Baruch Singer certainly doesn’t let any grass grow under his feet.

Just weeks after selling off one of his Hudson Yards properties for $15 million more than he paid, the uptown landlord has closed on two Harlem apartment buildings for almost exactly that amount.

City records show that Mr. Singer purchased a 41,000-square-foot, 88-unit apartment building at 48 West 138th Street for $10 million and a 38,000-square-foot, 51-unit apartment building at 2363 Adam Clayton Powell Boulevard for $5.7 million.

The Observer reported earlier in the week that Mr. Singer on May 18 sold 450 11th Avenue for $45 million. He purchased the 9,875-square-foot lot in July 2006 for $29.1 million.

Mr. Singer did not immediately return calls for comment about the Harlem purchase.