EX-10.1




 Exhibit 10.1 

BACKSTOP SUBSCRIPTION AGREEMENT 

This BACKSTOP SUBSCRIPTION AGREEMENT (this “Backstop Subscription Agreement”) is entered into on November 16, 2021, by
and among Altimar Acquisition Corp. II, a Cayman limited exempted company (the “Company”), Fathom Holdco, LLC, a Delaware limited liability company (“Fathom”), and CORE Industrial Partners Fund I, L.P.
(“CORE Fund I”) and CORE Industrial Partners Fund I Parallel, L.P. (“CORE Fund I Parallel” and, together with CORE Fund I, “Subscriber”). Prior to the closing of the Transactions (as defined below),
the Company will domesticate as a Delaware corporation in accordance with Section 388 of the Delaware General Corporation Law, as amended, and the Cayman Islands Companies Act (2021 Revision) (the “Domestication”). Capitalized
terms used herein but not defined shall have the respective meanings ascribed to such terms in the Transaction Agreement (as defined below). 

WHEREAS, the Company and Fathom entered into that certain Business Combination Agreement, dated as of July 15, 2021 and amended on
November 16, 2021, providing for a business combination between the Company and Fathom (as further amended, modified, supplemented or waived from time to time in accordance with its terms, the “Transaction Agreement” and the
transactions contemplated by the Transaction Agreement to be completed on and prior to the closing date thereof, the “Transactions”) pursuant to which, among other things, in the manner, and on the terms and subject to the
conditions and exclusions set forth in the Transaction Agreement, the Company is combining with Fathom; 
 WHEREAS, in connection with the
Transactions, Subscriber desires to subscribe for and purchase from the Company, following the Domestication but immediately prior to the consummation of the Transactions, that number of the Company’s Class A Common Stock, par value
$0.0001 per share (the “Class A Common Shares”), determined in accordance with the Backstop Condition Formula (as defined below) (such number of shares determined in accordance with the Backstop Condition Formula
and as specified in the Closing Notice, the “Subscribed Shares”) for a purchase price of $10.00 per share (the “Per Share Price” and the aggregate of such Per Share Price for all Subscribed Shares being referred to
herein as the “Purchase Price”), if and only if the sum of: (i) the expected balance in the Company’s Trust Account after giving effect to the Altimar Stockholder Redemption following the deadline to validly submit
redemption requests (it being understood that this clause (i) shall not take into account any potential or actual reversals of redemption requests and it being further understood that the Trust Account balance after giving effect to the Altimar
Stockholder Redemption in this clause (i) shall be certified or otherwise documented by the Company’s transfer agent as promptly as practicable following the redemption deadline) and (ii) the gross proceeds from the Original PIPE
Investment actually received by the Company (or its validly designated escrow agent) or reasonably expected by the Company to be received by the Company (or its validly designated escrow agent) prior to the Closing Date (the sum of foregoing clauses
(i) and (ii), the “Available Closing Date Cash”)), is less than $90,000,000 (such $90,000,000 amount, the “Minimum Cash Condition” and such condition to Subscriber’s purchase, the “Backstop
Condition”); 

  
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 WHEREAS, the number of Subscribed Shares to be purchased by Subscriber shall equal:
(i) the positive difference of the Minimum Cash Condition minus the Available Closing Date Cash (such amount, if applicable, the “Shortfall Amount”) divided by (ii) 10, provided, that (A) Subscriber’s obligation to
purchase Subscribed Shares shall be conditioned upon the Shortfall Amount being no greater than $10,000,000 and provided, further that (B) Subscriber shall in no event be obligated to purchase more than 1,000,000 Subscribed Shares for an
aggregate Subscription amount of $10,000,000 (the “Backstop Condition Formula”); and 
 WHEREAS, if and only if the
Backstop Condition is triggered (such determination to be made by the Company in its sole and absolute discretion, subject to Subscriber’s confirmation, such confirmation which shall not be unreasonably withheld by Subscriber), the Company
desires to issue and sell to Subscriber the Subscribed Shares in consideration of the payment of the Purchase Price by or on behalf of Subscriber to the Company (or its validly designated escrow agent). 

NOW, THEREFORE, in consideration of the foregoing and the mutual representations, warranties and covenants, and subject to the conditions
(including the Backstop Condition), herein contained, and intending to be legally bound hereby, the parties hereto hereby agree as follows: 

Section 1. Subscription. Subject to the terms and conditions hereof, at the Closing (as defined below), Subscriber hereby
agrees to subscribe for and purchase, and the Company hereby agrees to issue and sell to Subscriber, upon the payment of the Purchase Price, the Subscribed Shares (such subscription and issuance, the “Subscription”). For avoidance
of doubt, the respective obligations of CORE Fund I and CORE Fund I Parallel to purchase Subscribed Shares hereunder is expressly limited to the number of the Subscribed Shares listed by such fund’s respective name on Subscriber’s
signature page hereto (and in no event will either of CORE Fund I or CORE Fund I Parallel be obligated to purchase a greater number of the Subscribed Shares than so listed by such fund’s name on Subscriber’s signature page hereto).
Subscriber understands that, pursuant to the Domestication, the Subscribed Shares that will be issued pursuant hereto shall be shares of common stock in a Delaware corporation. Upon Subscriber’s request, the Company shall deliver to Subscriber:
(i) a duly completed and executed Internal Revenue Service Form W-9 or W-8BenE, as applicable and (ii) the names, email addresses and telephone numbers of two
company contacts (the “Wire Verification Information”). The Company shall deliver the Wire Verification Information as soon as practicable upon receiving such request from the Subscriber. 

Section 2. Closing. 

(a) The consummation of the Subscription contemplated hereby (the “Closing”) shall occur on the closing date of the
Transactions contemplated by the Transaction Agreement (the “Closing Date”), immediately prior to or substantially concurrently with the consummation of the Transactions to be completed on the Closing Date. The Company and
Subscriber hereby agree that, if the Backstop Condition is triggered, the Purchase Price proceeds shall be applied towards satisfying the Minimum Cash Condition. 

(b) At least two (2) Business Days before the anticipated Closing Date, the Company shall deliver written notice to Subscriber (the
“Closing Notice”) which shall: (i) indicate that the Backstop Condition has been triggered, (ii) specify the anticipated Closing Date, (iii) specify (x) the number of Subscribed Shares to be purchased by Subscriber in
accordance with the Backstop Condition Formula and (y) the Purchase Price, (iv) provide the wire instructions for delivery of the Purchase Price to the Company and (v) confirm the Wire Verification Information, if previously provided
to Subscriber upon request by Subscriber. No later than 5:00 PM New York 

  
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City time on one (1) Business Day prior to the Closing Date, Subscriber shall deliver the Purchase Price for the Subscribed Shares by wire transfer of United States dollars in immediately
available funds to the account specified by the Company in the Closing Notice, such funds to be held by the Company in escrow until the Closing, and deliver to the Company such information as is reasonably requested in the Closing Notice in order
for the Company to issue the Subscribed Shares to Subscriber, including, without limitation, the legal name(s) of the person(s) in whose name the Subscribed Shares are to be issued and a duly completed and executed Internal Revenue Service Form W-9 or appropriate Form W-8. Upon satisfaction (or, if applicable, waiver) of the conditions set forth in this Section 2, the Company shall deliver
to Subscriber (i) at the Closing, the Subscribed Shares in book entry form, free and clear of any liens or other restrictions (other than those arising under this Backstop Subscription Agreement or applicable securities laws), in the name of
Subscriber (or its nominee in accordance with its delivery instructions), and (ii) as promptly as practicable after the Closing, evidence from the Company’s transfer agent of the issuance to Subscriber of the Subscribed Shares on and as of
the Closing Date. In the event that (i) the Company does not accept the Subscription or (ii) the consummation of the Transactions does not occur within three (3) Business Days after the anticipated Closing Date specified in the
Closing Notice, unless otherwise agreed to in writing by the Company and Subscriber, the Company shall promptly (but in no event later than two (2) Business Days after the anticipated Closing Date specified in the Closing Notice) return the
funds so delivered by Subscriber to the Company by wire transfer in immediately available funds to the account specified by Subscriber, and any book entries shall be deemed cancelled. Notwithstanding such return or cancellation (x) a failure to
close on the anticipated Closing Date shall not, by itself, be deemed to be a failure of any of the conditions to Closing set forth in this Section 2 to be satisfied or waived on or prior to the Closing Date, and
(y) unless and until this Backstop Subscription Agreement is terminated in accordance with Section 7 herein, Subscriber shall remain obligated (A) to redeliver funds to the Company in escrow following the
Company’s delivery to Subscriber of a new Closing Notice and (B) to consummate the Closing upon satisfaction of the conditions set forth in this Section 2. For the purposes of this Backstop Subscription Agreement,
“Business Day” means any day other than a Saturday, Sunday or any other day on which commercial banks are required or authorized to close in the State of New York. 

