Document:

EX-4.2

 Exhibit 4.2 

EXAGEN INC. 
 AMENDED
AND RESTATED 
 INVESTORS’ RIGHTS AGREEMENT 

THIS AMENDED AND RESTATED INVESTORS’ RIGHTS AGREEMENT (this “Agreement”) is made as of July 12, 2019, by and among
Exagen Inc., a Delaware corporation (the “Corporation”), and the persons listed on Schedule A hereto (the “Holders”). 

RECITALS 
 WHEREAS,
certain of the Holders are party to that certain Amended and Restated Investors’ Rights Agreement of the Corporation dated January 2, 2019 (as amended, the “Prior Agreement”); 

WHEREAS, certain of the Holders and the Corporation have entered into that certain Series H Preferred Stock Purchase Agreement dated the date
hereof (the “Series H Purchase Agreement”), pursuant to which such Holders agreed to purchase from the Corporation, and the Corporation agreed to sell to such Holders, shares of the Corporation’s Series H Convertible Preferred
Stock, par value $0.001 per share (the “Series H Preferred Stock”); 
 WHEREAS, the Prior Agreement permits the
Corporation, the record or beneficial Holders owning at least 52% of the issued and outstanding shares of Series G Convertible Preferred Stock, par value $0.001 per share (the “Series G Preferred Stock”), Series F Convertible
Preferred Stock, par value $0.001 per share (the “Series F Preferred Stock”), Series E Convertible Preferred Stock, par value $0.001 per share (the “Series E Preferred Stock”), Series D Convertible Preferred Stock,
par value $0.001 per share (the “Series D Preferred Stock”), the Series C Convertible Preferred Stock, par value $0.001 per share (the “Series C Preferred Stock”), and the Series
B-3 Convertible Preferred Stock, par value $0.001 per share (the “Series B-3 Preferred Stock”), voting together as a single class, to amend the Prior
Agreement; and 
 WHEREAS, as a condition to the consummation of the transactions contemplated by the Series H Purchase Agreement, the
undersigned Holders, who are the record or beneficial Holder owning at least 52% of the shares of Series G Preferred Stock, Series F Preferred Stock, Series E Preferred Stock, Series D Preferred Stock, Series C Preferred Stock and Series B-3 Preferred Stock, voting together as a single class, outstanding as of the date hereof, and the Corporation desire to amend and restate the Prior Agreement in its entirety as set forth herein, to grant each of
the Holders the registration rights, information and inspection rights and other rights set forth herein with the intention that this Agreement shall become effective concurrently with the Closing (as defined in the Series H Purchase Agreement).

 AGREEMENT 

NOW THEREFORE, in consideration of the foregoing and of the mutual promises and covenants contained herein and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereby agree as follows: 
 ARTICLE 1 Certain
Definitions. As used in this Agreement, the following terms shall have the following respective meanings: 
 “Adversely Affected
Holder” shall have the meaning set forth in Section 5.1. 
 “Agreement” shall mean this Amended and Restated
Investors’ Rights Agreement, as the same may be amended from time to time. 
 “Affiliate” shall mean, with respect to
any Holder, any person or entity controlling, controlled by or under common control with such Holder, and (i) with respect to NMSIC Co-Investment Fund, L.P., shall include any affiliate of Sun Mountain
Capital Partners, LLC, (ii) with respect to PCM/Exagen, L.P., shall include Hunt Holdings L.P., (iii) with respect to Tullis-Dickerson Capital Focus III, L.P., shall include any pooled investment vehicle managed by Tullis Health Investors of
FL, LLC, and any of its affiliates. 
 “Blue Sky laws” shall mean applicable state securities laws and the rules and
regulations thereunder, all as the same shall be in effect from time to time. 
 “Board” shall mean the Corporation’s
Board of Directors. 
 “Certificate of Incorporation” shall mean the Corporation’s Amended and Restated Certificate of
Incorporation, as the same may be amended from time to time. 
 “Commission” shall mean the Securities and Exchange
Commission or any other federal agency at the time administering the Securities Act. 
 “Common Stock” shall mean the
Corporation’s Common Stock, $0.001 par value per share. 
 “Corporation” shall mean Exagen Inc., a Delaware
corporation, its successors and assigns. 
 “Exchange Act” shall mean the Securities Exchange Act of 1934, as amended, or
any successor federal statute, and the rules and regulations of the Commission promulgated thereunder, all as the same shall be in effect from time to time. 

“Form S-1” shall mean Form S-1 issued by the
Commission or any substantially similar form then in effect. 
 “Form S-3” shall
mean Form S-3 issued by the Commission or any substantially similar form then in effect. 

“H.I.G.” shall mean H.I.G. Bio-Exagen, L.P. and affiliates thereof. 

“Holders” shall mean the Holders and their permitted assigns under Section 2.8. 

“Holder Director” shall have the meaning set forth in Section 4.3. 

“Holder Indemnitors” shall have the meaning set forth in Section 4.3. 

  
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 “Indemnitees” shall have the meaning set forth in Section 4.1. 

“Investor Counsel” shall have the meaning set forth in Section 3.16. 

“Major Holder” shall mean, as of the date of determination, a Holder of at least 10,000,000 shares in the aggregate of Series
C Preferred Stock, Series D Preferred Stock, Series E Preferred, Series F Preferred Stock and/or Series H Preferred Stock (as adjusted for any stock splits, stock dividends, combinations and other similar recapitalizations affecting such shares).

 “Notice” shall have the meaning set forth in Section 5.4. 

“PCM/Hunt” shall mean PCM/Exagen, L.P. and Affiliates thereof. 

“Preferred Stock” shall mean the Series A-3 Preferred Stock, the Series B-3 Preferred Stock, Series C Preferred Stock, Series D Preferred Stock, Series E Preferred Stock, Series F Preferred Stock, Series G Preferred Stock and Series H Preferred Stock. 

“Prior Agreement” shall have the meaning set forth in the Recitals. 

“Registrable Securities” shall mean (i) all shares of Common Stock issued or issuable upon conversion of the Preferred
Stock, (ii) all shares of Common Stock issued or issuable upon exercise, conversion or exchange of any warrants or other securities exercisable, convertible or exchangeable for shares of Common Stock, and (iii) all shares of Common Stock
issued as (or issuable upon the conversion, exercise or exchange of any warrant, right or other security which is issued as) a dividend or other distribution with respect to, or in exchange for or in replacement of, such securities; provided,
however, that shares of Common Stock which are Registrable Securities shall cease to be Registrable Securities at such time, and for so long as, such shares are eligible for sale pursuant to Rule 144 under the Securities Act or a similar
exemption under the Securities Act is available for the sale of all of such Holder’s shares without registration and the Corporation shall have delivered to the Holder an opinion of counsel to such effect which opinion and counsel shall be
reasonably satisfactory to the Holder. 
 “Registration Expenses” shall mean all expenses (other than Selling Expenses)
incurred by the Corporation in complying with Sections 2.1 and 2.2, including without limitation, all federal and state registration, qualification, delivery expenses and filing fees, printing expenses, listing fees and disbursements of counsel for
the Corporation, blue sky fees and expenses, and the fees and disbursements of all independent certified public accountants of the Corporation, and fees and disbursements of underwriters, selling brokers, dealers, managers or similar securities
industry professionals relating to the distribution of Registrable Securities and all fees and expenses of any one special counsel for the Holders. 

“Related Transaction” shall mean a transaction whereby a current or former stockholder, director, officer or employee of the
Corporation or a relative or “associate” (as defined in the rules and regulations promulgated under the Exchange Act) of any such person or entity, directly or indirectly through his or its affiliation with any other person or entity, is a
party to a transaction with the Corporation providing for the furnishing of services (other than employment of such individuals by the Corporation) by or to, or the sale of products by or to, or rental of real or personal property from or to, or
otherwise requiring cash payments to or by, any such person or entity in excess of an aggregate of $1,000. 

  
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 “Requisite Party” shall be any of H.I.G., Sun Mountain (as defined below),
Tullis (as defined below) or PCM/Hunt, each for so long as it holds at least fifty percent (50%) of the shares of Preferred Stock that such party or its Affiliates held as of the date hereof. 

“Requisite Majority” shall mean (A) for so long as H.I.G. is a Requisite Party and three other Requisite Parties exist,
either (i) any three Requisite Parties or (ii) H.I.G. and any other single Requisite Party, (B) for so long as H.I.G. is a Requisite Party and two other Requisite Parties exist, H.I.G. and any other single Requisite Party,
(C) for so long as H.I.G. is a Requisite Party and one or no other Requisite Party exists, H.I.G., (D) if H.I.G. is not a Requisite Party, the majority of shares of Preferred Stock then held by the Requisite Parties, or (E) if no Requisite
Party exists, the Holders owning at least a majority of the issued and outstanding shares of Series H Preferred Stock, Series F Preferred Stock, Series E Preferred Stock, Series D Preferred Stock, Series C Preferred Stock and Series B-3 Preferred Stock, voting together as a single class. 
 “SBA” shall mean the United
States Small Business Administration. 
 “SBIC” shall mean both vSpring SBIC, L.P. and Wasatch Venture Fund III, L.L.C.

 “SBIC Act” shall mean the Small Business Investment Act of 1958, as amended. 

“Securities Act” shall mean the Securities Act of 1933, as amended, or any successor federal statute, and the rules and
regulations of the Commission promulgated thereunder, all as the same shall be in effect from time to time. 
 “Selling
Expenses” shall mean all underwriting discounts, selling commissions and counsel fees, if any, in excess of the expenses of one special counsel for the Holders paid for by the Corporation as provided in the definition of “Registration
Expenses,” of the selling stockholder applicable to the sale of Registrable Securities pursuant to this Agreement. 
 “Series A-3 Preferred Stock” shall mean the Corporation’s Series A-3 Preferred Stock, $0.001 par value per share. 

“Series B-3 Preferred Stock” shall have the meaning set forth in the Recitals. 

“Series C Preferred Stock” shall have the meaning set forth in the Recitals. 

“Series D Preferred Stock” shall have the meaning set forth in the Recitals. 

“Series E Preferred Stock” shall have the meaning set forth in the Recitals. 

“Series F Preferred Stock” shall have the meaning set forth in the Recitals. 

“Series G Preferred Stock” shall have the meaning set forth in the Recitals. 

  
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 “Series H Preferred Stock” shall have the meaning set forth in the
Recitals. 
 “Series H Purchase Agreement” shall have the meaning set forth in the Recitals. 

“Stockholders’ Agreement” shall have the meaning set forth in Section 3.16. 

“Sun Mountain” shall mean NMSIC Co-Investment Fund, L.P. and Affiliates thereof. 

“Tullis” shall mean Tullis-Dickerson Capital Focus III, L.P. and Affiliates thereof. 

“Underwriter’s Representative” shall have the meaning set forth in Section 2.1(e)(ii). 

1.1 Restrictions on Transfer. 

(a) No Holder shall transfer or otherwise dispose of in any manner all or any portion of any securities of the Corporation held by such Holder
unless and until the transferee thereof has agreed in writing for the benefit of the Corporation to be bound by this Section 1.1, provided and to the extent such Section is then applicable, and: 

(i) there is then in effect a registration statement under the Securities Act covering such proposed disposition and such disposition is made
in accordance with such registration statement; or 
 (ii) (A) such Holder shall have notified the Corporation of the proposed disposition
and shall have furnished the Corporation with a detailed statement of the circumstances surrounding the proposed disposition, and (B) if reasonably requested by the Corporation, such Holder shall have furnished the Corporation with an opinion
of counsel, reasonably satisfactory to the Corporation, that such disposition will not require registration of such shares under the Securities Act. It is agreed that the Corporation will not require opinions of counsel for transactions made
pursuant to Rule 144 under the Securities Act except in unusual circumstances. 
 (iii) Notwithstanding the provisions of paragraphs
(i) and (ii) above, no such registration statement or opinion of counsel shall be necessary for a transfer by a Holder which is (A) a partnership to its partners or retired partners in accordance with partnership interests, (B) a
corporation to its shareholders in accordance with their interest in the corporation, (C) a limited liability company to its members or former members in accordance with their interest in the limited liability company, or (D) to the
Holder’s family member or trust for the benefit of an individual Holder, provided the transferee will be subject to the terms of this Section 1.1 to the same extent as if such transferee were an original Holder hereunder. 

  
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 (b) Each certificate representing any securities of the Corporation shall (unless otherwise
permitted by the provisions of this Agreement) be stamped or otherwise imprinted with a legend substantially similar to the following (in addition to any legend required under applicable state securities laws): 

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES
ACT”), OR ANY OTHER SECURITIES LAWS. THESE SECURITIES HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO DISTRIBUTION OR RESALE. SUCH SECURITIES MAY NOT BE OFFERED FOR SALE, SOLD, DELIVERED AFTER SALE, OR TRANSFERRED, PLEDGED OR
HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT COVERING SUCH SECURITIES UNDER THE SECURITIES ACT AND ANY OTHER APPLICABLE SECURITIES LAWS, UNLESS THE HOLDER SHALL HAVE OBTAINED AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE
CORPORATION THAT SUCH REGISTRATION IS NOT REQUIRED OR UNLESS SOLD PURSUANT TO AN EXEMPTION UNDER THE SECURITIES ACT. 
 (c) The
Corporation shall be obligated to reissue promptly unlegended certificates at the request of any Holder thereof if the Holder shall have obtained an opinion of counsel at such Holder’s expense (which counsel may be counsel to the Corporation)
reasonably acceptable to the Corporation to the effect that the securities proposed to be disposed of may lawfully be so disposed of without registration, qualification or legend. 

ARTICLE 2 Registration Rights. The Corporation covenants and agrees as follows: 

2.1 Demand Registration. 

(a) Request for Registration on Form Other Than Form S-3. For a period of five (5) years
following the closing of the Corporation’s initial underwritten public offering of Common Stock pursuant to a registration statement, and in the event that the Corporation shall receive from the Holders of no less than 15% of the outstanding
Registrable Securities a written request that the Corporation effect any registration with respect to Registrable Securities on Form S-1, the Corporation shall promptly give notice thereof to all Holders of
Registrable Securities. Each Holder shall have the right, by giving notice to the Corporation within 15 days following receipt by it of such notice from the Corporation, to elect to have included in such registration such of its Registrable
Securities as such Holders shall request in such notice of election, subject to Section 2.1(c). The Corporation shall use its best efforts to effect registration of the Registrable Securities specified in such request and notice of election.
The Corporation shall not be obligated to effect more than two (2) registrations pursuant to this Section 2.1(a) in any calendar year; provided, that a registration shall not be counted for this purpose if (A) the Corporation
elects to sell stock pursuant to a registration at the same time as the registration requested hereunder and less than all the Registrable Securities for which registration was requested are included, (B) the registration statement does not
become effective or (C) the requesting Holders are not able to sell at least 90% of the Registrable Securities requested to be included in such registration statement. 

  
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 (b) Request for Registration on Form S-3. If
at any time and from time to time after the date which is 180 days after the closing of the Corporation’s initial underwritten public offering of Common Stock pursuant to a registration statement and thereafter, in the event that the
Corporation shall receive from the Holders of outstanding Registrable Securities a written request that the Corporation effect any registration with respect to Registrable Securities on Form S-3 (or any
successor form to Form S-3 regardless of its designation) at a time when the Corporation is eligible to register securities on Form S-3 (or any successor form to Form S-3 regardless of its designation) for an offering of Registrable Securities, the Corporation shall promptly give notice thereof to all Holders of Registrable Securities. Each Holder shall have the right, by giving
notice to the Corporation within 15 days following receipt by it of such notice from the Corporation, to elect to have included in such registration such of its Registrable Securities as such Holders shall request in such notice of election, subject
to Section 2.1(c). The Corporation shall use its best efforts to effect registration of the Registrable Securities specified in such request and notice of election; provided that the Corporation shall not be required to effect a
registration pursuant to this Section 2.1(b) unless Holders requesting registration propose to dispose of shares of Registrable Securities having an aggregate price to the public (before deduction of underwriting discounts and expenses of sale)
of at least $1,000,000; and provided, further, that the Corporation shall not be required to effect more than two (2) such registrations pursuant to this Section 2.1(b) within any twelve-month period. 

(c) Allocation of Shares in Demand Registration. In the event that the Underwriter’s Representative determines in good faith that
marketing factors require a limitation of the shares to be included in a registration pursuant to Section 2.1(a) or 2.1(b), each Holder requesting registration shall be entitled to include a portion of the Registrable Securities requested to be
included in such registration pro rata (based on the number of Registrable Securities held). In such event, such registration shall not be counted for the registration for purposes of Section 2.1(a) or 2.1(b), as the case may be, if such
registration does not include at least 90% of the Registrable Securities requested to be included in such registration statement pursuant to Section 2.1(a) or 2.1(b), as the case may be. 

