically will review or cause to be reviewed portfolio security holding disclosures in order to seek compliance with these policies and procedures. The Board of Trustees oversees disclosures through the reporting of the Chief Compliance Officer.

The Fund, Calamos Advisors and CFS do not receive compensation or other consideration for the disclosure of portfolio security holdings.

CONTROL PERSONS AND PRINCIPAL HOLDERS OF SECURITIES

A principal shareholder is any person who owns (either of record or beneficially) 5% or more of the outstanding Fund Shares of the Fund. A control person is one who owns, either directly or indirectly, more than 25% of the voting securities of a company or acknowledges the existence of control.

As of the date of this SAI, the Fund has not yet commenced operations. As a result, no person owns shares of the Fund.

INVESTMENT ADVISORY SERVICES

Investment Adviser

Investment management and certain other services are provided to the Trust by Calamos Advisors pursuant to a Management Agreement (the “Management Agreement”) dated April 8, 2026, as amended. Calamos Advisors also furnishes office space, equipment and management personnel to the Trust.

The Fund pays Calamos Advisors a fee based on its average daily net assets that is accrued daily and paid on a quarterly basis.

The Fund pays a fee on its average daily net assets at the annual rate of 0.79% on average daily net assets.

With respect to the Fund in the Calamos Family of Funds (each an “Acquiring Fund”) that invests in Fund Shares of Calamos Timpani Active SMID Growth ETF, Calamos Advisors agrees to waive an amount equal to the portion of the advisory fee payable to the Fund that is attributable to the Acquiring Fund’s investment in the Fund, based on daily net assets. In the event the Calamos Timpani Active SMID Growth ETF invests in another affiliated fund (the "Acquired Fund"), the portion of the Calamos Timpani Active SMID Growth ETF’s Investment Management Fee equal to the advisory fee payable to the Acquired Fund (based on average daily net assets invested) is waived.

Calamos Advisors is a wholly owned subsidiary of Calamos Investments LLC (“CILLC”). Calamos Asset Management, Inc. (“CAM”) is the sole manager of CILLC. As of December 31, 2025, approximately 22% of the outstanding interests of CILLC was owned by CAM and the remaining approximately 78% of CILLC was owned by Calamos Partners LLC (“CPL”) and Calamos Equity Partners LLC. CAM was owned by John P. Calamos, Sr. and John S. Koudounis, and CPL was owned by John S. Koudounis and Calamos Family Partners, Inc. (“CFP”). CFP was beneficially owned by members of the Calamos family, including John P. Calamos, Sr. In addition, Mr. Koudounis has the option to purchase a controlling interest in CPL upon the death or permanent disability of John P. Calamos, Sr., provided Mr. Koudounis is then serving as Chief Executive Officer of CAM and CILLC. John P. Calamos, Sr., is an affiliated person of the Fund and Calamos Advisors by virtue of his position as Chairman, Trustee and President of the Trust and Chairman and Global Chief Investment Officer (“Global CIO”) of Calamos Advisors. John S. Koudounis, Thomas P. Kiley, Thomas E. Herman, Erik D. Ojala, Stephen Atkins, Daniel Dufresne and Walter Kelly are affiliated persons of the Fund and Calamos Advisors by virtue of their positions as Trustee and Vice President; Vice President; Vice President and Chief Financial Officer; Vice President and Secretary; Treasurer; Vice President; and Chief Compliance Officer of the Trust; respectively, and as President and Chief Executive Officer; Senior Vice President and Chief Distribution Officer; Executive Vice President and Chief Financial Officer; Senior Vice President, General Counsel and Secretary; Senior Vice President and Head of Fund Administration; Executive Vice President and Chief Operating Officer; and Co-Chief Compliance Officer of Calamos Advisors, respectively.

The use of the name “Calamos” in the name of the Trust and in the name of the Funds are pursuant to licenses granted by Calamos Investments LLC, and the Trust has agreed to change the names to remove those references if Calamos Advisors ceases to act as Adviser to the Funds.

EXPENSES

Out of its management fee, the Adviser pays substantially all expenses of the Fund, including the cost of transfer agency, custody, fund administration, legal, audit and other service and license fees, except for distribution and service fees payable pursuant to a Rule 12b-1 plan, if any, acquired fund fees and expenses brokerage commissions and other expenses connected with the execution of portfolio transactions, taxes, interest, and extraordinary expenses.

