Hyundai and affiliate Kia slid in the U.S. Consumer Reports annual reliability ratings for 2013 released Monday. Hyundai dropped four notches from last year to 21st in the overall reliability ratings, while Kia fell six notches to 16th place.
Both automakers failed to make even the average rating of the 28 brands surveyed.
Consumer Reports said even until 2011, Hyundai and Kia not only surpassed most U.S. and European brands, but threatened even Japanese automakers, but then began to slide.
The annual ratings are based on 1.1 million responses to a survey by the Consumer Reports National Research Center.
Hyundai fell from 11th place in overall reliability rating in 2011 to 17th in 2012. Kia ranked among the top 10 brands in 2011 and 2012.
Japanese brands took seven of the top 10 spots in this year's survey. Lexus was voted the most reliable brand, followed by Toyota and Acura.