Salesforce → Slack
Salesforce's largest acquisition: about $27.7bn in cash and shares for Slack, the workplace-messaging company then fighting Microsoft Teams, bought to make chat the front door to Salesforce's customer-software suite.
A cash-and-stock purchase at a combined $45.86 a share, Salesforce's largest acquisition.
- Value
- $27.7B
- Announced
- December 2020
- Completed
- July 2021
- Sector
- Technology
- Deal type
- acquisition
- Acquirer
- Salesforce (United States)
- Target
- Slack (United States)
Why it mattered
Slack sold channel-based team messaging on a freemium model and listed directly on the New York Stock Exchange in June 2019. Its revenue reached $902.6m in the year to January 2021, but it still lost $292.5m, and its main rival came bundled with Microsoft's office software: Microsoft announced Teams in 2016 as a direct answer to Slack, and in July 2020 Slack complained to the European Commission that tying Teams to Office 365 broke EU competition rules. Salesforce, the leading seller of customer-relationship (CRM) software, had paid $15.7bn for Tableau in 2019 and wanted Slack to become the interface for its Customer 360 products.
The agreement of 1 December 2020 gave Slack shareholders $26.79 in cash and 0.0776 of a Salesforce share for each share, an enterprise value of about $27.7bn — roughly 30 times Slack's annual revenue. Salesforce lined up a $10bn bridge loan for the cash and later replaced most of it with bonds and a term loan. The US Department of Justice issued a second request on 16 February 2021, extending its review, and closed its investigation on 16 July. The deal completed on 21 July 2021, with Slack kept under its own brand and still led by its co-founder Stewart Butterfield.
What it left behind
Butterfield announced his departure in December 2022; his successor, Lidiane Jones, was replaced by Denise Dresser in November 2023, and Dresser left for OpenAI in December 2025. In January 2023 Salesforce cut about 10% of its workforce, some 8,000 jobs, the same month the activist Elliott Management said it was taking a large stake, and Slack said it would move its headquarters into Salesforce Tower.
The complaint against Microsoft outlived Slack's independence. The Commission opened a formal investigation in July 2023, Microsoft said it would make Teams an optional part of its bundle, and in June 2024 the Commission set out its preliminary view that the bundling may have given Teams a distribution advantage. Slack meanwhile became Salesforce's vehicle for AI: Agentforce agents arrived in Slack in May 2025, and in January 2026 Slackbot was rebuilt as an AI assistant using Anthropic's Claude. A buyer paying 30 times revenue to take on a bundled incumbent is betting on product and distribution it controls; relief from competition authorities, even when it comes, arrives on a regulator's timetable, not the integration plan's.