Exhibit 4.4

          

          

          

          AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT 

        AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

        THIS AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT (this “Agreement”),
          dated as of October 18, 2020, is made and entered into by and among South Mountain Merger Corp., a Delaware corporation (the “South Mountain”), South Mountain LLC, a Delaware limited liability company (the “Sponsor”), Factor
          Systems, Inc. (d/b/a Billtrust), a Delaware corporation (“Billtrust”) and the undersigned parties listed under Holder on the signature page hereto (each such party, together with the Sponsor and any person or entity who hereafter becomes a
          party to this Agreement pursuant to Section 5.2 or Section 5.10 of this Agreement, a “Holder” and collectively the “Holders”).

        RECITALS

        WHEREAS, South
            Mountain and Billtrust are party to that certain Business Combination Agreement, dated as of October 18, 2020 (as it may be amended, supplemented, restated or otherwise modified from time to time, the
          “BCA”), by and among South Mountain, BT Merger Sub I, Inc., a Delaware corporation, BT Merger Sub II, LLC, a Delaware limited liability company, and Billtrust, pursuant to which, among other things, the separate existence of Billtrust will cease to exist and Billtrust shall
            become a subsidiary of South Mountain, which shall survive as the surviving corporation (the “Business Combination” and, South Mountain following the consummation of the Business Combination, the “Company”);

        WHEREAS, as a
            condition to the consummation of the transactions contemplated by the BCA that the parties hereto enter into this Agreement, to be effective upon the consummation of the Business Combination;

        WHEREAS, South
            Mountain, the Sponsor and certain of the Holders entered into that certain Registration Rights Agreement, dated as of June 19, 2019 (as it may be amended, supplemented, restated or otherwise modified from time to time until the consummation of the Business Combination, the “Existing Agreement”);

        WHEREAS, upon
            the consummation of the Business Combination, the parties to the Existing Agreement desire to amend and restate the Existing Agreement in its entirety as set forth herein and South Mountain and the
            Holders desire to enter into this Agreement, pursuant to which the Company shall grant the Holders certain registration rights with respect to the Registrable
            Securities (as defined below) on the terms and conditions set forth in this Agreement.

        NOW,
          THEREFORE, in consideration of the representations, covenants and agreements contained herein, and certain other good and valuable consideration, the receipt and
            sufficiency of which are hereby acknowledged, the parties hereto, intending to be legally bound, hereby agree as follows:

        ARTICLE I 

        

        DEFINITIONS

        1.1 Definitions. The terms defined in this Article I
          shall, for all purposes of this Agreement, have the respective meanings set forth below:

        “Adverse Disclosure” shall mean any public disclosure of
          material non-public information, which disclosure, in the good faith judgment of the Chief Executive Officer or principal financial officer of the Company, after consultation with counsel to the Company, (i) would be required to be made in any
          Registration Statement or Prospectus in order for the applicable Registration Statement or Prospectus not to contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements contained therein (in
          the case of any prospectus and any preliminary prospectus, in the light of the circumstances under which they were made) not misleading, (ii) would not be required to be made at such time if the Registration Statement were not being filed, and
          (iii) the Company has a bona fide business purpose for not making such information public.

        “Agreement” shall have the meaning given in the Preamble.

        “Board” shall mean the Board of Directors of the Company.

        “Business Combination” shall have the meaning given in the
          Recitals hereto.

        “Business Day” means any day, other than a Saturday or a
          Sunday, that is neither a legal holiday nor a day on which banking institutions are generally authorized or required by law or regulation to close in the City of New York, New York.

      

    

    
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        “Cancellation Effective Time” shall have the meaning given
          in the Share and Warrant Cancellation Agreement.

        “Closing” shall have the meaning given in the BCA. 

        “Commission” shall mean the Securities and Exchange
          Commission.

        “Common Stock” shall mean the Class A common stock of the
          Company, par value $0.0001 per share.

        “Company” shall have the meaning given in the Recitals hereto.

        “Demand Registration” shall have the meaning given in subsection
            2.1.1.

        “Demanding Holder” shall have the meaning given in subsection
            2.1.1.

        “Exchange Act” shall mean the Securities Exchange Act of 1934,
          as it may be amended from time to time.

        “Form S-1” shall have the meaning given in subsection
            2.1.1.

        “Form S-3” shall have the meaning given in subsection 2.3.

        “Founder Shares” shall mean the shares of South Mountain’s
          Class B common stock, par value $0.0001 per share, issued pursuant to that certain Subscription Agreement, not forfeited by the Sponsor at the Cancellation Effective Time as described in the Share and Warrant Cancellation Agreement, and shall be
          deemed to include the shares of Common Stock issuable upon conversion thereof.

        “Founder Shares Lock-up Period” shall mean, with respect to
          the Founder Shares, the period ending on the earlier of (A) one year after the completion of the Business Combination or (B) subsequent to the Business Combination, (x) if the closing price of the Common Stock equals or exceeds $12.00 per share
          (as adjusted for stock splits, stock dividends, reorganizations, recapitalizations and the like) for any 20 trading days within any 30-trading day period commencing at least 150 days after the Business Combination or (y) the date on which the
          Company completes a liquidation, merger, capital stock exchange, reorganization or other similar transaction that results in all of the Company’s stockholders having the right to exchange their shares of Common Stock for cash, securities or other
          property.

        “Holders” shall have the meaning given in the Preamble.

        “Insider Letter” shall mean that certain letter agreement,
          dated as of June 19, 2019, by and among South Mountain, the Sponsor and each of South Mountain’s officers and directors.

        “Maximum Number of Securities” shall have the meaning given in subsection
          2.1.4.

        “Misstatement” shall mean an untrue statement of a material
          fact or an omission to state a material fact required to be stated in a Registration Statement or Prospectus, or necessary to make the statements in a Registration Statement or Prospectus (in the case of a Prospectus, in the light of the
          circumstances under which they were made) not misleading.

        “Permitted Transferees” shall mean any person or entity to
          whom a Holder of Registrable Securities is permitted to transfer such Registrable Securities prior to the expiration of the Founder Shares Lock-up Period and pursuant to the Insider Letter and any other applicable agreement between such Holder
          and the Company, in each case for so long as such agreements remain in effect, and to any transferee thereafter.

        “Piggyback Registration” shall have the meaning given in
            subsection 2.2.1.

        “Prospectus” shall mean the prospectus included in any
          Registration Statement, as supplemented by any and all prospectus supplements and as amended by any and all post-effective amendments and including all material incorporated by reference in such prospectus.

        “Qualified Additional Holder” shall mean any stockholder of
          Billtrust that is a director or officer of Billtrust or any other stockholder of Billtrust that is approved to become a “Holder” under this Agreement by the Holders holding a majority of the Registrable Securities then outstanding (such approval
          not to be unreasonably withheld, conditioned or delayed).

        “Registrable Security” shall mean (a) any outstanding shares
          of Common Stock, whether voting or non-voting, held by a Holder immediately following the Closing (including shares of Common Stock distributable pursuant to the BCA and the conversion of the Founder Shares), (b) the Warrant Shares, (c) any
          shares of Common Stock that 

      

    

    
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        may be acquired by Holders upon the exercise of a warrant or other right to acquire
          Common Stock held by a Holder immediately following the Closing, (d) any shares of Common Stock or any other equity security (including, without limitation, the shares of Common Stock issued or issuable upon the exercise of any other equity
          security and warrants) of the Company otherwise acquired or owned by a Holder following the date hereof to the extent that such securities are “restricted securities” (as defined in Rule 144) or are otherwise held by an “affiliate” (as defined in
          Rule 144) of the Company, (e) any other equity security of the Company issued or issuable with respect to any such securities referenced in clauses (a), (b), (c), or (d) above by way of a stock dividend or stock split or in connection with a
          recapitalization, merger, consolidation, spin-off, reorganization or similar transaction; provided, however, that, as to any particular Registrable Security, such securities shall cease to be Registrable Securities when: (A) a
          Registration Statement with respect to the sale of such securities shall have become effective under the Securities Act and such securities shall have been sold, transferred, disposed of or exchanged in accordance with such Registration
          Statement; (B) such securities shall have been otherwise transferred, new certificates or book entry provisions for such securities not bearing a legend restricting further transfer shall have been delivered by the Company and subsequent public
          distribution of such securities shall not require registration under the Securities Act; (C) such securities shall have ceased to be outstanding; (D) such securities may be sold without registration pursuant to Rule 144 promulgated under the
          Securities Act (or any successor rule promulgated by the Commission) without limitation as to volume and manner of sale; or (E) such securities have been sold to, or through, a broker, dealer or underwriter in a public distribution or other
          public securities transaction.

