Local representatives have been meeting with senior MLS executives at league offices in New York.
The investor group is working with Pennsylvania officials to identify the accounts and precise dollar amounts from which a promised $47 million in state funding would be drawn.
People familiar with the work accomplished during the last two weeks - since Gov. Rendell announced the award of state funding - believe the Philadelphia bid has assumed an aura of inevitability, capable of being derailed only by an impossible-to-foresee cataclysm.
"It's definitely Philly," said a Major League Soccer source, declining to be quoted by name in advance of an official announcement. "It's the market size, the ownership group. These are wealthy people. They're going to be strong owners."
The league source said that St. Louis, which has contended with Philadelphia to become the 16th MLS team, would be the presumed front-runner for any future expansion.
MLS spokesman Dan Courtemanche said yesterday the league was "continuing discussions with the potential ownership group to bring a Major League Soccer expansion team to Philadelphia." He had no further comment.
The team would play at a $115 million stadium to be built near the Commodore Barry Bridge in one of Pennsylvania's poorest cities. The arena would anchor a $500 million complex of stores, restaurants and housing.
The local group, which includes iStar Financial chief executive officer Robert Sugarman and Swarthmore Group chairman James Nevels, has spent months working to land a team, even as several other cities pressed their bids.
In mid-January, MLS officials confirmed that it had become a two-city race. St. Louis had a stadium deal but lacked sufficient financing. Philadelphia had strong ownership but no stadium deal - until Rendell's Jan. 31 announcement.