Priceline.com has signed a definitive agreement for the Priceline Group to acquire Kayak in a stock and cash transaction. 

Under the terms of the agreement, the transaction values Kayak at $1.8 billion - or $40 per share.

Priceline will pay approximately $500 million of the total in cash and $1.3 billion in equity and assumed stock options.

The boards of directors of the Priceline Group and Kayak have unanimously approved the transaction, which is subject to customary closing conditions, including a vote of Kayak’s shareholders and regulatory approvals.

The deal is expected to close by late first quarter 2013. 

Kayak’s current management team will continue to manage operations independently as part of the Priceline Group of companies.

Kayak is a leading travel research site that allows people to easily compare hundreds of travel sites at once when searching for flights, hotels, and rental cars, and gives travellers choices on where to book.

The company processes over 100 million user queries each month through its global websites and best in class mobile applications.

“Kayak has built a strong brand in online travel research and their track record of profitable growth is demonstrative of their popularity with consumers and value to advertisers,” said Priceline Group president Jeffery Boyd. 

“It also has world class technology and a tradition of innovation in building great user interfaces across multiple platforms and devices. 
“We believe we can be helpful with plans to build a global online travel brand.”