Expedia announced Thursday it will relocate its headquarters from downtown Bellevue to the 40-acre Amgen campus in Seattle, expecting to close on the $228.9 million property purchase later this year.

“It has been a tough decision to leave Bellevue, which has been a welcoming and supportive home to Expedia for many years,” said Dara Khosrowshahi, Expedia CEO, in a news release. “Owning an iconic waterfront headquarters will position us well in the competition for top talent and aligns with the work hard, play hard culture that defines Expedia. We are thrilled to make Seattle our permanent home with a new headquarters befitting the growing global technology company we are.”

The online travel company had hinted earlier this year it was looking elsewhere for more space to accommodate its growth — having recently acquired Travelocity and Orbitz.

Expedia currently occupies a majority of the 20-story, 414,964-square-foot Expedia Building in Bellevue, but expects to be expanding buildings on the Amgen campus beyond the available 750,000 square feet of office space there now. About 75 percent of Expedia’s workforce lives on the Eastside.

Seattle Mayor Ed Murray joined in Thursday’s announcement, expressing his desire for the city to work with Expedia to integrate the company and its presence into the city.

In a statement, Bellevue City Manager Brad Miyake expressed disappointment with Expedia’s decision to leave the city, but understandable given the limited office space in Bellevue. A number of office towers are now under construction, many expected to open in 2017.

“We see this as a real estate decision — pure and simple,” Miyake said. “With the Downtown Bellevue office space market as tight as it is, there just wasn’t the available space to accommodate Expedia’s expansion in the timeframe they needed.”

Amgen, a biotech company, announced recently it would be shutting down its regional operations here in 2015.