Shares of Tableau Software Inc. rocketed 34% in premarket trade Monday, after the data analytics company agreed to be bought out by Salesforce.com Inc. /zigman2/quotes/200515854/lastsale CRM -5.64% in a stock deal valued at $15.7 billion. Salesforce's stock fell 2.7%. Under terms of the agreement, Salesforce will exchange 1.103 of its shares for each Tableau share outstanding. Based on Friday's closing prices, that would value Tableau shares at $177.88 each, a 42% premium. The deal is expected to close during Salesforce's fiscal third quarter ending Oct. 31. It is expected to increase Salesforce's fiscal 2020 revenue by about $350 million to $400 million, reduce adjusted operating margin by about 75 basis points (0.75 percentage points) and decrease adjusted EPS by about 37 cents to 39 cents. "We are bringing together the world's #1 CRM with the #1 analytics platform," said Salesforce Chief Executive Marc Benioff. "Tableau helps people see and understand data, and Salesforce helps people engage and understand customers." Tableau's stock has gained 4.3% year to date and Salesforce shares have rallied 17.7%, while the S&P 500 /zigman2/quotes/210599714/realtime SPX -3.37% has advanced 14.6%.