        “Registration” shall mean a registration effected by
          preparing and filing a Registration Statement or similar document in compliance with the requirements of the Securities Act, and the applicable rules and regulations promulgated thereunder, and such Registration Statement becoming effective.

        “Registration Expenses” shall mean the out-of-pocket expenses
          of a Registration, including, without limitation, the following:

        (A) all registration and filing fees (including fees with respect
          to filings required to be made with the Financial Industry Regulatory Authority, Inc.) and any securities exchange on which the Common Stock is then listed;

        (B) fees and expenses of compliance with securities or blue sky
          laws (including reasonable fees and disbursements of counsel for the Underwriters in connection with blue sky qualifications of Registrable Securities);

        (C) printing, messenger, telephone and delivery expenses;

        (D) reasonable fees and disbursements of counsel for the Company;

        (E) reasonable fees and disbursements of all independent registered
          public accountants of the Company incurred specifically in connection with such Registration; and

        (F) reasonable fees and expenses of one (1) legal counsel selected
          by the majority-in-interest of the Demanding Holders initiating a Demand Registration to be registered for offer and sale in the applicable Registration.

        “Registration Statement” shall mean any registration
          statement that covers the Registrable Securities pursuant to the provisions of this Agreement, including the Prospectus included in such registration statement, amendments (including post-effective amendments) and supplements to such registration
          statement, and all exhibits to and all material incorporated by reference in such registration statement.

        “Requesting Holder” shall have the meaning given in subsection
            2.1.1.

        “Securities Act” shall mean the Securities Act of 1933, as
          amended from time to time.

        “Share and Warrant Cancellation Agreement” shall mean that
          certain Share and Warrant Cancellation Agreement, dated as of October 18, 2020, by and between South Mountain, the Sponsor, Billtrust, and each of the directors and officers of South Mountain.

        “Sponsor” shall have the meaning given in the Preamble hereto. 

        “Subscription Agreement” shall mean that certain Securities
          Subscription Agreement, dated as of April 19, 2019, between the Sponsor and South Mountain.

      

    

    
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        “Underwriter” shall mean a securities dealer who purchases
          any Registrable Securities as principal in an Underwritten Offering and not as part of such dealer’s market-making activities.

        “Underwritten Registration” or “Underwritten Offering”
          shall mean a Registration in which securities of the Company are sold to an Underwriter in a firm commitment underwriting.

        “Warrant Shares” shall have the meaning given in the Share and
          Warrant Cancellation Agreement.

        ARTICLE II 

        

        REGISTRATIONS

        2.1 Demand Registration.

        2.1.1 Request for Registration. Subject to the provisions of
          subsections 2.1.4, 2.1.6 and Section 2.4 hereof, at any time and from time to time, the Holders the then-outstanding number of Registrable Securities having an aggregate value of at least $40 million (the “Demanding Holders”) may make a
          written demand for Registration of all or part of their Registrable Securities, which written demand shall describe the amount and type of securities to be included in such Registration and the intended method(s) of distribution thereof (such
          written demand a “Demand Registration”). The Company shall, within five (5) Business Days of the Company’s receipt of the Demand Registration, notify, in writing, all other Holders of Registrable Securities of such demand, and each Holder
          of Registrable Securities who thereafter wishes to include all or a portion of such Holder’s Registrable Securities in a Registration pursuant to a Demand Registration (each such Holder that includes all or a portion of such Holder’s Registrable
          Securities in such Registration, a “Requesting Holder”) shall so notify the Company, in writing, within five (5) Business Days after the receipt by the Holder of the notice from the Company. Upon receipt by the Company of any such written
          notification from a Requesting Holder(s) to the Company, such Requesting Holder(s) shall be entitled to have their Registrable Securities included in a Registration pursuant to a Demand Registration and the Company shall effect, as soon
          thereafter as practicable, but not more than forty five (45) days after the Company’s receipt of the Demand Registration, the Registration of all Registrable Securities requested by the Demanding Holders and Requesting Holders pursuant to such
          Demand Registration. Under no circumstances shall the Company be obligated to effect more than an aggregate of two (2) Registrations pursuant to a Demand Registration under this subsection 2.1.1 with respect to any or all Registrable Securities;
          provided, however, that a Registration shall not be counted for such purposes unless a Form S-1 or any similar long-form registration statement that may be
          available at such time (“Form S-1”) has become effective and all of the Registrable Securities requested by the Requesting Holders to be registered on behalf of the Requesting Holders in such Form S-1 Registration have been sold, in
          accordance with Section 3.1 of this Agreement.

        2.1.2 Effective Registration. Notwithstanding the provisions
          of subsection 2.1.1 above or any other part of this Agreement, a Registration pursuant to a Demand Registration shall not count as a Registration unless and until (i) the Registration Statement filed with the Commission with respect to a
          Registration pursuant to a Demand Registration has been declared effective by the Commission and (ii) the Company has complied with all of its obligations under this Agreement with respect thereto; provided, further, that if,
          after such Registration Statement has been declared effective, an offering of Registrable Securities in a Registration pursuant to a Demand Registration is subsequently interfered with by any stop order or injunction of the Commission, federal or
          state court or any other governmental agency, then the Registration Statement with respect to such Registration shall be deemed not to have been declared effective, unless and until, (i) such stop order or injunction is removed, rescinded or
          otherwise terminated, and (ii) a majority-in-interest of the Demanding Holders initiating such Demand Registration thereafter affirmatively elect to continue with such Registration and accordingly notify the Company in writing, but in no event
          later than five (5) days, of such election; provided, further, that the Company shall not be obligated or required to file another Registration Statement until the Registration Statement that has been previously filed with respect
          to a Registration pursuant to a Demand Registration becomes effective or is subsequently terminated.

        2.1.3 Underwritten Offering. Subject to the provisions of subsections
            2.1.4, 2.1.6 and Section 2.4 hereof, if a majority-in-interest of the Demanding Holders so advise the Company as part of their Demand Registration that the offering of the Registrable Securities pursuant to such Demand Registration
          shall be in the form of an Underwritten Offering, then the right of such Demanding Holder and Requesting Holder (if any) to include its Registrable Securities in such Registration shall be conditioned upon such Holder’s participation in such
          Underwritten Offering and the inclusion of such Holder’s Registrable Securities in such Underwritten Offering 

      

    

    
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        to the extent provided herein. All such Holders proposing to distribute their
          Registrable Securities through an Underwritten Offering under this subsection 2.1.3 shall enter into an underwriting agreement in customary form with the Underwriter(s) selected for such Underwritten Offering by the majority-in-interest
          of the Demanding Holders initiating the Demand Registration.

        2.1.4 Reduction of Underwritten Offering. If the managing
          Underwriter or Underwriters in an Underwritten Registration pursuant to a Demand Registration, in good faith, advises the Company, the Demanding Holders and the Requesting Holders (if any) in writing that the dollar amount or number of
          Registrable Securities that the Demanding Holders and the Requesting Holders (if any) desire to sell, taken together with all other Common Stock or other equity securities that the Company desires to sell and the Common Stock, if any, as to which
          a Registration has been requested pursuant to separate written contractual piggy-back registration rights held by any other stockholders who desire to sell, exceeds the maximum dollar amount or maximum number of equity securities that can be sold
          in the Underwritten Offering without adversely affecting the proposed offering price, the timing, the distribution method, or the probability of success of such offering (such maximum dollar amount or maximum number of such securities, as
          applicable, the “Maximum Number of Securities”), then the Company shall include in such Underwritten Offering, as follows: (i) first, the Registrable Securities of the Demanding Holders and the Requesting Holders (if any) (pro
          rata based on the respective number of Registrable Securities that each Demanding Holder and Requesting Holder (if any) holds prior to such Underwritten Registration) that can be sold without exceeding the Maximum Number of Securities;
          (ii) second, to the extent that the Maximum Number of Securities has not been reached under the foregoing clause (i), the Registrable Securities of Holders (pro rata, based on the respective number of Registrable Securities that each Holder has
          requested be included in such Underwritten Registration) exercising their rights to register their Registrable Securities pursuant to subsection 2.2.1 hereof,; (iii) third, to the extent that the Maximum Number of Securities has not been reached
          under the foregoing clauses (i) and (ii), Common Stock or other equity securities that the Company desires to sell, which can be sold without exceeding the Maximum Number of Securities; and (iv) fourth, to the extent that the Maximum Number of
          Securities has not been reached under the foregoing clauses (i), (ii) and (iii), the Common Stock or other equity securities of other persons or entities that the Company is obligated to register in a Registration pursuant to separate written
          contractual arrangements with such persons and that can be sold without exceeding the Maximum Number of Securities.