(c) The Closing shall be subject to the satisfaction, or valid waiver in writing by each of the parties hereto, of the conditions that, on the
Closing Date: 
  

	 	(i)	 no suspension of the qualification of the Subscribed Shares for offering or sale or trading in any
jurisdiction, or any proceedings for any of such purposes, shall be ongoing; 


  

	 	(ii)	 all conditions precedent to the closing of the Transactions set forth in the Transaction Agreement shall have
been satisfied (as determined by the parties to the Transaction Agreement) or waived (other than those conditions which, by their nature, are to be satisfied at the closing of the Transactions pursuant to the Transaction Agreement or by the Closing
itself, but subject to their satisfaction or valid waiver at the closing of the Transactions), and the closing of the Transactions shall be scheduled to occur substantially concurrently with or immediately following the Closing; and




  
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	 	(iii)	 no governmental authority shall have enacted, issued, promulgated, enforced or entered any judgment, order,
law, rule or regulation (whether temporary, preliminary or permanent) which is then in effect and has the effect of making the consummation of the transactions contemplated hereby illegal or otherwise restraining or prohibiting consummation of the
transactions or the Subscription contemplated hereby and no such governmental authority shall have instituted or threatened in writing a proceeding seeking to impose any such restraint or prohibition. 



(d) The obligation of the Company to consummate the Closing shall be subject to the satisfaction or valid waiver in writing by the Company of
the additional conditions that, on the Closing Date: 
  

	 	(i)	 all representations and warranties of Subscriber contained in this Backstop Subscription Agreement shall be
true and correct in all material respects (other than representations and warranties that are qualified as to materiality or Subscriber Material Adverse Effect (as defined below), which representations and warranties shall be true and correct in all
respects) at and as of the Closing Date; and 


  

	 	(ii)	 Subscriber shall not be in material breach of any covenant, agreement or condition required by this Backstop
Subscription Agreement to be performed, satisfied or complied with by it at or prior to the Closing. 


 (e) The obligation
of Subscriber to consummate the Closing shall be subject to the satisfaction or valid waiver in writing by Subscriber of the additional conditions that, on the Closing Date: 
  

	 	(i)	 Each of the respective representations and warranties of each of the Company and Fathom contained in this
Backstop Subscription Agreement shall be true and correct in all material respects (other than representations and warranties that are qualified as to materiality or Company Material Adverse Effect and Fathom Material Adverse Effect (each as defined
below), which such respective representations and warranties shall be true and correct in all respects) at and as of the Closing Date; 


  

	 	(ii)	 the Company shall not be in material breach of any covenant, agreement or condition required by this Backstop
Subscription Agreement to be performed, satisfied or complied with by it at or prior to the Closing; and 


  

	 	(iii)	 the terms of the Transaction Agreement shall not have been amended or modified in a manner that would
materially and adversely affect Subscriber (in its capacity as such) without Subscriber’s prior written consent. 



(f) Prior to or at the Closing, each of the Company and Subscriber shall deliver all such other information as is reasonably requested by the
other party in order for the Company to issue the Subscribed Shares to Subscriber. 

  
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 Section 3. Company Representations and Warranties. The Company represents
and warrants to Subscriber (as defined below) that: 
 (a) The Company (i) is duly organized, validly existing and in good standing
under the laws of its jurisdiction of incorporation, (ii) has the requisite power and authority to own, lease and operate its properties, to carry on its business as it is now being conducted and to enter into, deliver and perform its
obligations under this Backstop Subscription Agreement, and (iii) is duly licensed or qualified to conduct its business and, if applicable, is in good standing under the laws of each jurisdiction (other than its jurisdiction of incorporation)
in which the conduct of its business or the ownership of its properties or assets requires such license or qualification, except, with respect to the foregoing clause (iii), where the failure to be in good standing would not reasonably be
expected to have a Company Material Adverse Effect. For purposes of this Backstop Subscription Agreement, a “Company Material Adverse Effect” means an event, change, development, occurrence, condition or effect with respect to the
Company and its subsidiaries, taken together as a whole (on a consolidated basis), that, individually or in the aggregate, would reasonably be expected to have a material adverse effect on the Company’s ability to consummate the transactions
contemplated hereby, including the issuance and sale of the Subscribed Shares. 
 (b) As of the Closing Date, the Subscribed Shares will be
duly authorized and, when issued and delivered to Subscriber against full payment therefor in accordance with the terms of this Backstop Subscription Agreement, will be validly issued, fully paid and
non-assessable and will not have been issued in violation of any preemptive rights created under the Company’s organizational documents (as adopted on or prior to the Closing Date), by contract, or the
laws of its jurisdiction of incorporation. 
 (c) This Backstop Subscription Agreement has been duly authorized, executed and delivered by
the Company, and assuming the due authorization, execution and delivery of the same by Subscriber and Fathom, this Backstop Subscription Agreement constitutes the valid and legally binding obligation of the Company, enforceable against the Company
in accordance with its terms, except as such enforceability may be limited by bankruptcy, insolvency, reorganization, moratorium and similar laws affecting creditors generally and by the availability of equitable remedies. 

(d) The execution and delivery of this Backstop Subscription Agreement, the issuance and sale of the Subscribed Shares and the compliance by
the Company with all of the provisions of this Backstop Subscription Agreement and the consummation of the transactions contemplated herein will not conflict with or result in a breach or violation of any of the terms or provisions of, or constitute
a default under, or result in the creation or imposition of any lien, charge or encumbrance upon any of the property or assets of the Company pursuant to the terms of (i) any indenture, mortgage, deed of trust, loan agreement, lease, license or
other agreement or instrument to which the Company is a party or by which the Company is bound or to which any of the property or assets of the Company is subject; (ii) the organizational documents of the Company; or (iii) any statute or
any judgment, order, rule or regulation of any court or governmental agency or body, domestic or foreign, having jurisdiction over the Company or any of its properties that, in the case of clauses (i) and (iii), would reasonably
be expected to have a Company Material Adverse Effect. 

  
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 (e) The Company is not required to obtain any consent, waiver, authorization or order of,
give any notice to, or make any filing or registration with, any court or other federal, state, local or other governmental authority, self-regulatory organization (including a national securities exchange such as the New York Stock Exchange (such
national securities exchange, the “Stock Exchange”)) or other person in connection with the execution, delivery and performance of this Backstop Subscription Agreement (including, without limitation, the issuance of the Subscribed
Shares), other than (i) filings required by applicable state securities laws, (ii), the filing of the Registration Statement pursuant to Section 6 below, (iii) those required by the Stock Exchange, including with
respect to obtaining stockholder approval, (iv) those required to consummate the Transactions as provided under the Transaction Agreement, (v) the filing of notification under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, if
applicable, and (vi) other filings, the failure of which to obtain would not reasonably be expected to have a Company Material Adverse Effect. 

(f) Except for such matters as have not had and would not reasonably be expected to have a Company Material Adverse Effect, there is no
(i) suit, action, investigation, proceeding or arbitration before a governmental authority or arbitrator pending, or, to the knowledge of the Company, threatened in writing against the Company or any of its directors or officers in their
capacities as such or (ii) judgment, decree, injunction, ruling or order of any governmental authority or arbitrator outstanding against the Company or any of its directors or officers in their capacities as such. 

(g) Assuming the accuracy of Subscriber’s representations and warranties set forth in Section 5 of this Backstop
Subscription Agreement, no registration under the Securities Act is required for the offer and sale of the Subscribed Shares by the Company to Subscriber. 

(h) Neither the Company nor any person acting on its behalf has engaged or will engage in any form of general solicitation or general
advertising (within the meaning of Regulation D under the Securities Act) in connection with any offer or sale of the Collective Subscribed Shares. Neither the Company nor any person acting on its behalf has offered or will offer any of the
Collective Subscribed Shares in a manner involving a public offering under, or in a distribution in violation of, the Securities Act or any state securities laws. 

(i) The Company is in compliance with all applicable laws and has not received any written communication from a governmental entity that
alleges that the Company is not in compliance with or is in default or violation of any applicable law, except where such non-compliance, default or violation would not, individually or in the aggregate,
reasonably be expected to have a Company Material Adverse Effect. 
 (j) The Company has filed each form, report, statement, schedule,
prospectus, proxy and registration statement (the “SEC Documents”) that the Company was required to file with the Securities and Exchange Commission (the “Commission”) since its initial registration of the
Class A Common Shares with the Commission and through the date hereof. As of their respective filing dates (the “Filing Dates”), the SEC Documents complied in all material respects with the requirements of the Securities Act,
the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and regulations of the Commission promulgated thereunder and currently in effect at the Filing Date, and none of the SEC Documents, when filed, or
if amended 

  
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prior to the date of this Backstop Subscription Agreement, as of the date of such amendment with respect to those disclosures that were amended, contained any untrue statement of a material fact
or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. A copy of each SEC Document is available to
Subscriber via the Commission’s EDGAR system. As of the date hereof, there are, and upon Closing there shall be, no outstanding or unresolved comments in comment letters from the staff of the Division of Corporation Finance of the Commission
with respect to any of the SEC Documents. 
 (k) As of the date hereof, the Company’s issued and outstanding Class A ordinary
shares (“Class A ordinary shares”) are registered pursuant to Section 12(b) of the Exchange Act, and are listed for trading on the New York Stock Exchange (“NYSE”) under the symbol
“ATMR” (it being understood that the trading symbol will be changed in connection with the Transactions). Except as disclosed in the SEC Documents, as of the date hereof, there is no suit, action, proceeding or investigation pending or, to
the knowledge of the Company, threatened against the Company by NYSE or the SEC, respectively, to prohibit or terminate the listing of the Company’s shares on NYSE or to deregister the shares under the Exchange Act. The Company has taken no
action that is designed to terminate the registration of the shares under the Exchange Act. Upon consummation of the Transactions, the issued and outstanding shares of Class A Common Shares will continue to be registered pursuant to
Section 12(b) of the Exchange Act and will be listed for trading on the Stock Exchange (as defined herein). 
 (l) The Company is not,
and immediately after receipt of payment for the Subscribed Shares and consummation of the Transactions, will not be, an “investment company” within the meaning of the Investment Company Act of 1940, as amended. 

