SONN / Sonnet BioTherapeutics Holdings, Inc. - SEC-Einreichungen, Jahresbericht, Proxy Statement

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended September 30, 2025 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET BIOTHE

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 15 CERTIFICATION AND NOTICE OF TERMINATION OF REGISTRATION UNDER SECTION 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR SUSPENSION OF DUTY TO FILE REPORTS UNDER SECTIONS 13

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 15 CERTIFICATION AND NOTICE OF TERMINATION OF REGISTRATION UNDER SECTION 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR SUSPENSION OF DUTY TO FILE REPORTS UNDER SECTIONS 13 AND 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number 001-35570 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as

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Hyperliquid Strategies Inc and Sonnet BioTherapeutics Holdings, Inc. Announce Closing of Business Combination Hyperliquid Strategies Common Stock Expected to Begin Trading on Nasdaq on Wednesday, December 3 Under the Ticker “PURR”

Exhibit 99.1 Hyperliquid Strategies Inc and Sonnet BioTherapeutics Holdings, Inc. Announce Closing of Business Combination Hyperliquid Strategies Common Stock Expected to Begin Trading on Nasdaq on Wednesday, December 3 Under the Ticker “PURR” NEW YORK, NY and PRINCETON, NJ, December 2, 2025 — Hyperliquid Strategies Inc (“HSI” or the “Company”) and Sonnet BioTherapeutics Holdings, Inc. (NASDAQ: SO

CERTIFICATE OF AMENDMENT TO THE CERTIFICATE OF INCORPORATION SONNET BIOTHERAPEUTICS HOLDINGS, INC.

Exhibit 3.1 CERTIFICATE OF AMENDMENT TO THE CERTIFICATE OF INCORPORATION OF SONNET BIOTHERAPEUTICS HOLDINGS, INC. Sonnet BioTherapeutics Holdings, Inc. (the “Corporation”), a corporation organized and existing under and by virtue of the General Corporation Law of the State of Delaware, as amended (the “DGCL”), does hereby certify as follows: 1. The Board of Directors of the Corporation (the “Board

BUSINESS COMBINATION AGREEMENT by and among HYPERLIQUID STRATEGIES INC, RORSCHACH MERGER SUB LLC TBS MERGER SUB INC, RORSCHACH I LLC SONNET BIOTHERAPEUTICS HOLDINGS, INC. Dated as of July 11, 2025 Table of Contents

EXHIBIT 2.1 BUSINESS COMBINATION AGREEMENT by and among HYPERLIQUID STRATEGIES INC, RORSCHACH MERGER SUB LLC TBS MERGER SUB INC, RORSCHACH I LLC and SONNET BIOTHERAPEUTICS HOLDINGS, INC. Dated as of July 11, 2025 Table of Contents Page ARTICLE I. DEFINITIONS 3 Section 1.01 Certain Definitions 3 Section 1.02 Further Definitions 14 Section 1.03 Construction 17 ARTICLE II. AGREEMENT AND PLAN OF MERGE

AMENDMENT NO. 1 TO BUSINESS COMBINATION AGREEMENT

Exhibit 2.2 AMENDMENT NO. 1 TO BUSINESS COMBINATION AGREEMENT This Amendment No. 1 to bUSINESS cOMBINATION AGREEMENT (this “Amendment”), dated as of September 22, 2025, is made by and among Hyperliquid Strategies Inc, a Delaware corporation (“Pubco”), Rorschach I LLC, a Delaware limited liability company (“Rorschach”), Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (the “Company”),

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 2, 2025 Sonnet BioTherap

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 2, 2025 Sonnet BioTherapeutics Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporati

Sonnet BioTherapeutics Holdings, Inc. Announces Stockholder Approval of Proposed Business Combination with Hyperliquid Strategies Inc

Exhibit 99.1 Sonnet BioTherapeutics Holdings, Inc. Announces Stockholder Approval of Proposed Business Combination with Hyperliquid Strategies Inc PRINCETON, NJ, December 2, 2025 — Sonnet BioTherapeutics Holdings, Inc., (NASDAQ: SONN) (“Sonnet” or the “Company”) today announced that its stockholders approved, among other things, the proposed business combination with Hyperliquid Strategies Inc (“H

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 2, 2025 Sonnet BioTherap

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 2, 2025 Sonnet BioTherapeutics Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporati

Sonnet BioTherapeutics Holdings, Inc. Announces Adjournment of Special Meeting

Filed by Hyperliquid Strategies Inc pursuant to Rule 425 under the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 under the Securities Exchange Act of 1934 Subject Company: Sonnet BioTherapeutics Holdings, Inc.

Filed by Hyperliquid Strategies Inc

Filed by Hyperliquid Strategies Inc pursuant to Rule 425 under the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 under the Securities Exchange Act of 1934 Subject Company: Sonnet BioTherapeutics Holdings, Inc. Commission File No. 001-35570 Date: November 18, 2025

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the SEC Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive P

Sonnet BioTherapeutics Holdings, Inc. Announces Adjournment of Special Meeting

Exhibit 99.1 Sonnet BioTherapeutics Holdings, Inc. Announces Adjournment of Special Meeting PRINCETON, NJ, November 18, 2025 — Sonnet BioTherapeutics Holdings, Inc., (NASDAQ: SONN) (“Sonnet” or the “Company”) today announced that it has adjourned its special meeting of stockholders (the “Special Meeting”) in order to provide stockholders additional time within which to vote on its proposed busines

Sonnet BioTherapeutics Holdings, Inc. Announces Adjournment of Special Meeting

Exhibit 99.1 Sonnet BioTherapeutics Holdings, Inc. Announces Adjournment of Special Meeting PRINCETON, NJ, November 18, 2025 — Sonnet BioTherapeutics Holdings, Inc., (NASDAQ: SONN) (“Sonnet” or the “Company”) today announced that it has adjourned its special meeting of stockholders (the “Special Meeting”) in order to provide stockholders additional time within which to vote on its proposed busines

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 18, 2025 Sonnet BioThera

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 18, 2025 Sonnet BioTherapeutics Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 18, 2025 Sonnet BioThera

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 18, 2025 Sonnet BioTherapeutics Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporat

Filed by Sonnet BioTherapeutics Holdings, Inc.

Filed by Sonnet BioTherapeutics Holdings, Inc. pursuant to Rule 425 under the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 under the Securities Exchange Act of 1934 Subject Company: Sonnet BioTherapeutics Holdings, Inc. Commission File No. 001-35570 Date: November 18, 2025

425

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant To Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant To Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Defin

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 26, 2025 Sonnet BioTher

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 26, 2025 Sonnet BioTherapeutics Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorpora

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UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended September 30, 2024 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET BIOTHE

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant To Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant To Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Defin

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET BIO

Employment Agreement by and between the Company and Raghu Rao, dated July 31, 2025.

Exhibit 10.1 EXECUTIVE EMPLOYMENT AGREEMENT THIS EXECUTIVE EMPLOYMENT AGREEMENT (the “Agreement”), dated as of July 31, 2025 is by and between RAGHU RAO. (the “Executive”) and SONNET BIOTHERAPEUTICS, INC., a New Jersey corporation (the “Company”). WHEREAS, on July 31, 2025, the Board of Directors of the Company approved the employment of the Executive as its Chief Executive Officer with certain co

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): July 31, 2025 SONNET BIOTHERAPEUT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): July 31, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): July 23, 2025 SONNET BIOTHERAPEUT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): July 23, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): July 18, 2025 SONNET BIOTHERAPEUT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): July 18, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

Form of PIPE Purchase Agreement.

EXHIBIT 10.3 SECURITIES PURCHASE AGREEMENT This Securities Purchase Agreement (this “Agreement”) is dated as of July 11, 2025, between Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation, and each purchaser identified on the signature pages hereto (each, including its successors and assigns, a “Purchaser” and collectively, the “Purchasers”). WHEREAS, subject to the terms and conditions s

Certificate of Designations.