Fees and expenses related to the Fund’s organization and registration and qualification of the Fund and its Fund Shares under federal and state securities laws will be borne by the Adviser.

MANAGEMENT APPROACH

Calamos Advisors employs a “team of teams” approach to portfolio management, led by the Global CIO and our CIO team consisting of five (5) Co-CIOs with specialized areas of investment expertise. The Global CIO and Co-CIO team are responsible for oversight of investment team resources, investment processes, performance and risk. As heads of investment verticals, Co-CIOs manage investment team members and, along with Co-Portfolio Managers and Associate Portfolio Managers, have day-to-day portfolio oversight and construction responsibilities of their respective investment strategies. While investment research professionals within each Co-CIO’s team are assigned specific strategy responsibilities, they also provide support to other investment team verticals, creating deeper insights across a wider range of investment strategies. The combination of specialized investment teams with cross-team collaboration results in what we call our team of teams approach.

This team of teams approach is further reflected in the composition of Calamos Advisors’ Investment Committee, made up of the Global CIO, the Co-CIO team, and the Global Head of Trading. Other members of the investment team participate in Investment Committee meetings in connection with specific investment-related issues or topics as deemed appropriate.

The structure and composition of the Investment Committee results in a number of benefits, as it:

●   Leads to broader perspective on investment decisions: multiple viewpoints and areas of expertise feed into consensus;

●   Promotes collaboration between teams; and

●   Functions as a think tank with the goal of identifying ways to outperform the market on a risk-adjusted basis.

The objectives of the Investment Committee are to:

●   Form the firm’s top-down macro view, market direction, asset allocation, and sector/country positioning.

●   Establish firm-wide secular and cyclical themes for review.

●   Review firm-wide and portfolio risk metrics, recommending changes where appropriate.

●   Review firm-wide, portfolio and individual security liquidity constraints.

●   Evaluate firm-wide and portfolio investment performance.

●   Evaluate firm-wide and portfolio hedging policies and execution.

●   Evaluate enhancements to the overall investment process.

Brandon Nelson is the Fund’s portfolio manager. The Portfolio Manager has responsibility for allocating the portfolio across the market capitalization spectrum, sectors, and geographies within the portfolio’s eligible investment universe and for reviewing the overall composition of the portfolio to ensure compliance with its stated investment objective. The Portfolio Manager, in collaboration with other members of the Calamos Advisors investment teams, has the responsibility of overseeing the integration of the Fund’s investment approach and framework to ensure compliance with the Fund’s stated investment approach.

The Portfolio Manager also have responsibility for the day-to-day management of accounts other than the Fund. Information regarding these other accounts as of May 31, 2026 is set forth below.

Other Accounts Managed and Assets by Account Type as of May 31, 2026.

Number of Accounts and Assets for which Advisory Fee is Performance Based as of May 31, 2026.

The Portfolio Manager may invest for his own benefit in securities held in brokerage and fund accounts. The information shown in the table does not include information about those accounts where the Portfolio Manager or members of his family have a beneficial or pecuniary interest because no advisory relationship exists with Calamos Advisors or any of its affiliates.

The Fund’s Portfolio Manager is responsible for managing both the Fund and other accounts, including separate accounts.

Other than potential conflicts between investment strategies, the side-by-side management of both the Fund and other accounts may raise potential conflicts of interest due to the interest held by Calamos Advisors in an account and certain trading practices used by the portfolio manager (e.g., cross trades between the Fund and another account and allocation of aggregated trades).

Calamos Advisors has developed policies and procedures reasonably designed to mitigate those conflicts. For example, Calamos Advisors will only place cross-trades in securities held by the Fund in accordance with the rules promulgated under the 1940 Act and has adopted policies designed to ensure the fair allocation of securities purchased on an aggregated basis. The allocation methodology employed by Calamos Advisors varies depending on the type of securities sought to be bought or sold and the type of client or group of clients. Generally, however, orders are placed first for those clients that have given Calamos Advisors brokerage discretion (including the ability to step out a portion of trades), and then to clients that have directed Calamos Advisors to execute trades through a specific broker. However, if the directed broker allows Calamos Advisors to execute with other brokerage firms, which then book the transaction directly with the directed broker, the order will be placed as if the client had given Calamos Advisors full brokerage discretion. Calamos Advisors and its affiliates frequently use a “rotational” method of placing and aggregating client orders and will build and fill a position for a designated client or group of clients before placing orders for other clients.

