X0206 3 2021-01-12 0 0001774155 BTRS Holdings Inc. BTRS 0001309469 BAIN CAPITAL VENTURE INVESTORS, LLC 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 0001540349 Bain Capital Venture Fund 2012, L.P. 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 0001540350 Bain Capital Venture Partners 2012, L.P. 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 0001408649 BCIP Venture Associates 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 0001408676 BCIP VENTURE ASSOCIATES-B 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 0001295402 Salem Enrique T C/O BAIN CAPITAL VENTURE INVESTORS, 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 0001708763 Agarwal Ajay C/O BAIN CAPITAL VENTURE INVESTORS, 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 Class 1 Common Stock 31518953 I See footnote Received on January 12, 2021 (the "Effective Date") in exchange for an aggregate of 3,931,414 shares of common stock of Factor Systems, Inc. (d/b/a Billtrust), a Delaware corporation ("Former Billtrust") (the "Common Stock"), pursuant to the Business Combination Agreement, dated as of October 18, 2020, by and among South Mountain Merger Corp. ("South Mountain" and, upon consummation of the business combination, the surviving Issuer as renamed BTRS Holdings Inc.), Former Billtrust, BT Merger Sub I, Inc., a Delaware corporation and a direct, wholly owned subsidiary of South Mountain, and BT Merger Sub II, LLC, a Delaware limited liability company and a direct, wholly owned subsidiary of South Mountain (as amended by Amendment No. 1, dated as of December 13, 2020), as more particularly described in footnote (2) below. Included are (i) 25,752,455 shares of the Issuer's Class 1 Common Stock, par value $0.0001 per share (the "Shares"), received on the Effective Date held by Bain Capital Venture Fund 2012, L.P. ("Venture Fund 2012") in exchange for 3,562,743 shares of Common Stock; (ii) 2,515,082 Shares received on the Effective Date held by BCIP Venture Associates ("BCIP VA") in exchange for 347,951 shares of Common Stock; and (iii) 149,770 Shares received on the Effective Date held by BCIP Venture Associates-B ("BCIP VA-B" and, together with Venture Fund 2012 and BCIP VA, the "Bain Capital Venture Entities") in exchange for 20,720 shares of Common Stock. In addition to those shares listed in footnote (2) herein, the reporting persons may receive the following Shares: (i) 1,405,394 Shares to be received by Venture Fund 2012, 137,256 Shares to be received by BCIP VA, and 8,173 Shares to be received by BCIP VA-B, if the Issuer's closing share price equals or exceeds $12.50 for any 20 trading days within any consecutive 30-trading day period prior to January 12, 2026; and (ii) 1,405,394 Shares to be received by Venture Fund 2012, 137,256 Shares to be received by BCIP VA, and 8,173 Shares to be received by BCIP VA-B, if the Issuer's closing share price equals or exceeds $15.00 for any 20 trading days within any consecutive 30-trading day period prior to January 12, 2026. Bain Capital Venture Investors, LLC ("BCVI") is the general partner of Bain Capital Venture Partners 2012, L.P. ("Venture Partners 2012"), which is the general partner of Venture Fund 2012. The governance, investment strategy and decision making process with respect to the investments held by the Bain Capital Venture Entities is directed by the Executive Committee of BCVI, which consists of Enrique Salem and Ajay Agarwal. As a result, each of BCVI, Venture Partners 2012 and Messrs. Salem and Agarwal may be deemed to share voting and dispositive power with respect to all of the Shares held by the Bain Capital Venture Entities. Each of BCVI, Venture Partners 2012 and Messrs. Salem and Agarwal disclaims beneficial ownership of such securities except to the extent of its or his pecuniary interest therein. Bain Capital Venture Investors, LLC, By: /s/ Enrique T. Salem, Name: Enrique T. Salem, Title: Managing Director 2021-01-22 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/ Enrique T. Salem, Name: Enrique T. Salem, Title: Managing Director 2021-01-22 Bain Capital Venture Partners 2012, L.P., By: Bain Capital Venture Investors, LLC, its general partner, By: /s/ Enrique T. Salem, Name: Enrique T. Salem, Title: Managing Director 2021-01-22 BCIP Venture Associates, By: Boylston Coinvestors, LLC, its managing partner, By: /s/ Enrique T. Salem, Name: Enrique T. Salem, Title: Authorized Signatory 2021-01-22 BCIP Venture Associates-B, By: Boylston Coinvestors, LLC, its managing partner, By: /s/ Enrique T. Salem, Name: Enrique T. Salem, Title: Authorized Signatory 2021-01-22 /s/ Enrique T. Salem 2021-01-22 /s/ Ajay Agarwal 2021-01-22