A 408,000-square-foot, four-story office complex at 3 Huntington Quadrangle in Melville has been sold for $35.77 million to a joint venture between Garden City-based real estate developer Treeline, and Ridgefield Park, New Jersey-based real estate owner and operator the KABR Group, according to a news release.

The building, which counts AmTrust Bank, Travelers Insurance Company and Northwell Health as major tenants and was 95 percent occupied at the time of the purchase, was sold by Texas-based real estate investment firm Hines REIT, which acquired it in 2007.

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“We are delighted to partner with the KABR Group in the acquisition of this prime asset, as both companies expand their respective footprints on Long Island,” said Michael Schor, chief investment officer of Treeline, in a statement.

The new owners plan to renovate the building’s six elevators, lobby, security desk, cafeteria seating areas and conference facilities.

“We expect to start improvements immediately and expect the plan to extend over the next 12 months,” Schor said in an interview.

“Other improvements are planned … including a new signage program for the building, which may include a new electronic directory system,” he said. “We are also planning to complete the bathroom renovation program that was started by prior ownership of the building.”