X0306 4 2021-07-06 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 2021-07-06 4 S 0 3151895 11.7294 D 28367064 I See footnotes On July 6, 2021, each of Bain Capital Venture Fund 2012, L.P. ("BCV Fund 2012"), BCIP Venture Associates ("BCIP Venture") and BCIP Venture Associates-B ("BCIP Venture-B" and, together with BCV Fund 2012 and BCIP Venture, the "Bain Capital Venture Entities") sold 2,856,323, 278,960 and 16,612 shares of the Issuer's Class 1 Common Stock, respectively, in an underwritten public offering. Following such sale, BCV Fund 2012, BCIP Venture and BCIP Venture-B held 25,706,922, 2,510,636 and 149,506 shares of the Issuer's Class 1 Common Stock, respectively. Bain Capital Venture Investors, LLC ("BCVI") is the general partner of Bain Capital Venture Partners 2012, L.P. ("BCV Partners 2012"), which is the general partner of BCV Fund 2012. Boylston Coinvestors, LLC is the managing partner of each of BCIP Venture and BCIP Venture-B. 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, BCV Partners 2012 and Messrs. Salem and Agarwal may be deemed to share voting and dispositive power with respect to the shares of the Issuer's Class 1 Common Stock held by the Bain Capital Venture Entities. Each of BCVI, BCV 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/ Matthew C. Harris, Title: Managing Director 2021-07-08 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 C. Harris, Title: Managing Director 2021-07-08 Bain Capital Venture Partners 2012, L.P., By: Bain Capital Venture Investors, LLC, its general partner, By: /s/ Matthew C. Harris, Title: Managing Director 2021-07-08 BCIP Venture Associates, By: Boylston Coinvestors, LLC, its managing partner, By: /s/ Matthew C. Harris, Title: Authorized Signatory 2021-07-08 BCIP Venture Associates-B, By: Boylston Coinvestors, LLC, its managing partner, By: /s/ Matthew C. Harris, Title: Authorized Signatory 2021-07-08 /s/ Enrique T. Salem 2021-07-08 /s/ Ajay Agarwal 2021-07-08