Sec Form 4 Filing - Henderson Cal @ Slack Technologies, Inc. - 2021-07-21

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 Henderson Cal 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 Technology Officer (Last) (First) (Middle) C/O SLACK TECHNOLOGIES, INC., 500 HOWARD STREET 3. Date of Earliest Transaction (MM/DD/YY) 07/21/2021 (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 07/21/2021 C 13,218,173 A 13,303,828 I By trust ( 2 ) Class A Common Stock 07/21/2021 C 222,200 A 222,200 I By trust ( 3 ) Class A Common Stock 07/21/2021 C 222,200 A 222,200 I By trust ( 4 ) Class A Common Stock 07/21/2021 C 222,200 A 222,200 I By trust ( 5 ) Class A Common Stock 07/21/2021 C 222,200 A 222,200 I By trust ( 6 ) Class A Common Stock 07/21/2021 C 56,632 A 56,632 I See footnote ( 7 ) Class A Common Stock 07/21/2021 C 33,706 A 33,706 I By trust ( 8 ) Class A Common Stock 07/21/202 1 C 8,427 A 8,427 I By trust ( 9 ) Class A Common Stock 07/21/2021 C 29,493 A 29,493 I By trust ( 10 ) Class A Common Stock 07/21/2021 C 12,640 A 12,640 I By trust ( 11 ) Class A Common Stock 07/21/2021 C 233,854 A 272,092 D Class A Common Stock 07/21/2021 U 13,303,828 D 0 I By trust ( 2 ) Class A Common Stock 07/21/2021 U 222,200 D 0 I By trust ( 3 ) Class A Common Stock 07/21/2021 U 222,200 D 0 I By trust ( 4 ) Class A Common Stock 07/21/2021 U 222,200 D 0 I By trust ( 5 ) Class A Common Stock 07/21/2021 U 222,200 D 0 I By trust ( 6 ) Class A Common Stock 07/21/2021 U 56,632 D 0 I See footnote ( 7 ) Class A Common Stock 07/21/2021 U 33,706 D 0 I By trust ( 8 ) Class A Common Stock 07/21/2021 U 8,427 D 0 I By trust ( 9 ) Class A Common Stock 07/21/2021 U 29,493 D 0 I By trust ( 10 ) Class A Common Stock 07/21/2021 U 12,640 D 0 I By trust ( 11 ) Class A Common Stock 07/21/2021 U 272,092 ( 13 ) D 0 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 Class B Common Stock ( 1 ) 07/21/2021 C 13,218,173 ( 1 ) ( 1 ) Class A Common Stock 13,218,173 $ 0 0 I By trust ( 2 ) Class B Common Stock ( 1 ) 07/21/2021 C 222,200 ( 1 ) ( 1 ) Class A Common Stock 222,200 $ 0 0 I By trust ( 3 ) Class B Common Stock ( 1 ) 07/21/2021 C 222,200 ( 1 ) ( 1 ) Class A Common Stock 222,200 $ 0 0 I By trust ( 4 ) Class B Common Stock ( 1 ) 07/21/2021 C 222,200 ( 1 ) ( 1 ) Class A Common Stock 222,200 $ 0 0 I By trust ( 5 ) Class B Common Stock ( 1 ) 07/21/2021 C 222,200 ( 1 ) ( 1 ) Class A Common Stock 222,200 $ 0 0 I By trust ( 6 ) Class B Common Stock ( 1 ) 07/21/2021 C 56,632 ( 1 ) ( 1 ) Class A Common Stock 56,632 $ 0 0 ( 14 ) I See footnote ( 7 ) Class B Common Stock ( 1 ) 07/21/2021 C 33,706 ( 1 ) ( 1 ) Class A Common Stock 33,706 $ 0 0 ( 15 ) I By trust ( 8 ) Class B Common Stock ( 1 ) 07/21/2021 C 8,427 ( 1 ) ( 1 ) Class A Common Stock 8,427 $ 0 0 ( 16 ) I By trust ( 9 ) Class B Common Stock ( 1 ) 07/21/2021 C 29,493 ( 1 ) ( 1 ) Class A Common Stock 29,493 $ 0 0 ( 17 ) I By trust ( 10 ) Class B Common Stock ( 1 ) 07/21/2021 C 12,640 ( 1 ) ( 1 ) Class A Common Stock 12,640 $ 0 0 ( 18 ) I By trust ( 11 ) Class B Common Stock ( 1 ) 07/21/2021 C 233,854 ( 1 ) ( 1 ) Class A Common Stock 233,854 $ 0 0 ( 19 ) D Class B Common Stock ( 1 ) ( 1 ) ( 1 ) Class A Common Stock 0 0 ( 15 ) ( 16 ) ( 19 ) I By trust ( 20 ) Class B Common Stock ( 1 ) ( 1 ) ( 1 ) Class A Common Stock 0 0 ( 14 ) ( 17 ) ( 18 ) I By trust ( 21 ) Restricted Stock Units ( 22 ) 07/21/2021 D 78,750 ( 23 ) ( 24 ) Class B Common Stock 78,750 $ 0 0 D Stock Option (Right to Buy) $ 10.56 07/21/2021 D 78,000 ( 25 ) 02/26/2029 Class B Common Stock 78,000 $ 0 0 D Stock Option (Right to Buy) $ 24.31 07/21/2021 D 103,122 ( 25 ) 04/05/2030 Class A Common Stock 103,122 $ 0 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Henderson Cal C/O SLACK TECHNOLOGIES, INC. 500 HOWARD STREET SAN FRANCISCO,, CA94105 Chief Technology Officer