EXHIBIT 3.1 SONNET BIOTHERAPEUTICS HOLDINGS, Inc. CERTIFICATE OF DESIGNATION OF PREFERENCES, RIGHTS AND LIMITATIONS OF SERIES 5 CONVERTIBLE PREFERRED STOCK PURSUANT TO SECTION 151 OF THE delaware GENERAL CORPORATION LAW The undersigned, Raghu Rao, does hereby certify that: 1. The undersigned is the Interim Chief Executive Officer of Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (th

Form of PIPE Purchase Agreement.

EXHIBIT 10.3 SECURITIES PURCHASE AGREEMENT This Securities Purchase Agreement (this “Agreement”) is dated as of July 11, 2025, between Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation, and each purchaser identified on the signature pages hereto (each, including its successors and assigns, a “Purchaser” and collectively, the “Purchasers”). WHEREAS, subject to the terms and conditions s

Sonnet BioTherapeutics, Inc. Announces $888 Million Business Combination to Launch a HYPE Cryptocurrency Treasury Reserve Strategy Combined company expected to become largest U.S.-based publicly listed company to hold HYPE in its treasury

Exhibit 99.1 Sonnet BioTherapeutics, Inc. Announces $888 Million Business Combination to Launch a HYPE Cryptocurrency Treasury Reserve Strategy Combined company expected to become largest U.S.-based publicly listed company to hold HYPE in its treasury PRINCETON, NJ, July 14, 2025 — Sonnet BioTherapeutics, Inc., (NASDAQ: SONN) (“Sonnet” or the “Company”) today announced that it has entered into a d

Business Combination Agreement.

EXHIBIT 2.1 BUSINESS COMBINATION AGREEMENT by and among HYPERLIQUID STRATEGIES INC, RORSCHACH MERGER SUB LLC TBS MERGER SUB INC, RORSCHACH I LLC and SONNET BIOTHERAPEUTICS HOLDINGS, INC. Dated as of July 11, 2025 Table of Contents Page ARTICLE I. DEFINITIONS 3 Section 1.01 Certain Definitions 3 Section 1.02 Further Definitions 14 Section 1.03 Construction 17 ARTICLE II. AGREEMENT AND PLAN OF MERGE

Form of Subscription Agreement.

EXHIBIT 10.2 THE SECURITIES DESCRIBED HEREIN HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 OR THE SECURITIES LAWS OF ANY STATE OR ANY OTHER JURISDICTION. THERE ARE FURTHER RESTRICTIONS ON THE TRANSFERABILITY OF THE SECURITIES DESCRIBED HEREIN. THE PURCHASE OF THE SECURITIES INVOLVES A HIGH DEGREE OF RISK AND SHOULD BE CONSIDERED ONLY BY PERSONS WHO CAN BEAR THE RISK OF THE LOSS OF THEI

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): July 11, 2025 SONNET BIOTHERAPEUT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): July 11, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

Certificate of Designations.

EXHIBIT 3.1 SONNET BIOTHERAPEUTICS HOLDINGS, Inc. CERTIFICATE OF DESIGNATION OF PREFERENCES, RIGHTS AND LIMITATIONS OF SERIES 5 CONVERTIBLE PREFERRED STOCK PURSUANT TO SECTION 151 OF THE delaware GENERAL CORPORATION LAW The undersigned, Raghu Rao, does hereby certify that: 1. The undersigned is the Interim Chief Executive Officer of Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (th

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): July 11, 2025 SONNET BIOTHERAPEUT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): July 11, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

Business Combination Agreement.

EXHIBIT 2.1 BUSINESS COMBINATION AGREEMENT by and among HYPERLIQUID STRATEGIES INC, RORSCHACH MERGER SUB LLC TBS MERGER SUB INC, RORSCHACH I LLC and SONNET BIOTHERAPEUTICS HOLDINGS, INC. Dated as of July 11, 2025 Table of Contents Page ARTICLE I. DEFINITIONS 3 Section 1.01 Certain Definitions 3 Section 1.02 Further Definitions 14 Section 1.03 Construction 17 ARTICLE II. AGREEMENT AND PLAN OF MERGE

Form of PIPE Warrant.

EXHIBIT 4.1 NEITHER THIS SECURITY NOR THE SECURITIES FOR WHICH THIS SECURITY IS EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTR

Form of Contribution Agreement.

EXHIBIT 10.1 THE MEMBERSHIP INTERESTS DESCRIBED HEREIN HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 OR THE SECURITIES LAWS OF ANY STATE OR ANY OTHER JURISDICTION. THERE ARE FURTHER RESTRICTIONS ON THE TRANSFERABILITY OF THE MEMBERSHIP INTERESTS DESCRIBED HEREIN. THE PURCHASE OF THE MEMBERSHIP INTERESTS INVOLVES A HIGH DEGREE OF RISK AND SHOULD BE CONSIDERED ONLY BY PERSONS WHO CAN BEA

Form of Contribution Agreement.

EXHIBIT 10.1 THE MEMBERSHIP INTERESTS DESCRIBED HEREIN HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 OR THE SECURITIES LAWS OF ANY STATE OR ANY OTHER JURISDICTION. THERE ARE FURTHER RESTRICTIONS ON THE TRANSFERABILITY OF THE MEMBERSHIP INTERESTS DESCRIBED HEREIN. THE PURCHASE OF THE MEMBERSHIP INTERESTS INVOLVES A HIGH DEGREE OF RISK AND SHOULD BE CONSIDERED ONLY BY PERSONS WHO CAN BEA

Form of PIPE Warrant.

EXHIBIT 4.1 NEITHER THIS SECURITY NOR THE SECURITIES FOR WHICH THIS SECURITY IS EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTR

Sonnet BioTherapeutics, Inc. Announces $888 Million Business Combination to Launch a HYPE Cryptocurrency Treasury Reserve Strategy Combined company expected to become largest U.S.-based publicly listed company to hold HYPE in its treasury

Exhibit 99.1 Sonnet BioTherapeutics, Inc. Announces $888 Million Business Combination to Launch a HYPE Cryptocurrency Treasury Reserve Strategy Combined company expected to become largest U.S.-based publicly listed company to hold HYPE in its treasury PRINCETON, NJ, July 14, 2025 — Sonnet BioTherapeutics, Inc., (NASDAQ: SONN) (“Sonnet” or the “Company”) today announced that it has entered into a d

Form of Subscription Agreement.

EXHIBIT 10.2 THE SECURITIES DESCRIBED HEREIN HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 OR THE SECURITIES LAWS OF ANY STATE OR ANY OTHER JURISDICTION. THERE ARE FURTHER RESTRICTIONS ON THE TRANSFERABILITY OF THE SECURITIES DESCRIBED HEREIN. THE PURCHASE OF THE SECURITIES INVOLVES A HIGH DEGREE OF RISK AND SHOULD BE CONSIDERED ONLY BY PERSONS WHO CAN BEAR THE RISK OF THE LOSS OF THEI

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): June 30, 2025 SONNET BIOTHERAPEUT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): June 30, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

Form of Warrant

Exhibit 4.2 NEITHER THIS SECURITY NOR THE SECURITIES FOR WHICH THIS SECURITY IS EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTR

Form of Convertible Note

Exhibit 4.1 THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”). THE SECURITIES MAY NOT BE SOLD, TRANSFERRED OR ASSIGNED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER SAID ACT, OR AN OPINION OF COUNSEL IN FORM, SUBSTANCE AND SCOPE CUSTOMARY FOR OPINIONS OF COUNSEL IN COMPARABLE TRANSACTION

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): May 30, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET BI

Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): April 4, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): March 31, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): March 26, 2025 SONNET BIOTHERAPEU

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): March 26, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation

Sonnet BioTherapeutics Receives Notice of Allowance for U.S. Patent Covering Composition of Matter of Specific Amino Acid Substitutions of its IL-18Binding Protein Resistant Variant Protein Sonnet’s variant human IL-18BPR is a key cytokine which comp

Exhibit 99.1 Sonnet BioTherapeutics Receives Notice of Allowance for U.S. Patent Covering Composition of Matter of Specific Amino Acid Substitutions of its IL-18Binding Protein Resistant Variant Protein Company advancing development of its modified version of Interleukin-18 (IL-18Binding Protein Resistant or IL-18BPR) that exhibits wild-type binding to the IL-18 receptor (IL-18Rc), coupled with un

