We almost never post on securities decisions, but we’re making an exception today. Our readers know that the initiation of MDLs and state court coordinated proceedings—often loaded with unvetted and bogus claims—can drive down defendants’ stock prices. When that happens the plaintiffs’ class action bar swoops in and files securities class actions, essentially trying to make the same defendant pay twice for the same claims.  Call it the “unholy alliance.” Today’s decision (another one arising out of the Zantac litigation) is notable because it strikes directly at the linkage between mass torts and the securities class actions that try to play piggyback.  In Roofers Loc. No. 149 Pension Fund v. GSK PLC, 2026 U.S. Dist. LEXIS 44087 (E.D. Pa. March 4, 2026), the information contained in mass tort filings and accompanying discovery were enough to bar the securities class action based on the statute of limitations.

We’ve blogged numerous times about the Zantac litigation (including on notable Rule 702 decisions here and here).  That litigation started in 2019, and a federal MDL was created in 2020. Id. at *5. Plaintiffs filed the class action at issue today in 2025. Defendants moved to dismiss the class action, arguing that the claims were time barred under the two-year statute of limitations in 28 U.S.C. § 1658(b).  The defendants claimed that the underlying mass tort provided enough information that the class plaintiffs should have discovered the facts giving rise to their lawsuit more than two years before they filed the complaint.

The court agreed with the defendants. Based on the plaintiffs’ own complaint, the court noted that there were “storm warnings” that “would have prompted a reasonably diligent plaintiff to begin investigating” the securities fraud claims more than two years before the filing. Id. at *13. Plaintiffs’ complaint alleged that there were documents unsealed in the MDL in 2022 that constituted “damning evidence” of the fraud and that investors “were shocked to learn the extensive liability [the defendant] would face.”  Id. at *14.  Plaintiffs also alleged that Credit Suisse published an analyst report in 2022 that estimated one of the defendant’s exposure in the $10 billion range. These allegations were enough for the court to conclude that the information alleged in the complaint “would have prompted a reasonably diligent plaintiff to investigate the MDL action and the potential securities fraud claims” more than two years before the date of filing. Id. at *15.

The court also looked to publicly available records.  The master complaint in the MDL alleged that a GSK researcher, whom the complaint identified by name, conducted studies showing that ranitidine could convert to NDMA in the human body. And complaints in other jurisdictions made similar allegations. Then in December, 2022, the MDL court issued its Rule 702 opinion (discussed here) that included a detailed summary of the study referenced in the amended complaint. Later the same month, the MDL court unsealed the underlying study. Given plaintiffs’ claims about “investor interest” in the MDL proceedings, the court held that “reasonably diligent” plaintiffs would have begun investigating the case and discovered the GSK study at least two years before the filing of the class complaint.

Plaintiffs tried to avoid the statute of limitations by arguing that they could not have discovered the facts relevant to their claims until the publication of a Bloomberg article in February 2023. The court gave no credence to that argument, holding that the facts identified in the Bloomberg article were all available to plaintiffs well before February 2023. Plaintiffs also argued that, since the defendants denied the allegations in the MDL complaint, those denials dissipated any importance of the allegations and prevented the plaintiffs from discovering the relevant facts. The court’s response to that? “Untenable.” Id. at *26.  A denial by a defendant of facts alleged in a complaint does not negate a party’s responsibility to investigate whether it may have a claim.

Plaintiffs also claimed that, because the GSK study was unsealed along with “more than 50,000 pages of previously confidential MDL documents,” they could not have timely identified the study within those materials. The court rightfully rejected that one too:

[N]umerous public records had previously identified and/or described the [GSK] study . . . . Moreover, given the specific facts that were already publicly available by [the date the study was unsealed], there is a smaller temporal disparity between the start of the investigation and the discovery of the facts constituting the violation.  The Court finds it difficult to believe that it would have taken a reasonably diligent plaintiff over one month to locate the [GSK] study, especially when there was strong investor interest in the Zantac litigation.

Id. at *30 (internal quotations and citations omitted).

The court rejected all of plaintiffs’ arguments and dismissed the securities class action complaint with prejudice. Since the MDL court held that the personal injury plaintiffs’ causation experts did not meet the standard for good and reliable science under Rule 702, effectively ending the MDL, it’s fitting that the securities class action was dismissed at the pleadings stage. Good riddance.