A client account may not receive an allocation of an order if: (a) the client would receive an unmarketable amount of securities based on account size; (b) the client has precluded Calamos Advisors from using a particular broker; (c) the cash balance in the client account will be insufficient to pay for the securities allocated to it at settlement; (d) current portfolio attributes make an allocation inappropriate; and (e) account specific guidelines, objectives and other account specific factors make an allocation inappropriate. Allocation methodology may be modified when strict adherence to the usual allocation is impractical or leads to inefficient or undesirable results. Calamos Advisors’ head trader must approve each instance that the usual allocation methodology is not followed and provide a reasonable basis for such instances and all modifications must be reported in writing to Calamos Advisors’ Chief Compliance Officer on a monthly basis. Investment opportunities for which there is limited availability generally are allocated among participating client accounts pursuant to an objective methodology (i.e., either on a pro rata basis or using a rotational method, as described above). However, in some instances, Calamos Advisors may consider subjective elements in attempting to allocate a trade, in which case the Fund may not participate, or may participate to a lesser degree than other clients, in the allocation of an investment opportunity. In considering subjective criteria when allocating trades, Calamos Advisors is bound by its fiduciary duty to its clients to treat all client accounts fairly and equitably.

As of December 31, 2025, Brandon Nelson receives all of his compensation from Calamos Advisors. Mr. Nelson receives compensation in the form of an annual base salary, a discretionary bonus (payable in cash) and is eligible for Calamos Advisors’ Long-Term Incentive (“LTI”) program, which is an incentive award vesting over time that reflects appreciation and depreciation in the value of both the funds managed by such professional and the company generally. LTI awards granted in 2024 vest on a three-year schedule (25% on or about the first anniversary of the award grant, 25% on or about the second anniversary of the award grant, and 50% on or about the third anniversary of the award grant). Each investment team LTI award will be allocated as follows: (i) 33.3% to track the value of the associate’s managed strategies, (ii) 33.3% to track the Calamos strategy of the associate’s choice, and (iii) 33.3% to track the value of the firm; all over the vesting period.

The existence of these separate asset or fee-based payments could create a conflict of interest with regard to each portfolio manager’s allocation of investment opportunities among the accounts for which they act as portfolio manager. Calamos Advisors maintains policies and procedures reasonably designed to mitigate such conflicts of interest.

This compensation structure considers annually the performance of the various strategies managed by the portfolio manager, among other factors, including, without limitation, the overall performance of the firm. The Fund had not yet publicly offered any Fund Shares for sale prior to the date of this SAI. Accordingly, the Portfolio Manager does not own any Fund Shares as of the date of this SAI.

DISTRIBUTOR

The Fund’s distributor is Calamos Financial Services LLC (“CFS” or the “Distributor”), 2020 Calamos Court, Naperville, Illinois, 60563. The Distributor has entered into a distribution agreement (the “Distribution Agreement”) with the Trust pursuant to which it distributes Fund Shares.

Fund Shares will be continuously offered for sale by the Trust through the Distributor only in Creation Units, as described below under “Transactions in Creation Units.” Fund Shares in less than Creation Units are not distributed by the Distributor. The Distributor also acts as agent for the Trust. The Distributor will deliver a Prospectus to persons purchasing Fund Shares in Creation Units and will maintain records of both orders placed with it and confirmations of acceptance furnished by it. The Distributor is a broker-dealer registered under the 1934 Act and a member of the Financial Industry Regulatory Authority, Inc.

The Distributor has no role in determining the investment policies of the Fund, or which securities are to be purchased or sold by the Fund.

12b-1 Plan. The Board has adopted a distribution and service plan (“Distribution and Service Plan”) pursuant to Rule 12b-1 under the Investment Company Act (“Plan”). In accordance with its Plan, the Fund is authorized to pay an amount up to 0.25% of its average daily net assets each year for certain distribution-related activities. In addition, if the payment of management fees by the Fund is deemed to be indirect financing by the Fund of the distribution of its Fund Shares, such payment is authorized by the Plan. Calamos Advisors may use management fee revenue, as well as past profits or other resources, to pay for expenses incurred in connection with providing services intended to result in the sale of Fund Shares. Calamos Advisors may pay amounts to third parties for distribution or marketing services on behalf of the Fund.