        2.1.5 Demand Registration Withdrawal. A majority-in-interest
          of the Demanding Holders initiating a Demand Registration or a majority-in-interest of the Requesting Holders (if any), pursuant to a Registration under subsection 2.1.1 shall have the right to withdraw from a Registration pursuant to
          such Demand Registration for any or no reason whatsoever upon written notification to the Company and the Underwriter or Underwriters (if any) of their intention to withdraw from such Registration prior to the effectiveness of the Registration
          Statement filed with the Commission with respect to the Registration of their Registrable Securities pursuant to such Demand Registration. Notwithstanding anything to the contrary in this Agreement, the Company shall be responsible for the
          Registration Expenses incurred in connection with a Registration pursuant to a Demand Registration prior to its withdrawal under this subsection 2.1.5.

        2.1.6 Shelf Registration The Company shall file within 45
          days of the Closing, and use commercially reasonable efforts to cause to be declared effective as soon as practicable thereafter, a Registration Statement for a Shelf Registration on Form S-1 (the “Form S-1 Shelf”) or, if the Company is
          eligible to use a Registration Statement on Form S-3, a Shelf Registration on Form S-3 (the “Form S-3 Shelf” and together with the Form S-1 Shelf, each a “Shelf”), in each case, covering the resale of all the Registrable Securities
          (determined as of two business days prior to such filing) on a delayed or continuous basis. Such Shelf shall provide for the resale of the Registrable Securities included therein pursuant to any method or combination of methods legally available
          to, and requested by, any Holder named therein. The Company shall maintain a Shelf in accordance with the terms hereof, and shall prepare and file with the SEC such amendments, including post-effective amendments, and supplements as may be
          necessary to keep a Shelf continuously effective, available for use and in compliance with the provisions of the Securities Act until such time as there are no longer any Registrable Securities. In the event the Company files a Form S-1 Shelf,
          the Company shall use its commercially reasonable efforts to convert the Form S-1 Shelf (and any Subsequent Shelf Registration) to a Form S-3 Shelf as soon as practicable after the Company is eligible to use Form S-3. Notwithstanding anything to
          the contrary herein, to the extent there is an active Shelf under this Section 2.1.6, covering a Holder’s or Holders’ Registrable Securities, and such Holder or Holders qualify as Demanding Holders pursuant to Section 2.1.1 and wish to 

      

    

    
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        request an Underwritten Offering from such Shelf, such Underwritten Offering shall
          follow the procedures of Section 2.1, (including Section 2.1.3 and Section 2.1.4) but such Underwritten Offering shall be made from the Shelf and shall count against the number of long form Demand Registrations that may be made pursuant to
          Section 2.1.1. The Company shall have the right to remove any persons no longer holding Registrable Securities from the Shelf or any other shelf registration statement by means of a post-effective amendment.

        2.2 Piggyback Registration.

        2.2.1 Piggyback Rights. If, at any time the Company proposes
          to file a Registration Statement under the Securities Act with respect to an offering of equity securities, or securities or other obligations exercisable or exchangeable for, or convertible into equity securities, for its own account or for the
          account of stockholders of the Company (or by the Company and by the stockholders of the Company including, without limitation, pursuant to Section 2.1 hereof), other than a Registration Statement (or any registered offering with respect
          thereto) (i) filed in connection with any employee stock option or other benefit plan, (ii) pursuant to a Registration Statement on Form S-4 (or similar form that relates to a transaction subject to Rule 145 under the Securities Act or any
          successor rule thereto), (iii) for an offering of debt that is convertible into equity securities of the Company, (iv) for an exchange offer or offering of securities solely to the Company’s existing stockholders, (v) for a dividend reinvestment
          plan, (vi) for a rights offering or (vii) for the exercise of any warrants, then the Company shall give written notice of such proposed filing to all of the Holders of Registrable Securities as soon as practicable but not less than five (5)
          Business Days before the anticipated filing date of such Registration Statement or, in the case of an Underwritten Offering pursuant to a Shelf Registration, the applicable “red herring” prospectus or prospectus supplement, which notice shall (A)
          describe the amount and type of securities to be included in such offering, the intended method(s) of distribution, and the name of the proposed managing Underwriter or Underwriters, if any, in such offering, and (B) offer to all of the Holders
          of Registrable Securities the opportunity to register the sale of such number of Registrable Securities as such Holders may request in writing within five (5) Business Days after receipt of such written notice (such Registration a “Piggyback
            Registration”). Subject to Section 2.2.2, the Company shall, in good faith, cause such Registrable Securities to be included in such Piggyback Registration and shall use its best efforts to cause the managing Underwriter or Underwriters of
          a proposed Underwritten Offering to permit the Registrable Securities requested by the Holders pursuant to this subsection 2.2.1 to be included in a Piggyback Registration on the same terms and conditions as any similar securities of the
          Company included in such Registration and to permit the sale or other disposition of such Registrable Securities in accordance with the intended method(s) of distribution thereof. All such Holders proposing to distribute their Registrable
          Securities through an Underwritten Offering under this subsection 2.2.1 shall enter into an underwriting agreement in customary form with the Underwriter(s) selected for such Underwritten Offering by the Company.

        2.2.2 Reduction of Piggyback Registration. If the managing
          Underwriter or Underwriters in an Underwritten Registration that is to be a Piggyback Registration, in good faith, advises the Company and the Holders of Registrable Securities participating in the Piggyback Registration in writing that the
          dollar amount or number of shares of Common Stock that the Company desires to sell, taken together with (i) the shares of Common Stock, if any, as to which Registration has been demanded pursuant to separate written contractual arrangements with
          persons or entities other than the Holders of Registrable Securities hereunder, (ii) the Registrable Securities as to which registration has been requested pursuant to Section 2.2 hereof, and (iii) the shares of Common Stock, if any, as
          to which Registration has been requested pursuant to separate written contractual piggy-back registration rights of other stockholders of the Company, exceeds the Maximum Number of Securities, then:

        (a) If the Registration is undertaken for the Company’s account,
          the Company shall include in any such Registration (A) first, Common Stock or other equity securities that the Company desires to sell, which can be sold without exceeding the Maximum Number of Securities; (B) second, to the extent that the
          Maximum Number of Securities has not been reached under the foregoing clause (A), the Registrable Securities of Holders exercising their rights to register their Registrable Securities pursuant to subsection 2.2.1 hereof (pro rata based on
          the respective number of Registrable Securities that such Holder has requested be included in such Registration), which can be sold without exceeding the Maximum Number of Securities; and (C) third, to the extent that the Maximum Number of
          Securities has not been reached under the foregoing clauses (A) and (B), Common Stock, if any, as to which Registration has been 

      

    

    
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        requested pursuant to written contractual piggy-back registration rights of other
          stockholders of the Company (pro rata based on the respective number of Registrable Securities that each stockholder holds prior to such Underwritten Registration), which can be sold without exceeding the Maximum Number of
          Securities;

        (b) If the Registration is pursuant to a request by persons or
          entities other than the Holders of Registrable Securities, then the Company shall include in any such Registration (A) first, Common Stock or other equity securities, if any, of such requesting persons or entities, other than the Holders of
          Registrable Securities, which can be sold without exceeding the Maximum Number of Securities; (B) second, to the extent that the Maximum Number of Securities has not been reached under the foregoing clause (A), the Registrable Securities of
          Holders exercising their rights to register their Registrable Securities pursuant to subsection 2.2.1, pro rata based on the number of Registrable Securities that each Holder has requested be included in such Registration and the
          aggregate number of Registrable Securities that the Holders have requested to be included in such Registration, which can be sold without exceeding the Maximum Number of Securities; (C) third, to the extent that the Maximum Number of Securities
          has not been reached under the foregoing clauses (A) and (B), the Common Stock or other equity securities that the Company desires to sell, which can be sold without exceeding the Maximum Number of Securities; and (D) fourth, to the extent that
          the Maximum Number of Securities has not been reached under the foregoing clauses (A), (B) and (C), and Common Stock or other equity securities for the account of other persons or entities that the Company is obligated to register pursuant to
          separate written contractual arrangements with such persons or entities, which can be sold without exceeding the Maximum Number of Securities.