(d) Registration of Other Securities in Demand Right. A registration pursuant to Section 2.1(a) or 2.1(b) may include securities
other than Registrable Securities included in such registration only with the prior consent of the Holders of more than 50% of the Registrable Securities requesting such registration; provided, that the Corporation may include its Common
Stock in such registration without such consent so long as such inclusion does not prevent in any manner whatsoever the Holders of Registrable Securities from including in such registration all of the Registrable Securities that such Holders elected
to so include pursuant to Section 2.1(a) or 2.1(b), as the case may be. 

  
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 (e) Underwriting in Demand Registration. 

(i) Notice of Underwriting. If the Holders intend to distribute the Registrable Securities covered by their request by means of an
underwriting, they shall so advise the Corporation as a part of their request made pursuant to this Section 2.1, and the Corporation shall include such information in the notice referred to in Section 2.2(a). 

(ii) Selection of Underwriter in Demand Registration. The Corporation shall, together with the Holders engaged in a registration, enter
into an underwriting agreement with the representative (“Underwriter’s Representative”) of the underwriter or underwriters selected for such underwriting by a majority of the Holders engaged in the registration
and approved by the Corporation. 
 (iii) Right of Withdrawal in Demand Registration. If a Holder disapproves of the terms of the
underwriting, it may elect to withdraw therefrom by notice to the Corporation and the Underwriter’s Representative delivered at least 10 days prior to the effective date of the registration statement. The securities so withdrawn shall also be
withdrawn from the registration statement. 
 (iv) Blue Sky in Demand Registration. In the event of any registration pursuant to
Section 2.1, the Corporation will exercise its best efforts to register and qualify the securities covered by the registration statement under such other securities or Blue Sky laws of such jurisdictions as the Holders shall reasonably request
and as shall be reasonably appropriate for the distribution of such securities; provided, however, that the Corporation shall not be required to qualify to do business or to file a general consent to service of process in any such
states or jurisdictions. 
 (v) Optimal Registration. The Holders agree that, in exercising their rights under Section 2.1, they
will permit the registration of the Registrable Securities on such forms issued by the Commission as will minimize the Corporation’s time and expense in effecting such registration without affecting the liquidity afforded by such registration
or otherwise adversely affecting the Holders, in each case as reasonably determined by the Holders. If, for example, the Holders wish to register Registrable Securities pursuant to Section 2.1(a) at a time when the Corporation is eligible to
use Form S-3 for purposes of registering such Registrable Securities, the Holders will permit the Corporation to fulfill its obligations under Section 2.1(a) by effecting such registration on Form S-3. 
 (vi) Delay of Registration. The Holders agree that for a period of 90 days following the
date of the effectiveness of a registration under Section 2.2 pursuant to which the Holders have sold not less than 75% of the aggregate amount of the Registrable Securities that the Holders specified in their notice to the Corporation pursuant
to Section 2.2(a), they will not exercise their right to demand a registration pursuant to Section 2.1(a) or 2.1(b). In addition, the Corporation shall not be required to effect a registration pursuant to this Section 2.1 if the
Corporation shall furnish to the Holders within thirty (30) days of any registration request a certificate signed by the President of the Corporation stating that in the good faith judgment of the Board, it would be seriously detrimental to the
Corporation and its stockholders for such registration to be effected at such time, in which event the Corporation shall have the right to defer the filing of the registration statement for a period of not more than ninety (90) days after the
receipt of the request of the Holder or Holders under this Section 2.1; provided, however, that the Corporation shall not utilize this right more than once in any twelve month period. 

  
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 2.2 Piggyback Registration. 

(a) Notice of Piggyback Registration and Inclusion of Registrable Securities. Subject to the terms of this Agreement, in the event
during the period of five (5) years following the closing of the Corporation’s initial underwritten public offering of Common Stock pursuant to a registration statement, the Corporation decides to register any of its Common Stock (either
for its own account or the account of Holders or other security holder exercising demand registration rights) (but without any obligation to do so), other than (i) a registration statement which exclusively relates to the registration of
securities under an employee stock option, purchase, bonus or other benefit plan, or (ii) a registration on any form that does not include substantially the same information (other than information relating specifically to this disposition of
the Registrable Securities and the Holders) as would be required to be included in a registration statement covering the sale of the Registrable Securities, the Corporation will: (A) promptly give the Holders written notice thereof (which shall
include a list of the jurisdictions in which the Corporation intends to attempt to qualify such securities under the applicable Blue Sky laws) and (B) include in such registration (and any related qualification under Blue Sky laws or other
compliance), and in any underwriting involved therein, all the Registrable Securities specified in a written request delivered to the Corporation by the Holders within 15 days after delivery of such written notice from the Corporation. 

(b) Underwriting in Piggyback Registration. 

(i) Notice of Underwriting. If the registration of which the Corporation gives notice is a registered public offering involving an
underwriting, the Corporation shall so advise the Holders as a part of the written notice given pursuant to Section 2.2(a). In such event the right of the Holders to registration shall be conditioned upon such underwriting and the inclusion of
a Holder’s Registrable Securities in such underwriting to the extent provided in this Section 2.2. The Holders shall, together with the Corporation, enter into an underwriting agreement with the Underwriter’s Representative for such
offering. The Holders shall have no right to participate in the selection of the underwriters for an offering pursuant to this Section 2.2. 

(ii) Marketing Limitation in Piggyback Registration. In the event the Underwriter’s Representative advises the Corporation and the
Holders engaged in a registration under Section 2.2(a) in writing that market factors (including, without limitation, the aggregate number of shares of Common Stock requested to be registered, the general condition of the market, and the status
of the persons proposing to sell securities pursuant to the registration) require a limitation of the number of shares to be underwritten, the Underwriter’s Representative (subject to the allocation priority set forth in clause
(iii) below) may exclude some or all of the Registrable Securities from such registration and underwriting. 
 (iii) Allocation of
Shares in Piggyback Registration. In the event that the Underwriter’s Representative limits the number of shares to be included in a registration pursuant to Section 2.2(a), each Holder, upon requesting registration shall be entitled
to include a portion of the Registrable Securities requested to be included in such registration pro rata (based on the number of Registrable Securities held) with all other requesting Holders. Unless all Registrable Securities and such other
piggybacking shares requested to be included in such registration are so included, no other securities may be included in the registration statement. 

  
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 (iv) Withdrawal in Piggyback Registration. If any Holder disapproves of the terms of
any such underwriting, it may elect to withdraw therefrom at no cost to such Holder by written notice to the Corporation and the underwriter delivered at least 10 days prior to the effective date of the registration statement. Any Registrable
Securities or other securities excluded or withdrawn from such underwriting shall be withdrawn from such registration. 
 (v) Blue Sky in
Piggyback Registration. In the event of any registration of Registrable Securities pursuant to Section 2.2(a), the Corporation will exercise its best efforts to register and qualify the securities covered by the registration statement under
the Blue Sky laws of such jurisdictions as the Holders shall reasonably request and as shall be reasonably appropriate for the distribution of such securities; provided, however, that the Corporation shall not be required to qualify to
do business or to file a general consent to service of process in any such states or jurisdictions. 
 (vi) Termination or
Postponement. Without any obligation to the Holders, upon notice to the Holders, the Corporation may terminate or postpone any registration commenced by it under Section 2.2. 

2.3 Expenses of Registration. All Registration Expenses incurred in connection with any registration hereunder shall be borne by the
Corporation. Selling Expenses to be borne by the selling stockholder shall be borne pro rata on the basis of the number of Registrable Securities registered by such selling stockholder. 

2.4 Registration Generally. Whenever required under this Article 2 to effect the registration of any Registrable Securities, the
Corporation shall, as expeditiously as reasonably possible: 
 (a) Prepare and file with the SEC a registration statement with respect to
such Registrable Securities and use its best efforts to cause such registration statement to become effective, and, upon the request of the Holders of a majority of the Registrable Securities registered thereunder, keep such registration statement
effective for up to 120 days; 
 (b) Prepare and file with the SEC such amendments and supplements to such registration statement and the
prospectus used in connection with such registration statement as may be necessary to comply with the provisions of the Act with respect to the disposition of all securities covered by such registration statement; 

(c) Furnish to the Holders such numbers of copies of a prospectus, including a preliminary prospectus, in conformity with the requirements of
the Act, and such other documents as they may reasonably request in order to facilitate the disposition of Registrable Securities owned by them; 

(d) Use its best efforts to register and qualify the securities covered by such registration statement under such other securities or Blue Sky
laws of such jurisdictions as shall be reasonably requested by the Holders, provided that the Corporation shall not be required in connection therewith or as a condition thereto to qualify to do business or to file a general consent to service of
process in any such states or jurisdictions; 

  
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 (e) In the event of any underwritten public offering, enter into and perform its obligations
under an underwriting agreement, in usual and customary form, with the managing underwriter of such offering. Each Holder participating in such underwriting shall also enter into and perform its obligations under such an agreement; 

(f) Notify each Holder of Registrable Securities covered by such registration statement at any time when a prospectus relating thereto is
required to be delivered under the Act of the happening of any event as a result of which the prospectus included in such registration statement, as then in effect, includes an untrue statement of a material fact or omits to state a material fact
required to be stated therein or necessary to make the statement therein not misleading in light of the circumstances then existing; 
 (g)
Cooperate with the selling Holders of Registrable Securities and the managing underwriters, if any, to facilitate the timely preparation and delivery of certificates representing Registrable Securities to be sold and not bearing any restrictive
legends; and enable such Registrable Securities to be in such denominations and registered in such names as the managing underwriters may request at least 3 days prior to any sale of Registrable Securities to the underwriters; 

(h) Cause all such Registrable Securities registered pursuant hereunder to be listed on each securities exchange on which similar securities
issued by the Corporation are then listed; 
 (i) Provide a transfer agent and registrar for all Registrable Securities registered pursuant
hereunder and a CUSIP number for all such Registrable Securities, in each case not later than the effective date of such registration; and 

(j) Use its best efforts to furnish, at the request of any Holder requesting registration of Registrable Securities pursuant to this Article 2,
on the date that such Registrable Securities are delivered to the underwriters for sale in connection with a registration pursuant to this Article 2, if such securities are being sold through underwriters, or, if such securities are not being sold
through underwriters, on the date that the registration statement with respect to such securities becomes effective, (i) an opinion, dated such date, of the counsel representing the Corporation for the purposes of such registration, in form and
substance as is customarily given to underwriters in an underwritten public offering, addressed to the underwriters, if any, and to the Holders requesting registration of Registrable Securities and (ii) a letter dated such date, from the
independent certified public accountants of the Corporation, in form and substance as is customarily given by independent certified public accountants to underwriters in an underwritten public offering, addressed to the underwriters, if any, and to
the Holders requesting registration of Registrable Securities. 

  
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 2.5 Information Furnished by Holders. 

(a) It shall be a condition precedent of the Corporation’s obligations under Article 2 of this Agreement to any Holder that such Holder
furnish to the Corporation such information regarding the Holder, the Registrable Securities held by it and the distribution proposed by the Holder as the Corporation may reasonably request to effect any such registration and as are customarily
provided by selling stockholders. 
 (b) The Corporation shall have no obligation with respect to any registration requested pursuant to
Section 2.1(a) or 2.1(b) hereof if, due to the failure of any Holder or Holders to provide the information requested pursuant to Section 2.5(a), the number of shares or the anticipated aggregate offering price of the Registrable Securities
to be included in the registration does not equal or exceed the number of shares or the anticipated aggregate offering price required to originally trigger the Corporation’s obligation to initiate such registration as specified in
Section 2.1(a) or 2.1(b), as applicable. 
 2.6 Indemnification. 

(a) Indemnification by the Corporation. In the event of the registration of any Registrable Securities under the Securities Act pursuant
to the provisions hereof, the Corporation will, to the extent permitted by law, indemnify and hold harmless each Holder, any underwriter (as defined in the Securities Act) for such Holder and each person, if any, who controls such Holder within the
meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act (each such person being hereinafter sometimes referred to as an “indemnified person”), from and against any losses, claims, damages,
liabilities or expenses, joint or several, to which such indemnified person may become subject under the Securities Act, the Exchange Act, state securities laws and Blue Sky laws or otherwise, insofar as such losses, claims, damages, liabilities or
expenses (or actions in respect thereof) arise out of or are based upon (i) any untrue statement or alleged untrue statement of any material fact contained or incorporated by reference in any registration statement or prospectus or any
amendment or supplement thereto or in any preliminary prospectus, or any document incorporated by reference therein, or (ii) the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make
the statements therein not misleading, or (iii) any violation of the Securities Act, the Exchange Act, any “blue sky” or other state securities laws or any regulation promulgated thereunder and the Corporation will reimburse each such
indemnified person for any legal or any other expenses reasonably incurred by such indemnified person in connection with investigating or defending any such loss, claim, damage, liability or action as such expenses are incurred; provided,
however, that the Corporation will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement or omission or alleged omission made
or incorporated by reference in the registration statement, prospectus, amendment or supplement in reliance upon and in conformity with written information furnished to the Corporation by such indemnified person stating specifically that it is for
use in preparation thereof; and provided, further, that the Corporation shall have no obligation hereunder nor any liability with respect to any settlement of any action or proceeding effected without its written consent, which consent
shall not be unreasonably withheld, delayed or conditioned, but if settled with its written consent, or if there be a final judgment for the plaintiff in any such action or proceeding, the Corporation agrees to indemnify and hold harmless such
indemnified parties from and against any loss or liability by reason of such settlement or judgment. Such indemnity shall remain in full force and effect regardless of any investigation made by or on behalf of such indemnified person and shall
survive the transfer of such Registrable Securities by such seller. 

  
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 (b) Indemnification by Holder of Registrable Securities. In the event of the
registration of any Registrable Securities under the Securities Act pursuant to the provisions hereof, each Holder on whose behalf such Registrable Securities shall have been registered will, to the extent permitted by law, indemnify and hold
harmless the Corporation, each director of the Corporation, each officer of the Corporation who signs the registration statement, each underwriter, broker and dealer, if any, who participates in the offering and sale of such Registrable Securities
and each other person, if any, who controls the Corporation or any such underwriter, broker or dealer within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act (each such person being hereinafter
sometimes referred to as an “indemnified person”), against any losses, claims, damages or liabilities, joint or several, to which the Corporation, such director, officer, underwriter, broker or dealer or controlling person may
become subject under the Securities Act, the Exchange Act, state securities laws and Blue Sky laws or otherwise, insofar as such losses, claims, damages, liabilities or expenses (or actions in respect thereof) arise out of or are based upon any
untrue statement or alleged untrue statement of a material fact contained or incorporated by reference in any registration statement or prospectus or any amendment or supplement thereto or any document incorporated by reference therein, or arise out
of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, which untrue statement or alleged untrue statement or omission or
alleged omission has been made or incorporated therein in reliance upon and in conformity with written information furnished to the Corporation by such Holder stating specifically that it is for use in preparation thereof, and will reimburse the
Corporation and each such indemnified person for any legal or any other expenses reasonably incurred by the Corporation or such indemnified person in connection with investigating or defending any such loss, claim, damage, liability or action;
provided, however, that the obligations of each holder hereunder shall be limited to an amount equal to the net proceeds to such Holder of securities sold as contemplated herein; and provided, further, that no holder
shall have any obligation hereunder or be liable with respect to any settlement of any action or proceeding effected without its written consent, which consent shall not be unreasonably withheld, delayed or conditioned. 

(c) Procedure. Promptly after receipt by an indemnified party under this Section 2.6 of notice of the commencement of any action
(including any governmental action), such indemnified party will, if a claim in respect thereof is to be made against any indemnifying party under this Section 2.6, deliver to the indemnifying party a written notice of the commencement thereof,
but the omission to so notify the indemnifying party will not relieve it from any liability which it may have to any indemnified party otherwise than pursuant to the provisions of this Section 2.6 except to the extent materially prejudiced
thereby. In case any such action is brought against any indemnified party, and it notifies an indemnifying party of the commencement thereof, the indemnifying party will have the right to participate in, and to the extent that the indemnifying party
so desires, jointly with any other indemnifying party similarly noticed, to assume the defense thereof with counsel mutually satisfactory to the parties; provided, however, that an indemnified party (together with all other indemnified
parties which may be represented without conflict by one counsel) shall have the right to retain one separate counsel, with the fees and expenses to be paid by the indemnifying party, if representation of such indemnified party by the counsel
retained by the indemnifying party would be inappropriate due to actual or potential differing interests between such indemnified party and any other party represented by such counsel in such proceeding. No indemnifying party will consent to the
entry 

  
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of any judgment or enter into any settlement which (i) does not include as an unconditional term thereof the giving by the claimant or plaintiff to such indemnified party of a release from
all liability in respect to such claim or litigation or (ii) includes a statement as to or an admission of fault, culpability or a failure to act by or on behalf of any indemnified party. 

