Slack Acquisition, Valuation, Funding & Investors
Slack was acquired by Salesforce for $28B in December 2020, a 33.4x multiple on $830M of revenue.
Slack revenue at acquisition
$830M
Last twelve months · Dec 2020
Slack revenue multiple at acquisition
33.4x
EV/Revenue · Dec 2020
Cumulative funding Slack raised
$1.4B
across 6 funding rounds
About Slack
Slack is a workplace messaging platform enabling team channels, direct messages, and app integrations. Headquartered in San Francisco, California, Slack connects with over 2,400 applications including Zoom, Salesforce, and Asana for streamlined workflows. Acquired by Salesforce in 2021, the service powers communication for enterprises like IBM, Shopify, and Oracle across sales, engineering, and HR functions.
Founded
2009
HQ
San Francisco, CAWebsite
Status
Acquired
Customer focus
B2B
Revenue model
Subscription
Revenue
$2.3B (Aug 2018)
Valuation
$7.1B (Aug 2018)
Slack Acquisition
Slack was acquired by Salesforce for $28B on 1 December 2020.
The acquisition price implies a 33.4x revenue multiple on $830M of revenue.
Before the acquisition Slack had raised $1.4B across 6 funding rounds.
| Acquirer | Date | Type | Price | EV/Revenue |
|---|---|---|---|---|
| 1 Dec 2020 | Strategic M&A | $28B | 33.4x |
Slack Valuation
Slack is currently valued at $7.1B, based on its Series H in August 2018.
The $427M round was led by Dragoneer and General Atlantic, with participation from Baillie Gifford, Wellington Management, SoftBank Group, Sands Capital Ventures, T. Rowe Price and 1 other investor.
Slack's valuation has grown 6.3x from $1.1B at its Series D in October 2014 to $7.1B in August 2018, across 5 priced rounds.
Slack valuation by funding round
Revenue multiple| Date | Stage | Valuation | Revenue Multiple |
|---|---|---|---|
| Aug 2018 | Series H | $7.1B | 3.1x |
| Sep 2017 | Series G | $5.1B | 25.5x |
| Apr 2016 | Series F | $3.8B | 50.7x |
| Apr 2015 | Series E | $2.8B | - |
| Oct 2014 | Series D | $1.1B | 93.3x |
Slack Revenue
Slack's latest recorded revenue is $2.3B, as of its Series H in August 2018. At a $7.1B valuation, that implies a 3.1x revenue multiple.
Revenue grew from $12M in October 2014 to $2.3B in August 2018, while the revenue multiple moved from 93.3x to 3.1x.
Slack revenue by funding round
| Date | Revenue * | Valuation | Revenue Multiple | Stage |
|---|---|---|---|---|
| Aug 2018 | $2.3B | $7.1B | 3.1x | Series H |
| Sep 2017 | $200M | $5.1B | 25.5x | Series G |
| Apr 2016 | $75M | $3.8B | 50.7x | Series F |
| Oct 2014 | $12M | $1.1B | 93.3x | Series D |
* Revenue (or ARR) figures are the values recorded alongside each funding round. Typically run-rate revenue at the time of the deal, or a reported LTM (last 12 months) revenue.
Slack Funding History
Slack has raised a total of $1.4B across 6 funding rounds.
Slack's first fundraising round was a $43M Series C in April 2014. The most recent completed round was a $427M Series H in August 2018.
