Jessica Guynn

USA TODAY

SAN FRANCISCO — Apple is suing supplier Qualcomm for $1 billion, accusing the company of overcharging for its wireless chips and engaging in monopolistic tactics.

The lawsuit filed Friday in San Diego federal court follows a complaint earlier this week by the Federal Trade Commission that Qualcomm used its dominant position to force "onerous and anticompetitive" terms on mobile phone makers such as Apple and Samsung, which together accounted for 40% of Qualcomm's $32.5 billion in revenue in the most recent fiscal year.

Qualcomm said it would "vigorously contest" the FTC complaint. On Friday, Qualcomm's general counsel Don Rosenberg said Apple's claims were "baseless."

"Apple has intentionally mischaracterized our agreements and negotiations, as well as the enormity and value of the technology we have invented, contributed and shared with all mobile device makers through our licensing program," he said in an emailed statement. "We welcome the opportunity to have these meritless claims heard in court where we will be entitled to full discovery of Apple’s practices and a robust examination of the merits."

In its lawsuit, Apple claims Qualcomm overcharged for its chips and then refused to pay $1 billion in rebates in retaliation for Apple cooperating with South Korean antitrust regulators probing Qualcomm. Those regulators fined Qualcomm more than $800 million for what they alleged were unfair practices in patent licensing. Qualcomm is appealing the decision.

Apple also challenged the validity of some Qualcomm patents for wireless technologies. If the patents are upheld, Apple asked the court to reduce the royalty amounts.

"Qualcomm built its business on older, legacy, standards but reinforces its dominance through exclusionary tactics and excessive royalties," Apple said in a statement.

According to the Apple complaint, it is forced to pay Qualcomm a percentage of the average selling price of an iPhone to use Qualcomm patents and to exclusively use Qualcomm chips in iPhones. Under the agreement, Apple received quarterly rebates from Qualcomm but Apple says Qualcomm began withholding those last year after Apple met with Korean regulators.

Qualcomm's Rosenberg said Apple "has been actively encouraging regulatory attacks on Qualcomm’s business in various jurisdictions around the world."

Qualcomm shares (QCOM) ended 2.4% lower Friday, adding to losses that followed the FTC complaint. Apple shares (AAPL) ended 0.2% higher.