RTW Investments (XGN) reports 4.99% Exagen stake including warrants

Rhea-AI Filing Summary

Exagen Inc. investor RTW Investments, LP and Managing Partner Roderick Wong reported a 4.99% beneficial stake in the company’s common stock. They disclosed beneficial ownership of 1,148,768 shares, including warrants to purchase 358,306 shares, calculated against 22,663,099 shares outstanding as of October 31, 2025.

The warrants are subject to a 4.99% beneficial ownership limitation, preventing exercises that would push their stake above that level. The filing states the securities are held in the ordinary course of business and not for the purpose of changing or influencing control of Exagen. Dividends and sale proceeds accrue to the RTW Funds advised by RTW Investments.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 6)

Exagen Inc.

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

30068X103

(CUSIP Number)

12/31/2025

(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)

SCHEDULE 13G

CUSIP No. 30068X103

1

Names of Reporting Persons

RTW Investments, 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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,148,768.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,148,768.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,148,768.00

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)

4.9 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP No. 30068X103

1

Names of Reporting Persons

Roderick Wong

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,148,768.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,148,768.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,148,768.00

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)

4.9 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Exagen Inc.
(b)	Address of issuer's principal executive offices: 1261 Liberty Way, Vista, CA, 92081.
Item 2.
(a)	Name of person filing: This statement is filed by. (i) RTW Investments, LP ("RTW Investments"), a Delaware limited partnership, and the investment adviser to certain funds (the "RTW Funds"), with respect to the Shares (as defined in Item 2(d) below) directly held by the RTW Funds; and (ii) Roderick Wong, M.D. ("Dr. Wong"), the Managing Partner and Chief Investment Officer of RTW Investments, with respect to the Shares directly held by the RTW Funds. The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." The filing of this statement should not be construed as an admission that any of the foregoing persons or any Reporting Person is, for the purposes of Section 13 of the Act, the beneficial owner of the Shares reported herein.
(b)	Address or principal business office or, if none, residence: The address of the business office of each of the Reporting Persons is 40 10th Avenue, Floor 7, New York, New York 10014.
(c)	Citizenship: RTW Investments is a Delaware limited partnership. Dr. Wong is a citizen of the United States.
(d)	Title of class of securities: Common Stock, par value $0.001 per share
(e)	CUSIP No.: 30068X103
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: The information required by Items 4(a) - (c) is set forth in Rows 5 - 11 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The amounts reported herein assume the exercise of warrants held by the Reporting Persons to purchase 358,306 Shares (the "Warrants"), the maximum amount that may be exercised given the current number of outstanding shares and the shares held by the Reporting Persons. Pursuant to the terms of the Warrants, the Reporting Persons cannot exercise any of the Warrants to the extent the Reporting Persons would beneficially own, after any such exercise, more than 4.99% of the outstanding Shares. The percentages set forth herein are calculated based upon 22,663,099 Shares outstanding as of October 31, 2025, as reported in the Company's Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2025, filed with the Securities and Exchange Commission on November 4, 2025, and assume the exercise of Warrants held by the Reporting Persons to purchase 358,306 Shares.
(b)	Percent of class: RTW Investments: 4.99% Dr. Wong: 4.99%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: RTW Investments: 0 Dr. Wong: 0
	(ii) Shared power to vote or to direct the vote: RTW Investments: 1,148,768 Shares Dr. Wong: 1,148,768 Shares
	(iii) Sole power to dispose or to direct the disposition of: RTW Investments: 0 Dr. Wong: 0
	(iv) Shared power to dispose or to direct the disposition of: RTW Investments: 1,148,768 Shares Dr. Wong: 1,148,768 Shares
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	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. The RTW 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 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.
	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:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and 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.

RTW Investments, LP

Signature:	/s/ Roderick Wong, M.D.
Name/Title:	Roderick Wong, M.D., Managing Partner
Date:	02/17/2026

Roderick Wong

Signature:	s/ Roderick Wong, M.D.
Name/Title:	Roderick Wong, M.D.
Date:	02/17/2026

Exhibit Information

Exhibit 99.1 Joint Filing Agreement

FAQ

What ownership stake in Exagen Inc. (XGN) does RTW Investments report?

RTW Investments and Roderick Wong report beneficial ownership of 4.99% of Exagen’s common stock. This represents 1,148,768 shares, including warrants to purchase 358,306 shares, based on 22,663,099 shares outstanding as of October 31, 2025.

How many Exagen (XGN) shares does RTW Investments beneficially own?

RTW Investments and Roderick Wong report beneficial ownership of 1,148,768 Exagen shares. This total includes common stock and warrants assumed exercisable for 358,306 shares, all aggregated for a 4.99% stake under Schedule 13G/A reporting.

What is the warrant ownership limitation disclosed for Exagen (XGN)?

The warrants held by the reporting persons are capped by a 4.99% beneficial ownership limitation. They cannot exercise any warrants if doing so would cause their beneficial ownership of Exagen common stock to exceed 4.99% of shares outstanding.

Whose economic interest is affected by the Exagen (XGN) shares held?

The RTW Funds have the right to receive dividends and sale proceeds from the Exagen shares reported. RTW Investments acts as investment adviser, and Roderick Wong is Managing Partner and Chief Investment Officer overseeing these positions.

Are RTW Investments and Roderick Wong seeking control of Exagen Inc. (XGN)?

No, the filing states the Exagen securities are held in the ordinary course of business. It further specifies they were not acquired and are not held to change or influence control of Exagen, consistent with a passive Schedule 13G/A filing.

What share count did RTW use to calculate its Exagen (XGN) ownership percentage?

The 4.99% ownership is calculated using 22,663,099 Exagen shares outstanding. This share count comes from Exagen’s Form 10-Q for the quarter ended September 30, 2025, which reported shares outstanding as of October 31, 2025.