(d) Contribution. If the indemnification provided for in this Section 2.6 is held by a court of competent jurisdiction to be
unavailable to a party that would have been an indemnified party under this Section 2.6 with respect to any losses, claims, damages, liabilities or expenses (or actions in respect thereof) referred to therein, then each party that would have
been an indemnifying party thereunder shall, in lieu of indemnifying such indemnified party, contribute to the amount paid or payable by such indemnified party as a result of such losses, claims, damages, liabilities or expenses (or actions in
respect thereof) in such proportion as is appropriate to reflect the relative fault of the indemnifying party on the one hand and such indemnified party on the other in connection with the statement or omission which resulted in such losses, claims,
damages, liabilities or expenses (or actions in respect thereof), as well as any other relevant equitable considerations. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a
material fact or the omission or alleged omission to state a material fact relates to information supplied by the indemnifying party or such indemnified party and the parties’ relative intent, knowledge, access to information and opportunity to
correct or prevent such statement or omission. The amount paid or payable by a party as a result of the losses, claims, damages, liabilities and expenses referred to above shall be deemed to include any legal or other fees or expenses reasonably
incurred by such party in connection with investigating or defending any action or claim. The Corporation and each holder of Registrable Securities agrees that it would not be just and equitable if contribution pursuant to this Section 2.6(d)
were determined by pro rata allocation or by any other method of allocation which does not take account of the equitable considerations referred to above in this Section 2.6(d). The amount paid or payable by an indemnified party as a result of
the losses, claims, damages, liabilities or expenses (or actions in respect thereof) referred to above in this Section 2.6 shall include any legal or other expenses reasonably incurred by such indemnified party in connection with investigation
or defending any such action or claim if the indemnifying Party has assumed the defense of any such action in accordance with the provisions thereof). No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the
Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. 
 (e)
Underwriting Agreement to Control. Notwithstanding the foregoing, to the extent that the provisions on indemnification and contribution contained in the underwriting agreement entered into in connection with an underwritten public offering
are in conflict with the foregoing provisions, as between the Corporation and the Holder, on the one hand, and the underwriter, on the other hand, the provisions in the underwriting agreement shall control. 

(f) Limitation on Liability. The liability of any Holder of Registrable Securities pursuant to this Section 2.6 shall not exceed
the net proceeds received by such holder from a sale of Registrable Securities pursuant to a registration hereunder. 

  
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 2.7 Current Public Information. At all times after the Corporation has filed a
registration statement pursuant to the Securities Act, and such registration statement has become effective, the Corporation will use its best efforts to file all reports required under the Securities Act or the Exchange Act and will take such
further action as may be reasonably required to enable any holder of “restricted securities” (as defined in Rule 144 adopted by the Commission under the Securities Act) to sell such securities pursuant to Rule 144, as amended from time to
time, or any similar rule or regulation hereafter adopted by the Commission. 
 2.8 Transfer of Registration Rights. The rights under
this Agreement may be assigned by any Holder to the extent of the Registrable Securities assigned to a transferee or assignee who acquires at least 1,000,000 shares of a Holder’s Preferred Stock or, if a Holder owns less than 1,000,000 shares
of Preferred Stock, all of such Holder’s Preferred Stock, or an equivalent amount of Registrable Securities issued upon conversion thereof (adjusted for any dividends, subdivisions, combinations or reclassifications with respect to such
shares), provided that (i) such transfer may otherwise be effected in accordance with applicable securities laws, (ii) the Corporation is given written notice by the Holder at the time of or within a reasonable time after said transfer,
stating the name and address of said transferee or assignee and identifying the securities with respect to which such registration rights are being assigned and (iii) the transferee or assignee of such rights assumes in writing the obligations
of such Holder under this Article 2. The foregoing share limitation shall not apply, however, to transfers by a Holder which is a limited partnership to its partners or retired partners. 

2.9 Limitations on Subsequent Registration Rights. From and after the date hereof, the Corporation shall not, without the prior written
consent of the Holders (which consent will not be unreasonably withheld) of not less than a majority of the Registrable Securities then held by all Holders, enter into any agreement with any prospective holder of any securities of the Corporation
which would allow such prospective holder to demand registration of its securities or to include such securities in any registration filed under Section 2.1 hereof, unless under the terms of such agreement, such prospective holder may include
such securities in any such registration only to the extent that the inclusion of such securities will not reduce the amount of the Registrable Securities of the Holders which are included. 

2.10 “Market Stand-Off” Agreement. Each Holder hereby agrees
that, for a period of duration specified by the Corporation and an underwriter of common stock or other securities of the Corporation (such period not to exceed 180 days) following the effective date of the first registration statement of the
Corporation filed under the Securities Act which covers securities to be sold on the Corporation’s behalf to the public in an underwritten offering, it shall not, to the extent requested by the Corporation and its underwriter, directly or
indirectly sell, offer to sell, contract to sell (including, without limitation, any short sale), grant any option to purchase or otherwise transfer or dispose of (other than to donees who agree to be similarly bound) any securities of the
Corporation held by it at any time during such period except Registrable Securities included in such registration; provided, however, that such agreement shall not be required unless all officers and directors of the Corporation and
all other persons with registration rights (whether or not pursuant to this Agreement) enter into similar agreements. Any discretionary waiver or termination of the restrictions of any or all of such agreements by the Corporation or the underwriters
shall apply pro rata to all Holders subject to such agreements, based on the number of shares subject to such agreements, subject to customary exceptions. In order to enforce the foregoing covenant, the Corporation may impose stop-transfer
instructions with respect to the Registrable Securities of each Holder (and the shares or securities of every other person subject to the foregoing restriction) until the end of such period. 

  
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 2.11 Termination of Registration Rights. The right of any Holder to request
registration or inclusion in any registration pursuant to this Agreement shall terminate after the later of: 
 (a) five (5) years
following the closing of the Corporation’s initial underwritten public offering of Common Stock; and 
 (b) such date, on or after the
closing of the Corporation’s initial underwritten public offering of Common Stock, on which such Holder holds less than one percent (1%) of the Corporation’s outstanding Common Stock (treating all shares of Preferred Stock on an as-converted basis) and may immediately sell all shares of its Registrable Securities under Rule 144 during any ninety-day period. 

ARTICLE 3 Covenants of the Corporation. The Corporation covenants and agrees that, as long as any shares of Preferred Stock remain
outstanding, it will observe and perform the following covenants and provisions: 
 3.1 Inspection. The Corporation will permit each
Major Holder or its representative, at such Major Holder’s expense, and examiners of the SBA, to visit and inspect the properties and assets of the Corporation, to examine its books of account and records, and to discuss the Corporation’s
affairs, finances and accounts with the Corporation’s officers, senior management and accountants, all at such reasonable times as may be requested by such Major Holder or the SBA. The Major Holder shall maintain the confidentiality of any
confidential and proprietary information so obtained by it which is not otherwise available from other sources that are free from similar restrictions; provided, however, that the foregoing shall in no way limit or otherwise restrict
the ability of each Major Holder or its authorized representatives to disclose any such information concerning the Corporation which it may be required to disclose (a) to its partners, board members or stockholders, to the extent required to
satisfy its fiduciary obligations to such persons, or (b) otherwise pursuant to or as required by law. 
 3.2 Financial
Statements. The Corporation will furnish or cause to be furnished: 
 (a) Monthly and Quarterly Reports. To each Major Holder,
(i) within thirty (30) days after the end of each month, consolidated monthly unaudited financial statements (including a balance sheet and a statement of operations for the month and year-to-date, each in comparative form with the previous month) for the previous month (all prepared in accordance with generally accepted accounting principles consistently applied), and (ii) within
forty-five (45) days of the end of each quarter, consolidated quarterly unaudited financial statements (including a balance sheet and a statement of operations for the quarter and
year-to-date, each in comparative form with the previous quarter) for the previous quarter (all prepared in accordance with generally accepted accounting principles
consistently applied), in each case with management’s analysis of results and a statement of the chief financial officer of the Corporation explaining any material differences from budget. The foregoing financial statements shall be certified
by the chief executive officer or chief financial officer of the Corporation to the effect that such statements fairly present the financial position and financial results of the Corporation for the fiscal period covered. 

  
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 (b) Annual Financial Statements. To each Holder, within one hundred twenty
(120) days after the end of each fiscal year of the Corporation (i) the consolidated and consolidating balance sheets of the Corporation and its subsidiaries as of the end of such year, and (ii) the related consolidated and
consolidating statements of income, retained earnings and cash flows for such year, setting forth in comparative form with respect to such consolidated financial statements figures for the previous fiscal year, all in reasonable detail, together
with the opinion thereon of the Corporation’s independent certified public accountants, which accountants shall be a nationally recognized accounting firm reasonably acceptable to the Holders, and which opinion shall state that such financial
statements have been prepared in accordance with generally accepted accounting principles applied on a basis consistent with that of the preceding fiscal year (except for changes, if any, which shall be specified and approved in such opinion) and
that the audit by such accountants in connection with such financial statements has been made in accordance with generally accepted auditing standards related to reporting. 

(c) Budget and Operating Forecast. To each Major Holder, for each fiscal year of the Corporation, at least thirty (30) days prior
to the beginning of each fiscal year, a business plan, projections and monthly budget for the coming year, together with a capital expenditures budget, approved by the Board; and such budget shall be accepted as the Corporation’s budget for
such fiscal year when it has been approved by a majority vote of the Board, including three Holder Directors (as defined hereinafter). The approved budget shall be reviewed by the Corporation periodically and all necessary changes or revisions to
such budget shall be resubmitted to the Board and shall be accepted when approved in accordance with, and the Corporation shall not make any such changes to the budget without such approval in accordance with, the majority of the Board, including a
majority of the Holder Directors. 
 (d) Termination of Certain Provisions. The provisions of paragraph (a), (b) and (c) of this
Section 3.2 shall terminate at the time the Corporation becomes subject to the reporting provisions of the Securities Exchange Act of 1934, as amended. 

(e) Auditor’s Letters. To each Major Holder, promptly following receipt by the Corporation, each audit response
letter, accountant’s management letter and other written report submitted to the Corporation by its independent public accountants in connection with an annual or interim audit of the books of the Corporation. 

(f) Use of Proceeds. The Corporation will deliver to each SBIC from time to time promptly following such SBIC’s request, a written
report, certified as correct by the Corporation’s chief financial officer, verifying the purposes and amounts for which proceeds from the investment in the Preferred Stock have been disbursed. The Corporation will supply to each SBIC such
additional information and documents as such SBIC reasonably requests with respect to its use of proceeds and will permit such SBIC to have access to any and all Corporation records, information and personnel as such SBIC deems necessary to verify
how such proceeds have been or are being used. 

  
 -17- 

 (g) Information Covenant. Within 60 days after the end of the fiscal year of the
Corporation, the Corporation will furnish or cause to be furnished to each SBIC information required by the SBA on an SBA form provided by each SBIC concerning the economic impact of such SBIC’s investment in the Corporation, for (or as of the
end of) such fiscal year, including but not limited to, information concerning full-time equivalent employees; Federal, state and local income taxes paid; gross revenue; source of revenue growth; after-tax
profit or loss; and Federal, state and local income tax withholding. The Corporation will also furnish or cause to be furnished to each SBIC such other information regarding the business, affairs and condition of the Corporation as such SBIC may
from time to time reasonably request. 
 3.3 Management Rights. Each Major Holder will be entitled to consult with and advise
management of the Corporation on significant business issues, including management’s proposed annual operating plans, and management will meet with Major Holders regularly during each year at the Corporation’s facilities at mutually
agreeable times for such consultation and advice and to review progress in achieving said plans. 
 3.4 Insurance. The Corporation
shall keep its insurable properties insured at all times to such extent and against such risks, including fire, and other risks insured against by extended coverage, as is customary with companies of comparable size and financial condition in the
same or similar businesses; maintain in full force and effect product liability insurance and public liability insurance against claims for personal injury or death or property damage occurring upon, in, about or in connection with the use of any
properties owned, occupied or controlled by the Corporation, in such amount as the Corporation shall reasonably deem necessary; and maintain workers’ compensation insurance and such other insurance as may be required by law. In addition, all of
the foregoing insurance maintained by the Corporation shall be of types and in amounts such that the Corporation at all times will be in compliance in all respects with all federal, state, local and foreign laws, ordinances, regulations and orders
applicable to its business that govern such insurance. 
 (a) The Corporation has as of the date hereof, or shall within thirty
(30) days of the date hereof, obtained from financially sound and reputable insurers term life insurance on the life of the Chief Executive Officer of the Corporation in the amount of at least one million dollars ($1,000,000). Such policy shall
name the Corporation as loss payee and shall not be cancelable by the Corporation without prior approval of the Board and Requisite Majority. 

(b) Notwithstanding any other provision of this Section 3.4 to the contrary, the Corporation shall not cease to maintain a Directors and
Officers liability insurance policy in an amount of at least two million dollars ($2,000,000) unless approved by the Requisite Majority, and the Corporation shall annually, upon request, within one hundred twenty (120) days after the end of
each fiscal year of the Corporation, deliver to each Requisite Party a certification that such a Directors and Officers liability insurance policy remains in effect. 

3.5 Obligations and Taxes. The Corporation shall pay all of its indebtedness and obligations promptly and in accordance with their terms
and pay and discharge promptly all taxes imposed upon it or its income or profits or in respect of its property, before the same shall become in default, as well as all lawful claims for labor and supplies or otherwise which, if unpaid, might become
a lien or charge upon such properties or any part thereof; provided, 

  
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however, that the Corporation shall not be required to pay and discharge or to cause to be paid and discharged any such taxes so long as the validity or amount thereof shall be contested
in good faith by appropriate proceedings, the Corporation, as applicable, shall set aside on its books such reserves as are required by generally accepted accounting principles with respect to any such taxes and no liens have been assessed against
the Corporation or any of its assets. 
 3.6 Existence; Maintenance of Property. The Corporation shall do or cause to be done all
things necessary to preserve, renew and keep in full force and effect its corporate existence, material rights, licenses, permits and franchises and comply with all laws and regulations applicable to the conduct of its business and the ownership of
its property; at all times maintain and preserve all material property necessary in the conduct of the business and keep the same in good repair, working order and condition, and from time to time make, or cause to be made, all needed and proper
repairs, renewals and replacements thereto, so that the business carried on in connection therewith may be properly conducted at all times. 

3.7 System of Accounting. The Corporation shall maintain a system of accounting established and administered in accordance with
generally accepted accounting principles. 
 3.8 Related Transaction. The Corporation shall not, directly or indirectly, enter into
any Related Transaction other than on an arm’s length basis, on terms no less favorable to the Corporation than could be obtained from non-related persons and with the prior approval of the Board,
including three Holder Directors. 
 3.9 Loans and Investments. The Corporation will not make any loan or advance (other than advances
in the ordinary course of business consistent with past practice with regard to valid business expenses) or extend credit to any person or entity (other than trade credit in the ordinary course consistent with past practice), or make any investment
in such person or entity, or its securities, except (a) investments in United States Treasury obligations, (b) certificates of deposit, bankers acceptances and other “money market instruments” issued by any bank or trust company
organized under the laws of the United States or any state thereof and having capital and surplus not less than $100,000,000, (c) open market commercial paper bearing Standard & Poor’s highest credit rating or by another similar
nationally recognized firm, and repurchase agreements with any bank or trust company organized under the laws of the United States or any state thereof and having capital and surplus not less than $100,000,000 relating to United States government
obligations, in each case maturing in less than one year, and (d) investments in mutual funds (registered under the Investment Company Act of 1940), which have net assets of at least $200,000,000 and at least eighty-five percent (85%) of whose
assets consist of obligations having an investment grade credit grading from either Standard & Poor’s Corporation or Moody’s Investors Service, Inc. and/or equity securities of entities that have obligations with such credit
ratings. 
 3.10 Compliance with Laws. The Corporation shall comply with all applicable laws, rules, regulations and orders,
noncompliance with which could adversely affect its business or condition, financial or otherwise. The Corporation will not offer, sell or solicit offers to buy or otherwise negotiate in respect of any security (as defined in the Securities Act)
that will be integrated with the sale of the Series H Preferred Stock in a manner that would require the registration of the Series H Preferred Stock under the Securities Act. 