(m) No document with respect to any PIPE Investment includes terms and conditions that are more materially advantageous to any PIPE Investor
than to Subscriber hereunder, and there has been no amendment, modification or waiver under any such PIPE Subscription Agreement following the date of such PIPE Subscription Agreement. 

(n) As of the date of this Backstop Subscription Agreement, the authorized capital stock of the Company consists of (a) 500,000,000 shares of
Class A ordinary shares, par value $0.0001 per share, of which 34,500,000 are issued and outstanding, (b) 50,000,000 shares of Class B ordinary shares, par value $0.0001 per share (“Class B ordinary
shares”), of which 8,625,000 are issued and outstanding, and (c) 5,000,000 preference shares, par value $0.0001 per share (“Preferred Shares”), of which no shares are issued and outstanding. As of the date of this Backstop
Subscription Agreement, the Company has 8,625,000 public warrants outstanding and 9,900,000 private placement warrants outstanding. Each private placement warrant and public warrant is exercisable for one Class A ordinary share at an exercise
price of $11.50 per share. Except as set forth in this Section 3(n), the SEC Documents, and pursuant to this Backstop Subscription Agreement, the PIPE Subscription Agreements and the Transaction Agreement, there are no
outstanding options, warrants or other rights to subscribe for, purchase or acquire from the Company any Class A ordinary shares, Class B ordinary shares or any other equity interests in the Company or any of its subsidiaries, or
securities convertible into or exchangeable or exercisable for any such Class A ordinary shares, Class B ordinary shares or other equity interests. There are no stockholder agreements, voting trusts or other agreements or understandings to
which the Company is a party or by which it is bound relating to the voting of any securities of the Company, other than (A) as set forth in the SEC Documents and (B) as contemplated by the Transaction Agreement. 

  
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 Section 4. Fathom Representations and Warranties. Fathom represents and
warrants to Subscriber that: 
 (a) Fathom (i) is duly organized, validly existing and in good standing under the laws of its
jurisdiction of formation, (ii) has the requisite power and authority to own, lease and operate its properties, to carry on its business as it is now being conducted and to enter into, deliver and perform its obligations under this Backstop
Subscription Agreement, and (iii) is duly licensed or qualified to conduct its business and, if applicable, is in good standing under the laws of each jurisdiction (other than its jurisdiction of formation) in which the conduct of its business
or the ownership of its properties or assets requires such license or qualification, except, with respect to the foregoing clause (iii), where the failure to be in good standing would not reasonably be expected to have a Fathom Material
Adverse Effect. For purposes of this Backstop Subscription Agreement, a “Fathom Material Adverse Effect” means an event, change, development, occurrence, condition or effect with respect to Fathom and its subsidiaries, taken
together as a whole (on a consolidated basis), that, individually or in the aggregate, would reasonably be expected to have a material adverse effect on Fathom’s ability to consummate the transactions contemplated hereby. 

(b) This Backstop Subscription Agreement has been duly authorized, executed and delivered by Fathom, and assuming the due authorization,
execution and delivery of the same by Subscriber and Company, this Backstop Subscription Agreement constitutes the valid and legally binding obligation of Fathom, enforceable against Fathom in accordance with its terms, except as such enforceability
may be limited by bankruptcy, insolvency, reorganization, moratorium and similar laws affecting creditors generally and by the availability of equitable remedies. 

(c) The execution and delivery of this Backstop Subscription Agreement, the issuance and sale of the Subscribed Shares and the compliance by
Fathom with all of the provisions of this Backstop Subscription Agreement and the consummation of the transactions contemplated herein will not conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a
default under, or result in the creation or imposition of any lien, charge or encumbrance upon any of the property or assets of Fathom pursuant to the terms of (i) any indenture, mortgage, deed of trust, loan agreement, lease, license or other
agreement or instrument to which Fathom is a party or by which Fathom is bound or to which any of the property or assets of Fathom is subject; (ii) the organizational documents of Fathom; or (iii) any statute or any judgment, order, rule
or regulation of any court or governmental agency or body, domestic or foreign, having jurisdiction over Fathom or any of its properties that, in the case of clauses (i) and (iii), would reasonably be expected to have a Fathom
Material Adverse Effect. 
 Section 5. Subscriber Representations and Warranties. Subscriber represents and warrants to
the Company and Fathom that: 
 (a) Subscriber (i) is duly organized, validly existing and in good standing under the laws of its
jurisdiction of incorporation or formation, and (ii) has the requisite power and authority to enter into and perform its obligations under this Backstop Subscription Agreement. 

  
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 (b) This Backstop Subscription Agreement has been duly executed and delivered by Subscriber,
and assuming the due authorization, execution and delivery of the same by the Company and Fathom, this Backstop Subscription Agreement constitutes the valid and legally binding obligation of Subscriber, enforceable against Subscriber in accordance
with its terms, except as such enforceability may be limited by bankruptcy, insolvency, reorganization, moratorium and similar laws affecting creditors generally and by the availability of equitable remedies. 

(c) The execution and delivery of this Backstop Subscription Agreement, the purchase of the Subscribed Shares and the compliance by Subscriber
with all of the provisions of this Backstop Subscription Agreement and the consummation of the transactions contemplated herein will not conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default
under, or result in the creation or imposition of any lien, charge or encumbrance upon any of the property or assets of Subscriber pursuant to the terms of (i) any indenture, mortgage, deed of trust, loan agreement, lease, license or other
agreement or instrument to which Subscriber is a party or by which Subscriber is bound or to which any of the property or assets of Subscriber is subject; (ii) the organizational documents of Subscriber; or (iii) any statute or any
judgment, order, rule or regulation of any court or governmental agency or body, domestic or foreign, having jurisdiction over Subscriber or any of its properties that, in the case of clauses (i) and (iii), would reasonably
be expected to have a Subscriber Material Adverse Effect. For purposes of this Backstop Subscription Agreement, a “Subscriber Material Adverse Effect” means an event, change, development, occurrence, condition or effect with respect
to Subscriber that would reasonably be expected to have a material adverse effect on Subscriber’s ability to consummate the transactions contemplated hereby, including the purchase of the Subscribed Shares. 

(d) Subscriber (i) is a “qualified institutional buyer” (as defined in Rule 144A under the Securities Act) or an institutional
“accredited investor” (within the meaning of Rule 501(a)(1), (2), (3), (7) (8), (9), (12) or (13) under the Securities Act) satisfying the applicable requirements set forth on Annex A, (ii) is acquiring the Subscribed Shares only
for its own account and not for the account of others, or if Subscriber is subscribing for the Subscribed Shares as a fiduciary or agent for one or more investor accounts, each owner of such account is a “qualified institutional buyer” (as
defined in Rule 144A under the Securities Act) or an institutional “accredited investor” (within the meaning of Rule 501(a)(1), (2), (3), (7) (8), (9), (12) or (13) under the Securities Act), and Subscriber has full investment
discretion with respect to each such account, and the full power and authority to make the acknowledgements, representations and agreements herein on behalf of each owner of each such account, and (iii) is not acquiring the Subscribed Shares
with a view to, or for offer or sale in connection with, any distribution thereof in violation of the Securities Act (and has provided the Company with the requested information on Annex A following the signature page hereto). Subscriber is not an
entity formed for the specific purpose of acquiring the Subscribed Shares and is an “institutional account” as defined by FINRA Rule 4512(c). 

(e) Subscriber understands that the Subscribed Shares are being offered in transactions not involving any public offering within the meaning of
the Securities Act and that the Subscribed Shares have not been registered under the Securities Act. Subscriber understands that the Subscribed Shares may not be offered, resold, transferred, pledged or otherwise disposed of by Subscriber absent an
effective registration statement under the Securities Act, except (i) to the 

