The Federal Aviation Administration's regional headquarters building in Renton has been sold.

Federal Partners, a Boston-based investment fund that focuses on office buildings leased by the federal government, paid $35.25. million for the five-story building, according to public records.

The sellers, JPMorgan and Seattle-based Unico Properties, paid slightly more — $36 million — when they bought the 200,000-square-foot building in 2007.

Unico will continue to manage the property, a spokesman said.

The building, at Lind Avenue Southwest and Southwest 16th Street, has housed the FAA's regional offices since it opened in 1990. Two years ago, however, it appeared the federal agency would move.

The General Services Administration (GSA), the federal government's real-estate arm, said the FAA needed more room — more than 500,000 square feet — and solicited proposals from developers, saying it wanted to sign a new lease by early 2011 and move by 2014.

That touched off a feeding frenzy among South King County developers. But the FAA later scaled back its space requirements, and the search for a new regional headquarters slowed.

In August 2010 the federal government signed a new, five-year lease for the Renton building, with options for up to two more years, GSA spokeswoman Stephanie Kenitzer said.

Her agency still is working with the FAA to pin down its space needs, she said, and hopes to have a plan for meeting them "in the near future."

The FAA employs more than 1,400 in Renton, said Alex Pietsch, the city's economic development director, "and we want to keep them."

Eric Pryne: 206-464-2231 or epryne@seattletimes.com