Seoul: Hyundai Motor Co and affiliate Kia Motors Corp plan to triple their number of fuel-efficient cars by 2020, addressing concerns about the pair’s green track record and competitiveness in fuel economy.

Investors have voiced concern about Hyundai’s latest Genesis and Kia’s Soul having lower fuel mileage than their predecessors, and about a $350 million fine in the United States for overstating vehicles’ fuel economy. The announcement on Wednesday came a week after the pair pledged to raise the fuel economy of their vehicles by 25 per cent by 2020 to meet emissions regulations in the United States and Europe and at home in South Korea.