Salesforce may be looking to make its largest acquisition to date, possibly snapping up Slack, the popular corporate message platform.

Slack helped define the corporate messaging market and is used by organizations of all sizes. Recently, the company has faced increasing competition from Microsoft Teams, which has eclipsed Slack’s user base.

Nonetheless, Slack is still wildly popular and continues to strike deals with major companies. In February, IBM announced it was deploying Slack to all 350,000 of its employees. Similarly, in June AWS announced it was deploying Slack to all of its employees. In return, Slack migrated its voice and video calling services to Amazon’s Chime platform.

The AWS deal also spurred talk that Amazon might be interested in acquiring Slack. Despite Microsoft Teams’ larger market share, Slack is seen as the safe choice for companies that compete with Microsoft and don’t want to rely on a rival for their corporate communication. Given that AWS and Microsoft are the first and second-largest cloud providers, Slack seemed like a natural choice for AWS.

It appears Salesforce may be interested in purchasing the message platform, however, according to a report by the Wall Street Journal. The talks appear to be preliminary, and therefore may ultimately come to nothing. Should the a deal be struck, however, it would be the largest in Salesforce history, since Slack is currently valued at $17 billion.

Salesforce and Slack already integrate with each other. Given that both companies are locked in heated competition with Microsoft, joining forces may make sense. Salesforce, in particular, has been under increased pressure lately, with some analysts believing Microsoft’s open approach to data gives it a significant advantage over Salesforce. Microsoft has also partnered with C3.ai and Adobe to target Salesforce’s core CRM business.

It remains to be seen if the talks will bear fruit, but it is also possible Saleforce’s interest could spark renewed interest from other parties, such as AWS. Larger companies content to partner with an independent Slack may not want to see it come under the control of a possible competitor. This, in turn, may motivate them to make a move of their own.