The U.S. Department of Commerce has ruled that South Korea unfairly subsidized memory-chip exports to the United States.

The preliminary ruling sets the stage for imposing countervailing duties of more than 57 percent on Hynix Semiconductor.

Hynix will be required to post a bond under which it will set aside a payment reflecting that percentage of the value of imported memory chips.

In the case of Samsung Electronics, however, the Commerce Department determined the net subsidy rate at only 16 hundredths of a percentage point ... indicating the company received virtually nothing from the South Korean government.

Rival memory chip maker Micron Technology of the United States filed a complaint ... alleging Hynix received billions of dollars in government-supported loans.

But Hynix is denying the allegation. It said the preliminary determination is unjustified since the loans came from private Hynix creditors that acted according to "market principles."

The Commerce Department is expected to make a final ruling in June.