  
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Company or a subsidiary thereof, or (ii) pursuant to an applicable exemption from the registration requirements of the Securities Act, and, in each of cases (i) and (ii), in accordance
with any applicable securities laws of the applicable states and other jurisdictions of the United States, and as a result of these transfer restrictions, Subscriber may not be able to readily resell the Subscribed Shares and may be required to bear
the financial risk of an investment in the Subscribed Shares for an indefinite period of time. Subscriber acknowledges and agrees that the Subscribed Shares will not be eligible for offer, resale, transfer, pledge or disposition pursuant to Rule 144
promulgated under the Securities Act (“Rule 144”) until at least one year from the Closing Date. Subscriber understands that it has been advised to consult legal counsel prior to making any offer, resale, pledge or transfer of any
of the Subscribed Shares. 
 (f) Subscriber understands and agrees that Subscriber is purchasing the Subscribed Shares directly from the
Company. Subscriber further acknowledges that there have not been, and Subscriber hereby agrees that it is not relying on, any of the respective representations, warranties, covenants or agreements made to Subscriber by each of the Company, Fathom
and any of their respective affiliates or any control persons, officers, directors, employees, partners, agents or representatives, any other party to the Transactions or any other person or entity, expressly or by implication, other than the
respective representations, warranties, covenants and agreements of each of the Company and Fathom expressly set forth in this Backstop Subscription Agreement. Subscriber acknowledges that certain information provided to Subscriber was based on
projections, and such projections were prepared based on assumptions and estimates that are inherently uncertain and are subject to a wide variety of significant business, economic and competitive risks and uncertainties that could cause actual
results to differ materially from those contained in the projections. 
 (g) In making its decision to purchase the Subscribed Shares,
Subscriber has relied solely upon independent investigation made by Subscriber. Subscriber acknowledges and agrees that Subscriber has received such information as Subscriber deems necessary in order to make an investment decision with respect to
the Subscribed Shares, including with respect to the Company and its subsidiaries and the Transactions. Subscriber represents and agrees that Subscriber and Subscriber’s professional advisor(s), if any, have had the opportunity to ask such
questions, receive such answers and obtain such information as Subscriber and such undersigned’s professional advisor(s), if any, have deemed necessary to make an investment decision with respect to the Subscribed Shares. Without limiting the
generality of the foregoing, Subscriber acknowledges that it has received (or in the case of documents filed with the Commission, had access to) the Company’s filings with the Commission and any disclosure documents provided by or on behalf of
the Company or Fathom in connection with this Subscription. Subscriber acknowledges that no statement or printed material contrary to any such disclosure documents has been made or given to Subscriber by or on behalf of the Company or Fathom. 

(h) Subscriber became aware of this offering of the Subscribed Shares solely by means of direct contact between Subscriber and the Company,
Fathom, or their respective representatives or affiliates, and the Subscribed Shares were offered to Subscriber solely by direct contact between Subscriber and the Company, Fathom or their respective affiliates. Subscriber did not become aware of
this offering of the Subscribed Shares, nor were the Subscribed Shares offered to Subscriber, by any other means. Subscriber acknowledges that the Company represents and warrants that the Subscribed Shares (i) were not offered by any form of
general solicitation or general advertising and (ii) are not being offered in a manner involving a public offering under, or in a distribution in violation of, the Securities Act, or any state securities laws. 

  
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 (i) Subscriber acknowledges that it is aware that there are substantial risks incident to
the purchase and ownership of the Subscribed Shares. Subscriber has such knowledge and experience in financial and business matters as to be capable of evaluating the merits and risks of an investment in the Subscribed Shares, and Subscriber has had
an opportunity to seek, and has sought, such accounting, legal, business and tax advice as Subscriber has considered necessary to make an informed investment decision. 

(j) Subscriber has adequately analyzed and fully considered the risks of an investment in the Subscribed Shares and determined that the
Subscribed Shares are a suitable investment for Subscriber and that Subscriber is able at this time and in the foreseeable future to bear the economic risk of a total loss of Subscriber’s investment in the Company. Subscriber acknowledges
specifically that a possibility of total loss exists. 
 (k) Subscriber understands and agrees that no federal or state agency has passed
upon or endorsed the merits of the offering of the Subscribed Shares or made any findings or determination as to the fairness of this investment. 

(l) Subscriber is not, and is not owned or controlled by or acting on behalf of (in connection with the Transactions), a Sanctioned Person.
Subscriber is not a non-U.S. shell bank or providing banking services to a non-U.S. shell bank. Subscriber represents that if it is a financial institution subject to
the Bank Secrecy Act (31 U.S.C. Section 5311 et seq.), as amended by the USA PATRIOT Act of 2001 and its implementing regulations (collectively, the “BSA/PATRIOT Act”), that Subscriber maintains, either directly or through the
use of a third-party administrator, policies and procedures reasonably designed to comply with applicable obligations under the BSA/PATRIOT Act. Subscriber also represents that it maintains, either directly or through the use of a third-party
administrator, policies and procedures reasonably designed for the screening of any investors against Sanctions-related lists of blocked or restricted persons. Subscriber further represents and warrants that, to its best knowledge, the funds held by
Subscriber and used to purchase the Subscribed Shares are derived from lawful activities. For purposes of this Agreement, “Sanctioned Person” means at any time any person or entity: (a) listed on any Sanctions-related list of
designated or blocked or restricted persons; (b) that is a national of, the government of, or any agency or instrumentality of the government of, or resident in, or organized under the laws of, a country or territory that is the target of
comprehensive Sanctions from time to time (as of the date of this Agreement, Cuba, Iran, North Korea, Syria, and the Crimea region); or (c) owned or controlled by or acting on behalf of any of the foregoing. “Sanctions” means
those trade, economic and financial sanctions laws, regulations, embargoes, and restrictive measures (in each case having the force of law) administered, enacted or enforced from time to time by (a) the United States (including without
limitation the U.S. Department of the Treasury, Office of Foreign Assets Control, the U.S. Department of State, and the U.S. Department of Commerce), (b) the European Union and enforced by its member states, (c) the United Nations, (d) Her
Majesty’s Treasury and (e) the Cayman Islands. 

  
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 (m) No foreign person (as defined in 31 C.F.R. Part 800.224) in which the national or
subnational governments of a single foreign state have a substantial interest (as defined in 31 C.F.R. Part 800.244) will acquire a substantial interest in the Company as a result of the purchase and sale of Subscribed Shares hereunder such that a
declaration to the Committee on Foreign Investment in the United States would be mandatory under 31 C.F.R. Part 800.401, and no foreign person will have control (as defined in 31 C.F.R. Part 800.208) over the Company from and after the Closing as a
result of the purchase and sale of Subscribed Shares hereunder. 
 (n) If Subscriber is an employee benefit plan that is subject to Title I
of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), a plan, an individual retirement account or other arrangement that is subject to section 4975 of the Internal Revenue Code of 1986, as amended (the
“Code”) or an employee benefit plan that is a governmental plan (as defined in section 3(32) of ERISA), a church plan (as defined in section 3(33) of ERISA), a non-U.S. plan (as described in
section 4(b)(4) of ERISA) or other plan that is not subject to the foregoing but may be subject to provisions under any other federal, state, local, non-U.S. or other laws or regulations that are similar to
such provisions of ERISA or the Code, or an entity whose underlying assets are considered to include “plan assets” of any such plan, account or arrangement (each, a “Plan”) subject to the fiduciary or prohibited
Transactions provisions of ERISA or section 4975 of the Code, Subscriber represents and warrants that (i) neither the Company, nor any of its respective affiliates (the “Transactions Parties”) has acted as the Plan’s
fiduciary, or has been relied on for advice, with respect to its decision to acquire and hold the Subscribed Shares, and none of the Transactions Parties shall at any time be relied upon as the Plan’s fiduciary with respect to any decision to
acquire, continue to hold or transfer the Subscribed Shares and (ii) none of the acquisition, holding and/or transfer or disposition of the Subscribed Shares will result in a non-exempt prohibited
Transactions under ERISA or Section 4975 of the Code or any similar law or regulation. 
 (o) Subscriber has, and at the Closing will
have, sufficient funds or immediate unconditional availability to sufficient funds, to pay the Purchase Price pursuant to Section 2 and any damages required to be paid after termination of this Agreement. 

(p) No broker or finder is entitled to any brokerage or finder’s fee or commission solely in connection with the sale of the Subscribed
Shares to Subscriber based on any arrangement entered into by or on behalf of Subscriber. 
 Section 6. Registration of Subscribed
Shares. 
 (a) The Company agrees that the Company will file with the Commission (at the Company’s sole cost and expense) a
registration statement registering the resale of the Subscribed Shares (the “Registration Statement”) no later than (30) calendar days after the Closing Date, and the Company shall use its commercially reasonable efforts to
have the Registration Statement declared effective as soon as practicable after the filing thereof, but no later than the earlier of (i) sixty (60) calendar days after the filing thereof (or, in the event the Commission reviews and has written
comments to the Registration Statement, the ninetieth (90th) calendar day following the filing thereof) and (ii) the tenth (10th) business day after the date the Company is notified (orally or in writing, whichever is earlier) by the Commission
that the Registration Statement will not be “reviewed” or will not be subject to further review ((i) and (ii) collectively, the “Effectiveness Deadline”); provided, that if such day falls on a Saturday, Sunday
or other day that the Commission is closed for business, the Effectiveness Deadline shall be extended to the next Business Day on 

