Billionaire financier and philanthropist George Soros has joined Washington entrepreneur Jonathan Ledecky's bid to purchase the Washington Nationals, Ledecky said in an interview yesterday.

"The Soros family shares my belief that the Washington Nationals are a community trust that can serve as a positive platform for the economic development of the inner city," Ledecky said.

Soros spokesman Michael Vachon declined to comment.

The Soros announcement is the latest in a flurry of activity in recent days as at least seven groups have filed initial bids for the Nationals with Major League Baseball, according to baseball sources. Several groups have added major partners in recent days: former secretary of state Colin L. Powell joined the Fred Malek-Jeffrey Zients group; Sallie Mae Chairman Albert L. Lord took over the William Collins-led group on Tuesday, and former Illinois senator Peter Fitzgerald became part of the Lord group.

Soros, 74, is worth $7.2 billion and is the 24th richest person in America, according to Forbes magazine. Soros's involvement is a major plus for Ledecky. Soros joins New York commercial real estate developer Marc S. Cohn and ABRY Partners, a private equity firm in Boston, as investors in Ledecky's group.

MLB, which owns the Nationals, is hoping the team will fetch up to $400 million, which would be one of the highest prices ever paid for a baseball team. The Nationals, formerly known as the Montreal Expos, are scheduled to move into a publicly built, $535 million stadium project along the Anacostia River waterfront in April 2008.

Nine groups originally deposited $100,000 each for the right to bid on the Nationals, and baseball sources who declined to identify themselves said seven of those groups had filed bids for the team as of yesterday. An eighth bid was expected soon, but one group had not bid as of yesterday.

One baseball source said David and Jed Walentas, father and son developers, had not filed a bid. However, Jed Walentas said yesterday that he and his father had bid on the team.

Stan Kasten, former president of the Atlanta Braves, was in the process of filing his bid, baseball sources said. The other would-be owners, nearly all of whom have confirmed on the record that they filed bids with baseball, are: Ledecky; the Lord group; the Lerner family, which runs a Washington area real estate empire; the Malek-Zients group; Chicago businessman Yusef Jackson and grocery store billionaire Donald Burkle; businessman Jeffrey Smulyan of Indianapolis, and the family of District-based financier and developer Franklin Haney Sr.

The sale process from this point is not certain. Baseball is expected to pare the group to about five bidders within the next few weeks, at which point the league may start interviewing individual groups. The league wants to have an owner by this summer.

Soros was one of the chief investors in MLS when the soccer league was launched in 1996. His company was involved with running D.C. United.

A native of Hungary, Soros has financed efforts to promote open societies in more than 50 countries around the world. Soros's investment vehicle has been the Quantum Fund, which has been renamed the Quantum Endowment Fund. A $100,000 investment in the Quantum Fund in 1969 was worth $150 million 25 years later.