XGN · Exagen Inc.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The option is exercisable as it vests. 25% of the shares subject to the option vest on February 21, 2027, and 1/48th of the total number of shares subject to the option vest at the end of each calendar month thereafter, subject to the Reporting Person's continued service to the Issuer through each such vesting date. In addition, the stock option may become fully vested upon a qualifying termination of employment in connection with a change in control.

The securities awarded are in the form of restricted stock units under the issuer's 2019 Incentive Award Plan. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. The restricted stock unit will vest with respect to 25% of the restricted stock units on each of the first, second, third and fourth anniversaries of February 21, 2026, subject to the Reporting Person's continued service through the applicable vesting date. In addition, the award may become fully vested upon a qualifying termination of employment in connection with a change in control.

The securities awarded are in the form of restricted stock units under the issuer's 2019 Incentive Award Plan. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. The restricted stock unit will vest with respect to 25% of the restricted stock units on each of the first, second, third and fourth anniversaries of February 21, 2026, subject to the Reporting Person's continued service through the applicable vesting date. In addition, the award may become fully vested upon a qualifying termination of employment in connection with a change in control.

The option is exercisable as it vests. 25% of the shares subject to the option vest on February 21, 2027, and 1/48th of the total number of shares subject to the option vest at the end of each calendar month thereafter, subject to the Reporting Person's continued service to the Issuer through each such vesting date. In addition, the stock option may become fully vested upon a qualifying termination of employment in connection with a change in control.

The sale reported on this Form 4 represents shares sold by the Reporting Person, at the direction of the Issuer, to cover tax withholding obligations in connection with the vesting and settlement of Restricted Stock Units. The sale is mandated solely by the Issuer and does not represent a discretionary transaction by the Reporting Person.

The reporting person is voluntarily reporting the acquisition of the Issuer's common stock pursuant to the Employee Stock Purchase Plan ("ESPP").

Represents shares of common stock purchased through ESPP in transactions that were exempt under both Rule 16b-3(d) and Rule 16b-3(c).

The reporting person is voluntarily reporting the acquisition of the Issuer's common stock pursuant to the Employee Stock Purchase Plan ("ESPP").

Represents shares of common stock purchased through ESPP in transactions that were exempt under both Rule 16b-3(d) and Rule 16b-3(c).

The sale reported on this Form 4 represents shares sold by the Reporting Person, at the direction of the Issuer, to cover tax withholding obligations in connection with the vesting and settlement of Restricted Stock Units. The sale is mandated solely by the Issuer and does not represent a discretionary transaction by the Reporting Person.

The sale reported on this Form 4 represents shares sold by the Reporting Person, at the direction of the Issuer, to cover tax withholding obligations in connection with the vesting and settlement of Restricted Stock Units. The sale is mandated solely by the Issuer and does not represent a discretionary transaction by the Reporting Person.

The sale reported on this Form 4 represents shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting and settlement of Restricted Stock Units ("RSUs"). The sale is mandated by the Issuer's satisfaction of tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary transaction by the Reporting Person.

The sale reported on this Form 4 represents shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting and settlement of Restricted Stock Units ("RSUs"). The sale is mandated by the Issuer's election to require the satisfaction of tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary transaction by the Reporting Person.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

1. The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

On June 12, 2025, the reporting person filed a Form 4 which inadvertently reported that, following his grant of 9,000 stock options, he beneficially owned 18,000 stock options. In fact, as reported in this amendment, the reporting person beneficially owned 9,000 stock options.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The shares reported on this form are held of record by NMSIC Co-Investment Fund, L.P. ("NMSIC"). Sun Mountain Capital Partners LLC ("Sun Mountain") is the general partner of NMSIC. The controlling members of Sun Mountain are Brian Birk, Sally Coming and Lee Rand. As such, each of these entities and individuals may be deemed to share beneficial ownership of the shares held of record by NMSIC. Each of Sun Mountain, Mr. Birk, Ms. Coming and Mr. Rand disclaims beneficial ownership of the securities held of record by NMSIC.

The reporting person is voluntarily reporting the acquisition of the Issuer's common stock pursuant to the Employee Stock Purchase Plan ("ESPP").

Represents shares of common stock purchased through ESPP in transactions that were exempt under both Rule 16b-3(d) and Rule 16b-3(c).

The option is exercisable as it vests. 25% of the shares subject to the option vest on February 21, 2026, and 1/48th of the total number of shares subject to the option vest at the end of each calendar month thereafter, subject to the Reporting Person's continued service to the Issuer through each such vesting date. In addition, the stock option may become fully vested upon a qualifying termination of employment in connection with a change in control.

