Sec Form 3 Filing - Zell Brandon @ Slack Technologies, Inc. - 2019-06-07

FORM 3 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 Zell Brandon 2. Issuer Name and Ticker or Trading Symbol Slack Technologies, Inc. [ WORK] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Accounting Officer (Last) (First) (Middle) C/O SLACK TECHNOLOGIES, INC., 500 HOWARD STREET 3. Date of Earliest Transaction (MM/DD/YY) 06/07/2019 (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 190,000 D

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 Restricted Stock Units ( 3 ) ( 1 ) 05/10/2024 Class B Common Stock ( 2 ) 25,000 D Restricted Stock Units ( 3 ) ( 4 ) 06/20/2025 Class B Common Stock ( 2 ) 25,000 D Restricted Stock Units ( 3 ) ( 5 ) 11/28/2025 Class B Common Stock ( 2 ) 120,000 D Restricted Stock Units ( 3 ) ( 6 ) 04/03/2026 Class B Common Stock ( 2 ) 20,000 D Stock Option (Right to Buy) $ 10.56 ( 7 ) 02/26/2029 Class B Common Stock ( 2 ) 72,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Zell Brandon C/O SLACK TECHNOLOGIES, INC. 500 HOWARD STREET SAN FRANCISCO,, CA94105 Chief Accounting Officer Signatures /s/ David Schellhase, as Attorney-in-Fact 06/07/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Restricted Stock Units (RSUs) are subject to time-based and performance-based vesting criteria. The time-based vesting occurs in 16 quarterly installments commencing on July 1, 2017, subject to the Reporting Person's continued service with the Issuer on each such date, and the performance-based criteria will be satisfied upon the Issuers listing and public trading of its Class A Common Stock. ( 2 )Each share of Class B Common Stock is convertible into one share of Class A Common Stock at the option of the Reporting Person and has no expiration date. ( 3 )Each RSU represents the right to receive one share of Class B Common Stock. ( 4 )The RSUs are subject to time-based and performance-based vesting criteria. The time-based vesting occurs in 16 quarterly installments commencing on July 1, 2018 subject to the Reporting Persons continued service with the Issuer on each such date, and the performance-based criteria will be satisfied upon the Issuers listing and public trading of its Class A Common Stock. ( 5 )The RSUs are subject to time-based and performance-based vesting criteria. The time-based vesting occurs in 16 quarterly installments commencing on November 1, 2018 subject to the Reporting Persons continued service with the Issuer on each such date, and the performance-based criteria will be satisfied upon the Issuers listing and public trading of its Class A Common Stock. ( 6 )The RSUs are subject to time-based and performance-based vesting criteria. The time-based vesting occurs in 16 quarterly installments commencing on July 1, 2019 subject to the Reporting Persons continued service with the Issuer on each such date, and the performance-based criteria will be satisfied upon the Issuers listing and public trading of its Class A Common Stock. ( 7 )The stock option shall vest and become exercisable in 24 equal quarterly installments commencing on May 1, 2019, subject to the Reporting Person's continued service with the Issuer on each such date.

Remarks: Exhibit 24.1 Power of Attorney

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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