Regulation FD Disclosure, Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): March 19, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation

Regulation FD Disclosure, Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): February 26, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporat

Sonnet BioTherapeutics Presents Compilation of Data Highlighting the Potential of SON-1010 as a Monotherapy or a Combination Therapy to Improve the Treatment of Solid Tumors Poster presented at the 2025 AACR:IO Conference Company’s novel platform tha

Exhibit 99.1 Sonnet BioTherapeutics Presents Compilation of Data Highlighting the Potential of SON-1010 as a Monotherapy or a Combination Therapy to Improve the Treatment of Solid Tumors Poster presented at the 2025 AACR:IO Conference Company’s novel platform that delivers either mono- or bifunctional immunomodulators linked to a Fully-Human, Albumin Binding scFv domain (FHAB®) provides enhanced t

Regulation FD Disclosure, Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): February 19, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporat

Sonnet BioTherapeutics Announces That Its Proprietary Antibody Drug Conjugate (ADC) Platform is Available for Drug Discovery Partnerships with Potential for Producing Multiple Pipeline Drug Candidates Building on proven targeting of the FHAB domain,

Exhibit 99.1 Sonnet BioTherapeutics Announces That Its Proprietary Antibody Drug Conjugate (ADC) Platform is Available for Drug Discovery Partnerships with Potential for Producing Multiple Pipeline Drug Candidates Building on proven targeting of the FHAB domain, Sonnet’s ADC platform offers flexible payload capacity and controllable drug-antibody ratios (DAR) An epidermal growth factor receptor 2

Employment Agreement by and between the Company and Stephen McAndrew, Ph.D., dated February 12, 2025.

Exhibit 10.6 EXECUTIVE EMPLOYMENT AGREEMENT THE EXECUTIVE EMPLOYMENT AGREEMENT (the “Agreement”), dated as of February 12, 2025 and effective as of the Effective Date (as defined below) is by and between STEPHEN MCANDREW (the “Executive”) and SONNET BIOTHERAPEUTICS, INC., a New Jersey corporation (the “Company”). WHEREAS, the Executive has been employed as the Company’s SVP of Business Development

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET

Results of Operations and Financial Condition, Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): February 13, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporat

Sonnet BioTherapeutics Provides Fiscal Year 2025 First Quarter Business and Earnings Update

Exhibit 99.1 Sonnet BioTherapeutics Provides Fiscal Year 2025 First Quarter Business and Earnings Update Completion of SON-1010 (IL12-FHAB) monotherapy dose escalation in Phase 1 SB101 trial. Stable disease (SD) at four months post-initiation of dosing was seen in 48% evaluable monotherapy patients, and one patient dosed at the MTD, resulting in a partial response (PR) Continued progress with clin

127,500 Shares of Common Stock 545,500 Shares of Common Stock issuable upon exercise of 545,500 Outstanding Pre-Funded Warrants 1,758,325 Shares of Common Stock issuable upon exercise of 1,758,325 Outstanding Common Warrants

Filed Pursuant to Rule 424(b)(3) Registration No. 333-284409 PROSPECTUS 127,500 Shares of Common Stock 545,500 Shares of Common Stock issuable upon exercise of 545,500 Outstanding Pre-Funded Warrants 1,758,325 Shares of Common Stock issuable upon exercise of 1,758,325 Outstanding Common Warrants This prospectus relates to the resale from time to time, by the selling stockholders identified in this

Up to 2,000,000 Shares of Common Stock

Filed Pursuant to Rule 424(b)(3) Registration No. 333-284409 PROSPECTUS Up to 2,000,000 Shares of Common Stock This prospectus relates to the potential offer and sale from time to time by Chardan Capital Markets LLC (“Chardan” or the “Selling Securityholder”) of up to 2,000,000 shares of our common stock, $0.0001 par value per share (“Common Stock”), that have been or may be issued by us to Charda

As filed with the Securities and Exchange Commission on January 30, 2025

As filed with the Securities and Exchange Commission on January 30, 2025 Registration No.

As filed with the Securities and Exchange Commission on January 30, 2025

As filed with the Securities and Exchange Commission on January 30, 2025 Registration No.

LETTER

January 28, 2025 Pankaj Mohan Chief Executive Officer Sonnet BioTherapeutics Holdings, Inc.

January 28, 2025

January 28, 2025 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

LETTER

January 28, 2025 Pankaj Mohan Chief Executive Officer Sonnet BioTherapeutics Holdings, Inc.

January 28, 2025

January 28, 2025 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

Sonnet BioTherapeutics Further Expands Global Intellectual Property Portfolio with Issuance of EU Patent for FHAB® Platform Technology European Patent Office (EPO) grants EU Patent No. EP3583125 B1 covering the Company’s Fully Human Albumin Binding (

Exhibit 99.1 Sonnet BioTherapeutics Further Expands Global Intellectual Property Portfolio with Issuance of EU Patent for FHAB® Platform Technology European Patent Office (EPO) grants EU Patent No. EP3583125 B1 covering the Company’s Fully Human Albumin Binding (FHAB®) domain fusion proteins In addition to the U.S. and EU, Sonnet’s global IP coverage now extends to China, Japan, Russia and New Zea

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 28, 2025 SONNET BIOTHERAP

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 28, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporati

Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-1 (Form Type) Sonnet BioTherapeutics Holdings, Inc.

Filing Fee Table.

EXHIBIT 107 Calculation of Filing Fee Tables Form S-1 (Form Type) Sonnet BioTherapeutics Holdings, Inc.

As filed with the Securities and Exchange Commission on January 22, 2025

As filed with the Securities and Exchange Commission on January 22, 2025 Registration No.

As filed with the Securities and Exchange Commission on January 22, 2025

As filed with the Securities and Exchange Commission on January 22, 2025 Registration No.

Sonnet BioTherapeutics Expands Phase 1 SB101 Trial to Evaluate Combination of SON-1010 with Trabectedin in Certain Sarcomas SON-1010, after receipt of data suggesting clinical benefit when administered as a monotherapy in patients with advanced solid

Exhibit 99.1 Sonnet BioTherapeutics Expands Phase 1 SB101 Trial to Evaluate Combination of SON-1010 with Trabectedin in Certain Sarcomas SON-1010, after receipt of data suggesting clinical benefit when administered as a monotherapy in patients with advanced solid tumors, enters combination evaluation with trabectedin (Yondelis®) with the potential to improve trabectedin’s therapeutic window in sof

Up to 625,000 Shares of Common Stock

Filed Pursuant to Rule 424(b)(3) Registration No. 333-280705 PROSPECTUS Up to 625,000 Shares of Common Stock This prospectus relates to the potential offer and sale from time to time by Chardan Capital Markets LLC (“Chardan” or the “Selling Securityholder”) of up to 625,000 shares of our common stock, $0.0001 par value per share (“Common Stock”), that have been or may be issued by us to Chardan pu

Regulation FD Disclosure, Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 21, 2025 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporati

As filed with the Securities and Exchange Commission on January 13, 2025

As filed with the Securities and Exchange Commission on January 13, 2025 Registration No.

Results of Operations and Financial Condition, Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): December 17, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended September 30, 2024 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET BIOTHE

Insider Trading Policy.*

Exhibit 19.1 SONNET BIOTHERAPEUTICS HOLDINGS, INC. INSIDER TRADING POLICY As Amended and Restated by the Board on December 16, 2024 The following Insider Trading Policy (“Policy”) has been approved by the Board of Directors (the “Board”) of Sonnet BioTherapeutics Holdings, Inc. (together with its subsidiaries, the “Company”). Two copies of this Policy are being provided to you. You must read, sign

Sonnet BioTherapeutics Reports Fiscal Year 2024 Financial Results and Provides Corporate Update Continued progress with both clinical trials of lead program, SON-1010, for solid tumors and Platinum-Resistant Ovarian Cancer (PROC) Executed licensing a

Exhibit 99.1 Sonnet BioTherapeutics Reports Fiscal Year 2024 Financial Results and Provides Corporate Update Continued progress with both clinical trials of lead program, SON-1010, for solid tumors and Platinum-Resistant Ovarian Cancer (PROC) Executed licensing agreement to support initiation of a Phase 2 clinical trial of SON-080 in Diabetic Peripheral Neuropathy (DPN) Multiple value-driving mile

Exhibit 4.8

Exhibit 4.8 DESCRIPTION OF SONNET BIOTHERAPEUTICS HOLDINGS, INC.’S SECURITIES REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934 Sonnet BioTherapeutics Holdings, Inc. (“us,” “our,” “we” or the “Company”) has two classes of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended: our voting common stock, $0.0001 par value per share and preferr

Form of Common Warrant (incorporated by reference to Exhibit 4.3 to the Company’s Current Report on Form 8-K filed with the SEC on December 10, 2024).

