Hyundai and affiliate Kia saw their combined share of the U.S. market dwindle to 7.7 percent in October, the lowest in nine month.
Hyundai sold 53,555 new cars in the U.S. in October, up 6.5 percent from the previous year, but Kia saw a 6.4 percent drop to 39,754 units, causing the two automakers' combined sales volume to rise a mere 0.6 percent.
By contrast, automakers on the whole posted an average 10.4 percent growth on-year in the U.S. last month. The big three U.S. automakers in particular showed stellar performances -- market leader General Motors' sales increased 15.7 percent, Ford's 13.9 percent, and Chrysler's 11 percent.
Hyundai and Kia's combined market share dropped in October as against 8.5 percent in the same month last year. It peaked at 10.1 percent in May 2011, when a massive earthquake in Japan hit their Japanese rivals.
Kia attributed sluggish sales to production disruption due to strikes at home in August and September, which it claimed led to delayed supply of popular models like the Sportage R and the Soul.
But given that the Optima and the Sorento R, which are produced in the U.S., are not as popular as they used to be, Kia may generally losing its appeal there, market watchers say.