Securities class action lawyers are looking to the U.S. Supreme Court this term to clear up an issue that has been at the center of several prominent securities class actions, specifically, what is the standard for class certification where the class members’ reliance on defendants’ alleged misstatements is presumed under the fraud-on-the-market theory of reliance. Last term, in a class action ruling in an employment case, Wal-Mart Stores, Inc. v. Dukes, 131 S. Ct. 1541 (2011), the Court signaled that class certification may require “a preliminary inquiry into the merits of a suit,” singling out elements of the fraud-on-the-market theory as an example.

On November 5, the Supreme Court heard argument in Amgen Inc. v. Connecticut Retirement Plans and Trust Funds, a securities fraud putative shareholder class action presenting the question of how far a court should consider a merits issue when deciding whether to certify a class. The appeal in Amgen is from a Ninth Circuit decision that affirmed the district court’s order certifying a plaintiff class of purchasers of Amgen stock. Defendants opposed class certification on the ground that the rebuttable presumption of reliance under the fraud-on-the-market theory requires not only that the market for Amgen stock was efficient, but that the alleged misstatements were material. Defendants offered evidence that the alleged misstatements in the case were immaterial. Therefore, according to defendants, reliance could not be presumed, and the proposed plaintiff class could not be certified because common issues did not predominate. The Supreme Court took the case in order to determine whether the district court was correct to disregard defendants’ evidence of immateriality on the ground that materiality is an issue appropriately considered at trial or at summary judgment rather than at the class certification stage.

During oral argument, defendants emphasized that the “very useful and powerful device” of the class action should not be wielded without an adequate showing that all the prerequisites are satisfied, and the prerequisites cannot be satisfied if the immateriality of defendants’ statements precludes the application of the fraud-on-the-market theory. Plaintiffs emphasized that the materiality of defendants’ statements is necessarily an issue common to the entire class and therefore appropriately argued on the merits, after the class is certified.

The outcome in Amgen is expected to have a profound effect on other cases involving the fraud-on-the-market presumption of reliance and other gating issues for class determination.