US-based TrueCar.com said Hyundai and Kia ranked No. 1 in its 2011 Annual Performance Scoreboard that checks such areas as sales growth, market share and customer brand loyalty.
It said the two carmakers, which are the flagship companies of Hyundai Motor Group, the world's fifth largest Automotive conglomerate, received an average "A-plus" rating in the eight categories. Meanwhile, Volkswagen AG and Volvo Cars both received an "A" rating to come in at second place.
The Web site said Cars made by Hyundai and Kia managed to sell more than 1.13 million units last year, up 26.5 percent from 2010, by pulling off solid growth while limiting unnecessary incentives. The total marks the first time that the South Korean Automotive group outpaced Japan's Nissan Motor Co. in the US market.