Hyundai and Kia capped another banner year in which the brands set U.S. sales records.
The brands released some new and redesigned products in high-volume segments when competitors Honda and Toyota were weakened by earthquake-related supply disruptions.
Hyundai sales totaled 645,691 units in 2011, up 20 percent from the record set in 2010. Hyundai's share of the market climbed a half-point, to 5.1 percent. The brand sold 50,765 vehicles in December for a 13 percent gain from December 2010.
Kia sales totaled 485,492 units in 2011, a 36 percent gain from 2010 and December sales totaled 43,390 vehicles, up 43 percent from December 2010. Kia accounted for 3.8 percent of U.S. sales last year, up from 3.1 percent at the end of 2010.
Sales of the redesigned Kia Optima mid-sized sedan more than tripled from 2010 to 84,590 units in 2011. Sales of the redesigned Hyundai Elantra compact totaled 186,361 units in 2011, up 41 percent from 2010.
High demand created inventory shortages for Hyundai and Kia dealers throughout the year.
With Hyundai and Kia factories in the United States and overseas running at or near capacity, supply woes are expected to continue and slow each brand's growth in 2012.