Abivax S.A. (ABVX) investors report 6.0% beneficial stake via Invus entities

Rhea-AI Filing Summary

Abivax S.A. has a significant shareholder group led by Invus Public Equities, L.P. and affiliated entities, which collectively report beneficial ownership of approximately 6.0% of Abivax’s Ordinary Shares as of June 30, 2026. This ownership is held through a combination of Ordinary Shares and American Depositary Shares.

Invus Public Equities beneficially holds 4,790,187 Shares, represented by 4,249,759 Ordinary Shares and 540,428 ADSs, while Avicenna Life Sci Master Fund LP holds 35,572 ADSs, with each ADS representing one Ordinary Share. Based on 79,800,669 Shares outstanding as of June 26, 2026, each reporting person is shown with 6.0% beneficial ownership. The reporting group certifies that the securities are held without the purpose or effect of changing or influencing control of Abivax S.A.

Key Figures

Invus Public Equities beneficial ownership: 4,790,187 Shares Avicenna Fund ADS holdings: 35,572 ADSs Total beneficial ownership for Raymond Debbane: 4,825,759 Shares +2 more

5 metrics

Invus Public Equities beneficial ownership 4,790,187 Shares Ordinary Shares and ADSs beneficially held as of June 30, 2026

Avicenna Fund ADS holdings 35,572 ADSs ADSs of Abivax S.A., each representing one Ordinary Share

Total beneficial ownership for Raymond Debbane 4,825,759 Shares Shares he may be deemed to beneficially own through controlled entities

Ownership percentage 6.0 % Beneficial ownership of Abivax Ordinary Shares for each reporting person

Shares outstanding baseline 79,800,669 Shares Ordinary Shares outstanding as of June 26, 2026, used for percentage calculations

Key Terms

American Depositary Shares, beneficially own, sole voting power, sole dispositive power, +1 more

5 terms

American Depositary Shares financial

"540,428 American Depositary Shares ("ADSs"), each of which ADS represents one Share"

American depositary shares (ADSs) are a way for investors in the United States to buy shares of foreign companies without dealing with international markets directly. They represent ownership in a foreign company's stock and are traded on U.S. stock exchanges, making it easier for American investors to buy, sell, and own parts of companies from around the world.

beneficially own financial

"may be deemed to beneficially own the Shares beneficially held by Invus Public Equities"

Beneficially own means having the economic rights and risks of a security—such as the right to receive dividends, sell the shares, or profit from price changes—whether or not your name appears on the official share register. Think of it like renting a car: you use it and reap the benefits even if the title lists someone else. Investors care because beneficial ownership determines who truly controls value, must be disclosed under securities rules, and can signal potential influence or trading activity that affects a stock’s price.

sole voting power financial

"5 | Sole Voting Power 4,790,187.00 6 | Shared Voting Power 0.00"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

sole dispositive power financial

"7 | Sole Dispositive Power 4,790,187.00 8 | Shared Dispositive Power 0.00"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

Ordinary Shares, nominal value Euro 0.01 per share financial

"Ordinary Shares, nominal value Euro 0.01 per share (the "Shares")"

FAQ

What percentage of Abivax S.A. (ABVX) does the Invus group report owning?

The Invus-related reporting persons collectively report beneficial ownership of 6.0% of Abivax S.A.’s Ordinary Shares, based on 79,800,669 Shares outstanding as of June 26, 2026, as referenced in the company’s Form 424(b)(5).

How many Abivax S.A. (ABVX) shares does Invus Public Equities hold?

Invus Public Equities, L.P. beneficially holds 4,790,187 Shares of Abivax S.A., consisting of 4,249,759 Ordinary Shares and 540,428 American Depositary Shares (ADSs), with each ADS representing one Ordinary Share of Abivax.

What is Raymond Debbane’s reported beneficial ownership in Abivax S.A. (ABVX)?

Raymond Debbane is reported as beneficially owning 4,825,759 Shares of Abivax S.A., reflecting control relationships over Invus and Avicenna entities. This represents 6.0% of the company’s Ordinary Shares, based on the reported outstanding share count.

How many Abivax S.A. (ABVX) ADSs does Avicenna Life Sci Master Fund LP hold?

Avicenna Life Sci Master Fund LP holds 35,572 American Depositary Shares (ADSs) of Abivax S.A. Each ADS represents one Ordinary Share with a nominal value of Euro 0.01 per share of Abivax S.A.

On what share count is the 6.0% Abivax S.A. (ABVX) ownership calculation based?

