Andreessen Horowitz Fund I SC 13G/A Slack / Andreessen Horowitz Fund I ownership change

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Schedule 13G

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

Slack Technologies, Inc.

(Name of Issuer)

Class A Common Stock

(Title of Class of Securities)

83088V102

(CUSIP Number)

December 31, 2020

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

¨ Rule 13d-1(b)

¨ Rule 13d-1(c)

x Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

(Continued on following pages)

Page 1 of 19 Pages

Exhibit Index Contained on Page 18

CUSIP NO.  83088V102 13 G Page 2 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Andreessen Horowitz Fund I, L.P. (“AH I”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	PN

CUSIP NO.  83088V102 13 G Page 3 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Andreessen Horowitz Fund I-A, L.P. (“AH I-A”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	PN

CUSIP NO.  83088V102 13 G Page 4 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Andreessen Horowitz Fund I-B, L.P. (“AH I-B”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	PN

CUSIP NO.  83088V102 13 G Page 5 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) AH Equity Partners I, L.L.C. (“AH Equity I”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	OO

CUSIP NO.  83088V102 13 G Page 6 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) AH Parallel Fund IV, L.P. (“AH Parallel IV”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	PN

CUSIP NO.  83088V102 13 G Page 7 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) AH Parallel Fund IV-A, L.P. (“AH Parallel IV-A”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	PN

CUSIP NO.  83088V102 13 G Page 8 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) AH Parallel Fund IV-B, L.P. (“AH Parallel IV-B”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	PN

CUSIP NO.  83088V102 13 G Page 9 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) AH Parallel Fund IV-Q, L.P. (“AH Parallel IV-Q”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	PN

CUSIP NO.  83088V102 13 G Page 10 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) AH Equity Partners IV (Parallel), L.L.C. (“AH Equity Parallel IV”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	OO

CUSIP NO.  83088V102 13 G Page 11 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) a16z Seed-III, LLC (“AH Seed III”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	OO

CUSIP NO.  83088V102 13 G Page 12 of 19

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) AH Equity Partners III, L.L.C. (“AH Equity III”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	OO

CUSIP NO.  83088V102 13 G Page 13 of 19

1	NAME OF REPORTING PERSONS Marc Andreessen (“Andreessen”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION U.S. Citizen

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares.
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 0 shares.
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	0
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.0%
12	TYPE OF REPORTING PERSON	IN

CUSIP NO.  83088V102 13 G Page 14 of 19

1	NAME OF REPORTING PERSONS Ben Horowitz (“Horowitz”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)     ¨      (b)      x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION U.S. Citizen

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 2,612,103 shares1
	6	SHARED VOTING POWER 0 shares.
	7	SOLE DISPOSITIVE POWER 2,612,103 shares1
	8	SHARED DISPOSITIVE POWER 0 shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON	2,612,1031
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9	0.5%2
12	TYPE OF REPORTING PERSON	IN

¹ Represents 2,612,103 shares of the Issuer’s Class A Common Stock held by a family trust for which the Reporting Person is a trustee.

² Based on 489,067,297 shares of the Issuer’s Class A Common Stock outstanding as of November 16, 2020, as reported by the Issuer in its Form 10-Q filed with the Securities and Exchange Commission on December 3, 2020.

CUSIP NO.  83088V102 13 G Page 15 of 19

This Amendment No. 1 amends the Schedule 13G previously filed by Andreessen Horowitz Fund I, L.P., a Delaware limited partnership, Andreessen Horowitz Fund I-A, L.P., a Delaware limited partnership, Andreessen Horowitz Fund I-B, L.P., a Delaware limited partnership, AH Equity Partners I, L.L.C., a Delaware limited liability company, AH Parallel Fund IV, L.P., a Delaware limited partnership, AH Parallel Fund IV-A, L.P., a Delaware limited partnership, AH Parallel Fund IV-B, L.P., a Delaware limited partnership, AH Parallel Fund IV-Q, L.P., a Delaware limited partnership, AH Equity Partners IV (Parallel), L.L.C., a Delaware limited liability company, a16z Seed-III, LLC, a Delaware limited liability company, AH Equity Partners III, L.L.C., a Delaware limited liability company, Marc Andreessen and Ben Horowitz. The foregoing entities and individuals are collectively referred to herein as the “Reporting Persons.” Only those items in the previously filed Schedule 13G as to which there has been a change are included in this Amendment No. 1.

