General Motors Corp. shares fell to their lowest level since 1954 after a Merrill Lynch & Co. analyst said the automaker may need to raise as much as $15 billion and faced the possibility of bankruptcy. The “dramatic drop-off” in the American sales market probably will continue through 2009, forcing GM to find additional funding, analyst John Murphy, who lowered the shares to “underperform” from “buy,” said in a report. “Bankruptcy is not impossible if the market continues to deteriorate.”

GM dropped $1.77, or 15%, to $9.98 in New York Stock Exchange composite trading. That was the lowest since September 2, 1954, adjusted for splits, according to Global Financial Data in Los Angeles. The shares’ daily percentage decline was the steepest since October 19, 1987.

Mr. Murphy’s assessment follows Detroit-based GM’s report Tuesday that its June auto sales in America fell 18%, as rising gasoline prices damped demand for pickups and sport-utility vehicles. Merrill’s figure on how much the largest American automaker may have to raise is more than estimates last month of as much as $8 billion by Bank of America Corp. and $10 billion by JPMorgan Chase & Co. Merrill also cut its share-price estimate by 75% to $7. The stock’s 74% drop in the past 12 months is the most among the 30 companies in the Dow Jones Industrial Average.