Slim currently owns about 8 percent of common shares, which would increase to about 17 percent if he exercises the warrants, according to a Reuters calculation using the New York Times’s latest SEC filing.

"The option is a lower price, I'm sure we should exercise the option, but we look at it like a financial investment that has been very good," Slim said in an interview at his offices in Mexico City late on Thursday.

Slim's warrants were part of a deal he made with the Times in 2009 when he loaned it $250 million during the height of the financial crisis. Then, many big city newspapers reported plunges in advertising revenue.

Slim, whose main source of wealth, America Movil, Latin America's biggest telecoms company, announced this week it will sell assets to cut its market share in Mexico to avoid tougher regulations, received the option to buy 15.9 million Class A shares at $6.36 each.

Shares in the Times fell 3.2 percent to $14.32 as of 17:00 GMT on Friday.

The warrants expire in January 2015 and the Times repaid the loan almost three years ago. The New York Times Co, which publishes the namesake newspaper, is controlled by the Ochs-Sulzberger family through Class B shares.

The New York Times declined to comment.

(This version of the story was refiled to fix the garble in stock price in the sixth paragraph.)

(Reporting Stephen Adler, Dave Graham and Christine Murray, editing by John Pickering)

Stocks treated in this article : The New York Times Company, America Movil SAB de CV