Prosecutors questioned the chairman of Hankook Tire & Technology Co., the nation's leading tiremaker, on Friday over alleged unfair intra-affiliate trading.

The Seoul Central District Prosecutors Office brought in Cho Hyun-bum for questioning as part of an investigation into the alleged violation of a law that bans unfair business practices among the group's affiliates.

The investigation came after the antitrust regulator decided to impose a fine of over 8 billion won ($6.2 million) on Hankook Tire for allegedly purchasing overpriced tire molds from its affiliate, Hankook Precision Works Co.

The alleged unfair business practice, which lasted from 2014 to 2017, was aimed at helping the company solidify its presence in the market, according to the Fair Trade Commission.

Over the period, the operating profit-to-sales ratio of Hankook Precision Works shot up to 32.5 percent from 13.8 percent tallied for an earlier four-year period, the FTC said.

Through the gains made through the deal, Hankook Precision Works was also able to pay off its debt of 34.85 billion won incurred during its acquisition by Hankook Tire in 2011, the regulator said. (Yonhap)