DETROIT - U.S. sales of cars and light trucks rose 13 percent in May when compared with April, even as two of the nation's automakers grappled with reorganizations.

Compared with May of last year, however, sales from major automakers fell nearly 34 percent, according to AutoData Corp. estimates. Company executives said buyers might have become "desensitized" to news about the bankruptcy filings of Chrysler L.L.C. and General Motors Corp. and opted to enter showrooms.

General Motors - still the largest U.S. automaker in terms of market share - said sales fell 30 percent from a year earlier, but they improved 11 percent from April as consumers pushed the automaker to its best sales month this year.

Chrysler's U.S. sales fell 47 percent in May, selling 79,010 cars and light trucks. The company said its sales were pulled lower because it did not sell any cars to fleet buyers like rental-car companies, but its retail sales to individual buyers were the best they have been all year.

Ford Motor Co. posted even better results as it continued to snatch market share from its crosstown rivals, pushing past Toyota Motor Corp. to capture the No. 2 spot in market share behind GM. Ford said its May U.S. sales fell 24 percent from last year, but rose 20 percent from April, and its share of the U.S. market rose to the highest level since 2006.

Other automakers reported month-to-month improvements yesterday.

Toyota said its U.S. sales fell 40 percent from last year, but climbed 21 percent from April. Honda Motor Co. Ltd. reported its year-over-year volumes dropped 41 percent, while Nissan Motor Co. Ltd. said sales fell 33 percent.

"The May results should be interpreted with some caution, given the current volatility in the marketplace," said Emily Kolinski Morris, senior U.S. economist for Ford, in a conference call with reporters.