Howard Marks, head of Oaktree Capital Group, just paid a record $52 million for a posh duplex on Park Ave. in New York. The previous record was $48.8 million back in 2008.

The eight-bedroom, 10,00- square-foot property was formerly owned by Courtney Ross, who is the widow of former Time Warner CEO Steven Ross. It had at one point been peddled privately at $75 million and the two units in the duplex had been listed at $25 and $35 million separately.

The property includes six outdoor terraces, two dining rooms, two kitchens and room for a live-in staff. It also has a pair of libraries and a gym.

The building at 740 Park Ave. has a long lineage of influential residents since its construction in 1930. It’s been home to John D. Rockefeller and Jacqueline Kennedy Onassis. Units in the building range from 9 to 34 rooms.

Marks primarily lives in Los Angeles, where Oaktree is based, and will presumably split time between coasts. He adds the New York property to a portfolio that includes two California homes and a flat in London.

His company, Oaktree Capital Group LLC, just reported a first quarter profit this year after losing ground in 2011.

Sources: Bloomberg, The Real Estalker