Slack funding rounds
| Date | Stage | Investors | Raised | Valuation | Deal Summary |
|---|---|---|---|---|---|
| Aug 2018 | Series H | Dragoneer (lead); General Atlantic (lead); Baillie Gifford; Wellington Management; SoftBank Group; Sands Capital Ventures; T. Rowe Price; Accel | $427M | $7.1B | Slack, the enterprise collaboration platform, raised $427 million in a Series H funding round on August 21, 2018, led by Dragoneer Investment Group and General Atlantic, with participation from T. Rowe Price Associates, Wellington Management, Baillie Gifford, Sands Capital, Accel, SoftBank Vision Fund, and other existing investors. The round achieved a post-money valuation exceeding $7.1 billion, following a prior $250 million raise led by SoftBank at a $5.1 billion valuation in 2017, bringing total funding to over $1.26 billion. This capital was intended to provide resources for growth amid intensifying competition from Microsoft Teams, Yammer, Alibaba's DingTalk, and others, while supporting product evolution and customer service. At the time, Slack reported more than 8 million daily active users and over 70,000 paid teams, demonstrating significant scale since its 2013 launch. The company had recently acquired Atlassian's HipChat and Stride to expand its user base. Investors highlighted Slack's potential to revolutionize workplace collaboration and productivity, with statements from Dragoneer and T. Rowe Price emphasizing long-term partnership and belief in its vision. The funding reflected a trend of private markets fueling growth for high-potential tech firms facing deep-pocketed rivals. |
| Sep 2017 | Series G | SoftBank Group (lead); Moonshots Capital; Global Founders Capital; AAFM; Accel | $413M | $5.1B | Slack, a San Francisco-based workplace collaboration platform with roots in Vancouver, raised $250 million in a funding round on September 17, 2017, led by SoftBank Vision Fund with participation from Accel and others including reports of AAFM, Global Founders Capital, and Moonshots Capital. The round brought total funding to $841 million and valued the company at $5.1 billion post-money, up from $3.8 billion in its prior April 2016 round. CEO Stewart Butterfield noted the capital provides operational flexibility, as prior funds remained largely untouched, positioning Slack to operate as a cash-generating entity amid international expansion and market evolution. At the time, Slack reported $200 million in annual recurring revenue (ARR), 100% year-over-year growth, 9 million weekly active users, 6 million daily active users, and 2 million paid subscribers. The platform had recently launched external communication features to compete with enterprise tools from Microsoft and Atlassian, targeting larger businesses beyond its Silicon Valley base. TechCrunch highlighted a 25x multiple on next-year revenue, reflecting strong growth potential despite competitive pressures and prior acquisition interest from Microsoft at higher valuations up to $9 billion. SoftBank's investment aligned with its focus on global tech platforms, with Deep Nishar praising Slack as the operating system for fast-moving businesses. Butterfield anticipated SoftBank's continued involvement post-IPO, expected in 2018, emphasizing reassurance for customers and hires. The round followed earlier reports of $500 million ambitions and built on partnerships like Accel from inception. |
| Apr 2016 | Series F | Thrive Capital (lead); Index Ventures; IVP; Ling Wong; Comcast Ventures; ACME Capital; Lowercase Capital; Social Capital; Accel; Notable Capital | $208M | $3.8B | Slack, a workplace messaging platform that integrates communication, workflows, and apps to replace email, raised $200 million in a VC round on April 1, 2016, led by Thrive Capital with participation from GGV, Comcast Ventures, and existing investors including Accel, Index Ventures, and Social Capital. This brought total funding to $540 million and post-money valuation to $3.8 billion, up from $2.8 billion in the prior round. The capital was intended to secure leadership, support growth plans, acquisitions, hires, and R&D including voice and video chat features. At the time, Slack had 2.7 million daily active users and rapid 3.5x user growth over the prior year. Around the round date, Slack reported strong revenue traction with $75 million ARR in April 2016, up from $64 million in February 2016 and $50 million in December 2015, driven by 800,000 paid seats at roughly $7.81 per seat per month. Pricing ranged from $6-12 per active user per month. By summer 2016, ARR surpassed $100 million with 1.25 million paid seats and 4 million daily active users. Full-year 2016 revenue reached $105.1 million. Slack's growth relied on product-led adoption and word-of-mouth, particularly via Twitter, with average paid team sizes around 20 users. It differentiated through network effects, app integrations, and developer ecosystem, positioning it ahead of competitors despite copyable core features. |
