Abivax S.A.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 20-F

(Mark One)

☐ REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES

OR

☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE

ACT OF 1934

For the fiscal year ended December 31, 2024

OR

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES

OR

☐ SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES

Date of event requiring this shell company report

Commission file number:001-41842

Abivax SA

(Exact name of Registrant as specified in its charter and translation of Registrant’s name into English)

France

(Jurisdiction of incorporation or organization)

7-11 boulevard Haussmann

75009 Paris, France

(Address of principal executive offices)

Marc de Garidel

Chief Executive Officer

7-11 boulevard Haussmann

75009 Paris, France

Tel:+33 (0)1 53 83 09 63

info@abivax.com

(Name, Telephone, Email and/or Facsimile number and Address of Company Contact Person)

Securities registered or to be registered pursuant to Section 12(b) of the Act.

*Not for trading, but only in connection with the registration of the American Depositary Shares.

Securities registered or to be registered pursuant to Section 12(g) of the Act. None

Securities for which there is a reporting obligation pursuant to Section 15(d) of the Act. None

Indicate the number of outstanding shares of each of the issuer’s classes of capital or common stock as of the close

of the period covered by the annual report.

Ordinary shares:63,347,837 shares outstanding as of December 31, 2024

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities

Act.☐ Yes☒ No

If this report is an annual or transition report, indicate by check mark if the registrant is not required to file reports

pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934.☐ Yes☒ No

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of

the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant

was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.☒ Yes ☐

No

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be

submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for

such shorter period that the registrant was required to submit such files).☒ Yes ☐ No

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer,

or an emerging growth company. See definition of “large accelerated filer,” “accelerated filer,” and “emerging

growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, indicate by

check mark if the registrant has elected not to use the extended transition period for complying with any new or

revised financial accounting standards† provided pursuant to Section 13(a) of the Exchange Act.☐

† The term “new or revised financial accounting standard” refers to any update issued by the Financial Accounting

Standards Board to its Accounting Standards Codification after April 5, 2012.

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of

the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15

U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial

statements of the registrant included in the filing reflect the correction of an error to previously issued financial

statements.☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of

incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery

period pursuant to §240.10D-1(b).☐

Indicate by check mark which basis of accounting the registrant has used to prepare the financial statements

included in this filing:

U.S. GAAP☐

International Financial Reporting Standards as issued by the International Accounting Standards Board☒ Other☐

If “Other” has been checked in response to the previous question, indicate by check mark which financial statement

item the registrant has elected to follow.☐ Item 17☐ Item 18

If this is an annual report, indicate by check mark whether the registrant is a shell company (as defined in Rule

12b-2 of the Exchange Act).☐ Yes☒ No

TABLE OF CONTENTS

INTRODUCTION