  
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which the Commission is open for business. The Company will use its commercially reasonable efforts to provide a draft of the Registration Statement to the undersigned for review and comment at
least two (2) Business Days in advance of filing the Registration Statement; provided that, for the avoidance of doubt, in no event shall the Company be required to delay or postpone the filing of such Registration Statement as a result of or
in connection with Subscriber’s review. Unless otherwise agreed to in writing by Subscriber, Subscriber shall not be identified as a statutory underwriter in the Registration Statement unless requested by the Commission or another regulatory
agency; provided, that if the Commission or another regulatory agency requests that a Subscriber be identified as a statutory underwriter in the Registration Statement, Subscriber will have the opportunity to withdraw from the Registration Statement
prior to the Registration Statement becoming effective upon its prompt written request to the Company. Notwithstanding the foregoing, if the Commission prevents the Company from including any or all of the shares proposed to be registered under the
Registration Statement due to limitations on the use of Rule 415 of the Securities Act for the resale of the Subscribed Shares by the applicable stockholders or otherwise, such Registration Statement shall register for resale such number of
Subscribed Shares which is equal to the maximum number of Subscribed Shares as is permitted by the Commission. In such event, the number of Subscribed Shares to be registered for each selling stockholder named in the Registration Statement shall be
reduced pro rata among all such selling stockholders and as promptly as practicable after being permitted to register additional Subscribed Shares under Rule 415 under the Securities Act, the Company shall amend the Registration Statement or file a
new Registration Statement to register such additional Subscribed Shares that were not included in the initial Registration Statement and cause such amendment or Registration Statement to become effective as promptly as practicable. The Company
agrees that, except for such times as the Company is permitted hereunder to suspend the use of the prospectus forming part of a Registration Statement, the Company will use its commercially reasonable efforts to cause such Registration Statement to
remain effective with respect to Subscriber until the earlier of (i) two years from the issuance of the Subscribed Shares, (ii) the date on which all of the Subscribed Shares shall have been sold, or (iii) on the first date on which
the undersigned can sell all of its Subscribed Shares (or shares received in exchange therefor) under Rule 144 without limitation as to the manner of sale or the amount of such securities that may be sold and without the requirement for the Company
to be in compliance with the current public information required under Rule 144(c)(1) (or Rule 144(i)(2), if applicable). If requested by Subscriber, the Company shall use its commercially reasonable efforts to (i) cause the removal of the
restrictive legends from any Subscribed Shares being sold under the Registration Statement or pursuant to Rule 144 at the time of sale of such Registrable Securities (as defined below) and, at the request of a Holder (as defined below), cause the
removal of all restrictive legends from any Registrable Securities held by such Holder that may be sold by such Holder without restriction under Rule 144, including without limitation, any volume and manner of sale restrictions, and (ii) cause
its legal counsel to deliver an opinion, if necessary, to the transfer agent in connection with the instruction under subclause (i) to the effect that the removal of such restrictive legends in such circumstances may be effected under the
Securities Act, in each case upon the receipt of customary representations and other documentation, if any, from the Holder as reasonably requested by the Company, its counsel or the transfer agent, establishing that restrictive legends are no
longer required. Any costs related to the foregoing, including fees of the transfer agent, DTC and legal counsel to the Company shall be borne by the Company. The Company will use commercially reasonable efforts to make and keep public information
available (as those terms are understood and defined in Rule 144) and file 

  
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all reports, and provide all customary and reasonable cooperation, necessary to enable Holder to resell Registrable Securities pursuant to the Registration Statement or Rule 144, as applicable,
qualify the Registrable Securities for listing on the applicable stock exchange on which the Company’s Class A Common Shares are then listed and update or amend the Registration Statement as necessary to include Registrable Securities.
“Registrable Securities” shall mean, as of any date of determination, the Subscribed Shares and any other equity security issued or issuable with respect to the Subscribed Shares by way of share split, dividend, distribution,
recapitalization, merger, exchange, replacement or similar event, provided, however, that such securities shall cease to be Registrable Securities at the earliest of (A) three (3) years, (B) the date all Subscribed Shares held by a Holder
may be sold by such Holder without volume or manner of sale limitations pursuant to Rule 144 and without the requirement for the Company to be in compliance with the current public information required under Rule 144(c)(1) (or Rule 144(i)(2), if
applicable), (C) the date on which such securities have actually been sold by a Holder, or (D) when such securities shall have ceased to be outstanding. “Holder” shall mean Subscriber or any affiliate of Subscriber to which the
rights under this Section 6 shall have been assigned. The Company’s obligations to include the Subscribed Shares in the Registration Statement are contingent upon Subscriber furnishing in writing to the Company such
information regarding Subscriber, the securities of the Company held by Subscriber and the intended method of disposition of the Subscribed Shares as shall be reasonably requested by the Company to effect the registration of the Subscribed Shares,
and Subscriber shall execute such documents in connection with such registration as the Company may reasonably request that are customary of a selling stockholder in similar situations, including providing that the Company shall be entitled to
postpone and suspend the effectiveness or use of the Registration Statement during any customary blackout or similar period or as permitted hereunder; provided that Subscriber shall not in connection with the foregoing be required to execute any lock-up or similar agreement or otherwise be subject to any contractual restriction on the ability to transfer Subscriber Shares. In the case of the registration effected by the Company pursuant to this Backstop
Subscription Agreement, the Company shall, upon reasonable request, inform Subscriber as to the status of such registration. Subscriber shall not be entitled to use the Registration Statement for an underwritten offering of Subscribed Shares.
Notwithstanding anything to the contrary contained herein, the Company may delay or postpone filing of such Registration Statement, and from time to time require Subscriber not to sell under the Registration Statement or suspend the use or
effectiveness of any such Registration Statement if it determines that in order for the registration statement to not contain a material misstatement or omission, an amendment thereto would be needed, or if, in the reasonable determination of the
Company’s board of directors, upon advice of legal counsel, such filing or use could materially affect a bona fide business or financing transaction of the Company or would require premature disclosure of information that could materially
adversely affect the Company (each such circumstance, a “Suspension Event”); provided, that, (w) the Company shall not so delay filing or so suspend the use of the Registration Statement for a period of more than sixty
(60) consecutive days or more than two (2) times in any three hundred sixty (360) day period and (x) the Company shall use commercially reasonable efforts to make such registration statement available for the sale by the
undersigned of such securities as soon as practicable thereafter. 
 (b) In the case of the registration effected by the Company pursuant to
this Backstop Subscription Agreement, the Company shall, upon reasonable request, inform Subscriber as to the status of such registration. At its expense the Company shall: 

  
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 (i) advise Subscriber, as expeditiously as possible: 

(i) when a Registration Statement or any amendment thereto has been filed with the Commission; 

(ii) after it shall receive notice or obtain knowledge thereof, of the issuance by the Commission of any stop order suspending
the effectiveness of any Registration Statement or the initiation of any proceedings for such purpose; 
 (iii) of the
receipt by the Company of any notification with respect to the suspension of the qualification of the Subscribed Shares included therein for sale in any jurisdiction or the initiation or threatening of any proceeding for such purpose; and 

(iv) subject to the provisions in this Backstop Subscription Agreement, of the occurrence of any event that requires the making
of any changes in any Registration Statement or prospectus so that, as of such date, the statements therein are not misleading and do not omit to state a material fact required to be stated therein or necessary to make the statements therein (in the
case of a prospectus, in light of the circumstances under which they were made) not misleading. 
  

	 	(ii)	 use its commercially reasonable efforts to obtain the withdrawal of any order suspending the effectiveness of
any Registration Statement as soon as reasonably practicable; 


  

	 	(iii)	 upon the occurrence of any event contemplated in Section 6(b)(i)(iv) above, except
for such times as the Company is permitted hereunder to suspend, and has suspended, the use of a prospectus forming part of a Registration Statement, the Company shall use its commercially reasonable efforts to as soon as reasonably practicable
prepare a post-effective amendment to such Registration Statement or a supplement to the related prospectus, or file any other required document so that, as thereafter delivered to purchasers of the Subscribed Shares included therein, such
prospectus will not include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein, in light of the circumstances under which they were made, not misleading; 



 

	 	(iv)	 use its commercially reasonable efforts to allow Subscriber to review disclosure regarding Subscriber in the
Registration Statement; and 


  

	 	(v)	 otherwise, in good faith, cooperate reasonably with, and take such customary actions as may reasonably be
requested by Subscriber, consistent with the terms of this Backstop Subscription Agreement, in connection with the registration of the Subscribed Shares. 



(c) Upon receipt of any written notice from the Company of the occurrence of any Suspension Event during the period that the Registration
Statement is effective or if as a result of a Suspension Event the Registration Statement or related prospectus contains any untrue statement of a material fact or omits to state any material fact required to be stated therein or necessary to make
the statements therein, in light of the circumstances under which they were made (in the case 

  
 15 












 
of the prospectus) not misleading, the undersigned agrees that (i) it will immediately discontinue offers and sales of the Subscribed Shares under the Registration Statement (excluding, for
the avoidance of doubt, sales conducted pursuant to Rule 144) until the undersigned receives copies of a supplemental or amended prospectus (which the Company agrees to promptly prepare) that corrects the misstatement(s) or omission(s) referred to
above and receives notice that any post-effective amendment has become effective or unless otherwise notified by the Company that it may resume such offers and sales, and (ii) it will maintain the confidentiality of any information included in
such written notice delivered by the Company unless otherwise required by law, subpoena or regulatory request or requirement. If so directed by the Company, the undersigned will deliver to the Company, or in the undersigned’s sole discretion
destroy, all copies of the prospectus covering the Subscribed Shares in the undersigned’s possession; provided, however, that this obligation to deliver or destroy all copies of the prospectus covering the Subscribed Shares shall not apply
(w) to the extent the undersigned is required to retain a copy of such prospectus (A) in order to comply with applicable legal, regulatory, self-regulatory or professional requirements or (B) in accordance with a bona fide pre-existing document retention policy or (x) to copies stored electronically on archival servers as a result of automatic data back-up. 