Signatures /s/ David Schellhase, as Attorney-in-Fact 07/21/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Upon consummation of the exchange offer (as described below), each share of tendered Class B common stock, par value $0.0001 per share, converted on a one-to-one basis into Class A common stock, par value $0.0001 per share. ( 2 )Shares held of record by Cal Henderson and Rebecca Reeve Henderson, Trustees of The Henderson Family Trust u/a/d/ 7/21/2016. ( 3 )Shares held of record by First Republic Trust Company of Delaware LLC and Cal Henderson, Trustees of The Theodore Henderson GST Exempt Trust under the Cal Henderson Family 2019 Irrevocable Trust dated May 22, 2019. ( 4 )Shares held of record by First Republic Trust Company of Delaware LLC and Cal Henderson, Trustees of The William Franklin Henderson GST Exempt Trust under the Cal Henderson Family 2019 Irrevocable Trust dated May 22, 2019. ( 5 )Shares held of record by First Republic Trust Company of Delaware LLC and Rebecca Reeve Henderson, Trustees of The Theodore Henderson GST Exempt Trust under the Rebecca Reeve Henderson Family 2019 Irrevocable Trust dated May 22, 2019. ( 6 )Shares held of record by First Republic Trust Company of Delaware LLC and Rebecca Reeve Henderson, Trustees of The William Franklin Henderson GST Exempt Trust under the Rebecca Reeve Henderson Family 2019 Irrevocable Trust dated May 22, 2019. ( 7 )Shares held of record by Rebecca Reeve Henderson, spouse of the Reporting Person, and as such, may be deemed to be beneficially held by the Reporting Person. ( 8 )Shares held of record by First Republic Trust Company of Delaware LLC and Cal Henderson, Trustees of The Cal Henderson 2019 Siblings Irrevocable Trust dated May 22, 2019. ( 9 )Shares held of record by First Republic Trust Company of Delaware LLC and Cal Henderson, Trustees of The Cal Henderson 2019 Parents Irrevocable Trust dated May 22, 2019. ( 10 )Shares held of record by First Republic Trust Company of Delaware LLC and Rebecca Reeve Henderson, Trustees of The Rebecca Reeve Henderson 2019 Siblings Irrevocable Trust dated May 22, 2019. ( 11 )Shares held of record by First Republic Trust Company of Delaware LLC and Rebecca Reeve Henderson, Trustees of The Rebecca Reeve Henderson 2019 Parents Irrevocable Trust dated May 22, 2019. ( 12 )Pursuant to the Agreement and Plan of Merger, dated as of December 1, 2020 (the "Merger Agreement"), by and among salesforce.com, inc. ("Salesforce"), Skyline Strategies I Inc., Skyline Strategies II LLC, and the Issuer, each share of the Issuer's common stock was tendered in exchange for (i) 0.0776 shares of Salesforce common stock and (ii) $26.79 in cash, together with cash in lieu of any fractional shares of Salesforce common stock. ( 13 )Includes 30,919 shares of Class A common stock subject to restricted stock units ("RSUs") of the Issuer. Pursuant to the Merger Agreement, at the effective time of the merger (the "Effective Time"), each of the Issuer's RSUs were assumed and converted into an RSU with respect to a number of shares of Salesforce common stock (rounded down to the nearest whole share) determined by multiplying (i) the number of shares of common stock subject to the Issuer RSU immediately prior to the Effective Time by (ii) the "option/RSU conversion ratio" as defined in the definitive proxy statement filed by the Issuer with the SEC on January 29, 2021. The converted RSU will otherwise be subject to the same terms and conditions as were applicable to the Issuer RSU prior to the Effective Time. ( 14 )Reflects 26,588 shares of Class A common stock distributed by The Rebecca Reeve Henderson 2019 Grantor Retained Annuity Trust dated May 22, 2019 to Rebecca Reeve Henderson on July 7, 2021, for no consideration, resulting in a change of form of beneficial ownership