Exhibit 4.3 NEITHER THIS SECURITY NOR THE SECURITIES FOR WHICH THIS SECURITY IS EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTR

Form of Registered Direct Pre-Funded Warrant (incorporated by reference to Exhibit 4.1 to the Company’s Current Report on Form 8-K filed with the SEC on December 10, 2024).

Exhibit 4.1 FORM OF PRE-FUNDED WARRANT SONNET BIOTHERAPEUTICS HOLDINGS, INC. PRE-FUNDED WARRANT TO PURCHASE COMMON STOCK Warrant No.: [ ] Number of Shares of Common Stock: [ ] Date of Issuance: [ ] (“Issuance Date”) Sonnet BioTherapeutics Holdings, Inc., a company organized under the laws of Delaware (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and suffi

Form of Private Placement Pre-Funded Warrant (incorporated by reference to Exhibit 4.2 to the Company’s Current Report on Form 8-K filed with the SEC on December 10, 2024).

Exhibit 4.2 NEITHER THIS SECURITY NOR THE SECURITIES FOR WHICH THIS SECURITY IS EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTR

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): December 9, 2024 SONNET BIOTHERAP

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): December 9, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact Name of Registrant as Specified in Charter) Delaware 001-35570 20-2932652 (State or Other Jurisdiction of Incorporation)

Form of Private Placement Securities Purchase Agreement, dated December 9, 2024, by and between the Company and the Purchasers (incorporated by reference to Exhibit 10.2 of the Company’s Current Report on Form 8-K filed with the SEC on December 10, 2024).

Exhibit 10.2 SECURITIES PURCHASE AGREEMENT This Securities Purchase Agreement (this “Agreement”) is dated as of December 9, 2024, between Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (the “Company”), and each purchaser identified on the signature pages hereto (each, including its successors and assigns, a “Purchaser” and collectively the “Purchasers”). WHEREAS, subject to the term

Sonnet BioTherapeutics Announces $3.9 Million Registered Direct Offering and Concurrent Private Placement Priced At- The-Market Under Nasdaq Rules

Exhibit 99.1 December 9, 2024 Sonnet BioTherapeutics Announces $3.9 Million Registered Direct Offering and Concurrent Private Placement Priced At- The-Market Under Nasdaq Rules PRINCETON, NJ, Dec. 09, 2024 (GLOBE NEWSWIRE) — Sonnet BioTherapeutics Holdings, Inc. (the “Company” or “Sonnet”) (NASDAQ:SONN), a clinical-stage company developing targeted immunotherapeutic drugs, announced today that it

768,000 Shares of Common Stock 317,325 Pre-Funded Warrants to Purchase up to 317,325 Shares of Common Stock 317,325 Shares of Common Stock Underlying the 317,325 Pre-Funded Warrants

PROSPECTUS SUPPLEMENT (To Prospectus dated January 4, 2024) Filed Pursuant to Rule 424(b)(5) Registration No.

Form of Registered Direct Securities Purchase Agreement, dated December 9, 2024, by and between the Company and the Purchasers (incorporated by reference to Exhibit 10.1 of the Company’s Current Report on Form 8-K filed with the SEC on December 10, 2024).

Exhibit 10.1 SECURITIES PURCHASE AGREEMENT This Securities Purchase Agreement (this “Agreement”) is dated as of December 9, 2024, between Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (the “Company”), and each purchaser identified on the signature pages hereto (each, including its successors and assigns, a “Purchaser” and collectively the “Purchasers”). WHEREAS, subject to the term

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 9, 2024 SONNET BIOTHERAP

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 9, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporati

Sonnet BioTherapeutics Announces Topline Safety Data Following Successful Completion of SON-1010 Monotherapy Dose Escalation in Phase 1 SB101 Trial The maximum tolerated dose (MTD) of SON-1010 was set at 1200 ng/kg, without dose-limiting toxicity or

Exhibit 99.1 Sonnet BioTherapeutics Announces Topline Safety Data Following Successful Completion of SON-1010 Monotherapy Dose Escalation in Phase 1 SB101 Trial The maximum tolerated dose (MTD) of SON-1010 was set at 1200 ng/kg, without dose-limiting toxicity or evidence of cytokine release syndrome at any dose level Stable disease (SD) at four months post-initiation of dosing was seen in 10 of 21

Regulation FD Disclosure, Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 4, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporati

Sonnet BioTherapeutics Announces Publication Detailing the Discovery and Development of SON-1010, an Albumin-Binding IL-12 Fusion Protein, Demonstrating Its Mechanism of Action Pankaj Mohan, CEO of Sonnet discusses what this publication means in a Vi

Exhibit 99.1 Sonnet BioTherapeutics Announces Publication Detailing the Discovery and Development of SON-1010, an Albumin-Binding IL-12 Fusion Protein, Demonstrating Its Mechanism of Action Pankaj Mohan, CEO of Sonnet discusses what this publication means in a Virtual Investor “What This Means” segment; access here PRINCETON, NJ, December 4, 2024 (GLOBE NEWSWIRE) — Sonnet BioTherapeutics Holdings,

Filing Fee Table*

Exhibit 107 CALCULATION OF FILING FEE TABLE Form S-8 (Form Type) Sonnet BioTherapeutics Holdings, Inc.

As filed with the Securities and Exchange Commission on November 26, 2024

As filed with the Securities and Exchange Commission on November 26, 2024 Registration No.

Underwriting Agreement, dated November 6, 2024, between the Company and Chardan Capital Markets, LLC (incorporated by reference to Exhibit 1.1 to the Company’s Current Report on Form 8-K filed with the SEC on November 8, 2024).

Exhibit 1.1 EXECUTION VERSION SONNET BIOTHERAPEUTICS HOLDINGS, INC. UNDERWRITING AGREEMENT November 6, 2024 CHARDAN CAPITAL MARKETS, LLC 17 State Street, Suite 2100 New York, NY 10004 As Representative of the several Underwriters (as defined herein) Ladies and Gentlemen: Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (the “Company”), proposes, subject to the terms and conditions sta

Sonnet BioTherapeutics Announces Pricing of $5.0 Million Underwritten Public Offering Priced At-The-Market Under Nasdaq Rules

Exhibit 99.1 November 6, 2024 Sonnet BioTherapeutics Announces Pricing of $5.0 Million Underwritten Public Offering Priced At-The-Market Under Nasdaq Rules PRINCETON, NJ, Nov. 06, 2024 (GLOBE NEWSWIRE) - Sonnet BioTherapeutics Holdings, Inc. (the “Company” or “Sonnet”) (NASDAQ: SONN), a clinical-stage company developing innovative targeted immunotherapeutic drugs, today announced the pricing of an

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of report (Date of earliest event reported): November 6, 2024 SONNET BIOTHERAP

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of report (Date of earliest event reported): November 6, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact Name of Registrant as Specified in Charter) Delaware 001-35570 20-2932652 (State or Other Jurisdiction (Commission (IRS E

155,000 Shares of Common Stock 956,111 Pre-Funded Warrants to Purchase up to 956,111 Shares of Common Stock 1,111,111 Common Warrants to Purchase up to 2,222,222 Shares of Common Stock 956,111 Shares of Common Stock issuable upon exercise of the Pre-

Filed Pursuant to Rule 424(b)(4) Registration No. 333-282850 PROSPECTUS 155,000 Shares of Common Stock 956,111 Pre-Funded Warrants to Purchase up to 956,111 Shares of Common Stock 1,111,111 Common Warrants to Purchase up to 2,222,222 Shares of Common Stock 956,111 Shares of Common Stock issuable upon exercise of the Pre-Funded Warrants 2,222,222 Shares of Common Stock issuable upon exercise of the

Form of Pre-Funded Warrant (incorporated by reference to Exhibit 4.23 to the Company’s Registration Statement on Form S-1/A filed with the SEC on November 6, 2024).

