PTC Therapeutics Inc. (NASDAQ: PTCT) announced plans to offer $500 million in convertible senior notes due 2031 through a private placement to qualified institutional buyers. The company intends to grant initial purchasers an option to purchase up to $50 million in additional notes within 13 days of issuance.

The notes will mature on June 15, 2031, unless converted, repurchased or redeemed earlier. Upon conversion, PTC will pay cash, shares of common stock, or a combination of both at the company's discretion. Interest will accrue and be paid semiannually.

PTC expects to use net proceeds to repurchase a portion of its 1.5% convertible senior notes due 2026 concurrently with the offering and to repay any remaining 2026 notes at maturity. The company also plans to repurchase approximately $50 million of common stock through privately negotiated transactions concurrent with the offering, though the actual amount may vary.

The company may conduct separate negotiations to repurchase 2026 notes for cash during the offering, though no assurance exists regarding the amount or terms of such repurchases. PTC noted that holders of 2026 notes who participate in repurchases may engage in derivative transactions or purchase common stock, which could affect share prices.

The offering will be conducted through a private offering memorandum under Rule 144A of the Securities Act of 1933. The notes and any shares issuable upon conversion have not been registered under securities laws and cannot be offered or sold without exemption from registration requirements.

Any remaining proceeds will support general corporate purposes, which may include additional 2026 notes repurchases following the offering. The interest rate, initial conversion rate and other terms will be determined at pricing.