        2.2.3 Piggyback Registration Withdrawal. Any Holder of
          Registrable Securities shall have the right to withdraw from a Piggyback Registration for any or no reason whatsoever upon written notification to the Company and the Underwriter or Underwriters (if any) of his, her or its intention to withdraw
          from such Piggyback Registration prior to the effectiveness of the Registration Statement filed with the Commission with respect to such Piggyback Registration. The Company (whether on its own good faith determination or as the result of a
          request for withdrawal by persons pursuant to separate written contractual obligations) may withdraw a Registration Statement filed with the Commission in connection with a Piggyback Registration at any time prior to the effectiveness of such
          Registration Statement. Notwithstanding anything to the contrary in this Agreement, the Company shall be responsible for the Registration Expenses incurred in connection with the Piggyback Registration prior to its withdrawal under this subsection
            2.2.3.

        2.2.4 Unlimited Piggyback Registration Rights. For purposes
          of clarity, any Registration effected pursuant to Section 2.2 hereof shall not be counted as a Registration pursuant to a Demand Registration effected under Section 2.1 hereof.

        2.3 Registrations on Form S-3. The Holders of Registrable
          Securities may, at any time and from time to time to the extent that its Registrable Securities are not covered by an effective Shelf, request in writing that the Company, pursuant to Rule 415 under the Securities Act (or any successor rule
          promulgated thereafter by the Commission), register the resale of any or all of their Registrable Securities on Form S-3 or any similar short form registration statement that may be available at such time (“Form S-3”), or if the Company is
          a well-known seasoned issuer (as defined in Rule 405 under the Securities Act), on an automatic shelf registration statement. Within five (5) Business Days of the Company’s receipt of a written request from a Holder or Holders of Registrable
          Securities for a Registration on Form S-3, the Company shall promptly give written notice of the proposed Registration on Form S-3 to all other Holders of Registrable Securities, and each Holder of Registrable Securities who thereafter wishes to
          include all or a portion of such Holder’s Registrable Securities in such Registration on Form S-3 shall so notify the Company, in writing, within ten (10) days after the receipt by the Holder of the notice from the Company. As soon as practicable
          thereafter, but not more than fifteen (15) days after the Company’s initial receipt of such written request for a Registration on Form S-3, the Company shall register all or such portion of such Holder’s Registrable Securities as are specified in
          such written request, together with all or such portion of Registrable Securities of any other Holder or Holders joining in such request as are specified in the written notification given by such Holder or Holders; provided, however,
          that the Company shall not be obligated to effect any such Registration pursuant to Section 2.3 hereof if (i) a Form S-3 is not available for such offering; or (ii) the Holders of Registrable Securities, together with the Holders of any
          other equity securities of the Company entitled to inclusion in such Registration, propose to sell the Registrable Securities and such other equity securities (if any) at any aggregate price to the public of less than $40,000,000.

      

    

    
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        Any request for an Underwritten Offering pursuant to a Form S-3
          shall follow the procedures of Section 2.1 (including Section 2.1.4) but shall not count against the number of long form Demand Registrations that may be made pursuant to Section 2.1.1.

        2.4 Restrictions on Registration Rights. If (A) during the
          period starting with the date sixty (60) days prior to the Company’s good faith estimate of the date of the filing of, and ending on a date one hundred and twenty (120) days after the effective date of, a Company initiated Registration and provided
          that the Company has delivered written notice to the Holders prior to receipt of a Demand Registration pursuant to subsection 2.1.1 and it continues to actively employ, in good faith, all reasonable efforts to cause the applicable
          Registration Statement to become effective; (B) the Holders have requested an Underwritten Registration and the Company and the Holders are unable to obtain the commitment of underwriters to firmly underwrite the offer; or (C) in the good faith
          judgment of the Board such Registration would be seriously detrimental to the Company and the Board concludes as a result that it is essential to defer the filing of such Registration Statement at such time, then in each case the Company shall
          furnish to such Holders a certificate signed by the Chairman of the Board stating that in the good faith judgment of the Board it would be seriously detrimental to the Company for such Registration Statement to be filed in the near future and
          that it is therefore essential to defer the filing of such Registration Statement. In such event, the Company shall have the right to defer such filing for a period of not more than thirty (30) days; provided, however, that the
          Company shall not defer its obligation in this manner more than once in any 12-month period. Notwithstanding anything to the contrary contained in this Agreement, no Registration by the Company shall be required, effected or permitted and no
          Registration Statement shall become effective, with respect to any Registrable Securities held by any Holder of Founder Shares, until after the expiration of the Founder Shares Lock-Up Period.

        2.5 No Limitations. Notwithstanding anything in this
          Agreement, none of the provisions of this Agreement shall in any way limit Special Situations Investing Group II, LLC (“Goldman”) or any of its affiliates from engaging in any brokerage, investment advisory, financial advisory, anti-raid
          advisory, principaling, merger advisory, financing, asset management, trading, market making, arbitrage, investment activity and other similar activities conducted in the ordinary course of their business. Notwithstanding anything to the contrary
          set forth in this Agreement, the restrictions contained in this Agreement shall not apply to Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock acquired by Goldman or any affiliate following the
          effective date of the first registration statement of the Company covering Common Stock (or other securities) to be sold on behalf of the Company in an underwritten public offering.

        2.6 Deemed Underwriter. The Company agrees that, if Goldman
          or any of its affiliates (each a “Goldman Entity”) could reasonably be deemed to be an “underwriter,” as defined in Section 2(a)(11) of the Act, in connection with any registration of the Company’s securities of any Goldman Entity
          pursuant to this Agreement, and any amendment or supplement thereof (any such registration statement or amendment or supplement a “Goldman Underwriter Registration Statement”), then the Company will cooperate with such Goldman
          Entity in allowing such Goldman Entity to conduct customary “underwriter’s due diligence” with respect to the Company and satisfy its obligations in respect thereof. In addition, at the request of Goldman, the Company will furnish to Goldman, on
          the date of the effectiveness of any Goldman Underwriter Registration Statement and thereafter from time to time on such dates as Goldman may reasonably request (a) a letter, dated such date, from the Company’s independent certified public
          accountants in form and substance as is customarily given by independent certified public accountants to underwriters in an underwritten public offering, addressed to Goldman, and (b) an opinion, dated as of such date, of counsel representing the
          Company for purposes of such Goldman Underwriter Registration Statement, in form, scope and substance as is customarily given in an underwritten public offering, including, without limitation, a standard “10b-5” opinion for such offering,
          addressed to Goldman. The Company will also permit legal counsel to Goldman to review and comment upon any such Goldman Underwriter Registration Statement at least five (5) business days prior to its filing with the SEC and all amendments and
          supplements to any such Goldman Underwriter Registration Statement within a reasonable number of days prior to their filing with the SEC and not file any Goldman Underwriter Registration Statement or amendment or supplement thereto in a form to
          which legal counsel to Goldman reasonably objects.

