X0306 4 2020-04-15 0 0001764925 Slack Technologies, Inc. WORK 0001419457 Accel X LP 500 UNIVERSITY AVENUE PALO ALTO CA 94301 0 0 1 0 0001430231 ACCEL X STRATEGIC PARTNERS LP 500 UNIVERSITY AVENUE PALO ALTO CA 94301 0 0 1 0 0001494996 Accel X Associates L.L.C. 500 UNIVERSITY AVENUE PALO ALTO CA 94301 0 0 1 0 0001494979 Accel Investors 2009 L.L.C. 500 UNIVERSITY AVENUE PALO ALTO CA 94301 0 0 1 0 Class A Common Stock 2020-04-15 4 J 0 3048780 0.00 D 986370 D Class A Common Stock 2020-04-15 4 J 0 228820 0.00 D 74030 I By Accel X Strategic Partners L.P. Class A Common Stock 2020-04-15 4 J 0 122400 0.00 D 39600 I By Accel Investors 2009 L.L.C. On April 15, 2020, Accel X L.P. distributed, for no consideration, 3,048,780 shares of Class A common stock of the Issuer (the "Accel X Shares") to its limited partners and to Accel X Associates L.L.C. ("Accel X GP"), the general partner of Accel X L.P., representing each such partner's pro rata interest in such Accel X Shares. On the same date, Accel X GP distributed, for no consideration, the Accel X Shares it received in the distribution by Accel X L.P. to its members, representing each such member's pro rata interest in such Accel X Shares. All of the aforementioned distributions were made in accordance with the exemptions afforded by Rules 16a-13 and 16a-9 of the Securities Exchange Act of 1934, as amended. These shares are held by Accel X L.P. Accel X GP is the general partner of each of Accel X L.P. and Accel X Strategic Partners L.P. (together, the "Accel X Entities"). Accel X GP has sole voting and dispositive power with regard to the shares held by the Accel X Entities. Accel X GP disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that such reporting person is the beneficial owner of such securities for Section 16 or any other purpose. On April 15, 2020, Accel X Strategic Partners L.P. distributed, for no consideration, 228,820 shares of Class A common stock of the Issuer (the "Accel X Strategic Shares") to its limited partners and to Accel X GP, the general partner of Accel X Strategic Partners L.P., representing each such partner's pro rata interest in such Accel X Strategic Shares. On the same date, Accel X GP distributed, for no consideration, the Accel X Strategic Shares it received in the distribution by Accel X Strategic Partners L.P. to its members, representing each such member's pro rata interest in such Accel X Strategic Shares. All of the aforementioned distributions were made in accordance with the exemptions afforded by Rules 16a-13 and 16a-9 of the Securities Exchange Act of 1934, as amended. These shares are held by Accel X Strategic Partners L.P. Accel X GP disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that such reporting person is the beneficial owner of such securities for Section 16 or any other purpose. On April 15, 2020, Accel Investors 2009 L.L.C. distributed, for no consideration, 122,400 shares of Class A common stock of the Issuer (the "Accel 2009 Shares") to its members, representing each such member's pro rata interest in such Accel 2009 Shares. All of the aforementioned distributions were made in accordance with the exemptions afforded by Rules 16a-13 and 16a-9 of the Securities Exchange Act of 1934, as amended. These shares are held by Accel Investors 2009 L.L.C. /s/ TRACY L. SEDLOCK, ATTORNEY IN FACT 2020-04-17