X0206 3 2021-01-12 0 0001774155 BTRS Holdings Inc. BTRS 0001627602 Harris Matthew C C/O BAIN CAPITAL VENTURE INVESTORS, LLC 200 CLARENDON STREET BOSTON MA 02116 1 0 1 0 Class 1 Common Stock 31518953 I See Footnote Consists of shares of the Issuer's Class 1 common stock held by Bain Capital Venture Fund 2012, L.P., BCIP Venture Associates and BCIP Venture Associates-B (collectively, the "Bain Capital Venture Entities") and includes up to 3,101,646 shares of the Issuer's Class 1 common stock that the Bain Capital Venture Entities have the right to receive upon the achievement of certain milestones tied to the trading price of the Issuer's Class 1 common stock. Bain Capital Venture Investors, LLC ("BCVI") is the ultimate general partner of Bain Capital Venture Fund 2012, L.P and governs the investment strategy and decision making process with respect to investments held by each of BCIP Venture Associates and BCIP Venture Associates-B. Mr. Harris is a Managing Director of BCVI. By virtue of the relationships described in this footnote, Mr. Harris may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Venture Entities. Mr. Harris disclaims (Continued from Footnote 1), beneficial ownership of such securities except to the extent of his pecuniary interest therein. /s/ Matthew C. Harris 2021-01-22