When we wrote our Columbus Circle Year-End Wrap Up 2 weeks ago, we said the 6,744 square foot apartment at 15 Central Park West that was being sold by former Citigroup chairman Sandy Weill for a record shattering $88 million had likely found a buyer. Today we can report that the owner of this gorgeous piece of New York real estate is Russian billionaire Dmitriy Rybolovlev, who has bought it for his daughter Ekaterina, at the full asking price. Ekaterina Rybolovleva is a legal resident of Monaco, currently studying at an undisclosed university in the United States. Her spokesman says she will use the apartment primarily as a pied-a-terre when traveling in New York. The deal has rocked the real estate world, clocking in as the largest private transaction in New York City history.