Exhibit 4.23 FORM OF PRE-FUNDED WARRANT SONNET BIOTHERAPEUTICS HOLDINGS, INC. PRE-FUNDED WARRANT TO PURCHASE COMMON STOCK Warrant No.: [ ] Number of Shares of Common Stock: [ ] Date of Issuance: [ ] (“Issuance Date”) Sonnet BioTherapeutics Holdings, Inc., a company organized under the laws of Delaware (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and suff

Form of Underwriting Agreement.

Exhibit 1.1 SONNET BIOTHERAPEUTICS HOLDINGS, INC. UNDERWRITING AGREEMENT November [ ● ], 2024 CHARDAN CAPITAL MARKETS, LLC 17 State Street, Suite 2100 New York, NY 10004 As Representative of the several Underwriters (as defined herein) Ladies and Gentlemen: Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (the “Company”), proposes, subject to the terms and conditions stated herein, to

Form of Common Warrant (incorporated by reference to Exhibit 4.22 of the Company’s Registration Statement on Form S-1/A filed with the SEC on November 6, 2024).

Exhibit 4.22 FORM OF COMMON WARRANT SONNET BIOTHERAPEUTICS HOLDINGS, INC. WARRANT TO PURCHASE COMMON STOCK Warrant No.: [ ] Number of Shares of Common Stock: [ ] Date of Issuance: [ ], 2024 (“Issuance Date”) Sonnet BioTherapeutics Holdings, Inc., a company organized under the law of Delaware (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of

[Signature Page to Follow]

November 6, 2024 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Re: Sonnet BioTherapeutics Holdings, Inc. Registration Statement on Form S-1, as amended File No. 333-282850 Request for Acceleration of Effective Date Ladies and Gentlemen: Pursuant to Rule 461 of the General Rules and Regulations under the Securities Act of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 6, 2024 SONNET BIOTHERAP

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 6, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporati

November 6, 2024

November 6, 2024 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

November 6, 2024

November 6, 2024 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

[Signature Page to Follow]

November 6, 2024 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Re: Sonnet BioTherapeutics Holdings, Inc. Registration Statement on Form S-1, as amended File No. 333-282850 Request for Acceleration of Effective Date Ladies and Gentlemen: Pursuant to Rule 461 of the General Rules and Regulations under the Securities Act of

As filed with the Securities and Exchange Commission on November 6, 2024

As filed with the Securities and Exchange Commission on November 6, 2024 Registration No.

November 6, 2024

November 6, 2024 VIA EDGAR Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

Sonnet BioTherapeutics Announces Issuance of U.S. Patent Covering a Variant IL-18 Incorporated into Two Novel Immunotherapeutic Drug Candidates IL-18 has significant importance for cancer immune-oncology and combination with IL-12 on Sonnet’s FHAB pl

Exhibit 99.1 Sonnet BioTherapeutics Announces Issuance of U.S. Patent Covering a Variant IL-18 Incorporated into Two Novel Immunotherapeutic Drug Candidates Both novel bifunctional (SON-1411) and monofunctional (SON-1400) fusion proteins exhibit wild-type binding to the IL-18 receptor (IL-18Rc), coupled with undetectable binding to the inhibitory IL-18 binding protein (IL-18BP) IL-18 has significa

November 6, 2024

November 6, 2024 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

As filed with the Securities and Exchange Commission on November 4, 2024

As filed with the Securities and Exchange Commission on November 4, 2024 Registration No.

LETTER

October 30, 2024 Pankaj Mohan Chief Executive Officer Sonnet BioTherapeutics Holdings, Inc.

Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-1 (Form Type) Sonnet BioTherapeutics Holdings, Inc.

As filed with the Securities and Exchange Commission on October 28, 2024

As filed with the Securities and Exchange Commission on October 28, 2024 Registration No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 16, 2024 SONNET BIOTHERAP

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 16, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporati

Sonnet BioTherapeutics Inc. Regains Compliance with Nasdaq

Exhibit 99.1 Sonnet BioTherapeutics Inc. Regains Compliance with Nasdaq PRINCETON, NJ / Globe Newswire / October 17, 2024 / Sonnet BioTherapeutics Holdings, Inc. (the “Company” or “Sonnet”) (NASDAQ: SONN), a clinical-stage company developing targeted immunotherapeutic drugs, today announced that it received notice on October 16, 2024 from The Nasdaq Stock Market LLC (“Nasdaq”) that the Company reg

Regulation FD Disclosure, Entry into a Material Definitive Agreement, Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 8, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporatio

License Agreement, dated October 8, 2024, between Sonnet BioTherapeutics, Inc., Sonnet BioTherapeutics CH SA and Alkem Laboratories Limited (incorporated by reference to Exhibit 10.1 to the Company’s Current Report on Form 8-K filed with the SEC on October 9, 2024).

Exhibit 10.1 CERTAIN IDENTIFIED INFORMATION HAS BEEN EXCLUDED FROM THIS EXHIBIT BECAUSE IT IS BOTH NOT MATERIAL AND IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE OR CONFIDENTIAL. INFORMATION THAT WAS OMITTED HAS BEEN NOTED IN THIS DOCUMENT WITH A PLACEHOLDER IDENTIFIED BY THE MARK “[***]” LICENSE AGREEMENT between SONNET BIOTHERAPEUTICS, INC and ALKEM LABORATORIES LIMITED Dated as of October 8

Sonnet BioTherapeutics Inc. Enters into Licensing Agreement with Alkem Laboratories Limited to Develop and Commercialize SON-080 for Diabetic Peripheral Neuropathy (DPN) in India Sonnet to receive $1.0 million in upfront payment and up to an addition

Exhibit 99.1 Sonnet BioTherapeutics Inc. Enters into Licensing Agreement with Alkem Laboratories Limited to Develop and Commercialize SON-080 for Diabetic Peripheral Neuropathy (DPN) in India Sonnet to receive $1.0 million in upfront payment and up to an additional $1.0 million in milestone payments with a royalty in the low double digits on net sales, less certain expenses, in the India market Al

Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Material Modification to Rights of Security Holders, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 25, 2024 Sonnet BioTherapeutics Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorpora

Certificate of Amendment of Certificate of Incorporation, as amended, of Sonnet BioTherapeutics Holdings, Inc., dated September 25, 2024 (incorporated by reference to Exhibit 3.1 to the Company’s Current Report on Form 8-K, filed with the SEC on September 30, 2024).

Exhibit 3.1 CERTIFICATE OF AMENDMENT TO THE CERTIFICATE OF INCORPORATION OF SONNET BIOTHERAPEUTICS HOLDINGS, INC. Sonnet BioTherapeutics Holdings, Inc. (the “Corporation”), a corporation organized and existing under and by virtue of the General Corporation Law of the State of Delaware, does hereby certify as follows: FIRST: That a resolution was duly adopted on August 7, 2024, by the Board of Dire

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 18, 2024 SONNET BIOTHER

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 18, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorpora

Sonnet BioTherapeutics Completes Enrollment in Phase 1 Study of SON-1010 (IL12-FHAB) as a Monotherapy (SB101) for the Treatment of Solid Tumors SON-1010 is a targeted immune activation cancer therapy designed to turn ‘cold’ tumors ‘hot’ Topline safet

Exhibit 99.1 CONFIDENTIAL DRAFT NOT FOR IMMEDIATE RELEASE Sonnet BioTherapeutics Completes Enrollment in Phase 1 Study of SON-1010 (IL12-FHAB) as a Monotherapy (SB101) for the Treatment of Solid Tumors SON-1010 is a targeted immune activation cancer therapy designed to turn ‘cold’ tumors ‘hot’ Topline safety data of SB101 Phase 1 study expected by Q4 2024 PRINCETON, NJ / GlobeNewswire / September

Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 12, 2024 Sonnet BioTherapeutics Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorpora

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of report (Date of earliest event reported): September 9, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact Name of Registrant as Specified in Charter) Delaware 001-35570 20-2932652 (State or Other Jurisdiction (Commission (IRS

Corporate Presentation by Sonnet BioTherapeutics Holdings, Inc.

