Amazon.com Inc. AMZN, +2.49% announced Friday that it's acquiring Whole Foods Market Inc. wfm for $42 per share in an all-cash transaction of about $13.7 billion, including Whole Foods' debt. The deal implies a $13.4 billion market cap for the natural and organic grocer. Whole Foods will continue to operate under the Whole Foods angle, and John Mackey will continue as chief executive of Whole Foods with its headquarters remaining in Austin, Tex. Both companies expect the transaction to close during the second half of 2017. Amazon shares are are down 0.5% in Friday premarket trading, and Whole Foods shares were halted. Shares of Amazon are up 34.4% for the past year, Whole Foods shares are up 7.3%, and the S&P 500 index SPX, +1.59% is up 17.1% for the period.