In a lawsuit, US chipmaker Nvidia claims that EU antitrust authorities violated a previous court decision that limited its merger authority on small transactions by granting an Italian request last year to examine its purchase of AI company Run:ai.

A decision in favor of Nvidia might further limit the regulator's merger authority, even if the case has no bearing on the Run:ai deal, which was ultimately approved by the EU competition watchdog in December of last year.

In recent years, businesses have been worried about the European Commission using its seldom used Article 22 power to evaluate modest acquisitions, even if they fall below the EU's merger revenue threshold.

Companies condemn such actions as regulatory overreach, but the EU executive says it is worried about killer acquisitions, where large corporations purchase startups to shut them down.

However, in a historic decision last September, the European Court of Justice ruled that the Commission cannot support or accept national enforcers' referrals of arrangements without a European component when those enforcers lack the authority to review such deals under their own national laws.

According to a posting on the court's website, Nvidia referenced the decision in its case before the General Court in Luxembourg, which is the second-highest court in Europe.

"The decision unlawfully accepted a referral request from the Italian Autorita Garante della Concorrenza (AGCM), regarding a transaction that fell below the EU Merger Regulation and member state merger control thresholds, based on the AGCM's exercise of loosely defined, ex post, discretionary call-in powers," Nvidia said.

It claimed that the decision by authorities to consider the Italian request violates the equal treatment, proportionality, legal certainty, and institutional balance criteria.