Slack shares surge 8% as CNBC sources say Salesforce will announce acquisition tomorrow

• Sources tell CNBC's David Faber that Salesforce's (NYSE:CRM) acquisition of Slack (NYSE:WORK) is expected to be announced tomorrow after the bell, which is when Salesforce will report earnings results.
• The source says the deal will be half cash, half stock and value Slack at a premium to its current price.
• The deal would become one of the largest software mergers in history, joining Microsoft's $27B acquisition of LinkedIn and IBM's $34B price tag to pick up Red Hat.
• Slack shares are up 8% pre-market to $43.94. The company has a $23.2B market cap. Salesforce is down 1%, erasing earlier gains.
• Previously: Salesforce stock gains ahead of Q3 earnings; bull outlines benefits of potential Slack purchase (Nov. 30 2020)