| Apr 2015 | Series E | Social Capital (lead) | $173M | $2.8B | Slack, the workplace communication and collaboration platform founded by Stewart Butterfield, raised $160 million in its Series E funding round on April 16, 2015, at a post-money valuation of $2.8 billion. The round included new investors Horizons Ventures, Digital Sky Technologies (DST Global), Index Ventures, Spark Capital Growth, and Institutional Venture Partners (IVP), with participation from existing backers such as Accel Partners, Andreessen Horowitz, The Social+Capital Partnership (Social Capital), Google Ventures, and Kleiner Perkins Caufield & Byers. This brought Slack's total funding to $340 million following a $120 million Series D in October 2014 at $1.12 billion valuation. At the time, Slack reported 750,000 daily active users and 200,000 paying users (paid seats), serving customers including Adobe, New York Times, Blue Bottle Coffee, BuzzFeed, Live Nation, Expedia, HBO, PayPal, and the U.S. State Department. The company emphasized its rapid growth and user stickiness, with daily active users more than doubling since the start of the year. CEO Butterfield noted the funds would go into the bank as a hedge, citing favorable market conditions, and highlighted Slack's capital efficiency, having not yet spent proceeds from the prior round. Social Capital, previously The Social+Capital Partnership, was a returning investor from earlier rounds but not the lead; the board included representatives from Accel, Andreessen Horowitz, and Social+Capital. Slack, headquartered in San Francisco with offices in Vancouver, positioned itself at the forefront of transforming business communications, attracting global investors reflective of its audience. |
| Oct 2014 | Series D | GV (lead); Kleiner Perkins (lead); Slow Ventures; Social Capital; Andreessen Horowitz; Accel | $111M | $1.1B | Slack, the enterprise collaboration platform co-founded by Stewart Butterfield, closed a $120 million funding round on October 31, 2014, co-led by Google Ventures (GV) and Kleiner Perkins Caufield & Byers (KPCB), with participation from Accel Partners, Andreessen Horowitz (A16Z), Social Capital, and Slow Ventures. The post-money valuation was $1.12 billion, bringing total funding to $180 million since exiting beta earlier that year. This marked rapid ascent for Slack as a leader in a new product category for workplace communication. At the time of the round, Slack reported strong early traction with 30,000 active teams sending over 200 million messages monthly and more than 73,000 paying customers from daily active users converted to paid seats. The company was adding $1 million in annual recurring revenue (ARR) every month, projecting to surpass $10 million ARR that year and positioning it as the fastest SaaS company to reach that milestone without sales and marketing spend. Retention was described as near perfect, supporting organic growth and monetization potential. CEO Stewart Butterfield emphasized the valuation reflected trajectory and proven willingness to pay, rather than speculation, amid a shift in communication tools. Funds provided flexibility for growth over the next 6-18 months, including new features like threaded comments, email integration, and emoji favorites, with plans to invest in sales and marketing. |
| Apr 2014 | Series C | Social Capital (lead); Rob Solomon; David O. Sacks; Jeremy Stoppelman; Andreessen Horowitz; FundersClub; John Collison; Biz Stone; Anthony Casalena; Jeff Weiner; Accel; Craft Ventures | $43M | - | Slack, the team collaboration platform co-founded by Stewart Butterfield, raised $42.75 million in its Series C funding round in April 2014, led by Social Capital, with participation from investors including Accel, Andreessen Horowitz, and individuals such as Anthony Casalena, Biz Stone, Bryan Rosenblatt, David O. Sacks, FundersClub, Jeff Weiner, Jeremy Stoppelman, John Collison, and Rob Solomon. The round aimed to scale operations and enhance product features following the platform's pivot from the failed gaming company Tiny Speck and its beta launch in August 2013, with public release in February 2014. By October 2014, shortly after the Series C, Slack reported strong early traction with 73,000 paid users, 268,000 daily active users, and 200 million monthly messages. The company was adding $1 million in annual run-rate revenue every four weeks, suggesting approximately $12 million in annualized revenue run rate at that time. This momentum led to a follow-on Series D round of $120 million in October 2014, co-led by Google Ventures and Kleiner Perkins, at a $1.12 billion post-money valuation, bringing total funding to $180 million. Slack positioned itself as a modern alternative to legacy enterprise tools like email and Yammer, emphasizing real-time messaging, integrations, and consumer-like usability for teams. The April 2015 Series E raised $172.7 million again led by Social Capital, followed by further rounds culminating in over $1.3 billion total raised by 2019. The company's rapid growth established it as a unicorn leader in workplace communication before its 2020 acquisition by Salesforce. |
Who has invested in Slack?
33 investors have backed Slack across its funding rounds, including Accel, Social Capital, Andreessen Horowitz, SoftBank Group, GV and Index Ventures.
Lead investors include Dragoneer, General Atlantic, SoftBank Group, Thrive Capital, Social Capital and 2 other investors.
Slack Investors
| Investor | HQ | Rounds | Role | First check |
|---|---|---|---|---|
| Palo Alto, CA | 5 | Participant | Apr 2014 | |
| San Francisco, CA | 4 | Lead | Apr 2014 | |
 Tokyo | 2 | Lead | Sep 2017 | |
| San Francisco, CA | 2 | Participant | Apr 2014 | |
 Edinburgh | 1 | Participant | Aug 2018 | |
| San Francisco, CA | 1 | Lead | Aug 2018 | |
| London | 1 | Participant | Apr 2016 | |
| Boston, MA | 1 | Participant | Aug 2018 | |
| San Francisco, CA | 1 | Participant | Apr 2016 | |
| San Francisco, CA | 1 | Lead | Oct 2014 | |
![](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 20 20"><rect fill="%23e5e7eb" width="20" height="20" rx="4"/></svg>){kind=small} Rob Solomon | San Francisco, CA | 1 | Participant | Apr 2014 |
| David O. Sacks | San Francisco, CA | 1 | Participant | Apr 2014 |
| San Francisco, CA | 1 | Lead | Oct 2014 | |
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Start Free TrialAcquisitions by Slack
Slack has acquired 8 companies to date.
