The Predominance Trap: Why the Energizer-Walmart Certification Denial is a Lethal Blow to Macro-Antitrust Class Actions

The Era of "Macro-Economic Hand-Waving" at the Certification Stage is Over

For the better part of a decade, the plaintiffs’ antitrust bar has relied on a predictable, lucrative playbook: allege a sprawling, headline-grabbing price-fixing conspiracy between market titans, hire an economist to build a macro-level pricing model showing an "inflated baseline," and sail through class certification. The operating assumption was that the sheer gravity of a conspiracy allegation would satisfy the commonality and predominance requirements of Rule 23. On September 29, 2026, a federal judge in San Jose effectively tore up that playbook.

In a closely watched multidistrict litigation, the district court definitively refused to certify both consumer and wholesale-purchaser class actions against Energizer and Walmart. The plaintiffs alleged that the battery manufacturer and the retail behemoth engaged in a coordinated scheme to keep the prices of disposable batteries artificially high. But the court slammed the brakes, ruling that the plaintiffs failed to demonstrate that key legal and factual issues were common across the proposed classes.

This is not just a procedural hiccup for the plaintiffs; it is a structural disaster for wholesale and consumer antitrust litigation. The ruling signals that federal district courts are no longer willing to accept generalized theories of "common impact" when the reality of retail and wholesale supply chains involves highly individualized pricing, varying discounts, and disparate purchasing environments.

The Ghost of Comcast Looms Large

To understand why the Energizer-Walmart denial is a watershed moment, practitioners must look to the rigorous demands of Federal Rule of Civil Procedure 23(b)(3). Under Rule 23(b)(3), plaintiffs must prove that questions of law or fact common to class members predominate over individualized inquiries. In antitrust cases, the battleground is almost always "antitrust impact"—whether the plaintiffs can prove, through common evidence, that all (or nearly all) class members actually suffered an overcharge.

The San Jose ruling is a direct descendant of Comcast Corp. v. Behrend, 569 U.S. 27 (2013), and Wal-Mart Stores, Inc. v. Dukes, 564 U.S. 338 (2011). In Comcast, the Supreme Court mandated that a plaintiff's damages model must perfectly match their theory of liability. What we are seeing in the Energizer-Walmart decision is the aggressive application of that principle to the reality of modern commerce.

"The plaintiffs had not shown that key legal and factual issues were common across the proposed classes."

Consider the proposed classes: consumers buying a four-pack of AA batteries at a corner pharmacy, and wholesalers buying pallets of batteries subject to complex, negotiated rebates and volume discounts. The plaintiffs' burden was to show that a single conspiracy artificially inflated the price for both groups in a uniform way. The district court rightly recognized that this is an economic fiction. When a wholesaler negotiates a massive, custom discount, the "artificially high baseline price" theory collapses into a morass of individualized mini-trials to determine who actually paid an overcharge and who negotiated their way out of it.

A Coordinated Appellate Crackdown on Expert Testimony

The Energizer-Walmart decision does not exist in a vacuum. It is part of a broader judicial reckoning regarding the intersection of Rule 23 and expert economic testimony. Look no further than the August 24, 2026, development in the elite university financial-aid antitrust litigation. A U.S. appeals court agreed to review a district judge’s order allowing a class action against Cornell and other universities, explicitly limiting its review to whether the lower court properly analyzed the plaintiffs' expert testimony on common proof of antitrust impact.

These parallel developments highlight a critical shift in federal civil procedure: The Daubert fight is now the certification fight.

Appellate courts are increasingly scrutinizing whether district judges are rigorously analyzing expert models at the class certification stage, rather than punting the reliability of those models to a jury. If an economist's model relies on averages that mask the fact that thousands of uninjured class members are swept into the litigation, predominance fails.

Strategic Takeaways for the Defense Bar

For corporate defense counsel, the Energizer-Walmart denial provides a clear strategic imperative: you must front-load your defense. Do not wait for summary judgment to attack the plaintiffs' economic models.

1. Exploit Supply Chain Complexity: If your client operates in a market with negotiated pricing, rebates, loyalty programs, or localized promotions, weaponize that complexity early. Use discovery to highlight the variance in what purchasers actually paid, destroying the illusion of a uniform "price umbrella."

2. Attack the Uninjured Class Member Problem: Focus relentlessly on the margins. If you can prove that a significant percentage of the proposed wholesale or consumer class bypassed the alleged overcharge (e.g., through loss-leader retail pricing or volume wholesaler discounts), you can defeat Rule 23(b)(3) predominance.

3. Force the Daubert Showdown at Certification: Demand that the district court conduct a rigorous Daubert analysis of the plaintiffs' common-impact model before ruling on certification. Remind the court that taking the plaintiffs' expert at their word is reversible error.

The plaintiffs' bar has spent years coasting on the assumption that a sufficiently scandalous antitrust allegation would compel a quick settlement once a class was certified. The Energizer-Walmart ruling proves that federal judges are finally looking under the hood of these economic models—and they are finding the engines missing.