CHICAGO – Nine potential buyers who have been preapproved by Major League Baseball have received the financial books on the Chicago Cubs, two people familiar with the process told The Associated Press on Wednesday.

The books went out Tuesday, with bids due back next month, according to the people who asked not to be identified because the owner, Tribune Co., is trying to keep details of the process confidential.

Two sets of books went out. One contains information on the Cubs, Wrigley Field and the regional cable TV network Comcast SportsNet Chicago. The other only concerns Wrigley, which Tribune still hopes to sell separately.

No dollar estimates were given for any assets.

Interested buyers are believed to include a group headed by John Canning, chairman of private equity firm Madison Dearborn Partners LLC; Internet billionaire and Dallas Mavericks owner Mark Cuban and the family of TD Ameritrade Holding Corp.’s founder Joe Ricketts.

Sports economists say the expressed interest of several billionaires, among other well-heeled investors, make it a good bet it will exceed the record $660 million paid for the Boston Red Sox in 2002 by a group headed by billionaire commodities trader John Henry.

The Cubs’ package includes not only Wrigley but Tribune’s 25 percent stake in the Comcast sports channel in Chicago, fueling widespread speculation the total could reach $1 billion.