in accordance with the exemption afforded by Rule 16a-13 of the Securities Exchange Act of 1934, as amended. ( 15 )Reflects 33,706 shares of Class A common stock distributed by The Cal Henderson 2019 Grantor Retained Annuity Trust dated May 22, 2019 to The Cal Henderson 2019 Siblings Irrevocable Trust on July 7, 2021, for no consideration, resulting in a change of form of beneficial ownership in accordance with the exemption afforded by Rule 16a-13 of the Securities Exchange Act of 1934, as amended. ( 16 )Reflects 8,427 shares of Class A common stock distributed by The Cal Henderson 2019 Grantor Retained Annuity Trust dated May 22, 2019 to The Cal Henderson 2019 Parents Irrevocable Trust on July 7, 2021, for no consideration, resulting in a change of form of beneficial ownership in accordance with the exemption afforded by Rule 16a-13 of the Securities Exchange Act of 1934, as amended. ( 17 )Reflects 29,493 shares of Class A common stock distributed by The Rebecca Reeve Henderson 2019 Grantor Retained Annuity Trust dated May 22, 2019 to The Rebecca Reeve Henderson 2019 Siblings Irrevocable Trust on July 7, 2021, for no consideration, resulting in a change of form of beneficial ownership in accordance with the exemption afforded by Rule 16a-13 of the Securities Exchange Act of 1934, as amended. ( 18 )Reflects 12,640 shares of Class A common stock dist ributed by The Rebecca Reeve Henderson 2019 Grantor Retained Annuity Trust dated May 22, 2019 to The Rebecca Reeve Henderson 2019 Parents Irrevocable Trust on July 7, 2021, for no consideration, resulting in a change of form of beneficial ownership in accordance with the exemption afforded by Rule 16a-13 of the Securities Exchange Act of 1934, as amended. ( 19 )Reflects 26,588 shares of Class A common stock distributed by The Cal Henderson 2019 Grantor Retained Annuity Trust dated May 22, 2019 to the Reporting Person on July 7, 2021, for no consideration, resulting in a change of form of beneficial ownership in accordance with the exemption afforded by Rule 16a-13 of the Securities Exchange Act of 1934, as amended. ( 20 )Shares held of record by Cal Henderson, Trustee of The Cal Henderson 2019 Grantor Retained Annuity Trust dated May 22, 2019. ( 21 )Shares held of record by Rebecca Reeve Henderson, Trustee of The Rebecca Reeve Henderson 2019 Grantor Retained Annuity Trust dated May 22, 2019. ( 22 )This RSU represents the right to receive shares of Class B common stock. ( 23 )Pursuant to the Merger Agreement, at the Effective Time, each of the Issuer's RSUs were assumed and converted into an RSU with respect to a number of shares of Salesforce common stock (rounded down to the nearest whole share) determined by multiplying (i) the number of shares of common stock subject to the Issuer RSU immediately prior to the Effective Time by (ii) the option/RSU conversion ratio. The converted RSU will otherwise be subject to the same terms and conditions as were applicable to the Issuer RSU prior to the Effective Time. ( 24 )Not applicable. ( 25 )Pursuant to the Merger Agreement, at the Effective Time, each outstanding option was assumed and converted into an option to purchase the number of shares of Salesforce common stock (rounded down to the nearest whole share) determined by multiplying (i) the number of shares of common stock subject to the Issuer option immediately prior to the Effective Time by (ii) the option/RSU conversion ratio, with an exercise price determined by dividing (i) the exercise price of the Issuer option immediately prior to the Effective Time by (ii) the option/RSU conversion ratio. The converted option will otherwise be subject to the same terms and conditions as were applicable to the Issuer option prior to the Effective Time.

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