The alternative asset manager Owl Rock Capital Partners has leased the entire 38th floor at 399 Park Ave. The 25,089 square feet had an asking rent of $125 per square foot.

Mark Weiss of Cushman & Wakefield represented Owl Rock, which is moving from a spot half that size on a portion of the 41st floor at 245 Park Ave.

Boston Properties, the owner of 399 Park, was represented by the CBRE team of Peter Turchin, Gregg Rothkin, Caroline Merck, Arkady Smolyansky and Evan Fiddle.

The building is undergoing a $120 million renovation that is 95 percent complete. It includes a new façade, lobby entrances and a new marquee that will be unveiled any day — plus several terraces with brand-new elevators.

“It gives the building a completely different perception,” Turchin said. “The market is appreciating repositioned product, and this is a building that has been completely repositioned.”

The 39th floor, which has higher ceilings and larger windows, is still available with an asking rent of $135 per square foot.