DETROIT — Foreign brands are on pace to outsell the traditional domestic brands this year for the first time in the U.S. retail auto market.

Through May, 52.9 percent of the new vehicles registered by retail customers were import brands and 47.1 percent were traditional domestic brands made by General Motors Corp., Ford Motor Co. and the Chrysler Group, according to the Automotive News.

The Automotive News analysis was based on new vehicle registration data from Southfield, Mich.-based R.L. Polk & Co. It included as imports the Ford-owned Volvo, Land Rover, Jaguar and Aston Martin brands and GM-owned Saab brand.

The Polk registration information is a key indicator because it focuses on retail sales to American consumers and excludes fleet sales: big-order sales to corporations, government agencies and rental-car companies.

Counting all sales, the traditional U.S. automakers account for 55 percent of the market, according to Autodata Corp., a Short Hills, N.J., research firm.

Toyota Motor Corp. and Honda Motor Co. initially won customers in the U.S. with their cars, but they've also made inroads into SUVs and other segments, said Erich Merkle, director of forecasting for Grand Rapids, Mich.-based IRN Inc.

The U.S. brands have better products coming, but Toyota and Honda should continue to make gains, he said.