Expedia has won approval from US antitrust officials to buy rival Orbitz, clearing the way for a $1.3 billion merger of the two pioneers of online travel booking.
The Justice Department said Wednesday that it had closed its six-month investigation into the acquisition after finding no harm to competition would result from the companies merging.
"We concluded that Expedia's acquisition of Orbitz is not likely to substantially lessen competition or harm US consumers," Bill Baer, head of the Justice Department's Antitrust Division, said in a statement.
"Many independent hotel operators, for example, do not contract with Orbitz, and those hotels that do often obtain very few bookings from its site," Baer said. "In addition, beyond Expedia and Orbitz, travel service providers have alternative ways to attract customers and obtain bookings, including Expedia's largest online travel agent rival, Priceline."
An Expedia representative said the company was "pleased" with the decision but did not say when the transaction is expected to close. Representatives for Orbitz did not respond to a request for comment on the decision.
The deal,, adds to Bellevue, Washington-based Expedia's long list of travel sites, which includes Hotels.com, Hotwire and Trivago. Expedia, founded in 1996, will get Orbitz's namesake website, along with consumer sites CheapTickets, ebookers and HotelClub, as well as business-travel sites.
Though Expedia will control only a small slice of the $1.3 trillion travel industry, opponents of the deal worried the merger would give Expedia control of 75 percent of the domestic online travel agency market.
A proliferation of travel and home-sharing sites -- including Hipmunk, Kayak and Airbnb -- has motivated the leaders of online travel to keep gobbling up other players in hopes of maintaining and growing their customer bases. In 2013, Expedia rival Priceline bought Kayak, which aggregates ticket information from other websites, for $1.8 billion.
The deal also shows online travel agencies' efforts to reduce their reliance on Google and TripAdvisor for traffic, with the companies buying up meta-search sites like Trivago and Kayak, or moving into more categories, like when Priceline last yearrestaurant-reservation site OpenTable for $2.6 billion.
The Justice Department's decision was announced after stock trading had concluded for the day, but rumors of the deal's approval boosted Expedia's shares nearly 5 percent, to $124.68. Shares of Chicago-based Orbitz climbed 6.4 percent, to $11.92.