Section 7. Termination. This Backstop Subscription Agreement shall terminate and be void and of no further force and effect, and
all rights and obligations of the parties hereunder shall terminate without any further liability on the part of any party in respect thereof, upon the earliest to occur of (a) such date and time as the Transaction Agreement is validly
terminated in accordance with its terms without being consummated, (b) upon the mutual written agreement of all parties hereto to terminate this Backstop Subscription Agreement, (c) if, on the Closing Date of the Transactions, (i) any
of the conditions to Closing set forth in Section 2 of this Backstop Subscription Agreement have not been satisfied as of the time required hereunder to be so satisfied or waived by the party entitled to grant such waiver and, as a result
thereof, the transactions contemplated by this Backstop Subscription Agreement are not consummated or (ii) the Minimum Cash Condition is satisfied without regard or giving effect to this Backstop Subscription Agreement (including any purchase
of Subcribed Shares by Subscriber) or (d) by written notice from Subscriber or any other party given anytime on or after December 31, 2021, if the Closing has not occurred by such date and the terminating party’s breach was not the
primary reason the Closing failed to occur by such date, (the termination events described in clauses (a)–(d) above, collectively, the “Termination Events”); provided, that nothing herein will relieve any party from liability for any
willful breach hereof prior to the time of termination or common law intentional fraud in the making of any representation or warranty hereunder, and each party will be entitled to any remedies at law or in equity to recover losses, liabilities or
damages arising from such breach or fraud. The Company shall notify Subscriber of the termination of the Transaction Agreement promptly after the termination thereof. Upon the occurrence of any Termination Event, except as set forth in the proviso
to the first sentence of this Section 7, this Backstop Subscription Agreement shall be void and of no further effect and any portion of the Purchase Price paid by Subscriber to Company in connection herewith shall promptly
(and in any event within two business days) following the Termination Event be returned to Subscriber. 

  
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 Section 8. Trust Account Waiver. Subscriber hereby acknowledges that the Company
has established a trust account (the “Trust Account”) containing the proceeds of its initial public offering (the “IPO”) and from certain private placements occurring simultaneously with the IPO (including interest
accrued from time to time thereon) for the benefit of the Company’s public stockholders and certain other parties (including the underwriters of the IPO). For and in consideration of the Company entering into this Backstop Subscription
Agreement, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Subscriber hereby (a) agrees that it does not now and shall not at any time hereafter have any right, title, interest or
claim of any kind in or to any assets held in the Trust Account, and shall not make any claim against the Trust Account, in each case arising out of or as a result of, in connection with or relating in any way to this Backstop Subscription Agreement
and the transactions contemplated by this Backstop Subscription Agreement, and regardless of whether such claim arises based on contract, tort, equity or any other theory of legal liability (any and all such claims are collectively referred to
hereafter as the “Released Claims”), (b) irrevocably waives any Released Claims that it may have against the Trust Account now or in the future as a result of, or arising out of this Backstop Subscription Agreement and the
transactions contemplated by this Backstop Subscription Agreement, and (c) will not seek recourse against the Trust Account for any reason whatsoever; provided, however, that nothing in this Section 8
shall be deemed to limit any Subscriber’s right to distributions from the Trust Account in accordance with the Company’s amended and restated certificate of incorporation in respect of shares of Class A Common Shares of the Company
acquired by any means other than pursuant to this Backstop Subscription Agreement. 
 Section 9. Indemnity. 

(a) The Company agrees to indemnify and hold harmless, to the extent permitted by law, Subscriber, its directors, and officers, employees, and
agents, and each person who controls Subscriber (within the meaning of the Securities Act or the Exchange Act) and each affiliate of Subscriber (within the meaning of Rule 405 under the Securities Act) from and against any and all losses, claims,
damages, liabilities and expenses (including, without limitation, any reasonable attorneys’ fees and expenses incurred in connection with defending or investigating any such action or claim) caused by any untrue or alleged untrue statement of
material fact contained in any Registration Statement, prospectus included in any Registration Statement or preliminary prospectus or any amendment thereof or supplement thereto or any omission or alleged omission of a material fact required to be
stated therein or necessary to make the statements therein not misleading, except insofar as the same are caused by or contained in any information furnished in writing to the Company by or on behalf of Subscriber expressly for use therein. 

(b) Subscriber severally but not jointly agrees to indemnify and hold harmless the Company, its directors, officers, employees and agents, and
each person who controls the Company (within the meaning of the Securities Act or the Exchange Act) and each affiliate of the Company against any losses, claims, damages, liabilities and expenses (including, without limitation, reasonable
attorneys’ fees and expenses incurred in connection with defending or investigating any such action or claim) resulting from any untrue statement of material fact contained in the Registration Statement, prospectus or preliminary prospectus or
any amendment thereof or supplement thereto or any omission or alleged omission of a material fact required to be stated therein or necessary to make the statements therein not misleading, but only to the extent that such untrue statement or
omission is contained in any information or affidavit so furnished in writing to the Company by or on behalf of Subscriber expressly for use therein. In no event shall the liability of either of CORE Fund I or CORE Fund I Parallel be greater in
amount than the dollar amount of the net proceeds received by the Company upon the sale of the portion of the Subscribed 

  
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Shares purchased by CORE Fund I or CORE Fund I Parallel, respectively, pursuant to this Backstop Subscription Agreement giving rise to such indemnification obligation. Each of the Company and
Fathom acknowledge and agree that each purchase by Subscriber of Subscribed Shares from the Company will constitute a reaffirmation of each of the respective acknowledgments, understandings, agreements, representations and warranties herein (as
modified by such notice) made by each of the Company and Fathom as of the time of such purchase. 
 (c) Any person entitled to
indemnification herein shall (1) give prompt written notice to the indemnifying party of any claim with respect to which it seeks indemnification (provided that the failure to give prompt notice shall not impair any person’s right to
indemnification hereunder to the extent such failure has not prejudiced the indemnifying party) and (2) permit such indemnifying party to assume the defense of such claim with counsel reasonably satisfactory to the indemnified party. If such
defense is assumed, the indemnifying party shall not be subject to any liability for any settlement made by the indemnified party without its consent. An indemnifying party who elects not to assume the defense of a claim shall not be obligated to
pay the fees and expenses of more than one counsel for all parties indemnified by such indemnifying party with respect to such claim, unless in the reasonable judgment of legal counsel to any indemnified party a conflict of interest exists between
such indemnified party and any other of such indemnified parties with respect to such claim. No indemnifying party shall, without the consent of the indemnified party, consent to the entry of any judgment or enter into any settlement which cannot be
settled in all respects by the payment of money (and such money is so paid by the indemnifying party pursuant to the terms of such settlement) or which settlement 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. 
 (d) The indemnification
provided for under this Backstop Subscription Agreement shall remain in full force and effect regardless of any investigation made by or on behalf of the indemnified party or any officer, director, employee, agent, affiliate or controlling person of
such indemnified party and shall survive the transfer of the Subscribed Shares purchased pursuant to this Backstop Subscription Agreement. 

(e) If the indemnification provided under this Section 9 from the indemnifying party is unavailable or insufficient
to hold harmless an indemnified party in respect of any losses, claims, damages, liabilities and expenses referred to herein, then the indemnifying party, in lieu of indemnifying the indemnified party, shall contribute to the amount paid or payable
by the indemnified party as a result of such losses, claims, damages, liabilities and expenses in such proportion as is appropriate to reflect the relative fault of the indemnifying party and the indemnified party, as well as any other relevant
equitable considerations. The relative fault of the indemnifying party and indemnified party shall be determined by reference to, among other things, whether any action in question, including any untrue or alleged untrue statement of a material fact
or omission or alleged omission to state a material fact, was made by, or relates to information supplied by or on behalf of, such indemnifying party or indemnified party, and the indemnifying party’s and indemnified party’s relative
intent, knowledge, access to information and opportunity to correct or prevent such action. The amount paid or payable by a party as a result of the losses or other liabilities referred to above shall be deemed to include, subject to the limitations
set forth above, any legal or other fees, charges or expenses reasonably incurred by such party in connection 

  
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with any investigation or proceeding. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution pursuant
to this Section 9 from any person who was not guilty of such fraudulent misrepresentation. Any contribution pursuant to this Section 9(e) by any seller of Subscribed Shares shall be limited in
amount to the amount of net proceeds received by such seller from the sale of such Subscribed Shares pursuant to this Backstop Subscription Agreement. Any contribution by either of CORE Fund I or CORE Fund I Parallel pursuant to this
Section 9(e) shall be limited in amount to the amount of net proceeds received by the Company upon the sale of the portion of the Subscribed Shares purchased by CORE Fund I or CORE Fund I Parallel, respectively, pursuant to
this Backstop Subscription Agreement. Notwithstanding anything to the contrary herein, in no event will any party be liable for consequential, special, exemplary or punitive damages in connection with this Backstop Subscription Agreement. 

Section 10. Miscellaneous. 

(a) All notices, requests, demands, claims, and other communications hereunder shall be in writing. Any notice, request, demand, claim, or
other communication hereunder shall be deemed duly given (i) when delivered personally to the recipient, (ii) when sent by electronic mail, on the date and time of transmission to such recipient, provided that no electronic mail is
undeliverable or other rejection notice is generated, (iii) one Business Day after being sent to the recipient by reputable overnight courier service (charges prepaid), or (iv) four (4) Business Days after being mailed to the recipient by
certified or registered mail, return receipt requested and postage prepaid, and, in each case, addressed to the intended recipient at its address or electronic mail address, as applicable, specified on the signature page hereof or to such electronic
mail address or address as subsequently modified by written notice given in accordance with this Section 10(a). 