Exhibit 99.1

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 28, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction (Commission (IR

Sonnet BioTherapeutics Enters into Clinical Collaboration Agreement to Commence Investigator-Initiated and Funded Phase 1/2a Study of SON-1210 in Combination with Chemotherapy for the Treatment of Pancreatic Cancer Preclinical data has demonstrated t

Exhibit 99.1 Sonnet BioTherapeutics Enters into Clinical Collaboration Agreement to Commence Investigator-Initiated and Funded Phase 1/2a Study of SON-1210 in Combination with Chemotherapy for the Treatment of Pancreatic Cancer Preclinical data has demonstrated the potential of SON-1210, the first albumin-binding bifunctional IL-12/IL-15 fusion protein, for solid tumor immunotherapy An Innovative

Regulation FD Disclosure, Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 19, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporatio

ARS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ց ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended September 30, 2023 Or տ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET BIOTHE

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant To Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant To Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Defin

Sonnet BioTherapeutics Reports Third Quarter Fiscal Year 2024 Financial Results and Provides Corporate Update Ongoing progress with both clinical trials of lead program, SON-1010, for solid tumors and Platinum-Resistant Ovarian Cancer (PROC) Partners

Exhibit 99.1 Sonnet BioTherapeutics Reports Third Quarter Fiscal Year 2024 Financial Results and Provides Corporate Update Ongoing progress with both clinical trials of lead program, SON-1010, for solid tumors and Platinum-Resistant Ovarian Cancer (PROC) Partnership efforts to support initiation of a Phase 2 clinical trial of SON-080 in Diabetic Peripheral Neuropathy (DPN) underway Granted composi

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET BIO

Results of Operations and Financial Condition, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): August 14, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporatio

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 5, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction (Commission (IRS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant To Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant To Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☒ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Defin

Sonnet BioTherapeutics Reports Encouraging Data from Phase 1b/2a Clinical Trial of SON-080 in Chemotherapy-Induced Peripheral Neuropathy (CIPN) That Support Advancement into Phase 2 Study

Exhibit 99.1 Sonnet BioTherapeutics Reports Encouraging Data from Phase 1b/2a Clinical Trial of SON-080 in Chemotherapy-Induced Peripheral Neuropathy (CIPN) That Support Advancement into Phase 2 Study ● Data indicates that SON-080 was well-tolerated at both doses, with no evidence of a pro-inflammatory cytokine response ● Pain and quality of life survey results suggest the potential for rapid impr

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 24, 2024 SONNET BIOTHERAPEUT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 24, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

What this Means: Sonnet BioTherapeutics Data from SON-080 Phase 1b/2 Study in Chemotherapy Induced Peripheral Neuropathy (CIPN)

Exhibit 99.2 What this Means: Sonnet BioTherapeutics Data from SON-080 Phase 1b/2 Study in Chemotherapy Induced Peripheral Neuropathy (CIPN) Participants: ● Pankaj Mohan, PhD – Founder and Chief Executive Officer ● Richard Kenney, M.D. – Chief Medical Officer ● Gael Hedou, PhD – Chief Operating Officer Sonnet BioTherapeutics (Nasdaq: SONN) Introduction: Jenene Thomas ● Welcome back for another Wha

5,770,140 Shares of Common Stock Issuable Upon Exercise of Outstanding Warrants

Filed Pursuant to Rule 424(b)(3) Registration No. 333-280705 PROSPECTUS 5,770,140 Shares of Common Stock Issuable Upon Exercise of Outstanding Warrants This prospectus relates to the resale of up to 5,770,140 shares of Sonnet BioTherapeutics Holdings, Inc. (the “Company,” “we,” “our” or “us”) common stock, $0.0001 par value per share (the “Common Stock”), by the Selling Stockholders listed in this

July 11, 2024

July 11, 2024 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

LETTER

July 10, 2024 Pankaj Mohan, Ph.D. CEO and Chairman Sonnet BioTherapeutics Holdings, Inc. 100 Overlook Center, Suite 102 Princeton, New Jersey 08540 Re: Sonnet BioTherapeutics Holdings, Inc. Registration Statement on Form S-3 Filed July 5, 2024 File No. 333-280705 Dear Pankaj Mohan Ph.D.: This is to advise you that we have not reviewed and will not review your registration statement. Please refer t

Filing Fee Table.

EXHIBIT 107 Calculation of Filing Fee Tables Form S-3 (Form Type) Sonnet BioTherapeutics Holdings, Inc.

As filed with the Securities and Exchange Commission on July 5, 2024

As filed with the Securities and Exchange Commission on July 5, 2024 Registration No.

Form of Placement Agent Warrant (incorporated by reference to Exhibit 4.2 of the Company’s Current Report on Form 8-K filed with the SEC on June 20, 2024).

Exhibit 4.2 NEITHER THIS SECURITY NOR THE SECURITIES FOR WHICH THIS SECURITY IS EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTR

Form of Common Warrant (incorporated by reference to Exhibit 4.1 to the Company’s Current Report on Form 8-K filed with the SEC on June 20, 2024).

Exhibit 4.1 NEITHER THIS SECURITY NOR THE SECURITIES FOR WHICH THIS SECURITY IS EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTR

Sonnet BioTherapeutics Announces Exercise of Warrants for $3.4 Million in Gross Proceeds

Exhibit 99.1 Sonnet BioTherapeutics Announces Exercise of Warrants for $3.4 Million in Gross Proceeds PRINCETON, N.J., June 20, 2024 (GLOBE NEWSWIRE) – Sonnet BioTherapeutics Holdings, Inc. (NASDAQ:SONN) (the “Company” or “Sonnet”), a clinical-stage company developing targeted immunotherapeutic drugs, announced today the entry into a definitive agreement for the immediate exercise of certain outst

Entry into a Material Definitive Agreement, Material Modification to Rights of Security Holders, Unregistered Sales of Equity Securities, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 19, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

Form of Inducement Letter (incorporated by reference to Exhibit 10.1 to the Company’s Current Report on Form 8-K filed with the SEC on June 20, 2024).

Exhibit 10.1 SONNET BIOTHERAEPEUTICS HOLDINGS, INC. June 19, 2024 Holder of Common Stock Purchase Warrants issued on October 27, 2023 Re: Inducement Offer to Exercise Common Stock Purchase Warrants Dear Holder: Sonnet BioTherapeutics Holdings, Inc. (the “Company”) is pleased to offer to you the opportunity to exercise all of the Common Stock Purchase Warrants to purchase an aggregate of 2,828,500

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of report (Date of earliest event reported): June 13, 2024 SONNET BIOTHERAPEUT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of report (Date of earliest event reported): June 13, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact Name of Registrant as Specified in Charter) Delaware 001-35570 20-2932652 (State or Other Jurisdiction (Commission (IRS Empl

Presentation by Sonnet BioTherapeutics Holdings, Inc., dated June 13, 2024

Exhibit 99.1

Sonnet BioTherapeutics Announces the Generation and Characterization of Two Novel Immunotherapeutic Pipeline Drug Candidates, SON-1411 and SON-1400, Each Containing a Variant IL-18 Domain

Exhibit 99.1 Sonnet BioTherapeutics Announces the Generation and Characterization of Two Novel Immunotherapeutic Pipeline Drug Candidates, SON-1411 and SON-1400, Each Containing a Variant IL-18 Domain ● Sonnet discovered and characterized a modified version of Interleukin-18 (IL-18Binding Protein Resistant or IL-18BPR) that exhibits wild-type binding to the IL-18 receptor (IL-18Rc), coupled with u

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 13, 2024 SONNET BIOTHERAPEUT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 13, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

