Ford Motor Co
Ford was also tops for brand loyalty in the Polk analysis of purchases by 5.2 million households, Polk said.
Loyalty rates are a measure of how many households buying a new vehicle purchase or lease the same kind. Measures include manufacturer, brands and models.
Ford-built vehicles, including its Ford and Lincoln brands, showed a loyalty rate of 63.1 percent in 2010, followed by GM at 59.9 percent and Toyota Motor Corp <7203.T> at 58.8 percent, Polk found.
The Ford brand itself showed a loyalty rate of 60.3 percent, over second-place Mercedes-Benz of Daimler
Each of those fop five brands showed gains of at least 1 percentage point but Toyota, which gained 0.4 percentage point, Polk said. In 2010, Toyota's vehicles had massive recalls and its safety was questioned in U.S. congressional hearings.
Ford improvement was the greatest for customer loyalty among the top manufacturers and brands listed, Polk said. Its manufacturer loyalty rate rose 3.9 percentage points and its Ford brand loyalty rate rose 4.5 percentage points.
In 2010, Ford's U.S. sales for its brands rose 19.5 percent, and it overtook Toyota to be No. 2 in sales in the United States. Toyota sales fell 0.4 percent in 2010 in the U.S. market.
GM held on to the top spot for U.S. auto sales in 2010, and showed a rise of 7.2 percent from the previous year.
Honda was fourth in U.S. auto sales last year, when its sale rose 6.9 percent.
Overall, the U.S. auto industry showed an 11 percent gain in sales to 11.6 million, according to Autodata.
(Reporting by Bernie Woodall; Editing by Steve Orlofsky)