Last acquisition by Slack was on May 1st 2021. Slack acquired Woven for undisclosed valuation.
Latest Acquisitions by Slack
| Description | Woven is a calendar visualization platform that maps events geographically and auto-calculates travel times between locations. Users reserve buffer times for commutes directly on their calendars, with collaboration features via email, Slack, or text for group scheduling. The service eliminates manual coordination, providing real-time insights for meetings across New York-based teams and remote workers. | Rimeto is a San Francisco-headquartered workplace collaboration platform featuring detailed employee directories and profiles. It enables searchable access to organizational information, fostering connections and productivity through its enterprise graph foundation. The tools support modern teams by making colleague data actionable for building projects and strengthening internal networks. | Astro Technology, acquired by Slack in September 2018 and based in Palo Alto, California, built intelligent email applications for Mac, iOS, and Android. Its AI assistant Astrobot delivered key emails and insights to Slack and Amazon Alexa integrations, backed by $10 million Series A funding from Redpoint Ventures, Harrison Metal, Aspect Ventures, and Upside Partnership. | Stride is a cloud-based team communication tool developed by Atlassian. Launched on September 7, 2017, it replaced the cloud version of HipChat with features for group chats, searchable rooms, and integrated collaboration tools. The platform supports voice and video conferencing for desktop and mobile, including shareable meeting URLs and guest access. Focus Mode and status settings enable distraction-free work. Atlassian discontinued Stride in 2019, migrating users to Slack integrations. | |
| HQ Country | | | | | |
| HQ City | San Francisco, CA | San Francisco, CA | San Francisco, CA | San Francisco, CA | |
| Deal Date | 1 May 2021 | 8 Jul 2020 | 24 Sep 2018 | 27 Jul 2018 | |
| Valuation | undisclosed | $40M | $43M | undisclosed | |
| EV/Revenue | |||||
| EV/EBITDA | |||||
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Investments by Slack
Slack has invested in 13 companies to date.
Latest investment by Slack was on April 27th 2023. Slack invested in Ctrl in their $9M Seed round.
Latest Investments by Slack
| Description | Ctrl is a Tel Aviv-based sales enablement platform founded in 2021 that unifies customer data from CRM, email, and support tools into custom dashboards. Sales teams access 360-degree customer views for faster opportunity tracking and task automation. Ctrl integrates with Salesforce, HubSpot, and Gong, serving B2B companies in Israel and the U.S. with no-code workspace builders. | Electric is a New York City-based provider of AI-powered IT management platforms tailored for small and mid-sized businesses across North America. Launched in 2016, its unified platform handles real-time IT support through over 100 technicians, alongside cybersecurity, endpoint management, network monitoring, cloud applications, employee lifecycle automation, procurement, and analytics. The company supports nearly 1,000 clients encompassing 45,000 end-users in sectors like technology, finance, and healthcare. | Crosschq is a SaaS platform that leverages references and assessments for talent acquisition and retention. The system collects insights from candidates and their networks to predict cultural fit and performance. Crosschq emphasizes bias reduction and data privacy in hiring processes. Founded in 2017, the Seattle-based company receives backing from GGV Capital and Bessemer Venture Partners. | Electric is a New York City-based provider of AI-powered IT management platforms tailored for small and mid-sized businesses across North America. Launched in 2016, its unified platform handles real-time IT support through over 100 technicians, alongside cybersecurity, endpoint management, network monitoring, cloud applications, employee lifecycle automation, procurement, and analytics. The company supports nearly 1,000 clients encompassing 45,000 end-users in sectors like technology, finance, and healthcare. | |
| HQ Country |  | | | | |
| HQ City | Tel Aviv | New York City, NY | San Francisco, CA | New York City, NY | |
| Deal Date | 27 Apr 2023 | 19 Oct 2021 | 21 Jul 2020 | 18 May 2020 | |
| Round | Seed | Series D | Seed | Series B | |
| Raised | $9M | $90M | $7M | $7M | |
| Investors | Jibe Ventures; Celonis; LocalGlobe; Intercom; DIG Ventures; Mandeep Singh; Earlybird VC | Greenspring Associates; Two Culture Capital; Harmonic Growth Partners; Vintage Investment Partners; Atreides Management; Everywhere Ventures; Bessemer Venture Partners; 01 Advisors; Primary Venture Partners; Notable Capital; Crew Capital | Rocketship.vc; Bessemer Venture Partners; Tiger Global; SAP.iO | 01 Advisors | |
| Valuation | undisclosed | $810M | undisclosed | undisclosed | |
| EV/Revenue | |||||
| EV/EBITDA | |||||
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Slack Competitors
Slack competitors include listed companies like Zoom, Twilio and Atlassian, and private ones like Telegram, Discord and Genesys.