Sonnet BioTherapeutics Announces Review of Strategic Alternatives

Exhibit 99.1 Sonnet BioTherapeutics Announces Review of Strategic Alternatives PRINCETON, NJ / ACCESSWIRE / May 22, 2024 / Sonnet BioTherapeutics Holdings, Inc. (NASDAQ:SONN) (the “Company” or “Sonnet”), a clinical-stage company developing targeted immunotherapeutic drugs, announced today that its Board of Directors has initiated a process to explore and review a range of strategic alternatives fo

Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 22, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

Regulation FD Disclosure, Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 20, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

Sonnet BioTherapeutics Announces Updated Clinical Data for SON-1010 as Monotherapy or Combined with an anti-PD-L1, along with an Increase in the Dose-Escalation Target

Exhibit 99.1 Sonnet BioTherapeutics Announces Updated Clinical Data for SON-1010 as Monotherapy or Combined with an anti-PD-L1, along with an Increase in the Dose-Escalation Target ● The SON-1010 studies have together enrolled 61 subjects, to date, as dose escalation continues in SB101 and SB221 at higher levels ● Patients have received up to 25 cycles of SON-1010 as monotherapy and 10 cycles of S

Up to 5,000,000 Shares of Common Stock

Filed Pursuant to Rule 424(b)(3) Registration No. 333-279095 PROSPECTUS Up to 5,000,000 Shares of Common Stock This prospectus relates to the potential offer and sale from time to time by Chardan Capital Markets LLC (“Chardan” or the “Selling Securityholder”) of up to 5,000,000 shares of our common stock, $0.0001 par value per share (“Common Stock”), that have been or may be issued by us to Charda

May 15, 2024

May 15, 2024 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

As filed with the Securities and Exchange Commission on May 15, 2024

As filed with the Securities and Exchange Commission on May 15, 2024 Registration No.

Sonnet BioTherapeutics Holdings, Inc. Consolidated Balance Sheets (unaudited)

Exhibit 99.1 Sonnet BioTherapeutics Provides Fiscal Year 2024 Second Quarter and Year-to-Date Business and Earnings Update ● Published Phase 1 data of SON-1010 in Frontiers in Immunology demonstrating the safety and tolerability of the FHAB-derived Interleukin 12 in healthy volunteers ● Announced early safety data from the company’s Phase 1b/2a clinical trial of SON-080 in patients with chemothera

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET BI

Presentation by Sonnet BioTherapeutics Holdings, Inc., dated May 14, 2024

Exhibit 99.1

Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of report (Date of earliest event reported): May 14, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact Name of Registrant as Specified in Charter) Delaware 001-35570 20-2932652 (State or Other Jurisdiction (Commission (IRS Emplo

Results of Operations and Financial Condition, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): May 14, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

LETTER

United States securities and exchange commission logo May 9, 2024 Pankaj Mohan, Ph.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 2, 2024 SONNET BIOTHERAPEUTIC

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 2, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation) (

Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-1 (Form Type) Sonnet BioTherapeutics Holdings, Inc.

ChEF Purchase Agreement, dated as of May 2, 2024, by and between Sonnet BioTherapeutics Holdings, Inc. and Chardan Capital Markets, LLC (incorporated by reference to Exhibit 10.1 to the Company’s Current Report on Form 8-K filed with the SEC on May 3, 2024).

Exhibit 10.1 Execution Version ChEF PURCHASE AGREEMENT This ChEF PURCHASE AGREEMENT is made and entered into as of May 2, 2024 (together with Annex I, this “Agreement”), by and between Chardan Capital Markets LLC, a New York limited liability company (the “Investor”), and Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (the “Company”). RECITALS WHEREAS, the parties desire that, upon

As filed with the Securities and Exchange Commission on May 3, 2024

As filed with the Securities and Exchange Commission on May 3, 2024 Registration No.

Registration Rights Agreement, dated as of May 2, 2024, by and between Sonnet BioTherapeutics Holdings, Inc. and Chardan Capital Markets, LLC (incorporated by reference to Exhibit 10.2 to the Company’s Current Report on Form 8-K filed with the SEC on May 3, 2024).

Exhibit 10.2 Execution Version REGISTRATION RIGHTS AGREEMENT THIS REGISTRATION RIGHTS AGREEMENT (this “Agreement”), dated as of May 2, 2024 is by and between Chardan Capital Markets LLC, a New York limited liability company (the “Investor”), and Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (the “Company”). RECITALS The Company and the Investor have entered into that certain ChEF P

Sonnet BioTherapeutics Announces Early Safety Data from the Company’s Phase 1b/2a Clinical Trial of SON-080 in Chemotherapy-Induced Peripheral Neuropathy (CIPN) Met the Study’s Initial Pre-Specified Objective

Exhibit 99.1 Sonnet BioTherapeutics Announces Early Safety Data from the Company’s Phase 1b/2a Clinical Trial of SON-080 in Chemotherapy-Induced Peripheral Neuropathy (CIPN) Met the Study’s Initial Pre-Specified Objective ● Safety in the Phase 1b part of Sonnet’s double-blind, randomized, controlled trial of SON-080 was reviewed by the study’s Data Safety Monitoring Board (DSMB) ● The adverse even

Regulation FD Disclosure, Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 Or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 11, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction (Commission (IRS

Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 6, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporation)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended December 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET

Sonnet BioTherapeutics Provides Fiscal Year 2024 First Quarter Business and Earnings Update

Exhibit 99.1 Sonnet BioTherapeutics Provides Fiscal Year 2024 First Quarter Business and Earnings Update ● Successfully raised approximately $4.55 million in gross proceeds through an underwritten public offering ● Extensive preclinical data on SON-1210 published in Frontiers in Immunology ● Received approval and executed agreement to sell New Jersey state net operating losses (NOLs) for expected

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): February 14, 2024 SONNET BIOTHERA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): February 14, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 1, 2024 SONNET BIOTHERAP

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 1, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporati

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 24, 2024 SONNET BIOTHERAP

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 24, 2024 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporati

January 3, 2024

January 3, 2024 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

US83548R3030 / SONNET BIOTHERAP / Markey John Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)* Sonnet BioTherapeutics Holdings, Inc. (Name of Issuer) COM NEW (Title of Class of Securities) 83548R303 (CUSIP Number) January 02, 2024 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to wh

LETTER

United States securities and exchange commission logo December 29, 2023 Pankaj Mohan, Ph.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 27, 2023 SONNET BIOTHERA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 27, 2023 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporat

As filed with the Securities and Exchange Commission on December 22, 2023

As filed with the Securities and Exchange Commission on December 22, 2023  Registration No.

Form of Senior Note (included in Exhibit 4.5).*

Exhibit 4.5 SONNET BIOTHERAPEUTICS HOLDINGS, INC., as Issuer and ● , as Trustee INDENTURE Dated as of ● Senior Debt Securities CROSS REFERENCE SHEET1 Between Provisions of the Trust Indenture Act of 1939 and the Indenture to be dated as of , 20 between SONNET BIOTHERAPEUTICS HOLDINGS, INC. and , as Trustee: Section of the Act Section of Indenture 310(a)(1) and (2) 5.08 310(a)(3) and (4) Inapplicab

Form of Subordinated Note (included in Exhibit 4.6).*

Exhibit 4.6 SONNET BIOTHERAPEUTICS HOLDINGS, INC., as Issuer and ●, as Trustee INDENTURE Dated as of ● Subordinated Debt Securities CROSS REFERENCE SHEET1 Between Provisions of the Trust Indenture Act of 1939 and the Indenture to be dated as of , 20 between SONNET BIOTHERAPEUTICS HOLDINGS, INC. and , as Trustee: Section of the Act Section of Indenture 310(a)(1) and (2) 5.08 310(a)(3) and (4) Inapp

Filing Fee table*

Exhibit 107 Calculation of Filing Fee Tables Form S-3 (Form Type) Sonnet BioTherapeutics Holdings, Inc.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 15, 2023 SONNET BIOTHERA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 15, 2023 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended September 30, 2023 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-35570 SONNET BIOTHE

Sonnet BioTherapeutics Provides Fiscal Year 2023 Business and Financial Update

Exhibit 99.1 Sonnet BioTherapeutics Provides Fiscal Year 2023 Business and Financial Update PRINCETON, NJ / ACCESSWIRE / December 14, 2023 / Sonnet BioTherapeutics Holdings, Inc. (NASDAQ:SONN) (“Sonnet” or the “Company”), a biopharmaceutical company developing innovative targeted biologic drugs focused on oncology, announced today its financial results for the fiscal year ended September 30th, 202

Subsidiaries of the Company (incorporated by reference to Exhibit 21.1 to the Company’s Annual Report on Form 10-K filed with the SEC on December 14, 2023).