The Plan was adopted in order to permit the implementation of the Fund’s method of distribution. No fees are currently paid by the Fund under the Plan, however, and there are no current plans to impose such fees. In the event such fees were to be charged, over time they would increase the cost of an investment in the Fund because they would be paid on an ongoing basis. If fees were charged under the Plan, the Trustees would receive and review at the end of each quarter a written report provided by the Distributor of the amounts expended under the Plan and the purpose for which such expenditures were made.

The Plan will remain in effect for a period of one year and is renewable from year to year with respect to the Fund, so long as its continuance is approved at least annually (1) by the vote of a majority of the Trustees and (2) by a vote of the majority of the independent trustees, cast in person at a meeting called for the purpose of voting on such approval. The Plan may not be amended to increase materially the amount of fees paid by the Fund unless such amendment is approved by majority vote of the outstanding Fund Shares and by the independent trustees in the manner described above. The Plan is terminable with respect to the Fund at any time by a vote of a majority of the independent trustees or by 1940 Act majority vote of the outstanding Fund Shares.

OTHER COMPENSATION TO INTERMEDIARIES

Calamos Advisors and its affiliates are currently subject to supplemental compensation payment requests by certain securities broker-dealers, banks or other intermediaries, including third party administrators of qualified plans (each an “Intermediary”) whose customers have purchased Fund Shares. In their discretion, Calamos Advisors and its affiliates may make payments to an Intermediary for various purposes. These payments do not increase the amount paid by you or the Fund, as they are paid from the legitimate profits from these entities in what is generally referred to as “revenue sharing.”

Revenue sharing payments are generally a percentage of the account’s average annual net assets. Calamos Advisors and its affiliates may make these payments to an Intermediary for various purposes, including to help defray costs incurred by the Intermediary to educate financial advisers about the Fund so they can make recommendations and provide services that are suitable and meet shareholder needs, to access the Intermediary’s representatives, to provide marketing support and other specified services. To the extent that the Fund does not pay for these costs directly, Calamos Advisors and its affiliates may also make payments to certain financial intermediaries for administrative services such as record keeping, sub-accounting for shareholder accounts, client account maintenance support, statement preparation, transaction processing, payment of ticket charges per purchase or exchange order placed by a financial intermediary, payment of networking fees in connection with certain trading systems, or one-time payments for services such as setting up the Fund on a intermediary’s trading system.

In addition, Calamos Advisors and its affiliates may also share certain marketing expenses with intermediaries, or pay for or sponsor informational meetings, seminars, client awareness events, support for marketing materials, sales reporting, or business building programs for such financial intermediaries to raise awareness of the Fund. Calamos Advisors and its affiliates may make payments to participate in intermediary marketing support programs which may provide Calamos Advisors, as applicable, with one or more of the following benefits: attendance at sales conferences, participation in meetings or training sessions, access to or information about intermediary personnel, use of an intermediary’s marketing and communication infrastructure, fund analysis tools, data and data analytics, business planning and strategy sessions with intermediary personnel, information on industry- or platform specific developments, trends and service providers, and other marketing-related services. Such payments may be in addition to, or in lieu of, the payments described above. These payments are intended to promote the sales of the Fund and to reimburse financial intermediaries, directly or indirectly, for the costs that they or their salespersons incur in connection with educational seminars, meetings, and training efforts about the Fund to enable the intermediaries and their salespersons to make suitable recommendations, provide useful services, and maintain the necessary infrastructure to make the Fund available to their customers.

These payments may provide Intermediaries with an incentive to favor Fund Shares of the Fund over sales of shares of other ETFs or non-ETF investments. These payments may influence the Intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your Intermediary’s website for more information. You may wish to take such payment arrangements into account when considering and evaluating any recommendations relating to Fund Shares and you should discuss this matter with your Intermediary and its representatives. The Fund may utilize an Intermediary that offers and sells Fund Shares to execute portfolio transactions for the Fund. The Fund and Calamos Advisors do not consider sales of Fund Shares as a factor in the selection of broker-dealers to execute portfolio transactions for the Fund.

