PTC Therapeutics, Inc. (NASDAQ: PTCT) has priced $500.0 million in aggregate principal amount of 0% Convertible Senior Notes due 2031 in a private placement to qualified institutional buyers under Rule 144A.

The notes carry no regular interest and mature on June 15, 2031. The initial conversion price is approximately $107.48 per share, representing a 40% premium over PTC's closing stock price of $76.77 on the Nasdaq Global Select Market on June 15, 2026. The conversion rate is set at 9.3042 shares per $1,000 principal amount.

PTC also granted initial purchasers an option to buy up to an additional $50.0 million in notes within 13 days of issuance. The sale is expected to close on June 18, 2026, subject to customary closing conditions.

Net proceeds are estimated at approximately $486.8 million, or $535.5 million if the overallotment option is exercised in full. PTC plans to use approximately $328.8 million of the proceeds to repurchase $222.0 million in aggregate principal amount of its existing 1.5% Convertible Senior Notes due 2026 through privately negotiated transactions. The remainder will be directed toward general corporate purposes, including potential additional repurchases or repayment of the 2026 notes at maturity.

PTC may not redeem the new notes before June 20, 2029. After that date, redemption is permitted if PTC's stock price reaches at least 130% of the conversion price for 20 of 30 consecutive trading days.

The notes are general senior unsecured obligations and were offered solely through a private offering memorandum. They have not been registered under the Securities Act of 1933 and may not be publicly offered or sold absent an applicable exemption.