The reported 6.0% beneficial ownership is calculated using 79,800,669 Ordinary Shares outstanding as of June 26, 2026, as reported by Abivax S.A. in its Form 424(b)(5) filed on July 2, 2026.

Is the Invus group seeking control of Abivax S.A. (ABVX) with this 6.0% stake?

The reporting persons certify that the securities were not acquired and are not held for the purpose or effect of changing or influencing the control of Abivax S.A., indicating a passive investment posture under this filing.

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Available on EDGAR 08/13/2026 - 10:55 AM Accepted by SEC EDGAR 08/13/2026 - 10:55 AM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 2)

Abivax S.A.

(Name of Issuer)

Ordinary Shares, nominal value Euro 0.01 per share

(Title of Class of Securities)

00370M103

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 00370M103

1

Names of Reporting Persons

Invus Public Equities, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

BERMUDA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 4,790,187.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,790,187.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,790,187.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.0 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: Invus Public Equities, L.P. holds an aggregate of 4,249,759 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares"), and 540,428 American Depositary Shares ("ADSs"), each of which ADS represents one Share of Abivax S.A. (the "Issuer").

SCHEDULE 13G

CUSIP Number(s): 00370M103

1

Names of Reporting Persons

Invus Public Equities Advisors, LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 4,790,187.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,790,187.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,790,187.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.0 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Invus Public Equities, L.P. holds an aggregate of 4,249,759 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares"), and 540,428 American Depositary Shares ("ADSs"), each of which ADS represents one Share of Abivax S.A. (the "Issuer").

SCHEDULE 13G

CUSIP Number(s): 00370M103

1

Names of Reporting Persons

Invus Global Management, LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 4,790,187.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,790,187.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,790,187.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.0 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Invus Public Equities, L.P. holds an aggregate of 4,249,759 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares"), and 540,428 American Depositary Shares ("ADSs"), each of which ADS represents one Share of Abivax S.A. (the "Issuer").

SCHEDULE 13G

CUSIP Number(s): 00370M103

1

Names of Reporting Persons

Siren, L.L.C.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 4,790,187.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,790,187.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,790,187.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.0 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Invus Public Equities, L.P. holds an aggregate of 4,249,759 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares"), and 540,428 American Depositary Shares ("ADSs"), each of which ADS represents one Share of Abivax S.A. (the "Issuer").

SCHEDULE 13G

CUSIP Number(s): 00370M103

1

Names of Reporting Persons

Avicenna Life Sci Master Fund LP

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 35,572.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 35,572.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

35,572.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0.0 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: Avicenna Life Sci Master Fund LP holds an aggregate of 35,572 American Depositary Shares ("ADSs"), each of which ADS represents one Ordinary Share, nominal value Euro 0.01 per share (the "Shares"), of Abivax S.A. (the "Issuer").

SCHEDULE 13G

CUSIP Number(s): 00370M103

1

Names of Reporting Persons

Avicenna Life Sci Master GP LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 35,572.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 35,572.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

35,572.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0.0 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Avicenna Life Sci Master Fund LP holds an aggregate of 35,572 American Depositary Shares ("ADSs"), each of which ADS represents one Ordinary Share, nominal value Euro 0.01 per share (the "Shares"), of Abivax S.A. (the "Issuer").

SCHEDULE 13G

CUSIP Number(s): 00370M103

1

Names of Reporting Persons

Ulys, L.L.C.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 35,572.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 35,572.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

35,572.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0.0 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Avicenna Life Sci Master Fund LP holds an aggregate of 35,572 American Depositary Shares ("ADSs"), each of which ADS represents one Ordinary Share, nominal value Euro 0.01 per share (the "Shares"), of Abivax S.A. (the "Issuer").

SCHEDULE 13G

CUSIP Number(s): 00370M103

1

Names of Reporting Persons

Raymond Debbane

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

PANAMA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 4,825,759.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,825,759.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,825,759.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.0 %

12

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person: Invus Public Equities, L.P. holds an aggregate of 4,249,759 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares"), and 540,428 American Depositary Shares ("ADSs"), and Avicenna Life Sci Master Fund LP holds an aggregate of 35,572 ADSs, each of which ADS represents one Share of Abivax S.A. (the "Issuer").