PORTFOLIO TRANSACTIONS

Calamos Advisors is responsible for decisions to buy and sell securities for the Fund, the selection of brokers and dealers to effect the transactions and the negotiation of prices and any brokerage commissions on such transactions.

Portfolio transactions on behalf of the Fund effected on stock exchanges involve the payment of negotiated brokerage commissions. There is generally no stated commission in the case of securities traded in the OTC markets, but the price the Fund pays usually includes an undisclosed dealer commission or mark-up. For securities purchased in an underwritten offering, the price the Fund pays includes a disclosed, fixed commission or discount retained by the underwriter or dealer.

In executing portfolio transactions, Calamos Advisors uses its best efforts to obtain for the Fund the most favorable combination of price and execution available. In seeking the most favorable combination of price and execution, Calamos Advisors considers all factors it deems relevant, including price, the size of the transaction, the nature of the market for the security, the amount of commission, the timing of the transaction taking into account market prices and trends, the execution capability of the broker-dealer and the quality of service rendered by the broker-dealer in other transactions.

In allocating the Fund’s portfolio brokerage transactions to unaffiliated broker-dealers, Calamos Advisors may take into consideration the research, analytical, statistical and other information and services provided by the broker-dealer, such as general economic reports and information, reports or analyses of particular companies or industry groups, market timing and technical information, and the availability of the brokerage firm’s analysts for consultation. Although Calamos Advisors believes these services have substantial value, they are considered supplemental to Calamos Advisors’ own efforts in performing its duties under the Management Agreement.

Calamos Advisors does not guarantee any broker the placement of a predetermined amount of securities transactions in return for the research or brokerage services it provides. Calamos Advisors does, however, have internal procedures for allocating transactions in a manner consistent with its execution policies to brokers that it has identified as providing research, research-related products or services, or execution-related services of a particular benefit to its clients. Calamos Advisors has entered into client commission agreements (“CCAs”) with certain broker-dealers under which the broker-dealers may use a portion of their commissions to pay third parties or other broker-dealers that provide Calamos Advisors with research or brokerage services, as permitted under Section 28(e) of the Exchange Act. CCAs allow Calamos Advisors to direct broker-dealers to pool commissions that are generated from orders executed at that broker-dealer, and then periodically direct the broker-dealer to pay third parties or other broker-dealers for research or brokerage services. All uses of CCAs by Calamos Advisors are subject to applicable law and their best execution obligations. Brokerage and research products and services furnished by brokers may be used in servicing any or all of the clients of Calamos Advisors and such research may not necessarily be used by Calamos Advisors in connection with the accounts which paid commissions to the broker providing such brokerage and research products and services.

As permitted by Section 28(e) of the 1934 Act, Calamos Advisors may pay a broker-dealer that provides brokerage and research services an amount of commission for effecting a securities transaction for the Fund in excess of the commission that another broker-dealer would have charged for effecting that transaction if Calamos Advisors believes the amount to be reasonable in relation to the value of the overall quality of the brokerage and research services provided. Other clients of Calamos Advisors may indirectly benefit from the availability of these services to Calamos Advisors, and the Fund may indirectly benefit from services available to Calamos Advisors as a result of research services received by Calamos Advisors through transactions for other clients. In addition, Calamos Advisors may execute portfolio transactions for the Fund, to the extent permitted by law, through broker-dealers affiliated with the Fund, Calamos Advisors, CFS, or other broker-dealers distributing Fund Shares of the Fund if it reasonably believes that the combination of price and execution is at least as favorable as with unaffiliated broker-dealers, and in such transactions any such broker-dealer would receive brokerage commissions paid by the Fund.

In certain cases, Calamos Advisors may obtain products or services from a broker that have both research and non-research uses. Examples of non-research uses are administrative and marketing functions. These are referred to as “mixed use” products. In each case, Calamos Advisors makes a good faith effort to determine the proportion of such products or services that may be used for research and non-research purposes. That determination is based upon the time spent by Calamos Advisors personnel for research and non-research uses. The portion of the costs of such products or services attributable to research usage may be defrayed by Calamos Advisors through brokerage commissions generated by transactions of its clients, including the Fund. Calamos Advisors pays the provider in cash for the non-research portion of its use of these products or services.

