• Billionaire hedge fund manager Dan Och has sold his penthouse condo 15 Central Park West. Sort of. The apartment, which had been owned by a trust in his wife's name until now, was sold yesterday to DAAJJ, LLC, a company that happens to be controlled by Och. A bit of year-end tax planning? A separation of assets? The jury's out on this one. [Cityfile]
• The former co-op of Edythe Acquavella—the late wife of Upper East Side gallery founder Nicholas Acquavella and mother of Bill Acquavella—has sold. The three-bedroom apartment at 31 East 79th Street, which first went on the market for $3.75 million last year, sold for $2.9 million. [Cityfile]

• Now that he's gone into contract to sell his condo at One Beacon Court, Martin Begun and his wife, real estate guru Louise Sunshine, are moving into a new apartment at 400 East 67th Street. The couple is reportedly in contract to buy a 2,000-square-foot apartment in the building for $3.2 million. [NYP]
• The 21-acre Old Westbury estate once owned by A.C. and Eleanor Bostwick has gone on the market for $17.75 million. For buyers looking to spend a little less, a seven-acre piece of the property (and the estate's 12,000-square-foot Colonial-style mansion) is available for $4.795 million. [Newsday, PDE]