      

    

    
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        ARTICLE III 

        

        COMPANY PROCEDURES

        3.1 General Procedures. If at any time the Company is
          required to effect the Registration of Registrable Securities, the Company shall use its reasonable best efforts to effect such Registration to permit the sale of such Registrable Securities in accordance with the intended plan of distribution
          thereof, and pursuant thereto the Company shall, as expeditiously as possible:

        3.1.1 prepare and file with the Commission as soon as practicable a
          Registration Statement with respect to such Registrable Securities and use its reasonable best efforts to cause such Registration Statement to become effective and remain effective until all Registrable Securities covered by such Registration
          Statement have been sold;

        3.1.2 prepare and file with the Commission such amendments and
          post-effective amendments to the Registration Statement, and such supplements to the Prospectus, as may be requested by the Holders or any Underwriter of Registrable Securities or as may be required by the rules, regulations or instructions
          applicable to the registration form used by the Company or by the Securities Act or rules and regulations thereunder to keep the Registration Statement effective until all Registrable Securities covered by such Registration Statement are sold in
          accordance with the intended plan of distribution set forth in such Registration Statement or supplement to the Prospectus;

        3.1.3 prior to filing a Registration Statement or prospectus, or
          any amendment or supplement thereto, furnish without charge to the Underwriters, if any, and the Holders of Registrable Securities included in such Registration, and such Holders’ legal counsel, copies of such Registration Statement as proposed
          to be filed, each amendment and supplement to such Registration Statement (in each case including all exhibits thereto and documents incorporated by reference therein), the Prospectus included in such Registration Statement (including each
          preliminary Prospectus), and such other documents as the Underwriters and the Holders of Registrable Securities included in such Registration or the legal counsel for any such Holders may request in order to facilitate the disposition of the
          Registrable Securities owned by such Holders;

        3.1.4 prior to any public offering of Registrable Securities, use
          its best efforts to (i) register or qualify the Registrable Securities covered by the Registration Statement under such securities or “blue sky” laws of such jurisdictions in the United States as the Holders of Registrable Securities included in
          such Registration Statement (in light of their intended plan of distribution) may request and (ii) take such action necessary to cause such Registrable Securities covered by the Registration Statement to be registered with or approved by such
          other governmental authorities as may be necessary by virtue of the business and operations of the Company and do any and all other acts and things that may be necessary or advisable to enable the Holders of Registrable Securities included in
          such Registration Statement to consummate the disposition of such Registrable Securities in such jurisdictions; provided, however, that the Company shall not be required to qualify generally to do business in any jurisdiction
          where it would not otherwise be required to qualify or take any action to which it would be subject to general service of process or taxation in any such jurisdiction where it is not then otherwise so subject;

        3.1.5 cause all such Registrable Securities to be listed on each
          securities exchange or automated quotation system on which similar securities issued by the Company are then listed;

        3.1.6 provide a transfer agent or warrant agent, as applicable, and
          registrar for all such Registrable Securities no later than the effective date of such Registration Statement;

        3.1.7 advise each seller of such Registrable Securities, promptly
          after it shall receive notice or obtain knowledge thereof, of the issuance of any stop order by the Commission suspending the effectiveness of such Registration Statement or the initiation or threatening of any proceeding for such purpose and
          promptly use its reasonable best efforts to prevent the issuance of any stop order or to obtain its withdrawal if such stop order should be issued;

        3.1.8 at least five (5) days prior to the filing of any
          Registration Statement or Prospectus or any amendment or supplement to such Registration Statement or Prospectus (other than by way of any document that is to be incorporated by reference into such Registration Statement or Prospectus), furnish a
          copy thereof to each seller of such Registrable Securities or its counsel;

      

    

    
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        3.1.9 notify the Holders at any time when a Prospectus relating
          to such Registration Statement is required to be delivered under the Securities Act, of the happening of any event as a result of which the Prospectus included in such Registration Statement, as then in effect, includes a Misstatement, and then
          to correct such Misstatement as set forth in Section 3.4 hereof;

        3.1.10 permit a representative of the Holders (such representative
          to be selected by a majority of the participating Holders), the Underwriters, if any, and any attorney or accountant retained by such Holders or Underwriter to participate, at each such person’s own expense, in the preparation of the Registration
          Statement, and cause the Company’s officers, directors and employees to supply all information reasonably requested by any such representative, Underwriter, attorney or accountant in connection with the Registration; provided, however,
          that such representatives or Underwriters enter into a confidentiality agreement, in form and substance reasonably satisfactory to the Company, prior to the release or disclosure of any such information;

        3.1.11 obtain a “cold comfort” letter from the Company’s
          independent registered public accountants in the event of an Underwritten Registration, in customary form and covering such matters of the type customarily covered by “cold comfort” letters as the managing Underwriter may reasonably request, and
          reasonably satisfactory to a majority-in-interest of the participating Holders;

        3.1.12 on the date the Registrable Securities are delivered for
          sale pursuant to such Registration, obtain an opinion, dated such date, of counsel representing the Company for the purposes of such Registration, addressed to the Holders, the placement agent or sales agent, if any, and the Underwriters, if any,
          covering such legal matters with respect to the Registration in respect of which such opinion is being given as the Holders, placement agent, sales agent, or Underwriter may reasonably request and as are customarily included in such opinions and
          negative assurance letters, and reasonably satisfactory to a majority in interest of the participating Holders;

        3.1.13 in the event of any Underwritten Offering, enter into and
          perform its obligations under an underwriting agreement, in usual and customary form, with the managing Underwriter of such offering;

        3.1.14 make available to its security holders, as soon as
          reasonably practicable, an earnings statement covering the period of at least twelve (12) months beginning with the first day of the Company’s first full calendar quarter after the effective date of the Registration Statement which satisfies the
          provisions of Section 11(a) of the Securities Act and Rule 158 thereunder (or any successor rule promulgated thereafter by the Commission);

        3.1.15 if the Registration involves the Registration of Registrable
          Securities involving gross proceeds in excess of $40,000,000, use its reasonable efforts to make available senior executives of the Company to participate in customary “road show” presentations that may be reasonably requested by the Underwriter
          in any Underwritten Offering; and

        3.1.16 otherwise, in good faith, cooperate reasonably with, and
          take such customary actions as may reasonably be requested by the Holders, in connection with such Registration, including, without limitation, making available senior executives of the Company to participate in any due diligence sessions that
          may be reasonably requested by the Underwriter in any Underwritten Offering.

        3.2 Registration Expenses. The Registration Expenses of all
          Registrations shall be borne by the Company. It is acknowledged by the Holders that the Holders shall bear all incremental selling expenses relating to the sale of Registrable Securities, such as Underwriters’ commissions and discounts, brokerage
          fees, Underwriter marketing costs and, other than as set forth in the definition of “Registration Expenses,” all reasonable fees and expenses of any legal counsel representing the Holders.

        3.3 Requirements for Participation in Underwritten Offerings.
          No person may participate in any Underwritten Offering for equity securities of the Company pursuant to a Registration initiated by the Company hereunder unless such person (i) agrees to sell such person’s securities on the basis provided in any
          underwriting arrangements approved by the Company and (ii) completes and executes all customary questionnaires, powers of attorney, indemnities, lock-up agreements, underwriting agreements and other customary documents as may be reasonably
          required under the terms of such underwriting arrangements.

        3.4 Suspension of Sales; Adverse Disclosure. Upon receipt of
          written notice from the Company that a Registration Statement or Prospectus contains a Misstatement, each of the Holders shall forthwith discontinue 

      

    

    
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        disposition of Registrable Securities until he, she or it has received copies of a
          supplemented or amended Prospectus correcting the Misstatement (it being understood that the Company hereby covenants to prepare and file such supplement or amendment as soon as practicable after the time of such notice), or until he, she or it
          is advised in writing by the Company that the use of the Prospectus may be resumed. If the filing, initial effectiveness or continued use of a Registration Statement in respect of any Registration at any time would require the Company to make an
          Adverse Disclosure or would require the inclusion in such Registration Statement of financial statements that are unavailable to the Company for reasons beyond the Company’s control, the Company may, upon giving prompt written notice of such
          action to the Holders, delay the filing or initial effectiveness of, or suspend use of, such Registration Statement for the shortest period of time, but in no event more than thirty (30) consecutive days or ninety (90) days in any rolling
          12-month period, determined in good faith by the Company to be necessary for such purpose. In the event the Company exercises its rights under the preceding sentence, the Holders agree to suspend, immediately upon their receipt of the notice
          referred to above, their use of the Prospectus relating to any Registration in connection with any sale or offer to sell Registrable Securities. The Company shall immediately notify the Holders of the expiration of any period during which it
          exercised its rights under this Section 3.4.

        3.5 Reporting Obligations. As long as any Holder shall own
          Registrable Securities, the Company, at all times while it shall be a reporting company under the Exchange Act, covenants to (i) make and keep public information available, as those terms are understood and defined in Rule 144, and (ii) file
          timely (or obtain extensions in respect thereof and file within the applicable grace period) all reports required to be filed by the Company after the date hereof pursuant to Sections 13(a) or 15(d) of the Exchange Act. The Company further
          covenants that it shall take such further action as any Holder may reasonably request, all to the extent required from time to time to enable such Holder to sell shares of Common Stock held by such Holder without registration under the Securities
          Act within the limitation of the exemptions provided by Rule 144 promulgated under the Securities Act (or any successor rule promulgated thereafter by the Commission), including providing any reasonably requested legal opinions. Upon the request
          of any Holder, the Company shall deliver to such Holder (i) a written certification of a duly authorized officer as to whether it has complied with such requirements, (ii) a copy of the most recent annual or quarterly reports of the Company and
          such other reports and documents so filed by the Company (it being understood that the availability of such report on the SEC’s EDGAR system shall satisfy this requirement) and (iii) such other information as may be necessary to permit the Holder
          to sell such securities pursuant to Rule 144 without registration.

