AURORA, Ontario — The largest horse track owner in the U.S. filed for Chapter 11 bankruptcy protection on Thursday, saying it was unable to obtain new financing while supporting its existing debt.

Magna Entertainment Corp., whose operations include Baltimore's famous Pimlico racetrack that hosts the vaunted Preakness race, said it would continue to operate while it reorganizes under the supervision of the U.S. Bankruptcy Court in Delaware.

"Simply put, MEC has far too much debt and interest expense," Chairman and Chief Executive Frank Stronach said in a statement. "MEC has previously pursued numerous out-of-court restructuring alternatives but has been unable to complete a comprehensive restructuring to date due, in part, to the current economic recession, severe downturn in the U.S. real estate market and global credit crisis."

MI Developments Inc., a property-management company that is Magna's controlling shareholder as well as its largest secured creditor, hopes to buy some of the racetrack company's assets for $195 million. Among the items included in that deal are Magna's interest in The Village at Gulfstream Park in South Florida, Palm Meadows Training Center in Boynton Beach, Fla., Lone Star Park in Grand Prairie, Texas and XpressBet, an account wagering company.

Magna Entertainment, based in Aurora, Ontario, said it has between $500 million and $1 billion in liabilities and more than $1 billion in assets, according to court filings.

It has between 10,000 and 25,000 creditors, including MI Development, which is owed $372 million.

Magna Entertainment was spun off from auto parts company Magna International in 2000 while MI Developments was spun off by Magna International in 2003.

MI Developments said it would offer Magna a six-month $62.5 million loan so it can continue to operate while undergoing bankruptcy proceedings.