Priceline purchase of Kayak approved by UK, deal to close May 21

The nail-biting is over.

The last major hurdle to Priceline's $1.8 billion of Kayak was removed when the UK's Office of Fair Trading today announced that it cleared the merger after conducting a regulatory review.

The transaction is slated to close May 21.

The merger had initially been slated to close during the first quarter of 2013, but in early March the OFT announced that decision day would be around May 9.

The U.S. Justice Department approved the merger in early January. Kayak shareholders overwhelmingly approved the merger in early March.

Kayak and Priceline will soon announce a closing date, and then it's game on with public company Kayak become part of the Priceline Group as Kayak will continue to operate its own brand and semi-independently.

Priceline is buying Kayak to improve Priceline's earnings, and to tap Kayak's mobile skills and technology talent. Being in the Priceline family could propel Kayak's international growth.

The OFT earlier cleared Expedia's majority stake in German hotel-metasearch site Trivago without much fuss.

Priceline is acquiring Kayak for at $40 per share, paying $500 million in cash, and $1.3 billion in equity and stock options.