Sec Form 4 Filing - Braccia Andrew @ Slack Technologies, Inc. - 2019-06-20

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Braccia Andrew 2. Issuer Name and Ticker or Trading Symbol Slack Technologies, Inc. [ WORK] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O SLACK TECHNOLOGIES, INC., 500 HOWARD STREET 3. Date of Earliest Transaction (MM/DD/YY) 06/20/2019 (Street) SAN FRANCISCO,, CA94105 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Common Stock 06/20/2019 S 6,725,250 D $ 38.5 10,420,830 I By Accel X L.P. ( 1 ) Class A Common Stock 06/20/2019 S 896,700 D $ 40.76 ( 2 ) 9,524,130 I By Accel X L.P. ( 1 ) Class A Common Stock 06/20/2019 S 504,750 D $ 38.5 782,123 I By Accel X Strategic Partners L.P. ( 3 ) Class A Common Stock 06/20/2019 S 67,300 D $ 40.76 ( 2 ) 714,823 I By Accel X Strategic Partners L.P. ( 3 ) Class A Common Stock 06/20/2019 S 270,000 D $ 38.5 418,373 I By Accel Investors 2009 L.L.C. ( 4 ) Class A Common Stock 06/20/2019 S 36,000 D $ 40.76 ( 2 ) 382,373 I By Accel Investors 2009 L.L.C. ( 4 ) Class A Common Stock 06/20/2019 J( 5 ) 348,826 A $ 0 348,826 I By trust Class A Common Stock 11,482,103 I See footnote ( 5 ) ( 6 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Braccia Andrew C/O SLACK TECHNOLOGIES, INC. 500 HOWARD STREET SAN FRANCISCO,, CA94105 X Signatures /s/ David Schellhase, as Attorney-in-Fact 06/24/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )These shares are held by Accel X L.P. Accel X Associates L.L.C. ("Accel X GP") is the general partner of each of Accel X L.P. and Accel X Strategic Partners L.P. The Reporting Person is a managing member of Accel X GP. The Reporting Person disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of his 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. ( 2 )The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $40.50 to $41.05. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. ( 3 )These shares are held by Accel X Strategic Partners L.P. The Reporting Person disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of his 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. ( 4 )These shares are held by Accel Investors 2009 L.L.C., of which the Reporting Person is a managing member. The Reporting Person disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of his 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. ( 5 )Represents 557,130 shares held by Accel X L.P., 41,823 shares held by Accel X Strategic Partners L.P., 22,373 shares held by Accel Investors 2009 L.L.C., 3,705,529 shares held by Accel Growth Fund III L.P., 174,942 shares held by Accel Growth Fund III Strategic Partners L.P., 245,497 shares held by Accel Growth Fund Investors 2014 L.L.C., 58,325 shares held by Accel Growth Fund Investors 2016 L.L.C. 6,937 shares held by Accel Growth Fund IV Strategic Partners L.P. 1,219,420 shares held by Accel Growth Fund IV L.P., 387,596 shares held by Accel Investors 2013 L.L.C., 51,924 shares held by Accel Leaders Fund Investors 2016 L.L.C., 1,086,756 shares held by Accel Leaders Fund L.P., 3,649,641 shares held by Accel XI L.P., and 274,210 shares held by Accel XI Strategic Partners L.P. (together, the "Accel Funds"). ( 6 )(Continued from Footnote 6) The Reporting Person is a managing member of the Accel Funds that are organized as limited liability companies and is a managing member of the general partners of the Accel Funds that are organized as limited partnerships. The Reporting Person disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of his 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.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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