Travel booking site Expedia says it's buying short-term rental marketplace HomeAway for $3.9 billion to boost its presence in the vacation rental market.

The Bellevue, Washington-based company announced the acquisition Wednesday, which includes all digital properties owned by the home-rental site including VacationRentals.com, VRBO, and Stayz.

Both companies' boards have approved the deal, which they expect to close next year.

"We're eager to benefit from Expedia's distribution, technology and expertise, which will allow us to provide an even better product and service experience for our owners, property managers and travelers,” said HomeAway CEO Brian Sharples. “In this way, I believe our combination with Expedia will turbocharge our growth and industry leadership for many years to come."

HomeAway Inc. says it has more than 1 million paid listings of vacation rental homes in 190 countries. By comparison, rival Airbnb says it has more 2 million listings in 34,000 cities. 

Along with its namesake site, Expedia's portfolio also includes Hotels.com, Orbitz and Travelocity.

The Associated Press contributed to this report.