        ARTICLE IV 

        

        INDEMNIFICATION AND CONTRIBUTION

        4.1 Indemnification.

        4.1.1 The Company agrees to indemnify, to the extent permitted by
          law, each Holder of Registrable Securities, its officers and directors and each person who controls such Holder (within the meaning of the Securities Act) against all losses, claims, damages, liabilities and expenses (including attorneys’ fees)
          caused by (i) any untrue or alleged untrue statement of material fact contained in any Registration Statement, Prospectus or preliminary Prospectus or any amendment thereof or supplement thereto, or any free writing prospectus used in connection
          with any offering, including but not limited to, any free writing prospectus used by the Company, the underwriters or the Holders, (ii) 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 such Holder expressly for use therein, or (iii) any information provided by the Company or at the
          instruction of the Company to any Person participating in the offer at the point of sale containing any untrue statement or alleged untrue statement of any material fact or omitting or allegedly omitting any material fact required to be included
          in such information or necessary to make the statements therein not misleading. The Company shall indemnify the Underwriters, their officers and directors and each person who controls such Underwriters (within the meaning of the Securities Act)
          to the same extent as provided in the foregoing with respect to the indemnification of the Holder.

        4.1.2 In connection with any Registration Statement in which a
          Holder of Registrable Securities is participating, such Holder shall furnish to the Company in writing such information and affidavits as the Company reasonably requests for use in connection with any such Registration Statement or Prospectus
          and, to the extent permitted by law, shall indemnify the Company, its directors and officers and agents and each person who controls the Company (within the meaning of the Securities Act) against any losses, claims, damages, liabilities and
          expenses (including without limitation reasonable attorneys’ fees) resulting from any untrue statement of material fact contained in the Registration Statement, Prospectus or preliminary Prospectus or any 

      

    

    
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        amendment thereof or supplement thereto or any 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 by such Holder expressly for use
          therein; provided, however, that the obligation to indemnify shall be several, not joint and several, among such Holders of Registrable Securities, and the liability of each such Holder of Registrable Securities shall be in
          proportion to and limited to the net proceeds received by such Holder from the sale of Registrable Securities pursuant to such Registration Statement. The Holders of Registrable Securities shall indemnify the Underwriters, their officers,
          directors and each person who controls such Underwriters (within the meaning of the Securities Act) to the same extent as provided in the foregoing with respect to indemnification of the Company.

        4.1.3 Any person entitled to indemnification herein shall (i) 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 materially prejudiced the indemnifying party) and (ii) unless in such indemnified party’s reasonable judgment a conflict of interest between such indemnified and indemnifying parties may exist with respect to such claim,
          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 (but such consent shall not be unreasonably withheld). An indemnifying party who is not entitled to, or 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 any indemnified party a conflict of interest may exist 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.

        4.1.4 The indemnification provided for under this 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 or controlling person of such indemnified party and shall survive the transfer of securities. The Company and
          each Holder of Registrable Securities participating in an offering also agrees to make such provisions as are reasonably requested by any indemnified party for contribution to such party in the event the Company’s or such Holder’s indemnification
          is unavailable for any reason.

        4.1.5 If the indemnification provided under Section 4.1
          hereof 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, 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; provided, however, that the liability of any Holder under this subsection 4.1.5
          shall be limited to the amount of the net proceeds received by such Holder in such offering giving rise to such liability. 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 in subsections 4.1.1, 4.1.2 and 4.1.3 above, any legal or other fees, charges or expenses reasonably incurred by such party in connection with any investigation or proceeding.
          The parties hereto agree that it would not be just and equitable if contribution pursuant to this subsection 4.1.5 were determined by pro rata allocation or by any other method of allocation, which does not take account of
          the equitable considerations referred to in this subsection 4.1.5. 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 subsection
            4.1.5 from any person who was not guilty of such fraudulent misrepresentation.

      

    

    
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        ARTICLE V 

        

        MISCELLANEOUS

        5.1 Notices. Any notice or communication under this Agreement
          must be in writing and given by (i) deposit in the United States mail, addressed to the party to be notified, postage prepaid and registered or certified with return receipt requested, (ii) delivery in person or by courier service providing
          evidence of delivery, or (iii) transmission by hand delivery, electronic mail, telecopy, telegram or facsimile. Each notice or communication that is mailed, delivered, or transmitted in the manner described above shall be deemed sufficiently
          given, served, sent, and received, in the case of mailed notices, on the third business day following the date on which it is mailed and, in the case of notices delivered by courier service, hand delivery, electronic mail, telecopy, telegram or
          facsimile, at such time as it is delivered to the addressee (with the delivery receipt or the affidavit of messenger) or at such time as delivery is refused by the addressee upon presentation. Any notice or communication under this Agreement must
          be addressed, if to the Company, to: 1009 Lenox Drive, Suite 101 Lawrenceville, New Jersey 08648, Attention: CEO, and, if to any Holder of Registrable Securities, at such Holder’s address or facsimile number as set forth in the Company’s books
          and records. Any party may change its address for notice at any time and from time to time by written notice to the other parties hereto, and such change of address shall become effective thirty (30) days after delivery of such notice as provided
          in this Section 5.1.

        5.2 Assignment; No Third Party Beneficiaries.

        5.2.1 This Agreement and the rights, duties and obligations of the
          Company hereunder may not be assigned or delegated by the Company in whole or in part.

        5.2.2 A Holder may assign or delegate such Holder’s rights, duties
          or obligations under this Agreement, in whole or in part, to a Permitted Transferee who agrees to become bound by the transfer restrictions set forth in this Agreement.

        5.2.3 This Agreement and the provisions hereof shall be binding
          upon and shall inure to the benefit of each of the parties and its successors and the permitted assigns of the Holders, which shall include Permitted Transferees.

        5.2.4 This Agreement shall not confer any rights or benefits on any
          persons that are not parties hereto, other than as expressly set forth in this Agreement and Section 5.2 hereof.

        5.2.5 No assignment by any party hereto of such party’s rights,
          duties and obligations hereunder shall be binding upon or obligate the Company unless and until the Company shall have received (i) written notice of such assignment as provided in Section 5.1 hereof and (ii) the written agreement of the
          assignee, in a form reasonably satisfactory to the Company, to be bound by the terms and provisions of this Agreement (which may be accomplished by an addendum or certificate of joinder to this Agreement). Any transfer or assignment made other
          than as provided in this Section 5.2 shall be null and void.

        5.3 Counterparts. This Agreement may be executed in multiple
          counterparts (including facsimile or PDF counterparts), each of which shall be deemed an original, and all of which together shall constitute the same instrument, but only one of which need be produced.

        5.4 Governing Law; Venue. NOTWITHSTANDING THE PLACE WHERE
          THIS AGREEMENT MAY BE EXECUTED BY ANY OF THE PARTIES HERETO, THE PARTIES EXPRESSLY AGREE THAT THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED UNDER THE LAWS OF THE STATE OF NEW YORK AS APPLIED TO AGREEMENTS AMONG NEW YORK RESIDENTS ENTERED INTO
          AND TO BE PERFORMED ENTIRELY WITHIN NEW YORK, WITHOUT REGARD TO THE CONFLICT OF LAW PROVISIONS OF SUCH JURISDICTION AND (II) THE VENUE FOR ANY ACTION TAKEN WITH RESPECT TO THE AGREEMENT SHALL BE ANY STATE OR FEDERAL COURT IN NEW YORK COUNTY IN
          THE STATE OF NEW YORK.

        EACH PARTY HERETO ACKNOWLEDGES AND AGREES THAT ANY CONTROVERSY WHICH
          MAY ARISE UNDER THIS AGREEMENT IS LIKELY TO INVOLVE COMPLICATED AND DIFFICULT ISSUES, AND, THEREFORE, EACH SUCH PARTY HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVES TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT SUCH PARTY MAY HAVE
          TO A TRIAL BY JURY IN RESPECT TO ANY ACTION DIRECTLY OR INDIRECTLY ARISING OUT OF, UNDER OR IN CONNECTION WITH OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED BY THIS AGREEMENT.

