Nektar Therapeutics announced the closing of its underwritten public offering of USD 373.8 million of shares of its common stock. Nektar sold 4,062,500 shares of common stock in the offering, which includes 529,891 shares sold upon exercise in full by the underwriters of their option to purchase additional shares of common stock in the offering. The shares of common stock were sold at a public offering price of USD 92 per share. The gross proceeds to Nektar from the offering were approximately USD 373.8 million, before deducting underwriting discounts and commissions and estimated offering expenses. All of the securities sold in this offering were offered by Nektar.

Jefferies, TD Cowen, and Piper Sandler acted as joint bookrunning managers for the offering. Citigroup also acted as a bookrunner for the offering.

The securities described above were offered pursuant to a shelf registration statement on Form S-3ASR (No. 333-291466) that was filed with the US Securities and Exchange Commission (the SEC) on November 12, 2025 and automatically became effective upon filing. This offering was made only by means of a prospectus supplement and an accompanying prospectus that form a part of the registration statement.

A final prospectus supplement related to and describing the terms of the offering was filed with the SEC and is available on the SEC's website. Copies of the final prospectus supplement and an accompanying prospectus related to the offering may also be obtained from Jefferies LLC.