SAN RAMON, Calif. (AP) — Business software pioneer Salesforce.com is buying work-chatting service Slack for $27.7 billion in a deal aimed at giving the two companies a better shot at competing against one of the industry's longtime powerhouses.

The acquisition announced Tuesday is by far the largest in the 21-year history of Salesforce, a San Francisco company that was one of the first to begin selling software as a subscription service that could be used on any internet-connected device instead of the more cumbersome process of installing the programs on individual computers.

According to the Associated Press, Salesforce purchased data analytics specialist Tableau Software for $15.7 billion last year.

The company’s current market value is $220 billion, the AP reported.

The AP reported that both companies are located about a block away from each other in San Francisco.