NEW YORK (CNN/Money) - A Wall Street buyout firm and a sports advisory company have offered to buy not just a single team, but all 30 teams in the National Hockey League, according to a published report.

Bain Capital Partners LLC and Game Plan International, both based in Boston, made an unprecedented offer on Tuesday to buy the league for $3.5 billion, according to the Toronto Star.

The NHL made another unprecedented move this year, when it became the first major North American pro sports league to cancel an entire season as the result of an ongoing player lockout. Bain managing partner Steven Pagliuca, co-owner of the NBA's Boston Celtics, and Game Plan, which recently acted as an adviser on the sale of hockey's Ottawa Senators, are betting that many NHL owners would welcome the chance to get out of the hockey business.

The NHL said its teams lost a collective $500 million over the past two seasons.

It's unknown whether many of the league's owners, especially those with teams in large markets like Toronto, Boston and New York, would accept the offer.

Maple Leaf officials declined to comment, as did a Game Plan spokesman. Representatives for Bain and the NHL couldn't be reached.

A person familiar with the matter said no subsequent discussions between the league and the two companies were scheduled.

"I'm not sure how serious you can take the offer because it's an all-or-nothing deal. You need all 30 owners on board to make it work," said one owner who attended the meeting.

If the owners ultimately accepted an offer of $3.5 billion that would put the average franchise value at about $117 million, although large-market teams like the Maple Leafs would be worth far more.

Forbes magazine estimated the average NHL franchise value was $163 million in 2003-04, although several recent team sales have fallen far short of that figure.

Last week, Walt Disney Co. sold the Anaheim Mighty Ducks for $75 million, including a $15 million training facility.

"Hockey can be a real tough business with the slimmest of profit margins, obviously," said Jeff Phillips, a sports banker at investment firm Houlihan, Lokey, Howard & Zukin.

Bain, which has $48 billion in assets under management, partnered in 1999 with the Ontario Teachers' Pension Plan in an investor group that bought Shoppers Drug Mart., Canada's largest drugstore chain. The teachers are majority owners of the Maple Leafs.