Exhibit 21.1 Subsidiaries of Sonnet BioTherapeutics Holdings, Inc. Name: Jurisdiction of Organization Sonnet BioTherapeutics, Inc. New Jersey Sonnet BioTherapeutics CH SA Switzerland SonnetBio Pty Ltd Australia

Clawback Policy*

Exhibit 97.1 SONNET BIOTHERAPEUTICS, INC. COMPENSATION RECOVERY POLICY (Adopted and approved on November 21, 2023) 1. Purpose Sonnet BioTherapeutics, Inc. (collectively with its subsidiaries, the “Company”) is committed to promoting high standards of honest and ethical business conduct and compliance with applicable laws, rules and regulations. As part of this commitment, the Company has adopted t

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): December 14, 2023 SONNET BIOTHERA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): December 14, 2023 SONNET BIOTHERAPEUTICS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 001-35570 20-2932652 (State or other jurisdiction of incorporat

Description of Securities*

Exhibit 4.8 DESCRIPTION OF SONNET BIOTHERAPEUTICS HOLDINGS, INC.’S SECURITIES REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934 As of September 30, 2023, Sonnet BioTherapeutics Holdings, Inc. (the “Company”) had two classes of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended: our voting common stock, $0.0001 par value per share and pr

SONN / Sonnet BioTherapeutics Holdings Inc / Markey John - 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)* Sonnet BioTherapeutics Holdings, Inc. (Name of Issuer) COM NEW (Title of Class of Securities) 83548R303 (CUSIP Number) November 17, 2023 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to w

SONN / Sonnet BioTherapeutics Holdings Inc / Markey John - AMENDED 13G Passive Investment

SC 13G/A 1 sonna1110623.htm AMENDED 13G UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)* Sonnet BioTherapeutics Holdings, Inc. (Name of Issuer) COM NEW (Title of Class of Securities) 83548R303 (CUSIP Number) November 06, 2023 (Date of Event which Requires Filing of this Statement) Check the appropriate

1,306,250 Shares of Common Stock 1,537,500 Pre-Funded Warrants to Purchase up to 1,537,500 Shares of Common Stock 5,687,500 Common Warrants to Purchase up to 5,687,500 Shares of Common Stock 85,312 Underwriter Warrants to Purchase up to 85,312 Shares

Filed Pursuant to Rule 424(b)(4) Registration No. 333-274581 PROSPECTUS 1,306,250 Shares of Common Stock 1,537,500 Pre-Funded Warrants to Purchase up to 1,537,500 Shares of Common Stock 5,687,500 Common Warrants to Purchase up to 5,687,500 Shares of Common Stock 85,312 Underwriter Warrants to Purchase up to 85,312 Shares of Common Stock 1,537,500 Shares of Common Stock issuable upon exercise of th

October 23, 2023

October 23, 2023 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

October 23, 2023

October 23, 2023 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Attention: Mr. Dillon Hagius Re: Sonnet BioTherapeutics Holdings, Inc. Registration Statement on Form S-1 File No. 333-274581 REQUEST FOR ACCELERATION OF EFFECTIVENESS Requested Date: October 24, 2023 Requested Time: 4:30 pm, Eastern Time Ladies and Gentlemen:

As filed with the Securities and Exchange Commission on October 19, 2023

As filed with the Securities and Exchange Commission on October 19, 2023 Registration No.

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-1 (Form Type) Sonnet BioTherapeutics Holdings, Inc.

Form of Underwriting Agreement

Exhibit 1.1 SONNET BIOTHERAPEUTICS HOLDINGS, INC. UNDERWRITING AGREEMENT October [ · ], 2023 CHARDAN CAPITAL MARKETS, LLC 17 State Street, Suite 2100 New York, NY 10004 LADENBURG THALMANN & CO. INC. 640 5th Avenue, 4th Floor New York, NY 10019 As Representatives of the several Underwriters (as defined herein) Ladies and Gentlemen: Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (the

As filed with the Securities and Exchange Commission on October 4, 2023

As filed with the Securities and Exchange Commission on October 4, 2023 Registration No.

September 28, 2023

September 28, 2023 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Attention: Mr. Dillon Hagius Re: Sonnet BioTherapeutics Holdings, Inc. Registration Statement on Form S-1 File No. 333-274581 REQUEST FOR ACCELERATION OF EFFECTIVENESS Requested Date: September 28, 2023 Requested Time: 4:30 pm, Eastern Time Ladies and Gentlem

Form of Underwriting Agreement

Exhibit 1.1 SONNET BIOTHERAPEUTICS HOLDINGS, INC. UNDERWRITING AGREEMENT [ ], 2023 CHARDAN CAPITAL MARKETS, LLC 17 State Street, Suite 2100 New York, NY 10004 LADENBURG THALMANN & CO. INC. 640 5th Avenue, 4th Floor New York, NY 10019 As Representatives of the several Underwriters (as defined herein) Ladies and Gentlemen: Sonnet BioTherapeutics Holdings, Inc., a Delaware corporation (the “Company”)

September 28, 2023

September 28, 2023 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

Form of Underwriter Warrant (filed as Exhibit 4.15 to the Company’s Registration Statement on Form S-1/A as filed on September 28, 2023, and incorporated herein by reference).

Exhibit 4.15 FORM OF UNDERWRITER WARRANT SONNET BIOTHERAPEUTICS HOLDINGS, INC. Warrant Shares: Initial Exercise Date: [●], 2023 Issue Date: [●], 2023 THIS COMMON STOCK PURCHASE WARRANT (the “Warrant”) certifies that, for value received, [Chardan Capital Markets, LLC (“Chardan”)] [Ladenburg Thalmann & Co., Inc. (“Ladenburg”)], or its assigns (the “Holder”) is entitled, upon the terms and subject to

Form of Pre-Funded Warrant (filed as Exhibit 4.14 to the Company’s Registration Statement on Form S-1/A as filed on September 28, 2023, and incorporated herein by reference).

Exhibit 4.14 FORM OF PRE-FUNDED WARRANT SONNET BIOTHERAPEUTICS HOLDINGS, INC. PRE-FUNDED WARRANT TO PURCHASE COMMON STOCK Warrant No.: [ ] Number of Shares of Common Stock: [ ] Date of Issuance: [ ] (“Issuance Date”) Sonnet BioTherapeutics Holdings, Inc., a company organized under the laws of Delaware (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and suff

As filed with the Securities and Exchange Commission on September 28, 2023

As filed with the Securities and Exchange Commission on September 28, 2023 Registration No.

Form of Common Warrant (filed as Exhibit 4.16 to the Company’s Registration Statement on Form S-1/A as filed on September 28, 2023, and incorporated herein by reference).

Exhibit 4.16 FORM OF COMMON WARRANT SONNET BIOTHERAPEUTICS HOLDINGS, INC. WARRANT TO PURCHASE COMMON STOCK Warrant No.: [ ] Number of Shares of Common Stock: [ ] Date of Issuance: [ ], 2023 (“Issuance Date”) Sonnet BioTherapeutics Holdings, Inc., a company organized under the law of Delaware (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of

September 28, 2023

September 28, 2023 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

September 28, 2023

September 28, 2023 VIA EDGAR CORRESPONDENCE U.S. Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Attention: Mr. Dillon Hagius Re: Sonnet BioTherapeutics Holdings, Inc. Registration Statement on Form S-1 Filed September 28, 2023 File No. 333-274581 WITHDRAWAL OF REQUEST FOR ACCELERATION OF EFFECTIVENESS Dear Mr. Hagius: Reference is made

LETTER

United States securities and exchange commission logo September 26, 2023 Pankaj Mohan, Ph.

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-1 (Form Type) Sonnet BioTherapeutics Holdings, Inc.