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Abivax S.A.
(b)	Address of issuer's principal executive offices: 7-11 boulevard Haussmann, 75009 Paris, France
Item 2.
(a)	Name of person filing: See Item 2(c) below.
(b)	Address or principal business office or, if none, residence: See Item 2(c) below.
(c)	Citizenship: (i) Invus Public Equities, L.P. ("Invus Public Equities") 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Bermuda limited partnership (ii) Invus Public Equities Advisors, LLC ("Invus PE Advisors") 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Delaware limited liability company (iii) Invus Global Management, LLC ("Global Management") 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Delaware limited liability company (iv) Siren, L.L.C. ("Siren") c/o The Invus Group, LLC, 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Delaware limited liability company (v) Avicenna Life Sci Master Fund LP ("Avicenna Fund") 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Cayman Islands limited partnership (vi) Avicenna Life Sci Master GP LLC ("Avicenna GP") 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Delaware limited liability company (vii) Ulys, L.L.C. ("Ulys") 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Delaware limited liability company (viii) Mr. Raymond Debbane 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Panama The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons."
(d)	Title of class of securities: Ordinary Shares, nominal value Euro 0.01 per share
(e)	CUSIP No.: 00370M103
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);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(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);
(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:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: As of June 30, 2026, Invus Public Equities beneficially held 4,790,187 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares") of Abivax S.A. (the "Issuer"), represented by (i) 4,249,759 Shares and (ii) 540,428 American Depositary Shares ("ADSs") directly held by Invus Public Equities, and Avicenna Fund directly held 35,572 ADSs. Each ADS represents one Share. Invus PE Advisors, as the general partner of Invus Public Equities, controls Invus Public Equities and, accordingly, may be deemed to beneficially own the Shares beneficially held by Invus Public Equities. Global Management, as the managing member of Invus PE Advisors, controls Invus PE Advisors and, accordingly, may be deemed to beneficially own the Shares that Invus PE Advisors may be deemed to beneficially own. Siren, as the managing member of Global Management, controls Global Management and, accordingly, may be deemed to beneficially own the Shares that Global Management may be deemed to beneficially own. Avicenna GP, as the general partner of Avicenna Fund, controls Avicenna Fund and, accordingly, may be deemed to beneficially own the Shares beneficially held by Avicenna Fund. Ulys, as the managing member of Avicenna GP, controls Avicenna GP and, accordingly, may be deemed to beneficially own the Shares that Avicenna GP may be deemed to beneficially own. Mr. Raymond Debbane, as the managing member of Siren and Ulys, controls Siren and Ulys and, accordingly, may be deemed to beneficially own the Shares that Siren and Ulys may be deemed to beneficially own.
(b)	Percent of class: As of June 30, 2026, each of the Reporting Persons may be deemed to be the beneficial owner of the Shares listed on such Reporting Person's cover page. Calculations of the percentage of Shares beneficially owned are based on 79,800,669 Shares outstanding as of June 26, 2026, as reported in the Issuer's Form 424(b)(5) filed with the Securities and Exchange Commission on July 2, 2026.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See each cover page hereof.
	(ii) Shared power to vote or to direct the vote: See each cover page hereof.
	(iii) Sole power to dispose or to direct the disposition of: See each cover page hereof.
	(iv) Shared power to dispose or to direct the disposition of: See each cover page hereof.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

Each of the Reporting Persons hereby makes the following certification: By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Invus Public Equities, L.P.

Signature:	/s/ Raymond Debbane
Name/Title:	Raymond Debbane, President of Invus Public Equities Advisors, LLC, its general partner
Date:	08/13/2026

Invus Public Equities Advisors, LLC

Signature:	/s/ Raymond Debbane
Name/Title:	Raymond Debbane, President
Date:	08/13/2026

Invus Global Management, LLC

Signature:	/s/ Raymond Debbane
Name/Title:	Raymond Debbane, President
Date:	08/13/2026

Siren, L.L.C.

Signature:	/s/ Raymond Debbane
Name/Title:	Raymond Debbane, President
Date:	08/13/2026

Avicenna Life Sci Master Fund LP

Signature:	/s/ Raymond Debbane
Name/Title:	Raymond Debbane, Chief Executive Officer of Avicenna Life Sci Master GP LLC, its general partner
Date:	08/13/2026

Avicenna Life Sci Master GP LLC

Signature:	/s/ Raymond Debbane
Name/Title:	Raymond Debbane, Chief Executive Officer
Date:	08/13/2026

Ulys, L.L.C.

Signature:	/s/ Raymond Debbane
Name/Title:	Raymond Debbane, President
Date:	08/13/2026

Raymond Debbane

Signature:	/s/ Raymond Debbane
Name/Title:	Raymond Debbane
Date:	08/13/2026