Priceline will purchase Kayak for $40 per share in cash and stock.
"We're excited to join the world's premier online travel company. The Priceline Group's global reach and expertise will accelerate our growth and help us further develop as a company," said teve Hafner, Kayak Chief Executive Officer and Cofounder, in a statement.
Kayak's initial public offering was only a few months ago on July 20. The company's stock priced at $26 per share in its IPO.
Kayak's stock traded around the $40 price offer in after-hours trading Thursday after news broke about its acquisition.