      

    

    
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        5.5 Amendments and Modifications. Upon the written consent
          of the Company and the Holders of at least a majority in interest of the Registrable Securities at the time in question, compliance with any of the provisions, covenants and conditions set forth in this Agreement may be waived, or any of such
          provisions, covenants or conditions may be amended or modified; provided, however, that notwithstanding the foregoing, any amendment hereto or waiver hereof that adversely affects one Holder, solely in his, her or its capacity as
          a holder of Registrable Securities, in a manner that is materially different from the other Holders (in such capacity) shall require the consent of the Holder so affected; provided, further, that the provisions of Sections 2.5,
          2.6, and this proviso of 5.5 may not be amended, modified or terminated without the prior written consent of Goldman. No course of dealing between any Holder or the Company and any other party hereto or any failure or delay on the
          part of a Holder or the Company in exercising any rights or remedies under this Agreement shall operate as a waiver of any rights or remedies of any Holder or the Company. No single or partial exercise of any rights or remedies under this
          Agreement by a party shall operate as a waiver or preclude the exercise of any other rights or remedies hereunder or thereunder by such party.

        5.6 Other Registration Rights. The Company represents and
          warrants that no person, other than a Holder of Registrable Securities has any right to require the Company to register any securities of the Company for sale or to include such securities of the Company in any Registration filed by the Company
          for the sale of securities for its own account or for the account of any other person. Further, the Company represents and warrants that this Agreement supersedes any other registration rights agreement or agreement with similar terms and
          conditions and in the event of a conflict between any such agreement or agreements and this Agreement, the terms of this Agreement shall prevail.

        5.7 Term. This Agreement shall terminate with respect to any
          Holder on the date that such Holder no longer holds any Registrable Securities. The provisions of Section 3.5 and Article IV shall survive any termination.

        5.8 Entire Agreement. This Agreement (including all
          agreements entered into pursuant hereto and all certificates and instruments delivered pursuant hereto and thereto) constitutes the entire agreement of the parties with respect to the subject matter hereof and supersedes all prior and
          contemporaneous agreements, representations, understandings, negotiations and discussions between the parties, whether oral or written.

        5.9 Titles and Headings. Titles and headings of sections of
          this Agreement are for convenience only and shall not affect the construction of any provision of this Agreement.

        5.10 Additional Holders. In the event that after the date of
          this Agreement, South Mountain or Billtrust wishes to provide any Qualified Additional Holders registration rights as contemplated by this Agreement, then, Billtrust and South Mountain shall cause such Qualified Additional Holder to become a
          party to this Agreement by executing a joinder agreement in the form attached hereto as Exhibit A, agreeing to be bound by and subject to the terms of this Agreement as a Holder and thereafter such Qualified Additional Holder shall be
          deemed a Holder for all purposes under this Agreement.

      

    

    
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        IN WITNESS WHEREOF, the undersigned have caused this Agreement to
          be executed as of the date first written above.

        	
                 

              	​	​	
                COMPANY:

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                SOUTH MOUNTAIN MERGER CORP.,

                

                a Delaware corporation

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​
	
                 

              	​	​	
                By:

              	​	​	
                /s/ Charles B. Bernicker

              
	
                 

              	​	​	
                 

              	​	​	
                Name:

              	​	​	
                Charles B. Bernicker

              
	
                 

              	​	​	
                 

              	​	​	
                Title:

              	​	​	
                Chief Executive Officer

              


      

    

    
      [Signature Page to Registration Rights Agreement]
        

      

    

    
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        IN WITNESS WHEREOF, the undersigned have caused this Agreement to
          be executed as of the date first written above.

        	
                 

              	​	​	
                FACTOR SYSTEMS, INC. (D/B/A BILLTRUST)

              
	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                By:

              	​	​	
                /s/ Flint Lane

              
	
                 

              	​	​	
                 

              	​	​	
                Name: Flint Lane

              
	
                 

              	​	​	
                 

              	​	​	
                Title: Chief Executive Officer

              


      

    

    
      SIGNATURE PAGE TO AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

      

    

    
      L-16

      

    

  

  
  
    
      


  

  
  
    
      
        	
                 

              	​	​	
                HOLDERS:

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                SOUTH MOUNTAIN LLC

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                 

              	​	​	
                By:

              	​	​	
                Harbour Reach Holdings, LLC, its managing member

              
	
                 

              	​	​	
                 

              	​	​	
                By:

              	​	​	
                Netherton Investments Limited, its managing member

              


        	
                 

              	​	​	
                By:

              	​	​	
                /s/ Mike Bell

              
	
                 

              	​	​	
                 

              	​	​	
                Name: Mike Bell

              
	
                 

              	​	​	
                 

              	​	​	
                Title: Director

              


      

    

    
      [Signature Page to Registration Rights Agreement]

      

    

    
      L-17

      

    

  

  
  
    
      


  

  
  
    
      
        IN WITNESS WHEREOF, the undersigned have caused this Agreement to
          be executed as of the date first written above.

        	
                 

              	​	​	
                STOCKHOLDER:

              
	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                W CAPITAL PARTNERS III, L.P.

              
	
                 

              	​	​	
                By:WCP GP III, L.P.,

              
	
                 

              	​	​	
                its general partner

              
	
                 

              	​	​	
                By:WCP GP III, LLC, 

              
	
                 

              	​	​	
                its general partner

              


        	
                 

              	​	​	
                By:

              	​	​	
                /s/ Blake Heston

              
	
                 

              	​	​	
                Name:

              	​	​	
                Blake Heston

              
	
                 

              	​	​	
                Title:

              	​	​	
                Managing Director

              


        	
                 

              	​	​	
                WCP HOLDINGS IV, L.P.

              
	
                 

              	​	​	
                By:WCP GP IV, L.P.,

              
	
                 

              	​	​	
                its general partner

              
	
                 

              	​	​	
                By:WCP GP IV, LLC,

              
	
                 

              	​	​	
                its general partner

              


        	
                 

              	​	​	
                By:

              	​	​	
                /s/ Blake Heston

              
	
                 

              	​	​	
                 

              	​	​	
                Name: Blake Heston

              
	
                 

              	​	​	
                 

              	​	​	
                Title: Member

              


        	
                 

              	​	​	
                W CAPITAL GREENWICH LLC

              
	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                By:

              	​	​	
                 

              
	
                 

              	​	​	
                Name: Stephen Wertheimer

              
	
                 

              	​	​	
                Title: Managing Member

              


      

    

    
      SIGNATURE PAGE TO AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

      

    

    
      L-18

      

    

  

  
  
    
      


  

  
  
    
      
        IN WITNESS WHEREOF, the undersigned have caused this Agreement to
          be executed as of the date first written above.

        	
                 

              	​	​	
                STOCKHOLDER:

              
	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                W CAPITAL PARTNERS III, L.P.

              
	
                 

              	​	​	
                By:WCP GP III, L.P.,

              
	
                 

              	​	​	
                its general partner

              
	
                 

              	​	​	
                By:WCP GP III, LLC,

              
	
                 

              	​	​	
                its general partner

              


        	
                 

              	​	​	
                By:

              	​	​	
                 

              
	
                 

              	​	​	
                Name: Blake Heston

              
	
                 

              	​	​	
                Title: Managing Director

              


        	
                 

              	​	​	
                WCP HOLDINGS IV, L.P.

              
	
                 

              	​	​	
                By:WCP GP IV, L.P.,

              
	
                 

              	​	​	
                its general partner

              
	
                 

              	​	​	
                By:WCP GP IV, LLC,

              
	
                 

              	​	​	
                its general partner

              


        	
                 

              	​	​	
                By:

              	​	​	
                 

              
	
                 

              	​	​	
                 

              	​	​	
                Name: Blake Heston

              
	
                 

              	​	​	
                 

              	​	​	
                Title: Member

              


        	
                 

              	​	​	
                W CAPITAL GREENWICH LLC

              
	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                By:

              	​	​	
                /s/ Stephen Wertheimer

              
	
                 

              	​	​	
                Name: Stephen Wertheimer

              
	
                 

              	​	​	
                Title: Managing Member

              


      

    

    
      SIGNATURE PAGE TO AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

      

    

    
      L-19

      

    

  

  
  
    
      


  

  
  
    
      
        IN WITNESS WHEREOF, the undersigned have caused this Agreement to
          be executed as of the date first written above.

