Salesforce.com Inc. is in advanced talks to buy Slack Technologies Inc., according to people familiar with the matter, a deal that would unite a giant in business software with a buzzy newcomer on a mission to replace office email.
The companies could reach a deal within days—possibly by the time Salesforce reports its third-quarter financial results Tuesday, some of the people said. Slack, with a market value of more than $17 billion as of Wednesday morning, would be Salesforce’s largest acquisition ever. There is no guarantee…