ITEM 4.	OWNERSHIP
	The following information with respect to the beneficial ownership of the Class A Common Stock of the Issuer by the Reporting Persons is provided as of December 31, 2020 and as of the date hereof.

(a)	Amount beneficially owned:
	See Row 9 of cover page for each Reporting Person.

(b)	Percent of Class:
	See Row 11 of cover page for each Reporting Person.

(c) Number of shares as to which such person has:

(i)	Sole power to vote or to direct the vote:
	See Row 5 of cover page for each Reporting Person.

(ii)	Shared power to vote or to direct the vote:
	See Row 6 of cover page for each Reporting Person.

(iii)	Sole power to dispose or to direct the disposition of:
	See Row 7 of cover page for each Reporting Person.

(iv)	Shared power to dispose or to direct the disposition of:
	See Row 8 of cover page for each Reporting Person.

ITEM 5.	OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS
	If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the follow: x Yes

ITEM 6.	OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.
	Not applicable.

CUSIP NO.  83088V102 13 G Page 16 of 19

SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: February 16, 2021

Andreessen Horowitz Fund I, L.P.
Andreessen Horowitz Fund I-A, L.P.
Andreessen Horowitz Fund I-B, L.P.
By: AH Equity Partners I, L.L.C.
Its: General Partner
By:	/s/ Scott Kupor
	Scott Kupor, Chief Operating Officer
AH Equity Partners I, L.L.C.
By:	/s/ Scott Kupor
	Scott Kupor, Chief Operating Officer
AH Parallel Fund IV, L.P.
AH Parallel Fund IV-A, L.P.
AH Parallel Fund IV-B, L.P.
AH Parallel Fund IV-Q, L.P.
By: AH Equity Partners IV (Parallel), L.L.C.
Its: General Partner
By:	/s/ Scott Kupor
	Scott Kupor, Chief Operating Officer
AH Equity Partners IV (Parallel), L.L.C.
By:	/s/ Scott Kupor
	Scott Kupor, Chief Operating Officer
a16z Seed-III, LLC
By:	/s/ Scott Kupor
	Scott Kupor, Chief Operating Officer
AH Equity Partners III, L.L.C.
By:	/s/ Scott Kupor
	Scott Kupor, Chief Operating Officer

CUSIP NO.  83088V102 13 G Page 17 of 19

Marc Andreessen

/s/ Scott Kupor

Scott Kupor, Chief Operating Officer

Attorney-in-fact for Marc Andreessen*

Ben Horowitz

/s/ Scott Kupor

Scott Kupor, Chief Operating Officer

Attorney-in-fact for Ben Horowitz*

*The Power of Attorney set forth in Exhibit 24 to the Initial Statement of Beneficial Ownership of Securities on Form 3 filed by such Reporting Person with the Securities and Exchange Commission on June 7, 2019 is incorporated herein by reference.

CUSIP NO.  83088V102 13 G Page 18 of 19

EXHIBIT INDEX

	Found on Sequentially
Exhibit	Numbered Page
Exhibit A:  Agreement of Joint Filing	19

CUSIP NO.  83088V102 13 G Page 19 of 19

exhibit A

Agreement of Joint Filing

The Reporting Persons agree that a single Schedule 13G (or any amendment thereto) relating to the Class A Common Stock of Slack Technologies, Inc. shall be filed on behalf of each of the Reporting Persons. Note that copies of the applicable Agreement of Joint Filing is already on file with the appropriate agencies.