The Seoul Central District Prosecutors' Office / Yonhap

Prosecutors raided the offices of seven major steelmakers Wednesday as part of their ongoing investigation into fixing bidding prices years ago.

The Seoul Central District Prosecutors' Office probing the case obtained relevant documents from the headquarters of the seven firms ― Hyundai Steel, Dongkuk Steel Mill, Daehan Still, KISCO, YK Steel, Hwan Young Steel and Hankook Still Mill.

The firms allegedly colluded to fix their quotations between 2012 and 2018 to bid on contracts put forward by the state procurement agency, helping them post a combined revenue of 5.5 trillion won ($3.8 billion) during the cited period.

The investigation came after the country's antitrust regulator, the Fair Trade Commission (FTC), imposed a combined fine of 256.5 billion won on the firms for fixing bidding prices.

The FTC also asked the prosecution to investigate seven steelmakers and nine of their former and existing officials over the alleged collusion. (Yonhap)