Citing the sharp decline in travel after Sept. 11, ANC Rental Corp and 45 units filed for Chapter 11 bankruptcy protection Tuesday, listing assets of $6.50 billion and debts of $5.95 billion, according to papers filed in the U.S. Bankruptcy Court in Delaware.

ANC, which owns and operates car rental businesses under the Alamo and National brand names, in recent weeks has announced restructuring including the hiring of a new president, Lawrence Raemakers, who specializes in turning around ailing companies.

Chief Executive Michael Egan said in a statement that Ft. Lauderdale, Florida-based ANC's decision to file for bankruptcy protection is a "positive and proactive step," which will allow the company to continue to serve customers while it tries to stabilize by cutting costs.

"It allows us to restructure our balance sheet, improve our operations and position ourselves for future profitability," Egan said.

ANC, which has about 3,000 locations worldwide including North and South America, Asia, Africa, and the Middle East, said its filings do not include its international and Canadian operations or individual National Car Rental franchisees.

Among the 35 largest unsecured creditors are Lehman Bros. Holdings Inc., with a $203.5 million debt claim that Lehman calls secured; and General Motors Corp.with a $35.7 million debt claim, court papers say. The remainder of the unsecured debt consists primarily of trade claims.

The names and percentages of those owning at least 5 percent of ANC voting securities are ESL Investments, 16.05 percent; Wayne Huizenga, 7.22 percent; Michael Egan, 7.64 percent; Michael De Groote, 5.49 percent; and Harris Hudson, 5.2 percent.

Shares of ANC last traded on the Nasdaq stock market at 60 cents on November 12, down 83 percent from its Sept. 10 closing price of $3.52.