NEKTAR THERAPEUTICS (0000906709) (Filer)

As filed with the Securities and Exchange Commission on October 19, 2026

Registration No. 333-      

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

NEKTAR THERAPEUTICS

(Exact name of registrant as specified in its charter)

455 Mission Bay Boulevard South

San Francisco, California 94158

(Address of Principal Executive Offices and Zip Code)

Nektar Therapeutics 2025 Inducement Plan

(Full Title of the Plan)

Elizabeth Zhang

Vice President, Legal and Secretary

Nektar Therapeutics

455 Mission Bay Boulevard South

San Francisco, California 94158

415-482-5300

(Name, Address, and Telephone Number, Including Area Code, of Agent for Service)

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

EXPLANATORY NOTE

On September 23, 2026, the Board of Directors (the “Board”) of Nektar Therapeutics (the “Registrant”) approved an amendment to the Registrant’s 2025 Inducement Plan (as amended, the “Plan”), to increase the number of shares of common stock, par value $0.0001 per share (the “Common Stock”), reserved and available for issuance under the Plan by 250,000 shares for a total of 500,000 shares. This Registration Statement on Form S-8 (the “Registration Statement”) registers these 250,000 additional shares of Common Stock. The additional shares available for issuance under the Plan are of the same class as other securities for which registration statements on Form S-8 relating to the Registrant’s employee benefit plans were previously filed and are effective. Accordingly, this Registration Statement incorporates by reference the contents of the Registrant’s prior registration statements filed on (i) Form S-8 (Registration No. 333-218777) on June 15, 2017; (ii) Form S-8 (Registration No. 333-226004) on June 29, 2018; (iii) Form S-8 (Registration No. 333-242327) on August 7, 2020; (iv) Form S-8 (Registration No. 333-258900) on August 18, 2021; (v) Form S-8 (Registration No. 333-266580) on August 5, 2022; (vi) Form S-8 (Registration No. 333-273962) on August 14, 2023; (vii) Form S-8 (Registration No. 333-285827) on March 14, 2025; (viii) Form S-8 (Registration No. 333-289394) on August 8, 2025; (ix) Form S-8 on November 12, 2025 (Registration No. 333-291471); and (x) Form S-8 on August 14, 2026 (Registration No. 333-298352) (collectively, the “Prior Registration Statements”).

The information contained in the Registrant’s Prior Registration Statements is hereby incorporated by reference pursuant to General Instruction E of Form S-8, except for “Item 8. Exhibits” which is being updated by this Registration Statement.

The Plan was adopted without stockholder approval pursuant to Nasdaq Listing Rule 5635(c)(4) and will be administered by the Organization and Compensation Committee of the Board.

The only persons eligible to receive grants of Awards (as defined below) under the Plan are individuals who satisfy the standards for inducement grants under Nasdaq Listing Rule 5635(c)(4). An “Award” means any right to receive the Registrant’s common stock, cash or other property granted under the Plan (including nonqualified stock options, restricted stock awards, restricted stock unit awards, stock appreciation rights, stock bonuses or other stock-based awards).

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 8. Exhibits.

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SIGNATURES

Pursuant to the requirements of the Securities Act, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of San Francisco, State of California, on October 19, 2026.

POWER OF ATTORNEY

Each person whose signature appears below constitutes and appoints Howard W. Robin and Elizabeth Zhang, and each of them, acting individually and without the other, as his or her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him or her and in his or her name, place, and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments, exhibits thereto, and other documents in connection therewith) to this Registration Statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and to perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or either of them individually, or their, his or her substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

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