Hyundai Motor Group’s share of the United States’ market for midsized sedans for the first quarter of the year rose to a record high, industry data showed Sunday.

According to industry data, 66,554 units of Hyundai Motor Co.’s Sonata and Kia Motors Corp.’s K5, known as the Optima in overseas markets, were sold in the U.S. during the first three months of the year, giving the companies’ a combined midsized sedan market share of 15.1 percent.

In terms of units sold, Hyundai Motor Group’s first quarter midsized sedan sales increased 62.3 percent compared to the 41,013 units ― the Sonata and the previous Optima which was sold as the Lotze in Korea ― sold during the same period last year.

The figure puts Hyundai Motor Group in the third place behind Toyota Motor Corp. and Nissan Motor Co. in terms of midsized sedan market share.

In the first quarter of the year, Toyota took 17.2 percent of the market while Nissan vehicles accounted for 15.6 percent of midsized sedans sold in the U.S. during the period.

Honda Motor Co., which had held the third largest share of the midsized market slipped to the fourth place with 14.8 percent.

While Hyundai Motor Group has made significant progress in the United States’ midsized market since the launch of the sixth generation Sonata last year, the South Korean auto giant had trailed behind the three Japanese rivals.

Last year, Hyundai and Kia’s combined share of the midsized market came in at 13.1 percent, rising above the 10 percent mark for the first time. Despite the rise, however, Hyundai Motor Group’s figure fell short of those held by Toyota, Nissan and Honda.

Of Hyundai Motor Group’s overall midsized sales, the Hyundai Sonata accounted for about 78 percent with 51,878 units, up 63.4 percent from a year ago.

While the Kia K5 contributed significantly less to the total, its introduction to the U.S. has boosted Kia’s presence in the midsized market by more than 50 percent.

The K5’s predecessor Lotze sales for last year’s first quarter came in at under 9,300 units. In comparison, first quarter K5 sales came in at 14,676 units, accounting for 14 percent of Kia’s total sales in the U.S. for the period.

In comparison, the Lotze accounted for 7.1 percent of Kia’s total U.S. figure for last year.

By Choi He-suk (cheesuk@heraldcorp.com)