(b) Subscriber acknowledges that the Company and Fathom will rely on the acknowledgments, understandings, agreements, representations and
warranties of Subscriber contained in this Backstop Subscription Agreement. Prior to the Closing, Subscriber agrees to promptly notify the Company and Fathom if it becomes aware that any of the acknowledgments, understandings, agreements,
representations and warranties of Subscriber set forth herein are no longer accurate in all material respects. Subscriber acknowledges and agrees that each purchase by Subscriber of Subscribed Shares from the Company will constitute a reaffirmation
of the acknowledgments, understandings, agreements, representations and warranties herein (as modified by any such notice) by Subscriber as of the time of such purchase. Each of the Company and Fathom acknowledge that Subscriber will rely on the
respective acknowledgments, understandings, agreements, representations and warranties made by each of the Company and Fathom contained in this Backstop Subscription Agreement. Prior to the Closing, each of the Company and Fathom agree to promptly
notify Subscriber if they become aware that any of their respective acknowledgments, understandings, agreements, representations and warranties set forth herein are no longer accurate in all material respects. 

(c) Each of the Company, Fathom and Subscriber and any other person or entity against whom a claim is brought with respect to the purchase of
the Subscribed Shares is irrevocably authorized to produce this Backstop Subscription Agreement or a copy hereof to any interested party in any administrative or legal proceeding or official inquiry with respect to the matters covered hereby. 

  
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 (d) Subscriber shall pay all of its own expenses in connection with this Backstop
Subscription Agreement and the transactions contemplated herein, except as expressly set forth herein. 
 (e) Neither this Backstop
Subscription Agreement nor any rights that may accrue to Subscriber hereunder (other than the Subscribed Shares acquired hereunder and Subscriber’s rights under Section 6 hereof) may be transferred or assigned. Neither
this Backstop Subscription Agreement nor any rights that may accrue to the Company hereunder may be transferred or assigned (provided, that, for the avoidance of doubt, the Company may transfer the Backstop Subscription Agreement and its rights
hereunder solely in connection with the consummation of the Transactions and exclusively to another entity under the control of, or under common control with, the Company), provided that no such assignment shall relieve the Company of its
obligations hereunder if any such assignee fails to perform such obligations. Notwithstanding the foregoing, Subscriber may assign its rights and obligations under this Backstop Subscription Agreement to one or more of its affiliates, other
investment funds or accounts managed or advised by the investment manager who acts on behalf of Subscriber or, with the Company’s prior written consent, to another person, provided that no such assignment shall relieve Subscriber of its
obligations hereunder if any such assignee fails to perform such obligations. 
 (f) All the agreements, representations and warranties made
by each party hereto in this Backstop Subscription Agreement shall survive the Closing. For the avoidance of doubt, if for any reason the Closing does not occur prior to the consummation of the Transactions, all representations, warranties,
covenants and agreements of the parties hereunder shall survive the consummation of the Transactions and remain in full force and effect. 

(g) The Company may request from Subscriber such additional information as the Company may reasonably deem necessary to evaluate the
eligibility of Subscriber to acquire the Subscribed Shares and to register the Subscribed Shares for resale, and Subscriber shall provide such information as may be reasonably requested to the extent readily available and to the extent consistent
with Subscriber’s internal policies and procedures; provided that the Company agrees to keep any such information provided by Subscriber confidential except to the extent such disclosure is required in connection with registration of the
Subscribed Shares for resale, by law, at the request of the staff of the Commission or under the regulations of the Stock Exchange. Subscriber acknowledges that subject to the conditions set forth in Section 10(t), the
Company may file a copy of this Backstop Subscription Agreement with the Commission as an exhibit to a periodic report of the Company or a registration statement of the Company. 

(h) This Backstop Subscription Agreement may not be amended, modified or waived except by an instrument in writing, signed by each of the
parties hereto. 
 (i) This Backstop Subscription Agreement constitutes the entire agreement, and supersedes all other prior agreements,
understandings, representations and warranties, both written and oral, among the parties, with respect to the subject matter hereof. 

  
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 (j) Except as otherwise provided herein (including the next sentence hereof), this Backstop
Subscription Agreement is intended for the benefit of the parties hereto and their respective affiliates and their respective heirs, executors, administrators, successors, legal representatives, and permitted assigns and is not for the benefit of,
nor may any provision hereof be enforced by, any other person. Except as set forth in Section 10(b), Section 10(c), Section 10(e) and this
Section 10(j), this Backstop Subscription Agreement shall not confer any rights or remedies upon any person other than the parties hereto, and their respective successor and assigns, and the parties hereto acknowledge that such
persons so referenced are third party beneficiaries of this Backstop Subscription Agreement for the purposes of, and to the extent of, the rights granted to them, if any, pursuant to the applicable provisions. 

(k) The parties hereto acknowledge and agree that (i) this Backstop Subscription Agreement is being entered into in order to induce the
Company and Fathom to execute and deliver the Transaction Agreement and (ii) irreparable damage would occur in the event that any of the provisions of this Backstop Subscription Agreement were not performed in accordance with their specific
terms or were otherwise breached and that money or other legal remedies would not be an adequate remedy for such damage. It is accordingly agreed that the parties shall be entitled to equitable relief, including in the form of an injunction or
injunctions to prevent breaches or threatened breaches of this Backstop Subscription Agreement and to enforce specifically the terms and provisions of this Backstop Subscription Agreement, this being in addition to any other remedy to which such
party is entitled at law, in equity, in contract, in tort or otherwise. The parties hereto acknowledge and agree that the Company and Fathom shall each be entitled to specifically enforce Subscriber’s obligations to fund the Subscription Amount
and the provisions of the Backstop Subscription Agreement, in each case, on the terms and subject to the conditions set forth herein. The parties hereto further acknowledge and agree: (x) to waive any requirement for the security or posting of
any bond in connection with any such equitable remedy; (y) not to assert that a remedy of specific enforcement pursuant to this Section 10(k) is unenforceable, invalid, contrary to applicable law or inequitable for any
reason; and (z) to waive any defenses in any action for specific performance, including the defense that a remedy at law would be adequate. 

(l) In any dispute arising out of or related to this Backstop Subscription Agreement, or any other agreement, document, instrument or
certificate contemplated hereby, or any transactions contemplated hereby or thereby, the applicable adjudicating body shall award to the prevailing party, if any, the costs and attorneys’ fees reasonably incurred by the prevailing party in
connection with the dispute and the enforcement of its rights under this Backstop Subscription Agreement or any other agreement, document, instrument or certificate contemplated hereby and, if the adjudicating body determines a party to be the
prevailing party under circumstances where the prevailing party won on some but not all of the claims and counterclaims, the adjudicating body may award the prevailing party an appropriate percentage of the costs and attorneys’ fees reasonably
incurred and documented by the prevailing party in connection with the adjudication and the enforcement of its rights under this Backstop Subscription Agreement or any other agreement, document, instrument or certificate contemplated hereby or
thereby. 
 (m) If any provision of this Backstop Subscription Agreement shall be invalid, illegal or unenforceable, the validity, legality
or enforceability of the remaining provisions of this Subscription Agreement shall not in any way be affected or impaired thereby and shall continue in full force and effect. 

  
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 (n) No failure or delay by a party hereto in exercising any right, power or remedy under
this Backstop Subscription Agreement, and no course of dealing between the parties hereto, shall operate as a waiver of any such right, power or remedy of such party. No single or partial exercise of any right, power or remedy under this Backstop
Subscription Agreement by a party hereto, nor any abandonment or discontinuance of steps to enforce any such right, power or remedy, shall preclude such party from any other or further exercise thereof or the exercise of any other right, power or
remedy hereunder. The election of any remedy by a party hereto shall not constitute a waiver of the right of such party to pursue other available remedies. No notice to or demand on a party not expressly required under this Backstop Subscription
Agreement shall entitle the party receiving such notice or demand to any other or further notice or demand in similar or other circumstances or constitute a waiver of the rights of the party giving such notice or demand to any other or further
action in any circumstances without such notice or demand. 
 (o) This Backstop Subscription Agreement may be executed and delivered in one
or more counterparts (including by facsimile or electronic mail or in .pdf) and by different parties in separate counterparts, with the same effect as if all parties hereto had signed the same document. All counterparts so executed and delivered
shall be construed together and shall constitute one and the same agreement. 
 (p) This Backstop Subscription Agreement shall be governed
by, and construed in accordance with, the laws of the State of New York, without regard to the principles of conflicts of laws that would otherwise require the application of the law of any other state. 

(q) EACH PARTY AND ANY PERSON ASSERTING RIGHTS AS A THIRD PARTY BENEFICIARY HEREBY WAIVES ITS RESPECTIVE RIGHTS TO A TRIAL BY JURY OF ANY
CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT OR RELATED TO THIS BACKSTOP SUBSCRIPTION AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY IN ANY ACTION, PROCEEDING OR OTHER LITIGATION OF ANY TYPE BROUGHT BY ANY PARTY AGAINST ANY OTHER PARTY OR
ANY AFFILIATE OF ANY OTHER SUCH PARTY, WHETHER WITH RESPECT TO CONTRACT CLAIMS, TORT CLAIMS OR OTHERWISE. THE PARTIES AGREE THAT ANY SUCH CLAIM OR CAUSE OF ACTION SHALL BE TRIED BY A COURT TRIAL WITHOUT A JURY. WITHOUT LIMITING THE FOREGOING, THE
PARTIES FURTHER AGREE THAT THEIR RESPECTIVE RIGHT TO A TRIAL BY JURY IS WAIVED BY OPERATION OF THIS SECTION AS TO ANY ACTION, COUNTERCLAIM OR OTHER PROCEEDING WHICH SEEKS, IN WHOLE OR IN PART, TO CHALLENGE THE VALIDITY OR ENFORCEABILITY OF THIS
BACKSTOP SUBSCRIPTION AGREEMENT OR ANY PROVISION HEREOF. THIS WAIVER SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS, RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS BACKSTOP SUBSCRIPTION AGREEMENT. 