  
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 3.11 Dividends. Except as otherwise provided for in the Certificate of Incorporation,
the Corporation shall not declare, set aside, or make any payment of a dividend or make any other distribution in respect of its capital stock, repurchase or redeem any of its capital stock or make any other payments to any holder of its outstanding
capital stock. 
 3.12 Reservation of Conversion Stock. The Corporation will, upon any increase in the number of shares of Common
Stock issuable upon conversion of the Preferred Stock, reserve additional shares of Common Stock for issuance upon such conversion, so that the number of shares of Common Stock so authorized will not at any time be less than the number of such
shares issuable upon such conversion. 
 3.13 Press Releases. The Corporation agrees to give the Major Holders advanced notice of, and
to consult with the Major Holders concerning the content of, any public announcements that the Corporation intends to make. 
 3.14
Internal Revenue Code Section 1202. The Corporation covenants that so long as any of the Preferred Stock (or Common Stock issued upon conversion thereof) are held by a Major Holder (or a permitted transferee in whose
hands such Preferred Stock or Common Stock is eligible to qualify as “qualified small business stock” as defined in Section 1202(c) of the Internal Revenue Code), it will use its best efforts (including complying with any applicable
filing or reporting requirements imposed by the Internal Revenue Code on issuers of “qualified small business stock”) to cause the Preferred Stock and Common Stock issued upon conversion thereof to qualify as “qualified small business
stock”; provided, however, that “best efforts’ as used in this Section 3.14 shall not be construed to require the Corporation to operate its business in a manner that would adversely affect its business, limit its
future prospects, or alter the timing or resource allocation related to its planned operations or financing activities. When requested by a Major Holder, the Corporation will provide a letter or certificate to the effect that the Preferred Stock and
Common Stock issued upon conversion or exercise thereof purchased from the Corporation are “qualified small business stock.” 

3.15 SBIC Permitted Activities and Proceeds. Neither the Corporation nor any of its Affiliates (as defined in the SBIC Act) will engage
in any activities or use directly or indirectly the proceeds from the sale of the Preferred Stock for any purpose for which a small business investment company is prohibited from providing funds by the SBIC Act, including 13 C.F.R. §107. The
general categories are (i) relenders or reinvestors, (ii) passive businesses, (iii) real estate businesses, (iv) project financing and (v) foreign investment. 

3.16 Expenses of Counsel. In the event of a transaction which is a Sale of the Corporation (as defined in the Amended and Restated
Stockholders’ Agreement (the “Stockholders’ Agreement”) of even date herewith among the Investors (as defined therein) and the Corporation), the reasonable fees and disbursements of one counsel for the Major
Investors (as defined in the Stockholders’ Agreement) (“Investor Counsel”), in their capacities as stockholders, shall be borne and paid by the Corporation. At the outset of considering a transaction which, if consummated would
constitute a Sale of the Corporation, the Corporation 

  
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shall obtain the ability to share with the Investor Counsel (and such counsel’s clients) and shall share the confidential information (including, without limitation, the initial and all
subsequent drafts of memoranda of understanding, letters of intent and other transaction documents and related noncompete, employment, consulting and other compensation agreements and plans) pertaining to and memorializing any of the transactions
which, individually or when aggregated with others would constitute the Sale of the Corporation. The Corporation shall be obligated to share (and cause the Corporation’s counsel and investment bankers to share) such materials when distributed
to the Corporation’s executives and/or any one or more of the other parties to such transaction(s). In the event that Investor Counsel deems it appropriate, in its reasonable discretion, to enter into a joint defense agreement or other
arrangement to enhance the ability of the parties to protect their communications and other reviewed materials under the attorney client privilege, the Corporation shall, and shall direct its counsel to, execute and deliver to Investor Counsel and
its clients such an agreement in form and substance reasonably acceptable to Investor Counsel. In the event that one or more of the other party or parties to such transactions require the clients of Investor Counsel to enter into a confidentiality
agreement and/or joint defense agreement in order to receive such information, then the Corporation shall share whatever information can be shared without entry into such agreement and shall, at the same time, in good faith work expeditiously to
enable Investor Counsel and its clients to negotiate and enter into the appropriate agreement(s) without undue burden to the clients of Investor Counsel. 

3.17 Termination of this Section 3. The provisions of this Section 3 shall terminate immediately upon the
closing of the Corporation’s initial underwritten public offering of Common Stock, unless earlier terminated pursuant to this Agreement. 

ARTICLE 4 Indemnification. 

4.1 The Corporation shall hold harmless and indemnify the Holders and their respective direct and indirect subsidiaries, Affiliates and
corporations, and each of their partners, officers, directors, managers, employees, stockholders, agents, and other representatives (collectively, referred to as the “Indemnitees”) against any and all expenses (including
attorneys’ fees), damages, judgments, fines, amounts paid in settlements, or any other amounts that an Indemnitee incurs as a result of any claim or threatened, pending or completed action, suit, arbitration, investigation or other proceeding
arising out of, or relating to the Indemnitee’s performance of its obligations or the exercise of its rights in accordance with the terms of this Agreement or the Certificate of Incorporation or Indemnitee’s status as a security holder of
the Corporation; provided, however, that no Indemnitee shall be entitled to be held harmless or indemnified by the Corporation for acts, conduct or omissions by any Indemnitee (i) if the Indemnitee failed to act in good faith or
in a manner that such Indemnitee reasonably believed to be in or not opposed to the best interests of the Corporation, or, (ii) with respect to any criminal action or proceeding, if the Indemnitee’s conduct was unlawful. 

4.2 The Corporation shall reimburse within 30 days after the receipt by the Corporation of a written statement or statements from an Indemnitee
requesting such reimbursement all reasonable expenses incurred by an Indemnitee (or any third party indemnitor of such Indemnitee) in connection with any threatened, pending or completed action, suit, arbitration, investigation or other proceeding
for which the Corporation is obligated to indemnify such Indemnitee according to Section 4.1 above. 

  
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 4.3 The Corporation hereby acknowledges that one (1) or more of the Senior Preferred
Directors (as defined in the Stockholders’ Agreement) (each a “Holder Director”) may have certain rights to indemnification, advancement of expenses and/or insurance provided by one or more of the Holders and certain of their
Affiliates (collectively, the “Holder Indemnitors”). The Corporation hereby agrees (a) that it is the indemnitor of first resort (i.e., its obligations to any such Holder Director are primary and any obligation of
the Holder Indemnitors to advance expenses or to provide indemnification for the same expenses or liabilities incurred by such Holder Director are secondary), (b) that it shall be required to advance the full amount of expenses incurred by such
Holder Director and shall be liable for the full amount of all expenses, judgments, penalties, fines and amounts paid in settlement by or on behalf of any such Holder Director to the extent legally permitted and as required by the Certificate of
Incorporation or the Bylaws of the Corporation (or any agreement between the Corporation and such Holder Director), without regard to any rights such Holder Director may have against the Holder Indemnitors, and, (c) that it irrevocably waives,
relinquishes and releases the Holder Indemnitors from any and all claims against the Holder Indemnitors for contribution, subrogation or any other recovery of any kind in respect thereof. The Corporation further agrees that no advancement or
payment by the Holder Indemnitors on behalf of any such Holder Director with respect to any claim for which such Holder Director has sought indemnification from the Corporation shall affect the foregoing and the Holder Indemnitors shall have a right
of contribution and/or be subrogated to the extent of such advancement or payment to all of the rights of recovery of such Holder Director against the Corporation. The Holder Directors and the Holder Indemnitors are intended third-party beneficiaries of this Subsection 4.3 and shall have the right, power and authority to enforce the provisions of this Subsection 4.3 as though they were a party to this Agreement. 

ARTICLE 5 Miscellaneous. 

5.1 Waivers and Amendments. This Agreement may not be amended, modified or waived at any time, unless such amendment, modification or
waiver is first approved in writing by (a) the Requisite Majority and (b) the Corporation; provided, however, that if any amendment, modification or waiver would apply to a Holder in a fashion different than how such
amendment, modification or waiver applies to all Holders (each, an “Adversely Affected Holder”), then such amendment, modification or waiver shall not be effective as to such Adversely Affected Holder unless consented to by such
Adversely Affected Holder. Any amendment, modification or waiver so effected shall be binding upon the Corporation, each of the parties hereto and any assignee of any such party. In addition, the Corporation may waive performance of any obligation
owing to it, as to some or all of the Holders, or agree to accept alternatives to such performance, without obtaining the consent of any Holder. No waiver of any breach of this Agreement extended by any party hereto to any other party shall be
construed as a waiver of any rights or remedies of any other party hereto or with respect to any subsequent breach. Notwithstanding the foregoing, without the written consent of the Major Holders holding at least a majority, collectively, of the
shares of Series C Preferred Stock, Series D Preferred Stock, Series E Preferred Stock, Series F Preferred Stock and Series H Preferred Stock issued and outstanding held by all such Major Holders, the obligations of the Corporation and the rights of
the parties under Sections 3.1, 3.2(a), 3.2(c), 3.2(e), 3.3, 3.14, 3.16 and 3.17 of this Agreement may not be amended, modified or waived (either generally or in a particular instance, either retroactively or prospectively, and either for a
specified period of time or indefinitely). 

  
 -22- 

 5.2 Governing Law. This Agreement shall be governed in all respects by the laws of
the State of Delaware, without regards to conflict of laws principles. Each of the Corporation and the Holders: (i) agrees that any legal suit, action or proceeding arising out of or relating to this Agreement and/or the transactions
contemplated hereby shall be instituted exclusively in New York Supreme Court, County of New York, or in the United States District Court for the Southern District of New York, (ii) waives any objection which it may have or hereafter to the
venue of any such suit, action or proceeding, and (iii) irrevocably consents to the jurisdiction of the New York Supreme Court, County of New York, and the United States District Court for the Southern District of New York in any such suit,
action or proceeding. 
 5.3 Effectiveness; Entire Agreement. This Agreement shall become effective concurrently with the consummation
of the purchase and sale of the Series H Preferred Stock under the Series H Purchase Agreement at the Closing. This Agreement and the other documents delivered in connection herewith constitute the full and entire understanding of the parties with
regard to the subjects hereof and thereof, and this Agreement shall supersede and cancel all prior agreements between the parties hereto with regard to the subject matter hereof, including the Prior Agreement. 

5.4 Notices, etc. All notices and other communications required or permitted hereunder (each, a “Notice”) shall be in
writing and shall be delivered by overnight courier service or mailed by first class mail, postage prepaid, certified or registered mail, return receipt requested, addressed (a) if to a Holder, at such party’s address as set forth in the
Corporation’s records, or at such other address as such party shall have furnished to the Corporation in writing or (b) if to the Corporation, to it at the address set forth on the Corporation’s signature page hereto or other address
as the Corporation shall have furnished to the Holder in writing. All Notices shall be deemed effectively given: (x) upon personal delivery to the party to be notified, (y) three (3) days after having been sent by first class mail, postage
prepaid, certified or registered mail, return receipt requested and (z) one (1) day after deposit with an overnight courier service. 

5.5 Severability. In case any provision of this Agreement shall be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions of this Agreement shall not in any way be affected or impaired thereby. 
 5.6 Title and
Subtitles. The titles of the sections and subsections of this Agreement are for convenience of reference only and are not to be considered in construing this Agreement. 

5.7 Attorneys’ Fees. If any action at law or in equity is necessary to enforce or interpret the terms of this Agreement, the
prevailing party shall be entitled to reasonable attorneys’ fees, costs and disbursements in addition to any other relief to which such party may be entitled. 

5.8 Counterparts; Execution by Facsimile Signature. This Agreement may be executed in any number of counterparts, each of which shall be
an original, but all of which together shall constitute one instrument. Counterparts may be delivered via facsimile, electronic mail (including pdf or any electronic signature complying with the U.S. federal ESIGN Act of 2000, e.g.,
www.docusign.com) or other transmission method and any counterpart so delivered shall be deemed to have been duly and validly delivered and be valid and effective for all purposes. 

  
 -23- 

 5.9 Aggregation of Stock. All shares of Preferred Stock and Common Stock of the
Corporation held or acquired by affiliated entities or persons shall be aggregated for the purpose of determining the availability of any rights under this Agreement. 

5.10 Additional Investors. Notwithstanding anything to the contrary contained herein, if the Corporation shall issue additional shares
of Preferred Stock from time to time, any purchaser of such shares of Preferred Stock may become a party to this Agreement by executing and delivering an additional counterpart signature page to this Agreement and shall be deemed a
“Holder” and a party hereunder. 
 * * * * * * * 

  
 -24- 

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated
Investors’ Rights Agreement as of the date first above written. 
  

			
	CORPORATION:
	
	EXAGEN INC.
		
	By:	 	 /s/ Ron Rocca

	Name:	 	Ron Rocca
	Title:	 	President and Chief Executive Officer
	
	Address:
	
	Exagen Inc.
	1261 Liberty Way
	Vista, CA 92081
	
	With a copy to:
	
	Latham & Watkins, LLP
	12670 High Bluff Drive
	San Diego, CA 92130
	Attention: Matthew T. Bush

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
			
	HOLDERS:
	
	H.I.G. Bio-Exagen, L.P.
		
	By:	 	 /s/ Bruce Robertson

	Name: Bruce Robertson
	Title: Managing Director

 
			
		
	Address:	 	1450 Brickell Avenue
		 	31st Floor
		 	Miami, FL 33131
	
	With a copy (which shall not serve as notice) to:
	
	 Goodwin Procter LLP
 100 Northern
Ave

	Boston, MA 02210
	Attention: Arthur R. McGivern

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
			
	NMSIC CO-INVESTMENT FUND, L.P.
	By: Sun Mountain Capital Partners LLC, its general partner
		
	By:	 	 /s/ Brian Birk

		 	    Brian Birk, Managing Partner
		
	By:	 	 /s/ Lee Rand

		 	    Lee Rand, Managing Member
	
	NMSIC FOCUSED LLC
	By: NMSIC Co-Investment Fund LP, its sole member
	By: Sun Mountain Capital Partners LLC, its general partner
		
	By:	 	 /s/ Brian Birk

		 	    Brian Birk, Managing Partner
		
	By:	 	 /s/ Lee Rand

		 	    Lee Rand, Managing Member

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
			
	 JAMES J. SCHWARZ and JEANETTE M.

SCHWARZ, CO-TRUSTEES OF THE

SCHWARZ TRUST

		
	By:	 	 /s/ James J. Schwarz

		 	    James J. Schwarz

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
			
	NEW TECH I, L.P.
		
	By:	 	 /s/ David Durgin

	Name: David Durgin
	Title: General Partner

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
			
	SOUTHWEST MEDICAL VENTURES, INC.
		
	By:	 	 /s/ Waneta C. Tuttle

	Name: Waneta C. Tuttle
	Title: President

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
			
	TULLIS-DICKERSON CAPITAL FOCUS III, L.P.
	By: Tullis-Dickerson Partners III, L.L.C., its general partner
		
	By:	 	 /s/ James L.L. Tullis

	Name: James L.L. Tullis
	Title: Manager
	
	TULLIS-GROWTH FUND, L.P.
		
	By:	 	Tullis-Growth Partners, L.L.C., its general partner
		
	By:	 	 /s/ James L.L. Tullis

	Name: James L.L. Tullis
	Title: Manager
	
	TULLIS-GROWTH FUND II, L.P.
		
	By:	 	Tullis-Growth Partners II, L.L.C., its general partner
		
	By:	 	 /s/ James L.L. Tullis

	Name: James L.L. Tullis
	Title: Manager
	
	 /s/ James L.L. Tullis

	JAMES L.L. TULLIS

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
			
	HUNT HOLDINGS LIMITED PARTNERSHIP
	By:	 	HuntVest, LLC, its General Partner
	By:	 	Hunt Guaranty Inc., its Sole Member
		
	By:	 	 /s/ Matthew D. Hunt

	Matthew D. Hunt, Managing Partner

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
			
	PCM/EXAGEN, L.P.
		
