A US federal judge has refused to dismiss a proposed class action alleging that Samsung, SK Hynix and Micron coordinated restrictions on conventional DRAM supply while shifting manufacturing capacity toward high-bandwidth memory for artificial-intelligence hardware. The ruling allows the case to proceed, but it does not establish that the companies violated antitrust law.
US District Judge Noël Wise of the Northern District of California denied the chipmakers' joint motion in full. At this stage, a court asks whether a complaint contains a plausible claim while treating its well-pleaded allegations as true. The consumers and small businesses bringing the case must still prove those allegations with evidence.
The lawsuit, filed in June by 17 plaintiffs from five states, concerns standardized DRAM used in computers, phones and servers. It alleges that the three manufacturers cut production beginning in late 2022, redirected capacity toward HBM beginning in 2023 and later wound down older DDR4 products. The complaint says the companies collectively represented more than 91% of worldwide DRAM revenue in the third quarter of 2025.
Because the plaintiffs do not allege direct evidence of an agreement, their case relies on parallel conduct and additional circumstances known in antitrust litigation as “plus factors.” Wise found the pleaded combination sufficient to move beyond the dismissal stage. That combination included the timing of supply reductions, long-term HBM commitments, alleged reluctance to sign long-term conventional-memory agreements and decisions affecting manufacturing capacity that would be difficult to reverse.
The defendants argued that the complaint resembled an earlier case, known as DRAM II, in which the Ninth Circuit upheld dismissal of claims concerning alleged restrictions from 2016 to 2018. Wise concluded that the new complaint contained materially different allegations. She also found that a gap of several months between Samsung's announced reduction and earlier moves by SK Hynix and Micron did not defeat the claimed pattern at the pleading stage.
The court gave no weight to several other points, including general statements to investors, unspecified meetings at industry conferences and the concentrated structure of the DRAM market. Its analysis instead focused on the specific conduct the plaintiffs said would be difficult to explain as independent business decisions.
The companies are due to answer the complaint by December 7, according to the ruling. An initial case-management conference was reset for January 12, 2027. The next phases could test the plaintiffs' theory through company records, testimony and economic evidence; the denial of dismissal should not be read as a finding that coordination occurred.
