William Zeckendorf and 927 Fifth Avenue

William Lie Zeckendorf could probably teach his legion of real estate brokers a thing or two about doing a deal. According to the New York Observer, the co-owner of Terra Holdings, parent company of Halstead Property and Brown Harris Stevens, flipped the top half of a 927 Fifth Avenue duplex for as much as $5 million profit in a matter of six months.

Sources told the Observer that the five-bedroom spread sold for “well over” its $31.5 million asking price, and may have even brought in more than $34 million. Zeckendorf paid $29.1 million for the portion of Bruce Wasserstein’s old duplex in a one-day auction in December. BHS’ John Burger brokered the deal but wasn’t available for comment.

This sale came on the heels of the $40 million Zeckendorf netted last year selling the penthouse at his very own 15 Central Park West — a building that was wildly successful in its own right, grossing $2 billion — which he and his brother developed under their company Zeckendorf Realty. That sale, of course, set city records for price per square foot at $10,259. [NYO]