	By:	 	 /s/ Ebetuel Pallares

	Name: Ebetuel Pallares
	Title: Managing Partner

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
			
	BURRELL DIVERSIFIED INVESTMENTS, LLC
		
	By:	 	 /s/ Daniel C. Burrell

	Name: Daniel C. Burrell
	Title: Operating Manager

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
	
	LINDA A. TULLIS
	
	 /s/ Linda A. Tullis

	LINDA A. TULLIS, TRUSTEE OF HPS IRREVOCABLE TRUST #3 U/A DTD 7/6/93

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 
			
	GERRIT JOHAN KREDIET
		
	By:	 	 /s/ Chris Krediet

	Name: Chris Krediet

  
 [Signature Page to
Amended and Restated Investors’ Rights Agreement] 

 SCHEDULE A 

HOLDERS 
 H.I.G. BioHealth
Partners, LLC 
 Wasatch Venture Fund III, LP 
 Wasatch New
Mexico Fund, LLC 
 vSpring SBIC, L.P. 
 vSpring, L.P. 

vSpring Partners, L.P. 
 NMSIC
Co-Investment Fund, L.P. 
 NMSIC Focused, LLC 

James J. Schwarz and Jeanette M. Schwarz, Co-Trustees of the Schwarz Trust 

New Tech I, L.P. 
 Pamela J. Sullivan and Thomas A. Tumolillo 

Quatro Ventures, LLC 
 Ray Radosevich 

Robert and Marcia Cates 
 Robert H. Nath 

Southwest Medical Ventures, Inc. 
 Sheryl A. Johnson 

John P. Alsobrook, II 
 Dale Olson 

Mesa Verde Venture Partners, L.P. 
 PCM/Exagen, L.P. 

Hunt Holdings L.P. 
 Tullis-Dickerson Capital Focus III, L.P. 

Tullis-Growth Fund, L.P. 
 Tullis-Growth Fund II, L.P. 

James L.L. Tullis 
 Linda A. Tullis 

Linda A. Tullis Trustee of HPS Irrevocable Trust #3 U/A DTD 7/6/93 

Berge K. Hagopian and Mary Ann Hagopian, Co-Trustees, Hagopian Family Trust UA DTD 03/25/88 

Timothy M. Pennington and Melissa J. Pennington as Trustees of the Pennington Family 

Endochoice, Inc. 
 Glenn Holdings, L.P. 

Burrell Diversified Investments, LLC 
 Gerrit Johan Krediet 

Samuel D. Riccitelli 
 Michael WalshEX-4.3

 Exhibit 4.3 

EXAGEN INC. 
 AMENDED
AND RESTATED 
 STOCKHOLDERS’ AGREEMENT 

THIS AMENDED AND RESTATED STOCKHOLDERS’ AGREEMENT (this “Agreement”) is made as of July 12, 2019, by and among
Exagen Inc., a Delaware corporation (the “Corporation”), and the persons listed on Schedule A hereto (the “Investors” and, each, an “Investor”). 

RECITALS 
 WHEREAS,
certain of the Investors (the “Existing Investors”) are party to that certain Amended and Restated Stockholders Agreement of the Corporation dated January 2, 2019 (as amended, the “Prior Agreement”); 

WHEREAS, in connection with the sale of shares of Series H Preferred Stock (as defined hereinafter) the Corporation has amended and restated
its Certificate of Incorporation (as defined hereinafter) to reflect an exchange of all outstanding shares of Series G Preferred Stock (as defined hereinafter) for shares of Series H Preferred Stock on a dollar-for-dollar basis; 
 WHEREAS, certain of the Investors and the Corporation have entered into
that certain Series H Preferred Stock Purchase Agreement dated the date hereof (the “Series H Purchase Agreement”), pursuant to which such Investors agreed to purchase from the Corporation, and the Corporation agreed to sell to such
Investors, shares of Series H Preferred Stock (as defined hereinafter); 
 WHEREAS, the Prior Agreement permits the Corporation, the record
or beneficial Investors owning at least 52% of the issued and outstanding shares of Series G Convertible Preferred Stock, par value $0.001 per share (the “Series G Preferred”), Series F Convertible Preferred Stock, par value $0.001
per share (the “Series F Preferred”), Series E Convertible Preferred Stock, par value $0.001 per share (the “Series E Preferred”), Series D Convertible Preferred Stock, par value $0.001 per share (the
“Series D Preferred”), the Series C Convertible Preferred Stock, par value $0.001 per share (the “Series C Preferred”), and the Series B-3 Convertible Preferred Stock, par
value $0.001 per share (the “Series B-3 Preferred”), voting together as a single class, to amend the Prior Agreement; and 

WHEREAS, as a condition to the consummation of the transactions contemplated by the Series H Purchase Agreement, the undersigned Investors,
who are inter alia the record or beneficial Investors owning at least 52% of the shares of the Series G Preferred, Series F Preferred, Series E Preferred, Series D Preferred, Series C Preferred and Series B-3
Preferred, voting together as a single class, outstanding as of the date hereof, and the Corporation desire to amend and restate the Prior Agreement in its entirety as set forth herein, to provide for the future voting of the Investors’ shares
of Capital Stock and to set forth their respective rights and obligations relating to certain transfers of such shares, in each case as set forth herein with the intention that this Agreement shall become effective concurrently with the Closing (as
defined in the Series H Purchase Agreement). 

 AGREEMENT 

NOW THEREFORE, in consideration of the foregoing and of the mutual promises and covenants contained herein and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereby agree as follows: 
 SECTION 1.
Definitions. As used in this Agreement, the following terms shall have the following respective meanings: 
 “Adversely
Affected Investor” shall have the meaning set forth in Section 10.4. 
 “Affiliate” shall mean, with respect
to any Investor, any person or entity controlling, controlled by or under common control with such Investor, and (i) with respect to vSpring SBIC, L.P., shall include any affiliate of vSpring Capital, LLC, (ii) with respect to Wasatch
Venture Fund III, L.L.C., shall include any venture capital fund managed by the general partners of Wasatch Venture Fund III, L.L.C., (iii) with respect to NMSIC Co-Investment Fund, L.P., shall include any
affiliate of Sun Mountain Capital Partners, LLC, (iv) with respect to PCM/Exagen, L.P., shall include Hunt Holdings L.P., and (v) with respect to Tullis-Dickerson Capital Focus III, L.P., shall include any pooled investment vehicle managed
by Tullis Health Investors of FL, LLC, and any of its affiliates. 
 “Agreement” shall mean this Amended and Restated
Stockholders’ Agreement, as the same may be amended from time to time. 
 “Approved Action” shall have the meaning set
forth in Section 10.1. 
 “Board” shall mean the Board of Directors of the Corporation. 

“Capital Stock” shall mean the Common Stock and Preferred Stock. For purposes of the number of shares of Capital Stock held
by an Investor or Key Holder (or any other calculation based thereon), all shares of Preferred Stock shall be deemed to have been converted into Common Stock at the then-applicable conversion ratio. 

“Certificate” shall mean the Amended and Restated Certificate of Incorporation of the Corporation, as the same may be amended
from time to time. 
 “Closing” shall have the meaning set forth in the Series H Purchase Agreement. 

“Common Director” shall have the meaning set forth in Section 4.1.(a)(ii). 

“Common Stock” shall mean the Corporation’s common stock, $0.001 par value per share. 

“Corporation Notice” means written notice from the Corporation notifying the Transferring Investors and each Investor that
the Corporation intends to exercise its Right of First Refusal as to some or all of the Transfer Stock with respect to any Proposed Transfer. 

  
 -2- 

 “Corporation” shall mean Exagen Inc., a Delaware corporation, its
successors and assigns. 
 “Deemed Liquidation Event” shall have the meaning set forth in Section 5.1. 

“Electing Investor” shall have the meaning set forth in Section 2.2. 

“Excluded Securities” shall mean Common Stock issued or issuable (a) pursuant to the Series H Purchase Agreement,
(b) upon conversion of the Preferred Stock, (c) to officers, directors or employees of, or consultants to, the Corporation pursuant to any stock option, incentive, bonus or compensation program approved by the Board or such other
arrangements, contracts, or plans as are recommended by management and approved by the Board, (d) by way of dividend or other distribution on shares of Preferred Stock or by way of distribution on shares of Common Stock or Preferred Stock
pursuant to stock splits, recapitalizations and similar transactions, (e) upon exercise of warrants to purchase shares of Preferred Stock or Common Stock, (f) in a transaction with respect to which the Requisite Majority (as defined below)
have waived their rights under Section 2 hereof, (g) in connection with a business acquisition of or by the Corporation approved by the Board, (h) pursuant to equipment lease financings or bank credit arrangements approved by the
Board, (i) for charitable purposes approved by the Board, (j) as part of a corporate partnering transaction approved by the Board or (k) shares of Common Stock issued or issuable in a firm-commitment underwritten public offering
pursuant to an effective registration statement under the Securities Act, before which or in connection with which all outstanding shares of Preferred Stock will be automatically converted into Common Stock pursuant to the terms of the Certificate.

 “Existing Investors” shall have the meaning set forth in the Recitals. 

“Financing Securities” shall have the meaning set forth in Section 2.1. 

“H.I.G.” shall mean H.I.G. Bio-Exagen, L.P. and affiliates thereof. 

“H.I.G. Director” shall have the meaning set forth in Section 4.1(a)(i)(D). 

“Independent Director” shall have the meaning set forth in Section 4.1.(a)(iii). 

“Investor” shall have the meaning set forth in the preamble. 

“Investor Notice” means written notice from any Investor notifying the Corporation and the Transferring Investor(s) that the
Investor providing notice intends to exercise its Secondary Refusal Right as to a portion of the Transfer Stock with respect to any Proposed Transfer. 

“Major Investor” and “Major Investors” shall have the meaning set forth in Section 2.1. 

“Non-electing Investor” shall have the meaning set forth in Section 2.2. 

“Notice of Acceptance” shall have the meaning set forth in Section 2.2. 

  
 -3- 

 “Offer” shall have the meaning set forth in Section 2.1. 

“Option” shall mean any security convertible into, or exchangeable or exercisable for, shares of Common Stock. 

“PCM/Hunt” shall have the meaning set forth in Section 4.1.(a)(i)(C). 

“PCM/Hunt Director” shall have the meaning set forth in Section 4.1.(a)(i)(C). 

“Preferred Stock” shall mean the Series A-3 Preferred, the Series B-3 Preferred, the Series C Preferred, the Series D Preferred, the Series E Preferred, the Series F Preferred, the Series G Preferred and the Series H Preferred. 

“Proposed Sale” shall have the meaning set forth in Section 5.3. 

“Proposed Transfer” shall mean any assignment, sale, offer to sell, pledge, mortgage, hypothecation, encumbrance, disposition
of or any other like transfer or encumbering of any Transfer Stock proposed by any Investor. 
 “Proposed Transfer Notice”
shall mean written notice from an Investor setting forth the terms and conditions of a Proposed Transfer. 
 “Prospective
Transferee” means any person to whom an Investor proposes to make a Proposed Transfer. 
 “pro rata share” shall
have the meaning set forth in Section 2.1. 
 “Registrable Securities” shall mean (i) all shares of Common Stock
issued or issuable upon conversion of the Preferred Stock, (ii) all shares of Common Stock issued or issuable upon exercise, conversion or exchange of any warrants or other securities exercisable, convertible or exchangeable for shares of
Common Stock, and (iii) all shares of Common Stock issued as (or issuable upon the conversion, exercise or exchange of any warrant, right or other security which is issued as) a dividend or other distribution with respect to, or in exchange for
or in replacement of, such securities; provided, however, that shares of Common Stock which are Registrable Securities shall cease to be Registrable Securities at such time, and for so long as, such shares are eligible for sale
pursuant to Rule 144 under the Securities Act (as defined hereinunder) or a similar exemption under the Securities Act is available for the sale of all of such Investor’s shares without registration and the Corporation shall have delivered to
the Investor an opinion of counsel to such effect which opinion and counsel shall be reasonably satisfactory to the Investor. 

“Requisite Party” shall be any of H.I.G., Sun Mountain (as defined below), Tullis (as defined below) or PCM/Hunt, each for so
long as it holds at least fifty percent (50%) of the shares of Preferred Stock that such party and its Affiliates held as of the date hereof. 

  
 -4- 

 “Requisite Majority” shall mean (A) for so long as H.I.G. is a
Requisite Party and three other Requisite Parties exist, either (i) any three Requisite Parties or (ii) H.I.G. and any other single Requisite Party, (B) for so long as H.I.G. is a Requisite Party and two other Requisite Parties exist,
H.I.G. and any other single Requisite Party, (C) for so long as H.I.G. is a Requisite Party and one or no other Requisite Party exists, H.I.G., (D) if H.I.G. is not a Requisite Party, the majority of shares of Preferred Stock then held by the
Requisite Parties, or (E) if no Requisite Party exists, Investors holding at least a majority of the shares of Senior Preferred (as defined below) then outstanding. 

“Remaining Securities” shall have the meaning set forth in Section 2.3. 

“Right of Co-Sale” shall mean the right, but not an obligation, of an Investor to
participate in a Proposed Transfer on the terms and conditions specified in the Proposed Transfer Notice. 
 “Right of First
Refusal” means the right, but not an obligation, of the Corporation, or its permitted transferees or assigns, to purchase some or all of the Transfer Stock with respect to a Proposed Transfer by an Investor, on the terms and conditions
specified in the Proposed Transfer Notice. 
 “ROFR/Co-Sale Investor” shall have
the meaning set forth in Section 3.1. 
 “Sale of the Corporation” shall have the meaning set forth in
Section 5.1. 
 “Secondary Refusal Right” means the right, but not an obligation, of each ROFR/Co-Sale Investor to purchase up to its pro rata portion (based upon the total number of shares of Capital Stock then held by all ROFR/Co-Sale Investors) of any Transfer
Stock not purchased pursuant to the Right of First Refusal, on the terms and conditions specified in the Proposed Transfer Notice. 

“Securities Act” shall mean the Securities Act of 1933, as amended, or any successor federal statute, and the rules and
regulations of the Commission promulgated thereunder, all as the same shall be in effect from time to time. 
 “Selling
Investors” shall have the meaning set forth in Section 5.2. 
 “Senior Preferred” shall mean the Series H
Preferred, Series F Preferred, Series E Preferred, Series D Preferred, Series C Preferred and the Series B-3 Preferred. 

“Senior Preferred Directors” shall have the meaning set forth in Section 4.1.(a)(i). 

“Series A-3 Preferred” shall mean the Corporation’s Series A-3 Preferred Stock, $0.001 par value per share. 
 “Series
B-3 Preferred” shall have the meaning set forth in the Recitals. 
 “Series C
Preferred” shall have the meaning set forth in the Recitals. 
 “Series D Preferred” shall have the meaning set
forth in the Recitals. 
 “Series E Preferred” shall have the meaning set forth in the Recitals. 

  
 -5- 

 “Series F Preferred” shall have the meaning set forth in the Recitals. 

“Series G Preferred” shall have the meaning set forth in the Recitals. 

“Series H Preferred” shall mean the Corporation’s Series H Convertible Preferred Stock, par value $0.001 per share. 

“Series H Purchase Agreement” shall have the meaning set forth in the Recitals. 

“Stock Sale” shall have the meaning set forth in Section 5.1. 

“Sun Mountain” shall have the meaning set forth in Section 4.1.(a)(i)(A). 

“Sun Mountain Director” shall have the meaning set forth in Section 4.1.(a)(i)(A). 

“Transferring Investor” shall have the meaning set forth in Section 3.1. 

“Transfer Stock” shall mean, with respect to any Investor, any of the following that is now owned or that is hereinafter
acquired: (i) any Common Stock, Preferred Stock or other class or series of capital stock of the Corporation; (ii) any security convertible, with or without consideration, into any Common Stock, Preferred Stock or other class or series of
capital stock of the Corporation; (iii) any security carrying any warrant or right to subscribe for or purchase shares of any class or series of capital stock of the Corporation; and (iv) any warrant, note, right, option or other
derivative security which provides the right to subscribe for or purchase any stock or securities of the types listed in any of clauses (i), (ii), or (iii) above. 

“Tullis” shall have the meaning set forth in Section 4.1.(a)(i)(B). 

“Tullis Director” shall have the meaning set forth in Section 4.1.(a)(i)(B). 

“Vote” shall have the meaning set forth in Section 4.1. 

“Voting Securities” shall mean, with respect to an Investor, (i) all Transfer Stock and all other shares of capital
stock and other securities of the Corporation now or hereafter owned of record, or beneficially, by such Investor, and (ii) all other Transfer Stock and other shares of capital stock and other securities over which the Investor has voting
control. 
 SECTION 2. Preemptive Rights. 

2.1. Except for Excluded Securities, the Corporation shall not issue, sell or exchange, agree to issue, sell or exchange, or reserve or set
aside for issuance, sale or exchange, (i) any shares of Common Stock, (ii) any other equity security of the Corporation, (iii) any debt security of the Corporation which by its terms is convertible into or exchangeable for, with or
without consideration, any equity security of the Corporation, (iv) any security of the Corporation that is a combination of debt and equity or (v) any security convertible into, or exchangeable or exercisable for, shares of Common Stock,
or warrant or other right to subscribe for, purchase or otherwise acquire any equity security or any such debt security of the type described in clause (iii) or (iv) above of the Corporation (collectively, the “Financing 

  
 -6- 

 
Securities”) unless in each case the Corporation shall have first offered to sell to each holder of Series H Preferred (each, a “Major Investor” and collectively, the
“Major Investors”) its pro rata share of the Financing Securities, at a price and on such other terms as the Corporation proposes to offer such Financing Securities to other parties and which shall have been specified by the
Corporation in writing (an “Offer”) delivered to the Major Investors, which Offer by its terms shall remain open and irrevocable for a period of fifteen (15) days from the date the Offer is received by the Major Investors (or,
if later, within five (5) days after the giving of any written notice of a material change in such Offer). As used in this Section 2.1, a Major Investor’s “pro rata share” shall be that amount of the Financing
Securities that equals (x) the aggregate amount of Financing Securities to be issued, sold or exchanged, multiplied by (y) a fraction, (A) the numerator of which is the number of shares of Common Stock issued or issuable upon the
conversion of all shares of Preferred Stock held by such Major Investor immediately prior to the Offer and (B) the denominator of which is the number of shares of Common Stock issued or issuable upon the conversion of all shares of Preferred
Stock held by all Major Investors immediately prior to the Offer. The Offer will specify (i) the aggregate amount of Financing Securities to be issued, sold or exchanged, (ii) the calculation of the Major Investor’s pro rata share and
(iii) the number of shares, principal amount or the like of the Financing Securities which such Major Investor may purchase. 
 2.2.
Notice of a Major Investor’s intention to accept, in whole or in part, an Offer shall be evidenced by a writing signed by the Major Investor and delivered to the Corporation at or prior to the end of the
15-day period commencing with the date the Offer is received by the Major Investor (or, if later, within 5 days after the giving of any written notice of a material change in such Offer), setting forth such
portion (specifying the number of shares, principal amount or the like) of the Financing Securities as the Major Investor elects to purchase (the “Notice of Acceptance”). If a Major Investor elects to purchase its full pro rata
share of Financing Securities (each, an “Electing Investor”), then such Electing Investor shall have a right of over-allotment such that if any other Major Investor fails to purchase its pro rata share (the “Non-electing Investor”), such Electing Investor may purchase, on a pro rata basis with other Electing Investors, the Non-electing Investor’s pro rata share. 

2.3. The Corporation shall have 180 days from the expiration of the foregoing 15-day period to sell all
or any part of such Financing Securities as to which a Notice of Acceptance has not been given by the Major Investors (the “Remaining Securities”) to any other persons or entities, but only upon terms and conditions in all material
respects, including without limitation, per share price and interest rates, which are no more favorable, in the aggregate, to such other persons or entities or less favorable to the Corporation than those set forth in the Offer. Upon the closing of
the sale to such other persons or entities of all or any part of the Remaining Securities, which shall include payment of the purchase price to the Corporation in accordance with the terms of the Offer, if the Major Investor has timely submitted a
Notice of Acceptance, it shall purchase from the Corporation, and the Corporation shall sell to the Major Investor, the Financing Securities in respect of which a Notice of Acceptance was delivered to the Corporation by the Preferred Investor, at
the terms specified in the Offer. The purchase by the Major Investor of any Financing Securities is subject in all cases to the preparation, execution and delivery by the Corporation and the Major Investor of a purchase agreement and other customary
documentation relating to such Financing Securities as is reasonably satisfactory in form and substance to the Preferred Investor and its counsel. 

  
 -7- 

 2.4. After the expiration of the 180-day period
referred to in Section 2.3, any Financing Securities not purchased by the Major Investors or by a person or entity in accordance with Section 2.3 may not be sold or otherwise disposed of until they are again offered to the Major Investors
under the procedures specified in Sections 2.1, 2.2 and 2.3 hereof. 
 2.5. Each Major Investor may assign its rights under this
Section 2 to its Affiliates. 
 SECTION 3. Right of Co-Sale. 

3.1. If any Transfer Stock subject to a Proposed Transfer is not purchased pursuant to Section 6 below and thereafter is to be sold to a
Prospective Transferee, each Investor which proposes to engage in a Proposed Transfer, (“Transferring Investor”) shall provide to each Investor who owns Series H Preferred, Series F Preferred, Series E Preferred, Series D Preferred
or Series C Preferred (each, a “ROFR/Co-Sale Investor”) a Proposed Transfer Notice. Each ROFR/Co-Sale Investor may elect to exercise its Right of Co-Sale and participate in the Proposed Transfer on a pro rata basis as set forth below and otherwise on the same terms and conditions specified in the Proposed Transfer Notice (provided that if the Proposed
Transfer is a transfer of Common Stock and a ROFR/Co-Sale Investor wishes to sell Preferred Stock, the price set forth in the Proposed Transfer Notice shall be appropriately adjusted based on the conversion
ratio of the Preferred Stock into Common Stock). Each ROFR/Co-Sale Investor who desires to exercise its Right of Co-Sale must give the Transferring Investor written
notice to that effect within fifteen (15) days after receipt of the Proposed Transfer Notice, and upon giving such notice, such Investor shall be deemed to have effectively exercised the Right of Co-Sale.

 3.2. Each ROFR/Co-Sale Investor who timely exercises such
ROFR/Co-Sale Investor’s Right of Co-Sale by delivering the written notice provided for above in Section 3.1 may include in the Proposed Transfer all or any
part of such ROFR/Co-Sale Investor’s Capital Stock equal to the product obtained by multiplying (i) the aggregate number of shares of Capital Stock subject to the Proposed Transfer by (ii) a
fraction, (A) the numerator of which is the number of shares of Common Stock issued or issuable upon the conversion of all shares of Preferred Stock held by such ROFR/Co-Sale Investor immediately before
consummation of the Proposed Transfer and (B) the denominator of which is the total number of shares of Common Stock issued or issuable upon the conversion of all shares of Preferred Stock held by all
ROFR/Co-Sale Investors immediately before consummation of the Proposed Transfer, plus the number of shares of Common Stock and shares of Common Stock issuable upon the conversion of all shares of Preferred
Stock held by the Transferring Investor immediately before consummation of the Proposed Transfer. To the extent one or more ROFR/Co-Sale Investors exercise a Right of
Co-Sale, the number of shares of Capital Stock that the Transferring Investor may sell in the Proposed Transfer shall be correspondingly reduced. 

3.3. Each ROFR/Co-Sale Investor who timely exercises its Right of
Co-Sale shall deliver to the Transferring Investor, no later than fifteen (15) days after such ROFR/Co-Sale Investor’s exercise of the Right of Co-Sale, one or more stock certificates, properly endorsed for transfer to the prospective transferee, representing the number of shares of Common Stock that such ROFR/Co-Sale
Investor elects to include in the Proposed Transfer or the number of shares of Preferred Stock that is at such time convertible into the number of shares 

  
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of Common Stock that such ROFR/Co-Sale Investor elects to include in the Proposed Transfer; provided, however, that if the prospective transferee objects
to the delivery of convertible Preferred Stock in lieu of Common Stock, such ROFR/Co-Sale Investor shall first convert the Preferred Stock into Common Stock and deliver Common Stock as provided above. The
Corporation agrees to make any such conversion concurrent with and contingent upon the actual transfer of such shares to the prospective transferee. 

3.4. Each stock certificate that a ROFR/Co-Sale Investor delivers to the Transferring Investor pursuant
to this Section 3 will be transferred to the prospective transferee against payment therefor in consummation of the sale thereof pursuant to the terms and conditions specified in the Proposed Transfer Notice and the purchase and sale agreement,
and the Transferring Investor shall concurrently therewith remit or direct payment to each ROFR/Co-Sale Investor of the portion of the sale proceeds to which such
ROFR/Co-Sale Investor is entitled by reason of its participation in such sale. If any prospective transferee refuses to purchase securities subject to the Right of
Co-Sale from any ROFR/Co-Sale Investor exercising its Right of Co-Sale hereunder, none of the
ROFR/Co-Sale Investors or the Transferring Investor may sell any Capital Stock to such prospective transferee unless and until, simultaneously with such sale, such Transferring Investor purchases all Capital
Stock subject to the Right of Co-Sale from the ROFR/Co-Sale Investor exercising its Right of Co-Sale on the same terms and
conditions as set forth in the Proposed Transfer Notice. 
 3.5. If any Proposed Transfer is not consummated within sixty (60) days
after receipt of the Proposed Transfer Notice, the Transferring Investor(s) proposing the Proposed Transfer may not sell any Capital Stock unless they first comply in full with each provision of this Section 3. The exercise or election not to
exercise any right by a ROFR/Co-Sale Investor hereunder shall not adversely affect such ROFR/Co-Sale Investor’s right to participate in any other sales of Capital
Stock subject to Section 3. 
 SECTION 4. Board of Directors. 

4.1. Composition. Each Investor shall hold all Voting Securities subject to, and shall vote or consent pursuant to an action by written
consent of the stockholders of the Corporation (“Vote”) such Voting Securities in accordance with, the provisions of this Agreement. 

(a) Election of Directors. 

(i) Senior Preferred Directors. On all matters relating to the election of the class of directors designated in the Certificate as
being elected only by the holders of Senior Preferred, the Investors holding Senior Preferred, acting together as a single class, shall Vote all of their respective Voting Securities so as to elect as a member of the Board four (4) individuals
(the “Senior Preferred Directors”) nominated as follows: 
 (A) For so long as NMSIC
Co-Investment Fund, L.P. or Affiliates thereof (“Sun Mountain”) owns any shares of Senior Preferred, one (1) director designated by Sun Mountain (the “Sun Mountain
Director”). The Sun Mountain Director shall initially be Brian Birk. 

  
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 (B) For so long as Tullis-Dickerson Capital Focus III, L.P. or Affiliates thereof
(“Tullis”) owns any shares of Senior Preferred, one (1) director designated by Tullis (the “Tullis Director”). The Tullis Director shall initially be James L.L. Tullis. 

(C) For so long as PCM/Exagen, L.P. or Affiliates thereof (“PCM/Hunt”) owns any shares of Senior Preferred, one
(1) director designated by PCM/Hunt (the “PCM/Hunt Director”). The PCM/Hunt Director shall initially be Ebetuel Pallares. 

(D) For so long as H.I.G. BioHealth Partners, LLC or Affiliates thereof (“H.I.G.”) owns any shares of Senior Preferred, one
(1) director designated by H.I.G. (the “H.I.G. Director”). The H.I.G. Director shall initially be Bruce Robertson. 

(E) If any or all of Sun Mountain, PCM/Hunt, Tullis or H.I.G. is no longer entitled to designate its director, as applicable, then the
director(s) to be elected by the holders of the issued and outstanding shares of Senior Preferred in lieu of such director shall be reasonably acceptable to the Requisite Majority. 

(ii) Common Director. On all matters relating to the election of the class of directors designated in the Certificate as being elected
only by the holders of Common Stock, the Investors holding Common Stock shall Vote all of their respective Voting Securities so as to elect one (1) director who shall be the Corporation’s then-current Chief Executive Officer (the
“Common Director”). The Common Director initially shall be Ron Rocca. 
 (iii) Independent Directors. On all matters
relating to the election of members of the Board other than the Senior Preferred Directors and the Common Director, the Investors shall Vote all of their respective Voting Securities so as to elect two (2) directors nominated by the Requisite
Majority, who shall be independent and not Affiliates of the Corporation or any Investor and who shall have industry experience (each an “Independent Director,” or together the “Independent Directors”). The Independent
Directors shall initially be Jeffrey Thomas Elliott and Tina Nova. 
 (iv) Additional Director. On all matters relating to the
election of members of the Board other than the Senior Preferred Directors, the Common Director and the Independent Directors, the Investors agree to Vote all of their respective Voting Securities so as to elect one (1) director designated by
the Requisite Majority (the “Additional Director”), who shall initially be Chet Burrell. 
 The obligation to Vote shares in accordance with
this Section 4 shall be specifically applicable to and enforceable against any transferees of the parties hereto. 
 (b) Vacancies;
Removal. Each of the directors elected pursuant to Section 4 shall hold office, subject to his or her resignation or earlier removal from the Board in accordance with the following sentence, in accordance with the Certificate, the Bylaws of
the Corporation and applicable law, until his or her successors shall have been elected 

  
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and shall have been duly qualified. No Investor shall vote to remove any director elected pursuant to this Section 4, or to fill any vacancy created by the resignation or removal of a
director elected pursuant to this Section 4, unless such action shall have been approved by the Investors entitled to nominate and elect such director in accordance with the provisions of the Certificate and this Section 4. 

(c) Meetings. The Board shall hold meetings no less frequently than quarterly as determined by a majority of the Board. 

(d) Committees of the Board. The Corporation shall establish and maintain a compensation committee and an audit committee and may also
form an executive committee or any other special committee of the Board. Each of such committees shall have at least two (2) of the Senior Preferred Directors as a member of such committees and each Senior Preferred Director shall have the
right but not the obligation to be a member of any such committees, in each case subject to compliance with applicable laws, including applicable securities laws and Commission rules. 

(e) Insurance. The Corporation shall obtain and maintain directors’ and officers’ liability insurance in reasonable amounts
(as determined by the Board which shall include at least three (3) Senior Preferred Directors) from established and reputable insurers. 

(f) Size of Board. Each Investor shall take all actions, do all things and execute and deliver all documents, including, without
limitation, approving an amendment to the Corporation’s Bylaws, and shall cause the Corporation to do the same, as may be necessary to ensure that the number of directors authorized and constituting the entire Board shall be eight (8), subject
to increase or decrease in accordance with the terms of the Certificate and pursuant hereto. 
 (g) Observer Rights. As long as
H.I.G. is a Requisite Party, the Corporation shall invite a representative of H.I.G. to attend all meetings of its Board in a nonvoting observer capacity and, in this respect, shall give such representative copies of all notices, minutes, consents,
and other materials that it provides to its directors at the same time and in the same manner as provided to such directors; provided, however, that such representative shall agree to hold in confidence and trust all information so provided; and
provided further, that the Corporation reserves the right to withhold any information and to exclude such representative from any meeting or portion thereof if access to such information or attendance at such meeting could adversely affect the
attorney-client privilege between the Corporation and its counsel, to protect highly confidential proprietary information or could result in a conflict of interest. 

(h) No Liability. No Investor, nor any Affiliate thereof, shall have any liability as a result of nominating a person for election as a
director, for any act or omission by such designated person in his or her capacity as a director of the Corporation, or as a result of voting for any such nominee in accordance with the provisions of this Agreement. 

  
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 (i) Irrevocable Proxy. Each party to this Agreement hereby grants to a stockholder
appointed by the Board, with full power of substitution, an irrevocable proxy with respect to the matters set forth herein, including, without limitation, the election of directors to the Board in accordance with Section 4.1(a) and
Section 4.1(b) hereof, and hereby authorizes such proxy to represent and to Vote, if and only if the party (i) fails to Vote, or (ii) attempts to Vote, in a manner which is inconsistent with the terms of this Agreement, all of such
party’s Voting Securities in favor of the election of directors to the Board determined pursuant to and in accordance with the terms and provisions of this Agreement. The proxy granted pursuant to the immediately preceding sentence is given in
consideration of the agreements and covenants of the parties in connection with the transactions contemplated by this Agreement and, as such, is coupled with an interest and shall be irrevocable unless and until this Agreement terminates pursuant to
the terms hereof. 
 SECTION 5. Drag-Along Right. 

