SK Group Chairman Chey Tae-won attended a session by the state antitrust regulator regarding allegations that he illegally earned large profits from the group's 2017 purchase of a wafer manufacturer.

Chey, who appeared at the Fair Trade Commission(FTC) headquarters Wednesday morning, was silent when asked by reporters about the allegations and why he was making the rare appearance.

The Solidarity for Economic Reform and others had filed for an FTC investigation into allegations that SK Holdings, the group's holding firm, purchased 70-point-six percent of LG Siltron, LG Group's wafer producer, in 2017, leaving the rest for Chey.

Chey bought the remaining 29-point-four-percent stake from creditor banks, allowing SK Holdings and Chey to wholly own the company, which has since been renamed SK siltron.

Under the fair trade law, large business groups with assets exceeding five trillion won are prohibited from giving undue profits to their chiefs through lucrative business opportunities.

SK claimed at the time that it was uncertain Chey could generate big profits from the purchase and that the group did not need to buy more than 70-point-six percent of the company.

The FTC is expected to decide if there was a violation of the law, and if so, the level of punitive action.