| Company | HQ | Status | Revenue | EBITDA | Valuation | Revenue Multiple |
|---|---|---|---|---|---|---|
| United States | Publicly listed | $4.9B | $2.6B | $27B | 3.9x | |
 Dubai | Private | - | - | $30B | - | |
| United States | Publicly listed | $5.1B | $251M | $38B | 6.3x | |
 Australia | Publicly listed | $6.6B | $142M | $49B | 7.2x | |
| San Francisco, CA | Private | $445M | - | $15B | 33.7x | |
| San Francisco, CA | Private | $2.1B | $900M | $15B | 7.1x |
Slack Public Comps
Slack is no longer listed, but its public comps include Zoom, Twilio, iFlytek, Dropbox, Atlassian, Amdocs, NICE, RingCentral, Tata Communications and Box.
| Last FY | EV/Revenue | EV/EBITDA | ||||||
|---|---|---|---|---|---|---|---|---|
| Revenue | EBITDA | Last FY | LTM | 2027E | Last FY | LTM | 2027E | |
| $4.9B | $2.6B | 4.0x | 3.9x | 7.7x | 9.1x | |||
| $5.1B | $251M | 7.1x | 6.3x | 144.6x | 30.2x | |||
| $4B | $465M | 3.7x | 3.4x | 31.7x | 40.6x | |||
| $2.5B | $854M | 4.4x | 4.4x | 12.9x | 9.4x | |||
| $6.6B | $142M | 7.4x | 7.2x | 342.1x | 23.7x | |||
| $4.5B | $922M | 1.6x | 1.5x | 7.9x | 6.0x | |||
| $2.9B | $849M | 2.1x | 1.9x | 7.1x | 6.3x | |||
| $2.5B | $339M | 3.0x | 2.9x | 22.1x | 10.5x | |||
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Common questions about Slack
| When was Slack founded? | Slack was founded in 2009. |
| Where is Slack headquartered? | Slack is headquartered in San Francisco, CA, United States. |
| Is Slack publicly listed? | No, Slack was acquired by Salesforce in December 2020. |
| Who acquired Slack? | Slack was acquired by Salesforce in December 2020. |
| How much was Slack acquired for? | Slack was acquired for $28B in December 2020, a 33.4x revenue multiple. |
| What is Slack's valuation? | Slack was last valued at $7.1B in its Series H in August 2018. |
| How much funding has Slack raised? | Slack has raised $1.4B across 6 funding rounds. |
| What was Slack's last funding round? | Slack's last funding round was a $427M Series H in August 2018, led by Dragoneer and General Atlantic. |
| Who are Slack's investors? | Slack's investors include Accel, Social Capital, SoftBank Group, Andreessen Horowitz, Baillie Gifford, Dragoneer, Index Ventures, Wellington Management, IVP, Kleiner Perkins and 23 others. |
| What is Slack's revenue? | Slack's latest recorded revenue is $2.3B (August 2018). |
| What is Slack's revenue multiple? | Slack's latest valuation implies a 3.1x revenue multiple ($7.1B valuation on $2.3B of revenue). |
| Which companies are comparable to Slack? | Companies comparable to Slack include Zoom, Telegram, Twilio, Atlassian, Discord and Genesys. |
| How many companies has Slack acquired? | Slack has acquired 8 companies, including Woven, Rimeto, Astro Technology, Stride and HipChat. |
| What was the largest acquisition by Slack? | The $43M acquisition of Astro Technology in September 2018 is the largest acquisition Slack has made to date. |
| How many companies has Slack invested in? | Slack has invested in 13 companies, including Ctrl, Electric, Crosschq, Meru Health, Sentry, Astound, Plato and Loom. |
| What was Slack's last investment? | In April 2023, Slack invested in Ctrl's $9M seed round alongside Jibe Ventures, Celonis, LocalGlobe and 4 other investors. |
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