| Item 1. | |
| (a) | Name of issuer:
SELLAS Life Sciences Group, Inc. |
| (b) | Address of issuer's principal executive offices:
7 Times Square, Suite 2503, New York, NY 10036 |
| Item 2. | |
| (a) | Name of person filing:
This statement is filed by Highbridge Capital Management, LLC ("Highbridge" or the "Reporting Person"), a Delaware limited liability company and the investment adviser to certain funds and accounts (the "Highbridge Funds"), with respect to the shares of common stock, par value $0.0001 per share ("Common Stock"), of SELLAS Life Sciences Group, Inc., a Delaware corporation (the "Issuer"), issuable upon exercise of warrants directly held by the Highbridge Funds.
The filing of this statement should not be construed as an admission that any of the foregoing persons or the Reporting Person is, for the purposes of Section 13 of the Securities Exchange Act of 1934, the beneficial owner of the securities reported herein. |
| (b) | Address or principal business office or, if none, residence:
The address of the business office of the Reporting Person is 390 Madison Avenue, 28th Floor, New York, NY 10017. |
| (c) | Citizenship:
Highbridge is a Delaware limited liability company. |
| (d) | Title of class of securities:
Common Stock, par value $0.0001 per share |
| (e) | CUSIP No.:
81642T209 |
| Item 3. | If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: |
| (a) |  Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
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| (b) | Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
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| (c) | Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
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| (d) | Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
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| (e) |  An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
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| (f) | An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
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| (g) | A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
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| (h) | A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
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| (i) | A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
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| (j) | A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
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| (k) | Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
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| Item 4. | Ownership |
| (a) | Amount beneficially owned:
The information required by Item 4(a) is set forth in Row 9 of the cover page for the Reporting Person and is incorporated herein by reference.
The percentage set forth in this Schedule 13G as of December 31, 2025 is calculated based upon an aggregate of 142,442,239 shares of Common Stock outstanding as of November 11, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2025, filed with the Securities and Exchange Commission on November 12, 2025, and assumes the exercise of the warrants held by the Highbridge Funds. The percentage set forth in this Schedule 13G as of the date hereof is calculated based upon an aggregate of 170,282,026 shares of Common Stock outstanding as of January 7, 2026, as reported in the Issuer's Current Report on Form 8-K, filed with the Securities and Exchange Commission on January 8, 2026, and assumes the exercise of the warrants held by the Highbridge Funds. |
| (b) | Percent of class:
3.7% |
| (c) | Number of shares as to which the person has:
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| | (i) Sole power to vote or to direct the vote:
The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for the Reporting Person and is incorporated herein by reference.
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| | (ii) Shared power to vote or to direct the vote:
The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for the Reporting Person and is incorporated herein by reference.
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| | (iii) Sole power to dispose or to direct the disposition of:
The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for the Reporting Person and is incorporated herein by reference.
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| | (iv) Shared power to dispose or to direct the disposition of:
The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for the Reporting Person and is incorporated herein by reference.
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| Item 5. | Ownership of 5 Percent or Less of a Class. |
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Ownership of 5 percent or less of a class
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| Item 6. | Ownership of more than 5 Percent on Behalf of Another Person. |
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If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
See Item 2(a). The Highbridge Funds have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the shares of Common Stock reported herein. |
| Item 7. | Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person. |
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Not Applicable
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| Item 8. | Identification and Classification of Members of the Group. |
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Not Applicable
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| Item 9. | Notice of Dissolution of Group. |
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Not Applicable
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