The securities awarded are in the form of restricted stock units under the issuer's 2019 Incentive Award Plan. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. The restricted stock unit will vest with respect to 25% of the restricted stock units on each of the first, second, third and fourth anniversaries of February 21, 2025, subject to the Reporting Person's continued service through the applicable vesting date. In addition, the award may become fully vested upon a qualifying termination of employment in connection with a change in control.

The securities awarded are in the form of restricted stock units under the issuer's 2019 Incentive Award Plan. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. The restricted stock unit will vest with respect to 25% of the restricted stock units on each of the first, second, third and fourth anniversaries of February 21, 2025, subject to the Reporting Person's continued service through the applicable vesting date. In addition, the award may become fully vested upon a qualifying termination of employment in connection with a change in control.

The option is exercisable as it vests. 25% of the shares subject to the option vest on February 21, 2026, and 1/48th of the total number of shares subject to the option vest at the end of each calendar month thereafter, subject to the Reporting Person's continued service to the Issuer through each such vesting date. In addition, the stock option may become fully vested upon a qualifying termination of employment in connection with a change in control.

The shares reported on this form are held of record by NMSIC Co-Investment Fund, L.P. ("NMSIC"). Sun Mountain Capital Partners LLC ("Sun Mountain") is the general partner of NMSIC. The controlling members of Sun Mountain are Brian Birk, Sally Coming and Lee Rand. As such, each of these entities and individuals may be deemed to share beneficial ownership of the shares held of record by NMSIC. Each of Sun Mountain, Mr. Birk, Ms. Coming and Mr. Rand disclaims beneficial ownership of the securities held of record by NMSIC.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $2.84 to $3.25, inclusive. The reporting person undertakes to provide Exagen Inc., any security holder of Exagen Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (1) to this form 4.

The securities awarded are in the form of restricted stock units under the issuer's 2019 Incentive Award Plan. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. The restricted stock unit will vest with respect to 25% of the restricted stock units on each of the first, second, third and fourth anniversaries of September 1, 2024, subject to the Reporting Person's continued service through the applicable vesting date. In addition, the award may become fully vested upon a qualifying termination of employment in connection with a change in control.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The option is exercisable as it vests. The total number of shares of common stock subject to the option vests in 36 equal monthly installments over the three-year period beginning on July 10, 2024, subject to the Reporting Person's continued service to the Issuer through each such vesting date.

The shares were sold by the reporting person to generate proceeds used to satisfy the tax withholding obligation that arose upon the vesting of certain restricted stock units granted to the reporting person on February 23, 2021.

The shares were sold by the reporting person to generate proceeds used to satisfy the tax withholding obligation that arose upon the vesting of certain restricted stock units granted to the reporting person on March 1, 2023.

Represents shares of common stock purchased through Employee Stock Purchase Plan in transactions that were exempt under both Rule 16b-3(d) and Rule 16b-3(c).

Represents 75,000 restricted stock units. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. The restricted stock units will vest with respect to 25% of the restricted stock units on each of the first, second, third and fourth anniversaries of March 1, 2024, subject to the Reporting Person's continued service through the applicable vesting date. In addition, the award may become fully vested upon a qualifying termination of employment in accordance with the Company's Amended and Restated Executive Change in Control Severance Plan, as the same may be amended from time to time.

Represents 175,000 restricted stock units. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. The restricted stock units will vest with respect to 25% of the restricted stock units on each of the first, second, third and fourth anniversaries of March 1, 2024, subject to the Reporting Person's continued service through the applicable vesting date. In addition, the award may become fully vested upon a qualifying termination of employment in accordance with the Company's Amended and Restated Executive Change in Control Severance Plan, as the same may be amended from time to time.

The shares were sold by the reporting person to generate proceeds used to satisfy the tax withholding obligation that arose upon the vesting of certain restricted stock units granted to the reporting person on February 4, 2022.

The shares were sold by the reporting person to generate proceeds used to satisfy the tax withholding obligation that arose upon the vesting of certain restricted stock units granted to the reporting person on October 16, 2022.

Represents shares of common stock purchased through Employee Stock Purchase Plan in transactions that were exempt under both Rule 16b-3(d) and Rule 16b-3(c).

The option is exercisable as it vests. The total number of shares of common stock subject to the option vests in 36 equal monthly installments over the three-year period beginning on August 24, 2023, subject to the Reporting Person's continued service to the Issuer through each such vesting date.

The transaction reported herein was effected by Tullis Growth Fund II, L.P. ("Tullis Growth II").

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 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.

The entire number of shares subject to this option becomes fully vested and exercisable on the earlier of June 9, 2024 or the date of the Issuer's 2024 Annual Meeting of Stockholders, subject to the Reporting Person's continued service to the Issuer through such vesting date.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.