Ctrip, China’s top travel site, this afternoon announced it has taken a US$400 million stake in long-time arch-rival eLong.

Ctrip, China’s top travel site, this afternoon announced it has taken a US$400 million stake in long-time arch-rival eLong. The deal, which closed today, was done by acquiring eLong shares from Expedia.

Ctrip now has a 37.6 percent stake in its erstwhile rival.

Expedia has sold off its entire 62.4 percent stake in eLong, worth US$671 million, by selling the remaining shares to three other buyers (Keystone Lodging Holdings, Plateno Group, and Luxuriant Holdings), the US-based company said today.

See: China’s mobile travel bookings up more than 400% in past year

As a result of this deal, Ctrip says that it and Expedia have agreed to cooperate with each other on “certain travel product offerings for specified geographic markets.”

Expedia’s brief statement did not make clear why it’s exiting eLong.

Battle won; war rumbles on

The huge Expedia sell-off marks a major sea-change in China’s highly competitive travelecommerce sector. It seems to be a huge win for Ctrip, which has now tamed its closest competitor.

That leaves Ctrip freer to focus on newer and fast-growing rivals such as Baidu-owned Qunar, Tuniu, and LY.

Ctrip has US backing of its own in the form of Priceline, which owns about eight percent of the company.