5.1. A “Sale of the Corporation” shall mean either (a) a transaction or series of related transactions in which a person,
or a group of related persons, acquires from stockholders of the Corporation shares representing more than fifty percent (50%) of the outstanding voting power of the Corporation (a “Stock Sale”) or (b) a transaction that is
deemed to be a liquidation under Section 3.2 of the Certificate (a “Deemed Liquidation Event”). 
 5.2. In the event
that (i) the Requisite Majority (the “Selling Investors”) and (ii) the Board approves a Sale of the Corporation in writing, specifying that this Section 5 shall apply to such transaction, then each Investor hereby
agrees: 
 (a) if such transaction requires stockholder approval, with respect to all Capital Stock that such Investor owns or over which
such Investor exercises voting power, to vote, in person, by proxy, or by written consent, all Capital Stock in favor of, and adopt, such Sale of the Corporation (together with any related amendment to the Certificate required in order implement
such Sale of the Corporation) and to vote in opposition to any and all other proposals that could delay or impair the ability of the Corporation to consummate such Sale of the Corporation; 

(b) if such transaction is a Stock Sale, to sell the same proportion of shares of capital stock of the Corporation beneficially held by such
Investor as is being sold by the Selling Investors to the person to whom the Selling Investors propose to sell their Capital Stock, and, except as permitted in Section 5.2(c) below, on the same terms and conditions as the Selling Investors;

 (c) to execute and deliver all related documentation and take such other action in support of the Sale of the Corporation as shall
reasonably be requested by the Corporation or the Selling Investors in order to carry out the terms and provisions of this Section 5, including without limitation executing and delivering instruments of conveyance and transfer, and any purchase
agreement, merger agreement, indemnity agreement, escrow agreement, consent, waiver, governmental filing, share certificates duly endorsed for transfer (free and clear of impermissible liens, claims and encumbrances) and any similar or related
documents; 

  
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 (d) not to deposit, and to cause their Affiliates not to deposit, except as provided in
this Agreement, any Capital Stock owned by such Investor or Affiliate in a voting trust or subject any Capital Stock to any arrangement or agreement with respect to the voting of such Capital Stock, unless specifically requested to do so by the
acquiror in connection with the Sale of the Corporation; 
 (e) to refrain from exercising any dissenters’ rights or rights of
appraisal under applicable law at any time with respect to such Sale of the Corporation; and 
 (f) if the consideration to be paid in
exchange for the Capital Stock pursuant to this Section 5 includes any securities and due receipt thereof by any Investor would require under applicable law (x) the registration or qualification of such securities or of any person as a
broker or dealer or agent with respect to such securities or (y) the provision to any Investor of any information other than information as a prudent issuer would generally furnish in an offering made solely to “accredited investors”
as defined in Regulation D promulgated under the Securities Act, the Corporation may cause to be paid to any such Investor in lieu thereof, against surrender of the Capital Stock which would have otherwise been sold by such Investor, an amount in
cash equal to the fair value (as determined in good faith by the Corporation) of the securities which such Investor would otherwise receive as of the date of the issuance of such securities in exchange for the Capital Stock. 

5.3. Notwithstanding the foregoing, an Investor will not be required to comply with Section 5.2.(b) above in connection with any proposed
Sale of the Corporation (the “Proposed Sale”) unless: 
 (a) any representations and warranties to be made by such Investor
in connection with the Proposed Sale are limited to representations and warranties related to authority, ownership and the ability to convey title to such Capital Stock, including but not limited to representations and warranties that (a) the
Investor holds all right, title and interest in and to the Capital Stock such Investor purports to hold, free and clear of all liens and encumbrances, (b) the obligations of the Investor in connection with the transaction have been duly
authorized, if applicable, (c) the documents to be entered into by the Investor have been duly executed by the Investor and delivered to the acquirer and are enforceable against the Investor in accordance with their respective terms and
(d) neither the execution and delivery of documents to be entered into in connection with the transaction, nor the performance of the Investor’s obligations thereunder, will cause a breach or violation of the terms of any agreement, law or
judgment, order or decree of any court or governmental agency; 
 (b) the Investor is not required to agree (unless such Investor is an
officer or employee of the Corporation) to any covenant not to compete or exclusivity covenant in connection with the Proposed Sale); 
 (c)
the Investor shall not be liable for the inaccuracy of any representation or warranty made by any other person in connection with the Proposed Sale, other than the Corporation (except to the extent that funds may be paid out of an escrow established
to cover breach of representations, warranties and covenants of the Corporation as well as breach by any Investor of any of identical representations, warranties and covenants provided by all Investors); 

  
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 (d) the liability for indemnification, if any, of such Investor in the Proposed Sale and
for the inaccuracy of any representations and warranties made by the Corporation or its Investors in connection with such Proposed Sale, is several and not joint with any other Person (except to the extent that funds may be paid out of an escrow
established to cover breach of representations, warranties and covenants of the Corporation as well as breach by any Investor of any of identical representations, warranties and covenants provided by all Investors), and is pro rata in proportion to,
and does not exceed, the amount of consideration paid to such Investor in connection with such Proposed Sale; 
 (e) liability shall be
limited to such Investor’s applicable share (determined based on the respective proceeds payable to each Investor in connection with such Proposed Sale in accordance with the provisions of the Certificate) of a negotiated aggregate
indemnification amount that applies equally to all Investors but that in no event exceeds the amount of consideration otherwise payable to such Investor in connection with such Proposed Sale, except with respect to claims related to fraud by such
Investor, the liability for which need not be limited as to such Investor; 
 (f) upon the consummation of the Proposed Sale, (i) each
holder of each class or series of the Corporation’s stock will receive the same form of consideration for their shares of such class or series as is received by other holders in respect of their shares of such same class or series of stock,
(ii) each holder of a series of Preferred Stock will receive the same amount of consideration per share of such series of Preferred Stock as is received by other holders in respect of their shares of such same series, (iii) each holder of
Common Stock will receive the same amount of consideration per share of Common Stock as is received by other holders in respect of their shares of Common Stock, and (iv) the aggregate consideration receivable by all holders of the Preferred
Stock and Common Stock shall be allocated among the holders of Preferred Stock and Common Stock on the basis of the relative liquidation preferences to which the holders of each respective series of Preferred Stock and the holders of Common Stock
are entitled in a Deemed Liquidation Event (assuming for this purpose that the Proposed Sale is a Deemed Liquidation Event) in accordance with the Certificate in effect immediately prior to the Proposed Sale; provided, however, that,
notwithstanding the foregoing, if the consideration to be paid in exchange for an Investor’s Capital Stock pursuant to this 5.2.(e) includes any securities and due receipt thereof by any Investor would require under applicable law (x) the
registration or qualification of such securities or of any person as a broker or dealer or agent with respect to such securities or (y) the provision to any Investor of any information other than such information as a prudent issuer would
generally furnish in an offering made solely to “accredited investors” as defined in Regulation D promulgated under the Securities Act, the Corporation may cause to be paid to any such Investor in lieu thereof, against surrender of the
Investor’s Capital Stock which would have otherwise been sold by such Investor, an amount in cash equal to the fair value (as determined in good faith by the Corporation) of the securities which such Investor would otherwise receive as of the
date of the issuance of such securities in exchange for the Investor’s Capital Stock; and 

  
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 (g) subject to the immediately preceding paragraph, requiring the same form of
consideration to be available to the holders of any single class or series of capital stock, if any holders of any capital stock of the Corporation are given an option as to the form and amount of consideration to be received as a result of the
Proposed Sale, all holders of such capital stock will be given the same option; provided, however, that nothing in this Section 5.2.(f) shall entitle any holder to receive any form of consideration that such holder would be ineligible to
receive as a result of such holder’s failure to satisfy any condition, requirement or limitation that is generally applicable to the Corporation’s Investors. 

5.4. Proxy. Each Investor hereby grants to the Selling Investors (i) an irrevocable proxy, coupled with an interest, to Vote all
Voting Securities owned by such Investor, and (ii) an irrevocable power of attorney, which is coupled with an interest, to take such other actions, in each case to the extent necessary to carry out the provisions of this Section 5 in the
event of any breach by such Investor of its obligations hereunder. 
 SECTION 6. Right of First Refusal. 

6.1. Grant. Subject to the terms of Section 7 below, each Investor hereby unconditionally and irrevocably grants to the Corporation
a Right of First Refusal to purchase all or any portion of Transfer Stock that such Transferring Investor may propose to transfer in a Proposed Transfer, at the same price and on the same terms and conditions as those offered to the Prospective
Transferee. 
 6.2. Notice. Each Investor proposing to make a Proposed Transfer must deliver a Proposed Transfer Notice to the
Corporation and each Investor not later than forty-five (45) days prior to the consummation of such Proposed Transfer. Such Proposed Transfer Notice shall contain the material terms and conditions (including price and form of consideration) of
the Proposed Transfer, the identity of the prospective transferee and the intended date of the Proposed Transfer. To exercise its Right of First Refusal under this Section 6, the Corporation must deliver a Corporation Notice to the Transferring
Investor and the Investors within fifteen (15) days after delivery of the Proposed Transfer Notice specifying the number of shares of Transfer Stock to be purchased by the Corporation. In the event of a conflict between this Agreement and any
other agreement that may have been entered into by an Investor with the Corporation that contains a preexisting right of first refusal, the Corporation and the Investor acknowledge and agree that the terms of this Agreement shall control and the
preexisting right of first refusal shall be deemed satisfied by compliance with Subsection 6.1 and this Subsection 6.2. 
 6.3. Grant of
Secondary Refusal Right to Investors. Subject to the terms of Section 7 below, each Investor hereby unconditionally and irrevocably grants to the ROFR/Co-Sale Investors a Secondary Refusal Right to
purchase all or any portion of the Transfer Stock not purchased by the Corporation pursuant to the Right of First Refusal, as provided in this Subsection 6.3. If the Corporation does not provide the Corporation Notice exercising its Right of First
Refusal with respect to all Transfer Stock subject to a Proposed Transfer, the Corporation must deliver a Secondary Notice to the Transferring Investor and to each other ROFR/Co-Sale Investor to that effect no
later than fifteen (15) days after the Transferring Investor delivers the Proposed Transfer Notice to the Corporation. To exercise its Secondary Refusal Right, a ROFR/Co-Sale Investor must deliver an
Investor Notice to the Transferring Investor and the Corporation within ten (10) days after the Corporation’s deadline for its delivery of the Secondary Notice as provided in the preceding sentence. 

  
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 6.4. Undersubscription of Transfer Stock. If options to purchase have been exercised
by the Corporation and the ROFR/Co-Sale Investors pursuant to Subsections 6.2 and 6.3 with respect to some but not all of the Transfer Stock by the end of the ten (10) day period specified in the last
sentence of Subsection 6.3 (the “Investor Notice Period”), then the Corporation shall, within five (5) days after the expiration of the Investor Notice Period, send written notice (the “Corporation Undersubscription
Notice”) to those ROFR/Co-Sale Investors who fully exercised their Secondary Refusal Right within the Investor Notice Period (the “Exercising Investors”). Each Exercising Investor
shall, subject to the provisions of this Subsection 6.4, have an additional option to purchase all or any part of the balance of any such remaining unsubscribed shares of Transfer Stock on the terms and conditions set forth in the Proposed Transfer
Notice. To exercise such option, an Exercising Investor must deliver an Undersubscription Notice to the Transferring Investor and the Corporation within ten (10) days after the expiration of the Investor Notice Period. In the event there are
two (2) or more such Exercising Investors that choose to exercise the last-mentioned option for a total number of remaining shares in excess of the number available, the remaining shares available for purchase under this Subsection 6.4 shall be
allocated to such Exercising Investors pro rata based on the number of shares of Transfer Stock such Exercising Investors have elected to purchase pursuant to the Secondary Refusal Right (without giving effect to any shares of Transfer Stock that
any such Exercising Investor has elected to purchase pursuant to the Corporation Undersubscription Notice). If the options to purchase the remaining shares are exercised in full by the Exercising Investors, the Corporation shall reasonably promptly
notify all of the Exercising Investors and the Transferring Investor of that fact. 
 6.5. Notwithstanding the foregoing, if the total number
of shares of Transfer Stock that the Corporation and the ROFR/Co-Sale Investors have agreed to purchase in the Corporation Notice, Investor Notices and Undersubscription Notices is less than the total number
of shares of Transfer Stock, then the Corporation and the ROFR/Co-Sale Investors shall be deemed to have forfeited any right to purchase such Transfer Stock, and the Transferring Investor shall be free to sell
all, but not less than all, of the Transfer Stock to the Prospective Transferee on terms and conditions substantially similar to (and in no event more favorable than) the terms and conditions set forth in the Proposed Transfer Notice, it being
understood and agreed that (i) any such sale or transfer shall be subject to the other terms and restrictions of this Agreement, including, without limitation, the terms and restrictions set forth in Sections 3 and Subsection 10.13; (ii) any
future Proposed Transfer shall remain subject to the terms and conditions of this Agreement, including this Section 6; and (iii) such sale shall be consummated within forty-five (45) days after receipt of the Proposed Transfer Notice
by the Corporation and, if such sale is not consummated within such forty-five (45) day period, such sale shall again become subject to the Right of First Refusal and Secondary Refusal Right on the terms set forth herein. 

6.6. Consideration; Closing. If the consideration proposed to be paid for the Transfer Stock is in property, services or other non-cash consideration, the fair market value of the consideration shall be as determined in good faith by the Board and as set forth in the Corporation Notice. If the Corporation or any ROFR/Co-Sale Investor cannot for any reason 

  
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pay for the Transfer Stock in the same form of non-cash consideration, the Corporation or such ROFR/Co-Sale
Investor may pay the cash value equivalent thereof, as determined in good faith by the Board and as set forth in the Corporation Notice. The closing of the purchase of Transfer Stock by the Corporation and the
ROFR/Co-Sale Investors shall take place, and all payments from the Corporation and the ROFR/Co-Sale Investors shall have been delivered to the Transferring Investor, by
the later of (i) the date specified in the Proposed Transfer Notice as the intended date of the Proposed Transfer; and (ii) forty-five (45) days after delivery of the Proposed Transfer Notice. 

SECTION 7. Exempt Transfers. 

7.1. Notwithstanding the foregoing or anything to the contrary herein, the provisions of Sections 3 and 6 shall not apply (a) in the case
of an Investor that is an entity, upon a transfer by such Investor to its Affiliates, stockholders, members, partners or other equity holders, (b) to a repurchase of Transfer Stock from an Investor by the Corporation at a price no greater than
that originally paid by such Investor for such Transfer Stock and pursuant to an agreement containing vesting and/or repurchase provisions approved by a majority of the Board, or (c) in the case of an Investor that is a natural person, upon a
transfer of Transfer Stock by such Investor made for bona fide estate planning purposes, either during his or her lifetime or on death by will or intestacy to his or her spouse, child (natural or adopted), or any other direct lineal descendant of
such Investor (or his or her spouse) (all of the foregoing collectively referred to as “family members”), or any other person approved by unanimous consent of the Board, or any custodian or trustee of any trust, partnership or limited
liability company for the benefit of, or the ownership interests of which are owned wholly by such Investor or any such family members, or (in the case of an Investor that is a trust) solely to any beneficiary of such trust, any family members of
any such beneficiary or any other trust established solely for the benefit of any such beneficiary or family member thereof; or (d) to the sale by the Investor of up to 1% of the Transfer Stock held by such Investor as of the date that such
Investor first became party to this Agreement; provided that in the case of clause(s) (a), (c), or (d), such Investor shall deliver prior written notice to the Investors of such pledge, gift or transfer and such shares of Transfer Stock shall at all
times remain subject to the terms and restrictions set forth in this Agreement and such transferee shall, as a condition to such issuance, deliver a counterpart signature page to this Agreement as confirmation that such transferee shall be bound by
all the terms and conditions of this Agreement as an Investor (but only with respect to the securities so transferred to the transferee), including the obligations of an Investor with respect to Proposed Transfers of such Transfer Stock pursuant to
Sections 3 and 6; and provided further in the case of any transfer pursuant to clause (a) or (c) above, that such transfer is made pursuant to a transaction in which there is no consideration actually paid for such transfer. 

7.2. Notwithstanding the foregoing or anything to the contrary herein, the provisions of Section 6 shall not apply to the sale of any
Transfer Stock (a) to the public in an offering pursuant to an effective registration statement under the Securities Act; or (b) pursuant to a Deemed Liquidation Event. 

7.3. Notwithstanding the foregoing, no Investor shall transfer any Transfer Stock to (a) any entity which, in the determination of the
Board, directly or indirectly competes with the Corporation; or (b) any customer, distributor or supplier of the Corporation, if the Board should determine that such transfer would result in such customer, distributor or supplier receiving
information that would place the Corporation at a competitive disadvantage with respect to such customer, distributor or supplier. 

