After the New York City penthouse at 15 Central Park West sold for a reported $88 million, shattering the city's record for a single residential sale, anything else seems modest.

But Unit #28D has sold for $21 million, according to city records, which still represents the very top of the Manhattan real estate market.

The sellers were Kock-Yen Tsang, a cardiologist, and June Yuen-Ron Tsang of New Jersey. They bought the condo for around $9 million in 2008.

The buyer was Christopher Property Investments Ltd, based in the British Virgin Islands -- more evidence that foreign buyers or investors continue to flock to the city.

Debra Powell, an attorney for the buyer, didn't immediately return a call seeking comment.

Carrie Chang and Janet Wong of the Corcoran Group were the listing brokers for the unit, which had an asking price of $25 million.

According to the listing, the 3,173 square foot apartment has three bedrooms and four bathrooms, along with a corner living room, library and dining room.

Below, a floorplan of the apartment from the Corcoran Group: