Maurice Greenberg, the former head of insurer American International Group Inc. (AIG) has been buying shares of New York Times Co. (NYT) to try to break the Sulzberger family's hold on the media company, the New York Post reported Wednesday, citing unnamed sources.

That story, along with a report from CNBC later in the day that Greenberg was interested in launching a takeover for the company, helped push New York Times shares up more than 8 percent.

Greenberg has been buying hundreds of thousands of Times shares, the Post reported, putting him in league with other shareholders, such as Morgan Stanley Investment Management who have been questioning the Sulzbergers' holding of a more powerful class of stock.

"I can't comment about Mr. Greenberg's stock purchases," said Mark Corallo, a spokesman for the former insurance executive. Corallo said that Greenberg "is exploring several options involving media companies."

The New York Times said that the Sulzberger family has control of the company's future through its dual class share structure.

"The Ochs-Sulzberger family has no intention of changing the dual class structure," spokeswoman Catherine Mathis said.

She said that she was not aware of Greenberg buying shares, but that the company has 145 million shares outstanding.

The New York Times has both publicly traded, Class A shares, and non-publicly traded, Class B shares. The Sulzberger family owns about 20 percent of the total equity of the company and 19 percent of the company's Class A shares, she said.

The holders of Class B stock, which own less than 1 percent of the company, elect nine of the company's 13 directors.

Greenberg, 81, has sold more than $1.5 billion in AIG shares since May. He is also interested in making a bid for Tribune Co. according to reports.

Earlier this month, Morgan Stanley submitted a proposal to the company that is aimed at cutting the Sulzberger family's long-standing control of the company by changing the voting structure so that shareholders have equal voting rights.

The Sulzbergers are descendants of Adolph Ochs, who bought the newspaper more than a century ago.

New York Times shares gained $1.92, or 8.3 percent, to $24.95 on Wednesday, but are still far from their 52-week high of $28.98 on Feb. 22, on the New York Stock Exchange.

Options were also active because of the takeover rumors, according to William Lefkowitz, an options strategist at brokerage firm vFinance Investments.

"The rumor is that Greenberg is trying to take over the New York Times. Investors obviously believe that there is some truth to the story," he said, saying that volume was three times as high as normal.

He said that more than 1,673 contracts have changed hands, indicating new positions are being put on.