  
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 SECTION 8. “Market Stand-Off”
Agreement. 
 8.1. Each Investor hereby agrees that, for a period of duration specified by the Corporation and an underwriter of common
stock or other securities of the Corporation (such period not to exceed 180 days) following the effective date of the first registration statement of the Corporation filed under the Securities Act, which covers securities to be sold on the
Corporation’s behalf to the public in an underwritten offering, it shall not, to the extent requested by the Corporation and its underwriter, directly or indirectly sell, offer to sell, contract to sell (including, without limitation, any short
sale), grant any option to purchase or otherwise transfer or dispose of (other than to donees who agree to be similarly bound) any securities of the Corporation held by it at any time during such period except Registrable Securities included in such
registration; provided, however, that such agreement shall not be required unless all officers and directors of the Corporation and all other persons with registration rights (whether or not pursuant to this Agreement) enter into similar agreements.
Any discretionary waiver or termination of the restrictions of any or all of such agreements by the Corporation or the underwriters shall apply pro rata to all Investors subject to such agreements, based on the number of shares subject to such
agreements, subject to customary exceptions. In order to enforce the foregoing covenant, the Corporation may impose stop-transfer instructions with respect to the Registrable Securities of each Investor (and the shares or securities of every other
person subject to the foregoing restriction) until the end of such period. 
 SECTION 9. Reverse Stock Split. 

9.1. If the Corporation does not complete a firm-commitment underwritten public offering pursuant to an effective registration statement under
the Securities Act prior to December 31, 2019, the Corporation and the Investors each agree in good faith to take all actions necessary to effect a reverse stock split on terms and at a time reasonably acceptable to the Requisite Majority,
including H.I.G., provided however that this Section 9.1 may be waived solely by the written consent of H.I.G. 
 SECTION 10.
Miscellaneous. 
 10.1. Voting Agreement. In the event that the taking of any one or more of the actions listed in Article
Fourth, Section 7 of the Certificate (an “Approved Action”) would require a separate vote by the holders of either of the Series A-3 Preferred or the Series
B-3 Preferred under Section 242(b)(2) of the General Corporation Law of the State of Delaware, then, in such event, each holder of Series A-3 Preferred and Series B-3 Preferred, as applicable, hereby agrees, with respect to all shares of Series A-3 Preferred or Series B-3 Preferred over which he,
she or it exercises voting or dispositive authority, to Vote all of such Series A-3 Preferred or Series B-3 Preferred in favor of the Approved Action if the holders of
at least 50% of the then outstanding Senior Preferred, voting together as a single class, Vote to approve the taking of such Approved Action. 

  
 -18- 

 10.2. Assignment of Rights. This Agreement and the rights and obligations of the
parties hereunder shall inure to the benefit of, and be binding upon, the parties’ respective successors, assigns and legal representatives; provided, however, that the rights of the Investors hereunder are only assignable to a
assignee or transferee (i) who acquires all of the securities of the Corporation purchased by an Investor or at least ten percent (10%) of such class and series of securities or (ii) who is a partner or retired partner of a partnership,
and it shall be a requirement of such transfer that such assignee shall then become a party to this Agreement. 
 10.3. Term. This
Agreement shall terminate upon the earlier of (i) the closing of a firmly underwritten initial public offering pursuant to an effective registration statement under the Securities Act, or (ii) the acquisition of the Corporation by another
entity by means of any transaction or series of related transactions (including, without limitation, any reorganization, merger or consolidation) or a sale of all or substantially all of the assets of the Corporation, unless the Corporation’s
stockholders of record as constituted immediately prior to such acquisition or sale will, immediately after such acquisition or sale (by virtue of securities issued as consideration for the Corporation’s acquisition or sale or otherwise) hold
at least 50% of the voting power of the surviving or acquiring entity. 
 10.4. Waivers and Amendments. This Agreement may not be
amended, modified or waived at any time, unless such amendment, modification or waiver is first approved in writing by (a) the Requisite Majority and (b) the Corporation; provided, however, that (i) if any amendment, modification or
waiver would apply to an Investor (each, an “Adversely Affected Investor”) in a fashion different than how such amendment, modification or waiver applies to all Investors, then such amendment, modification or waiver shall not be
effective as to such Adversely Affected Investor unless consented to by such Adversely Affected Investor, (ii) any amendment, modification or waiver of Section 4.1.(a)(i)(A), Section 4.1.(b) (insofar as it relates to the Sun Mountain
Director), or of this clause (ii) shall require the approval of Sun Mountain if at the time of such amendment, modification or waiver, Sun Mountain is entitled to designate a Senior Preferred Director pursuant to Section 4.1.(a)(i)(A),
(iii) any amendment, modification or waiver of Section 4.1.(a)(i)(B), Section 4.1.(b) (insofar as it relates to the Tullis Director), or of this clause (iii) shall require the approval of Tullis if at the time of such amendment,
modification or waiver, Tullis is entitled to designate a Senior Preferred Director pursuant to Section 4.1.(a)(i)(B), (iv) any amendment, modification or waiver of Section 4.1.(a)(i)(C), Section 4.1.(b) (insofar as it relates to the
PCM/Hunt Director) or of this clause (iv) shall require the approval of PCM/Hunt if at the time of such amendment, modification or waiver, PCM/Hunt is entitled to designate a Senior Preferred Director pursuant to Section 4.1.(a)(i)(C), (v)
any amendment, modification or waiver of Section 4.1(a)(i)(D), Section 4.1(b) (insofar as it relates to the H.I.G. Director), Section 4.1(g), or of this clause (v) shall require the approval of H.I.G. if at the time of such
amendment, modification or waiver, H.I.G. is entitled to designate a Senior Preferred Director pursuant to Section 4.1(a)(i)(D), or (v) any amendment, modification or waiver of Section 4.1(a)(iii), Section 4.1(a)(iv),
Section 4.1(b) (in so far as it relates to an Independent Director or the Additional Director) or of this clause (v) shall require the consent of the Requisite Majority. Any amendment, modification or waiver so effected shall be binding
upon the Corporation, each of the parties hereto and any assignee of any such party. In addition, the Corporation may waive performance of any obligation owing to it, as to some or all of the Investors, or agree to accept alternatives to such
performance, without obtaining the consent of any Investor. No waiver of any breach of this Agreement extended by any party hereto to any other party shall be construed as a waiver of any rights or remedies of any other party hereto or with respect
to any subsequent breach. 

  
 -19- 

 10.5. Governing Law. This Agreement shall be governed in all respects by the laws of
the State of Delaware, without regards to conflict of laws principles. Each of the Corporation and the Investors: (i) agrees that any legal suit, action or proceeding arising out of or relating to this Agreement and/or the transactions
contemplated hereby shall be instituted exclusively in New York Supreme Court, County of New York, or in the United States District Court for the Southern District of New York, (ii) waives any objection which it may have or hereafter to the
venue of any such suit, action or proceeding, and (iii) irrevocably consents to the jurisdiction of the New York Supreme Court, County of New York, and the United States District Court for the Southern District of New York in any such suit,
action or proceeding. 
 10.6. Effectiveness; Entire Agreement; Waiver of Preemptive Rights. This Agreement shall become effective
concurrently with the consummation of the purchase and sale of the Series H Preferred under the Series H Purchase Agreement at the Closing. This Agreement and the other documents delivered in connection herewith constitute the full and entire
understanding of the parties with regard to the subjects hereof and thereof. Upon execution of this Agreement by the Corporation, Burrell Diversified Investments, LLC, and the Existing Investors owning at least 52% of the issued and outstanding
shares of Series G Preferred, Series F Preferred, Series E Preferred, Series D Preferred, Series C Preferred and the Series B-3 Preferred, voting together as a single class, the Prior Agreement shall
thereafter be of no further force and effect and is hereby amended in its entirety and restated herein, and all provisions of rights granted and covenants made in the Prior Agreement are hereby waived, released and superseded in their entirety and
shall have no further force or effect including, without limitation, all preemptive rights or rights of first offer and any notice period associated therewith otherwise applicable to the transactions contemplated by the Series H Purchase Agreement.

 10.7. Notices, etc. All notices and other communications required or permitted hereunder (each, a “Notice”) shall
be in writing and shall be delivered by overnight courier service or mailed by first class mail, postage prepaid, certified or registered mail, return receipt requested, addressed (a) if to an Investor, at such party’s address as set forth
in the Corporation’s records, or at such other address as such party shall have furnished to the Corporation in writing or (b) if to the Corporation, to it at the address set forth on the Corporation’s signature page hereto or other
address as the Corporation shall have furnished to the Investor in writing. All Notices shall be deemed effectively given: (x) upon personal delivery to the party to be notified, (y) three (3) days after having been sent by first class
mail, postage prepaid, certified or registered mail, return receipt requested and (z) one (1) day after deposit with an overnight courier service. 

10.8. Severability. In case any provision of this Agreement shall be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions of this Agreement shall not in any way be affected or impaired thereby. 

  
 -20- 

 10.9. Title and Subtitles. The titles of the sections and subsections of this
Agreement are for convenience of reference only and are not to be considered in construing this Agreement. 
 10.10. Attorneys’
Fees. If any action at law or in equity is necessary to enforce or interpret the terms of this Agreement, the prevailing party shall be entitled to reasonable attorneys’ fees, costs and disbursements in addition to any other relief to which
such party may be entitled. 
 10.11. Counterparts; Execution by Facsimile Signature. This Agreement may be executed in any number of
counterparts, each of which shall be an original, but all of which together shall constitute one instrument. Counterparts may be delivered via facsimile, electronic mail (including pdf or any electronic signature complying with the U.S. federal
ESIGN Act of 2000, e.g., www.docusign.com) or other transmission method and any counterpart so delivered shall be deemed to have been duly and validly delivered and be valid and effective for all purposes. 

10.12. Aggregation of Stock. All shares of Preferred Stock and Common Stock of the Corporation held or acquired by affiliated entities
or persons shall be aggregated for the purpose of determining the availability of any rights under this Agreement. 
 10.13. Additional
Investors. Notwithstanding anything to the contrary contained herein, if the Corporation shall issue additional shares of Preferred Stock from time to time, any purchaser of such shares of Preferred Stock may become a party to this Agreement by
executing and delivering an additional counterpart signature page to this Agreement and shall be deemed an “Investor” and a party hereunder. 

10.14. Specific Performance. The parties hereto hereby declare that it is impossible to measure in money the damages which will accrue
to a party hereto or to their heirs, personal representatives, successors or assigns by reason of the failure of a party to perform any of the obligations under this Agreement and agree that the terms of this Agreement shall be specifically
enforceable. If any party hereto or such party’s heirs, personal representatives, or assigns institutes any action or proceeding to specifically enforce the provisions hereof, any person against whom such action or proceeding is brought hereby
waives the claim or defense therein that such party or such personal representative has an adequate remedy at law, and such person shall not offer in any such action or proceeding the claim or defense that such remedy at law exists. 

* * * * * * * 

  
 -21- 

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Stockholders
Agreement as of the date first above written. 
  

			
	CORPORATION:
	
	EXAGEN INC.
		
	By:	 	 /s/ Ron Rocca            

	Name: Ron Rocca
	Title: President and Chief Executive Officer

 
			
		
	Address:	 	1261 Liberty Way, Suite C
		 	Vista, CA 92081

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
			
	INVESTORS:
	
	H.I.G. Bio-Exagen, L.P.
		
	By:	 	 /s/ Bruce Robertson

	Name: Bruce Robertson
	Title: Managing Director

 
			
		
	Address:	 	1450 Brickell Avenue
		 	31st Floor
		 	Miami, FL 33131
	
	With a copy (which shall not serve as notice) to:
	
	 Goodwin Procter LLP
 100 Northern
Ave

	Boston, MA 02210
	Attention: Arthur R. McGivern

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
			
	NMSIC CO-INVESTMENT FUND, L.P.
	By: Sun Mountain Capital Partners LLC,its general partner
		
	By:	 	 /s/ Brian Birk

		 	Brian Birk, Managing Partner
		
	By:	 	 /s/ Lee Rand

		 	Lee Rand, Managing Member
	
	NMSIC FOCUSED LLC
	By: NMSIC Co-Investment Fund LP, its sole member
	By: Sun Mountain Capital Partners LLC, its general partner
		
	By:	 	 /s/ Brian Birk

		 	Brian Birk, Managing Partner
		
	By:	 	 /s/ Lee Rand

		 	Lee Rand, Managing Member

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
			
	JAMES J. SCHWARZ and JEANETTE M. SCHWARZ, CO-TRUSTEES OF THE SCHWARZ TRUST
		
	By:	 	 /s/ James J. Schwarz

		 	James J. Schwarz

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
			
	NEW TECH I, L.P.
		
	By:	 	 /s/ David Durgin

	Name: David Durgin
	Title: General Partner

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
			
	SOUTHWEST MEDICAL VENTURES, INC.
		
	By:	 	 /s/ Waneta C. Tuttle

			
	Name:	 	Waneta C. Tuttle
	Title:	 	President

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
			
	TULLIS-DICKERSON CAPITAL FOCUS III, L.P.
	By: Tullis-Dickerson Partners III, L.L.C., its general partner
		
	By:	 	 /s/ James L.L. Tullis

	Name: James L.L. Tullis
	Title: Manager
	
	TULLIS-GROWTH FUND, L.P.
		
	By:	 	Tullis-Growth Partners, L.L.C., its general partner
		
	By:	 	 /s/ James L.L. Tullis

	Name: James L.L. Tullis
	Title: Manager
	
	TULLIS-GROWTH FUND II, L.P.
		
	By:	 	Tullis-Growth Partners II, L.L.C., its general partner
		
	By:	 	 /s/ James L.L. Tullis

	Name: James L.L. Tullis
	Title: Manager
	
	 /s/ James L.L. Tullis

	JAMES L.L. TULLIS

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
			
	HUNT HOLDINGS LIMITED PARTNERSHIP
	By:	 	HuntVest, LLC, its General Partner
	By:	 	Hunt Guaranty Inc., its Sole Member
		
	By:	 	 /s/ Matthew D. Hunt

	Matthew D. Hunt, Managing Partner

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
			
	PCM/EXAGEN, L.P.
		
	By:	 	 /s/ Ebetuel Pallares

			
	Name:	 	Ebetuel Pallares
	Title:	 	Managing Partner

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
			
	BURRELL DIVERSIFIED INVESTMENTS, LLC
		
	By:	 	 /s/ Daniel C. Burrell

			
	Name:	 	Daniel C. Burrell
	Title:	 	Operating Manager

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
	
	LINDA A. TULLIS
	
	 /s/ Linda A. Tullis

	LINDA A. TULLIS, TRUSTEE OF HPS IRREVOCABLE TRUST #3 U/A DTD 7/6/93

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 
			
	GERRIT JOHAN KREDIET
		
	By:	 	 /s/ Chris Krediet

 

			
	Name:	 	Chris Krediet

  

  
 [Signature Page to
Amended and Restated Stockholders Agreement] 

 SCHEDULE A 

INVESTORS 
 H.I.G. BioHealth
Partners, LLC 
 Wasatch Venture Fund III, LP 
 Wasatch New
Mexico Fund, LLC 
 vSpring SBIC, L.P. 
 vSpring, L.P. 

vSpring Partners, L.P. 
 NMSIC
Co-Investment Fund, L.P. 
 NMSIC Focused, LLC 

James J. Schwarz and Jeanette M. Schwarz, Co-Trustees of the Schwarz Trust 

New Tech I, L.P. 
 Pamela J. Sullivan and Thomas A. Tumolillo 

Quatro Ventures, LLC 
 Ray Radosevich 

Robert and Marcia Cates 
 Robert H. Nath 

Southwest Medical Ventures, Inc. 
 Sheryl A. Johnson 

John P. Alsobrook, II 
 Dale Olson 

Mesa Verde Venture Partners, L.P. 
 PCM/Exagen, L.P. 

Hunt Holdings L.P. 
 Tullis-Dickerson Capital Focus III, L.P. 

Tullis-Growth Fund, L.P. 
 Tullis-Growth Fund II, L.P. 

James L.L. Tullis 
 Linda A. Tullis 

Linda A. Tullis Trustee of HPS Irrevocable Trust #3 U/A DTD 7/6/93 

Berge K. Hagopian and Mary Ann Hagopian, Co-Trustees, Hagopian Family Trust UA DTD 03/25/88 

Timothy M. Pennington and Melissa J. Pennington as Trustees of the Pennington Family 

Endochoice, Inc. 
 Glenn Holdings, L.P. 

Burrell Diversified Investments, LLC 
 Gerrit Johan Krediet 

Samuel D. Riccitelli 
 Michael Walsh 

  
 A-1

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