The nation’s state-run antitrust watchdog said Sunday it has imposed a combined fine of almost 300 billion won ($281 million) on seven steelmakers for fixing prices of their steel products.

Companies subject to the fine worth 291.8 billion won include POSCO, POSCO C&C, Union Steel, Dongbu Steel, Hyundai Hysco, Seah Steel and Seil Steel, according to the Fair Trade Commission.

Seven companies are said to have been involved in separate price-collusion cases between 2004 and 2010 through shady meetings of their sales executives.

The FTC has investigated their price-fixing since 2009 after they were suspected to have increased prices of their steel products at the same rate and simultaneously.

Companies were also found to have colluded to impose surcharges on clients to make up discrepancies between soaring zinc and falling iron ore prices.

The FTC said it plans to ask the prosecution to investigate the six companies aside from Seil Steel.

POSCO and its affiliate POSCO C&C, however, denied the allegation that they have led the price-fixing of zinc-coated steel plates using its market leader position.

“We have no reason to fix prices in the iron steel market, 60 percent of which we dominate. We will prove our innocence through an administrative lawsuit against the FTC,” said a POSCO spokesperson.

By Lee Ji-yoon (jylee@heraldcorp.com)