        	
                 

              	​	​	
                STOCKHOLDER:

              
	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                Robert J Migliorino 2007 Trust

              
	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                By:

              	​	​	
                /s/ Mary F. Migliorino

              
	
                 

              	​	​	
                Name: Mary F Migliorino

              
	
                 

              	​	​	
                Title: Trustee

              


      

    

    
      SIGNATURE PAGE TO AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

      

    

    
      L-20

      

    

  

  
  
    
      


  

  
  
    
      
        IN WITNESS WHEREOF, the undersigned have caused this Agreement to
          be executed as of the date first written above.

        	
                 

              	​	​	
                STOCKHOLDER:

              
	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                BAIN CAPITAL VENTURE FUND 2012, L.P.

              
	
                 

              	​	​	
                By:Bain Capital Venture Partners 2012, L.P.,

              
	
                 

              	​	​	
                its general partner

              
	
                 

              	​	​	
                By:Bain Capital Venture Investors, LLC,

              
	
                 

              	​	​	
                its general partner

              


        	
                 

              	​	​	
                By:

              	​	​	
                /s/ Matthew Harris

              
	
                 

              	​	​	
                Name: Matthew Harris

              
	
                 

              	​	​	
                Title: A Duly Authorized Representative

              


        	
                 

              	​	​	
                BCIP VENTURE ASSOCIATES

              
	
                 

              	​	​	
                By: Bain Capital Investors, LLC,

              
	
                 

              	​	​	
                its managing partner

              
	
                 

              	​	​	
                By:Bain Capital Venture Investors, LLC,

              
	
                 

              	​	​	
                its Attorney-in-fact

              


        	
                 

              	​	​	
                By:

              	​	​	
                /s/ Matthew Harris

              
	
                 

              	​	​	
                Name: Matthew Harris

              
	
                 

              	​	​	
                Title: Authorized Person

              


        	
                 

              	​	​	
                BCIP VENTURE ASSOCIATES-B

              
	
                 

              	​	​	
                By:Bain Capital Investors, LLC,

              
	
                 

              	​	​	
                its managing partner

              
	
                 

              	​	​	
                By:Bain Capital Venture Investors, LLC,

              
	
                 

              	​	​	
                its Attorney-in-fact

              


        	
                 

              	​	​	
                By:

              	​	​	
                /s/ Matthew Harris

              
	
                 

              	​	​	
                Name: Matthew Harris

              
	
                 

              	​	​	
                Title: Authorized Person

              


      

    

    
      SIGNATURE PAGE TO AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

      

    

    
      L-21

      

    

  

  
  
    
      


  

  
  
    
      
        IN WITNESS WHEREOF, the undersigned have caused this Agreement to
          be executed as of the date first written above.

        	
                 

              	​	​	
                STOCKHOLDER:

              
	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                RIVERWOOD CAPITAL PARTNERS II L.P.

              
	
                 

              	​	​	
                By:Riverwood Capital II L.P.,

              
	
                 

              	​	​	
                its general partner

              
	
                 

              	​	​	
                By:Riverwood Capital II GP Ltd.,

              
	
                 

              	​	​	
                its general partner

              


        	
                 

              	​	​	
                By:

              	​	​	
                /s/ Francisco Alvarez-Demalde

              
	
                 

              	​	​	
                Name: Francisco Alvarez-Demalde

              
	
                 

              	​	​	
                Title: Managing Partner

              


        	
                 

              	​	​	
                RIVERWOOD CAPITAL PARTNERS II 

                

                (PARALLEL-B) L.P.

              
	
                 

              	​	​	
                By:Riverwood Capital II L.P., 

              
	
                 

              	​	​	
                its general partner

              
	
                 

              	​	​	
                By:Riverwood Capital II GP Ltd., 

              
	
                 

              	​	​	
                its general partner

              


        	
                 

              	​	​	
                By:

              	​	​	
                /s/ Francisco Alvarez-Demalde

              
	
                 

              	​	​	
                Name: Francisco Alvarez-Demalde

              
	
                 

              	​	​	
                Title: Managing Partner

              


      

    

    
      SIGNATURE PAGE TO AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

      

    

    
      L-22

      

    

  

  
  
    
      


  

  
  
    
      
        IN WITNESS WHEREOF, the undersigned have caused this Agreement to
          be executed as of the date first written above.

        	
                 

              	​	​	
                STOCKHOLDER:

              
	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                SPECIAL SITUATIONS INVESTING 

                

                GROUP II, LLC

              
	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                By: /s/ Antoine Munfa

              
	
                 

              	​	​	
                Name: Antoine Munfa

              
	
                 

              	​	​	
                Title: Managing Director

              
	
                 

              	​	​	
                Date: 10/18/2020

              


      

    

    
      [Signature Page to Amended and Restated Registration Rights Agreement]

      

    

    
      L-23

      

    

  

  
  
    
      


  

  
  
    
      
        IN WITNESS WHEREOF, the undersigned have caused this Agreement to
          be executed as of the date first written above.

        	
                 

              	​	​	
                /s/ Flint Lane

              
	
                 

              	​	​	
                Flint Lane

              


        	
                 

              	​	​	
                FLINT LANE 2009 GRANTOR RETAINED ANNUITY TRUST

              
	
                 

              	​	​	
                By:

              	​	​	
                /s/ Flint Lane

              
	
                 

              	​	​	
                 

              	​	​	
                Name: Flint Lane

              
	
                 

              	​	​	
                 

              	​	​	
                Title: Trustee

              


      

    

    
      [Signature Page to Amended and Restated Registration Rights
          Agreement] 

      

    

    
      L-24

      

    

  

  
  
    
      


  

  
  
    
      
        Exhibit A

        Form of Joinder

      

    

    
      [Signature Page to Amended and Restated Registration Rights
          Agreement] 

      

    

    
      L-25

      

    

  

  
  
    
      


  

  
  
    
      
        FORM OF JOINDER TO AMENDED AND RESTATED 

        

        REGISTRATION RIGHTS AGREEMENT

        [   ], 20  

        Reference is made to that certain Amended and Restated Registration
          Rights Agreement (as may be amended and/or restated from time to time, the “Registration Rights Agreement”), dated as of October 18, 2020, by and among South Mountain Merger Corp., a Delaware corporation (“South Mountain”), South
          Mountain LLC, a Delaware limited liability company (the “Sponsor”), Factor Systems, Inc. (d/b/a Billtrust), a Delaware corporation (“Billtrust”) and the undersigned parties listed under Holder on the signature page thereto.
          Capitalized terms used but not otherwise defined herein shall have the meanings ascribed to such terms in the Registration Rights Agreement.

        The undersigned hereby agrees to and does become party to the
          Registration Rights Agreement as a Holder thereunder. This Joinder shall serve as a counterpart signature page to the Registration Rights Agreement and by executing below the undersigned is deemed to have executed the Registration Rights
          Agreement with the same force and effect as if originally named a party thereto.

        This Joinder may be executed in multiple counterparts, including by
          means of facsimile or electronic signature, each of which shall be deemed an original, but all of which together shall constitute the same instrument.

        [Remainder of Page Intentionally Left Blank.]

      

    

    
      [Signature Page to Amended and Restated Registration Rights
          Agreement] 

      

    

    
      L-26

      

    

  

  
  
    
      


  

  
  
    
      
        IN WITNESS WHEREOF, the undersigned have duly executed this
          Joinder as of the date first set forth above.

        HOLDER

        	
                Printed Name of Holder:

              	​	​	
                                           

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                By:

              	​	​	
                                       

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                 

              	​	​	
                Name:

              	​	​	
                                   

              
	
                 

              	​	​	
                 

              	​	​	
                Title:

              	​	​	
                                   

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                Common Stock:

              	​	​	
                                          

              
	
                Aggregate Purchase Price:

              	​	​	
                                          

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                Address:

              	​	​	
                 

              	​	​	
                                   

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​	​	
                                   

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​	​	
                                   

              
	
                 

              	​	​	
                 

              	​	​	
                 

              	​	​	
                 

              
	
                 

              	​	​	
                Date:

              	​	​	
                 

              	​	​	
                                   

              


      

    

    
      [Signature Page to Registration Rights Agreement] 

      

    

    
      L-27