ADDITIONAL INFORMATION CONCERNING THE FUND SHARES

Organization and Description of Shares of Beneficial Interest

The Trust is a Delaware statutory trust and registered open-end investment company. The Trust was organized on June 17, 2013, and has authorized capital of unlimited Fund Shares of beneficial interest of no-par value that may be issued in more than one class or series. Currently, the Trust consists of forty-five actively managed series. The Board of Trustees may designate additional series.

Under Delaware law, the Trust is not required to hold an annual shareholders’ meeting if the 1940 Act does not require such a meeting. Shareholders holding two-thirds of Fund Shares outstanding of the relevant Fund may remove Trustees from office by votes cast at a meeting of Trust shareholders or by written consent.

All Fund Shares are freely transferable. Fund Shares will not have preemptive rights or cumulative voting rights, and none of the Fund Shares will have any preference to conversion, exchange, dividends, retirements, liquidation, redemption, or any other feature. Fund Shares have equal voting rights. The Trust Instrument confers upon the Board the power, by resolution, to alter the number of Fund Shares constituting a Creation Unit or to specify that Fund Shares may be individually redeemable. The Trust reserves the right to adjust the stock prices of Fund Shares to maintain convenient trading ranges for investors. Any such adjustments would be accomplished through stock splits or reverse stock splits that would have no effect on the NAV of the Fund.

The Trust Instrument of the Trust disclaims liability of the shareholders or the officers of the Trust for acts or obligations of the Trust that are binding only on the assets and property of the Trust. The Trust Instrument provides for indemnification out of the Fund’s property for all loss and expense of the Fund’s shareholders being held personally liable solely by reason of his or her being or having been a shareholder and not because of his or her acts or omissions or for some other reason. The risk of a Trust shareholder incurring financial loss on account of shareholder liability is limited to circumstances in which the Fund itself would not be able to meet the Trust’s obligations and this risk should be considered remote.

If the Fund does not grow to a size to permit it to be economically viable, the Fund may cease operations. In such an event, shareholders may be required to liquidate or transfer their Fund Shares at an inopportune time and shareholders may lose money on their investment.

Book Entry Only System

The following information supplements, and should be read in conjunction with, the section in the Prospectus entitled “Fund Facts — Book Entry.”

The Depository Trust Company (“DTC”) acts as Securities Depository for Fund Shares. Fund Shares are represented by securities registered in the name of DTC or its nominee and deposited with, or on behalf of, DTC.

DTC, a limited purpose trust company, was created to hold securities of its participants (the “DTC Participants”) and to facilitate the clearance and settlement of securities transactions among the DTC Participants in such securities through electronic book entry changes in accounts of the DTC Participants, thereby eliminating the need for physical movement of securities certificates. DTC Participants include securities brokers and dealers, banks, trust companies, clearing corporations and certain other organizations, some of whom (and/or their representatives) own DTC. More specifically, DTC is owned by a number of its DTC Participants and by NYSE and FINRA. Access to the DTC system is also available to others such as banks, brokers, dealers and trust companies that clear through or maintain a custodial relationship with a DTC Participant, either directly or indirectly (the “Indirect Participants”).

Beneficial ownership of Fund Shares is limited to DTC Participants, Indirect Participants and persons holding interests through DTC Participants and Indirect Participants. Ownership of beneficial interests in Fund Shares (owners of such beneficial interests are referred to herein as “Beneficial Owners”) is shown on, and the transfer of ownership is effected only through, records maintained by DTC (with respect to DTC Participants) and on the records of DTC Participants (with respect to Indirect Participants and Beneficial Owners that are not DTC Participants). Beneficial Owners will receive from or through the DTC Participant written confirmation relating to their purchase and sale of Fund Shares.

Conveyance of all notices, statements and other communications to Beneficial Owners is effected as follows. Pursuant to the Depositary Agreement between the Trust and DTC, DTC is required to make available to the Trust upon request and for a fee to be charged to the Trust a listing of the Fund Shares held by each DTC Participant. The Trust shall inquire of each such DTC Participant as to the number of Beneficial Owners holding Fund Shares, directly or indirectly, through such DTC Participant. The Trust shall provide each such DTC Participant with copies of such notice, statement or other communication, in such form, number and at such place as such DTC Participant may reasonably request, in order that such notice, statement or communication may be transmitted by such DTC Participant, directly or indirectly, to such Beneficial Owners. In addition, the Trust shall pay to each such DTC Participant a fair and reasonable amount as reimbursement for the expenses attendant to such transmittal, all subject to applicable statutory and regulatory requirements.

