Kayak (KYAK) acquired by Priceline.com Inc. (PCLN)

Priceline.com Inc. (PCLN) is buying Kayak just a few months after the online-travel-aggregator's public debut, in a cash-and-stock deal that values it at $1.8 billion. The transaction, which would be Priceline's biggest ever, offers $40 a share in cash and stock for Kayak, a 29% premium to its Thursday close price and 54% higher than its initial public offering price. Kayak shares surged 26% to $39.18 after hours.

Priceline, which is based in Norwalk, Conn., announced that it was buying Kayak for $40 a share, in a deal worth $1.8 billion deal.

Priceline Chief Executive Jeffery Boyd cited Kayak’s “strong brand in online travel research and their track record of profitable growth”

Kayak Chief Executive Steve Hafner said joining Priceline “will accelerate our growth and help us further develop as a company.”

The announcement came just as Kayak reported its results for the third quarter.

Kayak, which also is also based in Norwalk, reported a profit of $7.18 million, or 19 cents a share, compared with a profit of $4.03 million, or 18 cents a share, for the year-earlier period. Revenue was $78.6 million, up from $61.16 million. Adjusted profit was 26 cents a share.

Analysts were expecting a profit of 18 cents a share, on revenue of $77.36 million, according to a consensus survey by FactSet.

Kayak went public in July when its initial public offering priced at $26 a share.