(r) The parties agree that all disputes, legal actions, suits and proceedings arising out of or relating to this Backstop Subscription
Agreement must be brought exclusively in the United States District Court for the Southern District of New York, the Supreme Court of the State of New York or the federal courts of the United States of America located in the State of New York
(collectively the “Designated Courts”). Each party hereby consents and submits to the exclusive 

  
 22 












 
jurisdiction of the Designated Courts. No legal action, suit or proceeding with respect to this Backstop Subscription Agreement may be brought in any other forum. Each party hereby irrevocably
waives all claims of immunity from jurisdiction, and any objection which such party may now or hereafter have to the laying of venue of any suit, action or proceeding in any Designated Court, including any right to object on the basis that
any dispute, action, suit or proceeding brought in the Designated Courts has been brought in an improper or inconvenient forum or venue. Each of the parties also agrees that delivery of any process, summons, notice or document to a party hereof in
compliance with Section 10(a) of this Backstop Subscription Agreement shall be effective service of process for any action, suit or proceeding in a Designated Court with respect to any matters to which the parties have
submitted to jurisdiction as set forth above. 
 (s) This Backstop Subscription Agreement may only be enforced against, and any claim,
action, suit or other legal proceeding based upon, arising out of, or related to this Backstop Subscription Agreement, or the negotiation, execution or performance of this Backstop Subscription Agreement, may only be brought against the entities
that are expressly named as parties or third party beneficiaries hereto and then only with respect to the specific obligations set forth herein with respect to such party or third party beneficiary. No past, present or future director, officer,
employee, incorporator, manager, member, partner, stockholder, affiliate, agent, attorney or other representative of any party hereto or of any affiliate of any party hereto, or any of their successors or permitted assigns, shall have any liability
for any obligations or liabilities of any party hereto under this Backstop Subscription Agreement or for any claim, action, suit or other legal proceeding based on, in respect of or by reason of the transactions contemplated hereby. 

(t) Subscriber hereby consents to the publication and disclosure in any press release issued by the Company, Fathom or any of their respective
affiliates, any Form 8-K or Form 6-K or other filing with a governmental authority filed by the Company, Fathom or any of their respective affiliates with the Commission
in connection with the execution and delivery of the Transaction Agreement or the transactions contemplated thereby and the Proxy Statement/Consent Solicitation Statement/Prospectus (as defined in the Transaction Agreement) (and, as and to the
extent otherwise required by the federal securities laws, exchange rules, the Commission or any other securities authorities or any rules and regulations promulgated thereby, any other documents or communications provided by the Company, Fathom or
any of their respective affiliates to any governmental entity or to any securityholders of the Company) of Subscriber’s identity and beneficial ownership of the Subscribed Shares and the nature of Subscriber’s commitments, arrangements and
understandings under and relating to this Agreement and, if deemed appropriate by the Company, Fathom or any of their respective affiliates, a copy of this Agreement, all solely to the extent determined by such person or entity to be required by
applicable law or any regulation or stock exchange listing requirement. Subscriber will promptly provide any information reasonably requested by the Company, Fathom or any of their respective affiliates for any regulatory application or filing made
or approval sought in connection with the Transactions (including filings with the Commission). Notwithstanding the foregoing, any such person shall provide to Subscriber a copy of any proposed disclosure relating to Subscriber in accordance with
the provisions of this Section 10(t) a reasonable period of time in advance of any publication thereof and shall include such revisions to such proposed disclosure as Subscriber shall reasonably request. 

  
 23 












 (u) The Company shall, by 9:00 a.m., New York City time, on the second (2nd) Business Day
immediately following the date of this Backstop Subscription Agreement, issue one or more press releases or file with the Commission a Current Report on Form 8-K (collectively, the “Disclosure
Document”) disclosing all material terms of the Backstop Subscription Agreement. Notwithstanding anything in this Backstop Subscription Agreement to the contrary, neither the Company nor Fathom shall (i) publicly disclose the name of
Subscriber or any of its affiliates or advisers, or include the name of Subscriber or any of its affiliates or advisers in any press release, without the prior written consent of Subscriber or (ii) publicly disclose the name of Subscriber or
any of its affiliates or advisers, or include the name of Subscriber or any of its affiliates or advisers in any filing with the Commission or any regulatory agency or trading market, without the prior written consent of Subscriber, except
(A) as required by the federal securities law and (B) to the extent such disclosure is required by law, at the request of the staff of the Commission or regulatory agency or under the regulations of the Stock Exchange. Subscriber will
promptly provide any information reasonably requested by the Company, Fathom or any of their respective affiliates for any regulatory application or filing made or approval sought in connection with the Transactions (including filings with the
Commission). 
 (v) The obligations of Subscriber under this Backstop Subscription Agreement are the obligations of the Subscriber only. The
decision of Subscriber to purchase Subscribed Shares pursuant to this Backstop Subscription Agreement has been made by Subscriber independently of any other investor and independently of any information, materials, statements or opinions as to the
business, affairs, operations, assets, properties, liabilities, results of operations, condition (financial or otherwise) or prospects of the Company, Fathom or any of their respective subsidiaries which may have been made or given by any investor
or by any agent or employee of any investor, and neither Subscriber nor any of its agents or employees shall have any liability to any investor (or any other person) relating to or arising from any such information, materials, statements or
opinions. Subscriber shall be entitled to independently protect and enforce its rights, including without limitation the rights arising out of this Subscription Agreement, and it shall not be necessary for any investor to be joined as an additional
party in any proceeding for such purpose. 
 [Signature pages follow.] 

  
 24 












 IN WITNESS WHEREOF, each of the Company, Fathom and Subscriber has executed or caused
this Backstop Subscription Agreement to be executed by its duly authorized representative as of the date first set forth above. 
  

			
	ALTIMAR ACQUISITION CORP. II
		
	By:	 	 /s/ Tom Wasserman

		 	Name: Tom Wasserman
		 	Title: Chief Executive Officer
	
	Address for Notices:
	
	  

	  

	  

	 ATTN: ____________________
 EMAIL:
____________________
  
 with a copy (not to constitute notice) to:

 
 Paul, Weiss, Rifkind, Wharton & Garrison LLP

1285 Avenue of the Americas

New York, New York 10019 
Attn: Raphael M. Russo, Esq.

rrusso@paulweiss.com



 [Signature Page to Backstop Subscription Agreement] 












			
	FATHOM HOLDCO, LLC
		
	By:	 	 /s/ John May

		 	Name: John May
		 	Title: President
	
	Address for Notices:
	
	 c/o CORE Industrial Partners, LLC

150 N. Riverside Plaza, Suite #2050
 Chicago, Illinois 60606

ATTN: John May
 EMAIL: john@coreipfund.com

	
	 with a copy (not to constitute notice) to:
  

Winston & Strawn LLP
 35 W. Wacker Drive

Chicago, IL 60601
 ATTN: Steven J. Gavin, Matthew F.

Bergmann and Jason D. Osborn
 EMAIL: SGavin@winston.com,

MBergmann@winston.com and
 JOsborn@winston.com



 [Signature Page to Backstop Subscription Agreement] 












							
		 		 	SUBSCRIBER:
			
		 		 	CORE INDUSTRIAL PARTNERS FUND I, L.P.
		 		 	By: CORE Industrial Partners GP I, LLC, its general partner
				
		 		 	By:	 	 /s/ John May

		 		 		 	Name: John May
		 		 		 	Title: Managing Partner
			
		 		 	CORE INDUSTRIAL PARTNERS FUND I PARALLEL, L.P.
		 		 	By: CORE Industrial Partners GP I, LLC, its general partner
				
		 		 	By:	 	 /s/ John May

		 		 		 	Name: John May
		 		 		 	Title: Managing Partner
			
		 		 	Address for Notices:
			
		 		 	  

		 		 	  

			
		 		 	Names in which shares are to be registered:
			
		 		 	CORE Industrial Partners Fund I, L.P.
			
		 		 	CORE Industrial Partners Fund I Parallel, L.P.
			
	Number of Subscribed Shares:	 		 	Up to 1,000,000
			
		 		 	CORE Industrial Partners Fund I, L.P.:
		 		 	Up to 870,000 Subscribed Shares
			
		 		 	CORE Industrial Partners Fund I Parallel, L.P.:
		 		 	Up to 130,000 Subscribed Shares
			
	Price Per Subscribed Share:	 		 	$10.00
			
	Aggregate Purchase Price:	 		 	Up to $10,000,000

 You must pay the Purchase Price by wire transfer of United States dollars in immediately available funds to the account of the
Company specified by the Company in the Closing Notice 
 [Signature Page to Backstop Subscription Agreement] 











 ANNEX A 

[omitted]