Fund distributions shall be made to DTC or its nominee, Cede & Co., as the registered holder of all Fund Shares. DTC or its nominee, upon receipt of any such distributions, shall immediately credit DTC Participants’ accounts with payments in amounts proportionate to their respective beneficial interests in Fund Shares as shown on the records of DTC or its nominee. Payments by DTC Participants to Indirect Participants and Beneficial Owners of Fund Shares held through such DTC Participants will be governed by standing instructions and customary practices, and will be the responsibility of such DTC Participants.

The Trust has no responsibility or liability for any aspect of the records relating to or notices to Beneficial Owners, or payments made on account of beneficial ownership interests in such Fund Shares, or for maintaining, supervising or reviewing any records relating to such beneficial ownership interests, or for any other aspect of the relationship between DTC and the DTC Participants or the relationship between such DTC Participants and the Indirect Participants and Beneficial Owners owning through such DTC Participants.

DTC may decide to discontinue providing its service with respect to Fund Shares at any time by giving reasonable notice to the Trust and discharging its responsibilities with respect thereto under applicable law. Under such circumstances, the Trust shall take action to find a replacement for DTC to perform its functions at a comparable cost.

The Trust is required to disclose on a quarterly basis the complete schedule of the Fund’s portfolio holdings with the SEC on Form N-PORT. Form N-PORT for the Trust is available on the SEC’s website at https://www.sec.gov. The Fund’s Form N-PORT may also be reviewed and copied at the SEC’s Public Reference Room in Washington, D.C. and information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The Trust’s Forms N-PORT are available without charge, upon request, by calling (866) 363-9219 or by writing to Calamos ETF Trust, 2020 Calamos Court, Naperville, IL 60563.

CREATION AND REDEMPTION OF CREATION UNITS

General

The Fund will issue and sell Fund Shares only in Creation Units on a continuous basis, without an initial sales load, at their NAV next determined after receipt, on any Business Day (as defined herein), of an order in proper form. An Authorized Participant (defined below) that is not “qualified institutional buyer,” as such term is defined under Rule 144A of the Securities Act, will not be able to receive, as part of a redemption, restricted securities eligible for resale under Rule 144A.

A “Business Day” with respect to the Fund is any day on which the NYSE is open for business. As of the date of this SAI, the NYSE observes the following holidays: New Year’s Day, Martin Luther King, Jr. Day, President’s Day (Washington’s Birthday), Good Friday, Memorial Day (observed), Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day.

Distribution of Fund Shares

In connection with its launch, the Fund was seeded through the sale of one or more Creation Units to one or more initial investors. Initial investors participating in the seeding may be Authorized Participants or a lead market maker, other third-party investor or an affiliate of the Fund or the Adviser purchasing from an Authorized Participant. Each such initial investor may sell some or all of the Fund Shares underlying the Creation Unit(s) held by them pursuant to the registration statement for the Fund (each, a “Selling Shareholder”), which Fund Shares have been registered to permit the resale from time to time after purchase. No Fund will receive any of the proceeds from the resale by the Selling Shareholders of these Fund Shares. Selling Shareholders may sell Fund Shares owned by them directly or through broker-dealers, in accordance with applicable law, on any national securities exchange on which the Fund Shares may be listed or quoted at the time of sale, through trading systems, in the over-the-counter market or in transactions other than on these exchanges or systems at fixed prices, at prevailing market prices at the time of the sale, at varying prices determined at the time of sale, or at negotiated prices. These sales may be effected through brokerage transactions, privately negotiated trades, block sales, entry into options or other derivatives transactions or through any other means authorized by applicable law. Selling Shareholders may redeem the Fund Shares held in Creation Unit size by them through an Authorized Participant. Any Selling Shareholder and any broker-dealer or agents participating in the distribution of Fund Shares may be deemed to be “underwriters” within the meaning of Section 2(a)(11) of the Securities Act, in connection with such sales. Any Selling Shareholder and any other person participating in such distribution will be subject to any applicable provisions of the Exchange Act and the rules and regulations thereunder.