On January 10, 2025, a California federal judge certified an End-User class of indirect purchasers of suspension assemblies (SAs)—a critical component in hard disk drives (HDDs)—where the HDDs were sold either as standalone products or incorporated into computers and other electronic devices.

applEcon’s Dr. Janet S. Netz provided expert economic testimony as to the class-wide impact of an alleged price-fixing scheme among manufacturers of SAs, which precisely suspend a head over a spinning disk to read or write memory on an HDD. Specifically, Dr. Netz opined on whether common methods and evidence could show that the efforts of Defendants TDK and NHK—who, plaintiffs allege, shared confidential price and market share information to raise the prices of SAs—resulted in higher prices for purchasers of electronic devices containing HDDs. She also estimated the aggregate economic impact on End-Users affected by the alleged scheme.

In her class certification reports, Dr. Netz proposed and implemented methods for modeling: (1) the alleged overcharge faced by HDD manufacturers; (2) the pass-through of that overcharge to End-Users of computers and other HDD-containing products; and (3) the total economic damages stemming from the alleged conduct. Doing so involved measuring the extent to which cost changes increased prices at the bottom of a supply chain that included, among other levels, SA and HDD manufacturers, electronics manufacturers, distributors, and retailers.

The Court found that Dr. Netz’s testimony—which also withstood a Daubert challenge in December 2023—proposed a reasonable method for establishing an overcharge, pass-through, and damages across the class. Judge Maxine M. Chesney ultimately certified the End-User class alongside a separate class of resellers of HDD-containing devices.