Hedge-fund billionaire Eddie Lampert sure knows a bargain when he sees one.

In little more than a month, the 49-year-old native New Yorker has reaped nearly $175 million in paper profits by adding to his stake in Sears Holdings, the troubled operator of Sears and Kmart stores that he controls through his hedge funds and personal portfolio.

In January, Lampert, who controls more than 60 percent of Sears shares, disclosed he had picked up an additional $130 million of Sears stock. The shares weren’t bought on the open market, but from one of the clients in his hedge fund, ESL Investments.

Bloomberg News reported yesterday that the seller was the Ziff family, including brothers Dirk, Robert and Daniel, the heirs to magazine mogul William Ziff, the former publisher of PC Magazine and PCWeek. Lampert and the Ziffs declined to comment.

Lampert bought 4.46 million Sears shares at $29.20 apiece for a total of $130 million, according to a regulatory filing.

At the time, the purchase was viewed as a sign that his investors were growing weary of the struggling retailer, which was one of the Standard & Poor’s 500 index’s worst performers last year.

Since the beginning of the year, however, Sears shares have more than doubled and suddenly Lampert is looking like a serious bargain hunter.

The shares rose another 10.5 percent yesterday to close at $68.31, valuing the former Ziff stake at nearly $305 million — and earning a profit of almost $175 million for Lampert.

Yesterday’s gain followed a 19 percent jump on Thursday when Lampert announced plans to spin off 1,200 Sears stores and sell 11 to raise $770 million.

Still, Sears shares trail their 2007 peak of nearly $190, and the Ziff brothers could end up looking smarter than Lampert in the end if his turnaround plan fails.