Summary Box: IBM to buy DemandTec for $440 million

THE PURCHASE: IBM is buying DemandTec Inc., a price-management software company, to expand its commerce service offerings aimed at businesses.

PRICE TAG: $440 million in cash. IBM is paying $13.20 per share, a 57 percent premium to DemandTec’s closing stock price of $8.43 on Wednesday.

THE BIG PICTURE: It’s the latest in a series of large tech deals focused on cloud-based software, which is delivered to businesses over an Internet connection rather than by installing it on computers.