Sec Form 4 Filing - TULLIS DICKERSON CAPITAL FOCUS III, L.P. @ EXAGEN INC. - 2019-09-19

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person TULLIS DICKERSON CAPITAL FOCUS III, L.P. 2. Issuer Name and Ticker or Trading Symbol EXAGEN INC. [ XGN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 11770 US HIGHWAY ONE, SUITE 503 3. Date of Earliest Transaction (MM/DD/YY) 09/19/2019 (Street) PALM BEACH GARDENS, FL33408 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 09/19/2019 X 11,498 A $ 14.3235 11,597 I See footnote ( 1 ) Common Stock 09/19/2019 F 8,865 D $ 18.58 2,732 I See footnote ( 1 ) Common Stock 09/23/2019 C 1,786,853 A $ 0 1,789,585 I See footnote ( 1 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Warrants $ 14.3235 09/19/2019 X 11,498 ( 3 ) ( 3 ) Common Stock ( 4 ) 11,498 $ 14.3235 0 I See footnotes ( 1 ) ( 5 ) Series A-3 Redeemable Convertible Preferred Stock ( 6 ) 09/23/2019 C 468,321 ( 6 ) ( 6 ) Common Stock 2,550 ( 6 ) 0 I See footnotes ( 1 ) ( 2 ) Series C Redeemable Convertible Preferred Stock ( 7 ) 09/23/2019 C 5,446,902 ( 7 ) ( 7 ) Common Stock 95,069 ( 7 ) 0 I See footnotes ( 1 ) ( 2 ) Series E Redeemable Convertible Preferred Stock ( 8 ) 09/23/2019 C 53,251,030 ( 8 ) ( 8 ) Common Stock 929,432 ( 8 ) 0 I See footnotes ( 1 ) ( 9 ) Series F Redeemable Convertible Preferred Stock ( 10 ) 09/23/2019 C 81,166,266 ( 10 ) ( 10 ) Common Stock 441,998 ( 10 ) 0 I See footnotes ( 1 ) ( 11 ) Series H Redeemable Convertible Preferred Stock ( 12 ) 09/23/2019 C 58,359,932 ( 12 ) ( 12 ) Common Stock 317,804 ( 12 ) 0 I See footnotes ( 1 ) ( 13 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other TULLIS DICKERSON CAPITAL FOCUS III, L.P. 11770 US HIGHWAY ONE, SUITE 503 PALM BEACH GARDENS, FL33408 X Tullis Growth Fund, L.P. 11770 US HIGHWAY ONE, SUITE 503 PALM BEACH GARDENS, FL33408 X TULLIS GROWTH FUND II, L.P. 11770 US HIGHWAY ONE, SUITE 503 PALM BEACH GARDENS, FL33408 X TULLIS DICKERSON PARTNERS III, L.L.C. 11770 US HIGHWAY ONE, SUITE 503 PALM BEACH GARDENS, FL33408 X Signatures Tullis Growth Fund II, L.P., By: Tullis-Growth Partners II, L.L.C., its general partner, /s/ James L. L. Tullis, Name: James L.L. Tullis, Title: Manager 09/23/2019 Signature of Reporting Person Date Tullis Growth Fund, L.P., By: Tullis-Growth Partners, L.L.C., its general partner, /s/ James L. L. Tullis, Name: James L.L. Tullis, Title: Manager 09/23/2019 Signature of Reporting Person Date Tullis-Dickerson Capital Focus III, L.P., By: Tullis-Dickerson Partners, L.L.C., its general partner, /s/ James L. L. Tullis, Name: James L.L. Tullis, Title: Manager 09/23/2019 Signature of Reporting Person Date Tullis-Dickerson Partners III, L.L.C., /s/ James L. L. Tullis, Name: James L.L. Tullis, Title: Manager 09/23/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The shares reported on this form are held of record by Tullis-Dickerson Capital Focus III, L.P. ("Tullis"), Tullis Growth Fund, L.P. ("Tullis Growth") and Tullis Growth Fund II, L.P. ("Tullis Growth II"). Tullis-Dickerson Partners III, LLC ("Tullis Partners") is the general partner of Tullis and may be deemed to beneficially own the securities held by Tullis. Tullis Growth Partners, LLC and Tullis Growth Partners II, LLC are the general partners of Tullis Growth and Tullis Growth II, respectively, and may be deemed to beneficially own the securities held by Tullis Growth and Tullis Growth II. James L.L. Tullis is a Principal of each of the foregoing entities and may be deemed to possess voting and investment control over, and may be deemed to have an indirect beneficial ownership with respect to, the shares held by Tullis, Tullis Growth and Tullis Growth II. ( 2 )Represents securities held of record by Tullis. ( 3 )The warrants are currently exercisable and will terminate upon closing of the Issuer's initial public offering. ( 4 )Represents warrants that previously entitled the holders to purchase Series E Redeemable Convertible Preferred Stock, which, pursuant to their terms, were settled in shares of the Issuer's Common Stock. ( 5 )Includes warrants held by Tullis and Tullis Growth, respectively, to purchase 43 shares of the Issuer's Common Stock and warrants to purchase 11,455 shares of the Issuer's Common Stock. ( 6 )The Series A-3 Redeemable Convertible Preferred Stock (the "Series A-3") is convertible into the Issuer's Common Stock on a 183.635-for-one basis at the holder's election and has no expiration date. The Series A-3 automatically converted into Common Stock upon the closing of the Issuer's initial public offering. ( 7 )The Series C Redeemable Convertible Preferred Stock (the "Series C") is convertible into the Issuer's Common Stock on a 57.294-for-one basis at the holder's election and has no expiration date. The Series C automatically converted into Common Stock upon the closing of the Issuer's initial public offering. ( 8 )The Series E Redeemable Convertible Preferred Stock (the "Series E") is convertible into the Issuer's Common Stock on a 57.294-for-one basis at the holder's election and has no expiration date. The Series E automatically converted into Common Stock upon the closing of the Issuer's initial public offering. ( 9 )Includes 656,282 and 273,150 shares of common stock underlying the Series E shares held by Tullis and Tullis Growth, respectively. ( 10 )The Series F Redeemable Convertible Preferred Stock ("Series F") is convertible into the Issuer's Common Stock on a 183.635-for-one basis at the holder's election and has no expiration date. The Series F automatically converted into Common Stock upon the closing of the Issuer's initial public offering. ( 11 )Includes 242,226 and 199,771 shares of common stock underlying the Series F shares held by Tullis and Tullis Growth, respectively. ( 12 )The Series H Redeemable Convertible Preferred Stock ("Series H") is convertible into the Issuer's Common Stock on a 183.635-for-one basis at the holder's election and has no expiration date. The Series H automatically converted into Common Stock upon the closing of the Issuer's initial public offering. ( 13 )Includes 106,897 shares, 105,453 shares and 105,453 shares of common stock underlying the Series H shares held by Tullis, Tullis Growth and Tullis Growth II, respectively.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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