SAN DIEGO — Qualcomm said late Tuesday that it would fight a ruling by South Korea’s top trade regulator that fined the San Diego wireless company $865 million for violating competition laws with its patent licensing practices.

The fine comes after an investigation by the Korea Fair Trade Commission, which appears to want Qualcomm to change “unfair” business practices in the way it licenses its 3G/4G intellectual property.

“This case is meaningful in that the Korea Fair Trade Commission is the first to rectify Qualcomm’s unfair business model under which Qualcomm has refused to license competing chipset companies while coercing unilateral license terms on handset companies in order to strengthen its monopolistic power in the patent license market and the chipset market,” said the KFTC in a statement.

The ruling is a blow to Qualcomm, which called the action unprecedented. The company says that regulators are upending patent royalty practices that have been in place for more than two decades worldwide and benefited South Korean companies including Samsung and LG.

“Qualcomm strongly believes that the Korea Fair Trade Commission findings are inconsistent with the facts, disregard the economic realities of the marketplace and misapply fundamental tenets of competition law,” said Don Rosenberg, the company’s general counsel, in a statement.

The company said its patent royalties collected on smartphones sold in South Korea amounted to less than $230 million for its 2016 fiscal year ending in September – highlighting that the fine is unreasonable for the size of the Korean market.

“For decades, Qualcomm has worked hand-in-hand with Korean companies to foster the growth of the wireless internet,” said Rosenberg. “Qualcomm’s technology and its business model have helped those companies grow into global leaders in the wireless industry. This decision ignores that win-win relationship.”

Qualcomm has been a long time supplier of smartphone chips to both LG Electronics and Samsung, the world’s largest seller of Android smartphones. Samsung also manufactures Qualcomm’s Snapdragon chips at its semiconductor factories.

Qualcomm makes money not only designing mobile semiconductors but also by licensing its vast portfolio of wireless patents on key cellular technology. It charges patent royalties based on the wholesale price of the smartphone.