United States · Series H startup
Funding summaryUpdated 26 Oct 2026
$1.2Braised across 10 rounds since 2009, from 10 sources
Each circle is a round, placed by date and sized by amount. The line above is the running total.
Reported by BetaKit: funding
Andreessen Horowitz
Accel
Index Ventures
Google Ventures
Kleiner Perkins Caufield & Byers
Spark Capital
IVP
Social Capital
Horizons Ventures
DST GlobalFrom a historical funding record
Andreessen HorowitzAccelGoogle VenturesKleiner Perkins Caufield & Byers
Slow VenturesSocial CapitalFrom a historical funding record
From a historical funding record
The busiest backers across the latest rounds. A filled square is a round they joined; a dark one, a round they led.
AccelAndreessen HorowitzSocial CapitalIndex VenturesGoogle VenturesKleiner Perkins Caufield & ByersThe Social+Capital Partnership
Thrive CapitalL
SV AngelSpark CapitalMissing a round, or an investor who was in one? Tell us.
These 20 firms list Slack as a portfolio company on their own websites, but no report of a round names them. They are the firms' own claims, kept apart from the rounds above.
Slack's investors include Accel, Andreessen Horowitz, Social Capital, Index Ventures and Google Ventures, and 21 more on record.
Slack has raised $1.2B across 10 rounds since 2009. One round did not disclose an amount, so the total is a floor.
Slack's most recent round was a Series H of $427M in Aug 2018.
Its most recent round, $427M in Aug 2018, is also its largest on record.
Slack's first round on record, in Jan 2009, was backed by Accel, Marc Andreessen and Jeff Weiner and 2 others.
Slack's latest named round is a Series H, in Aug 2018.
Slack is based in the United States.
Thrive Capital led the Growth in 2016.
In the same sector, and raised in the last eighteen months.
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United States · 
