In November 2012, the United States Supreme Court will again hear an appeal of a federal securities class action in Amgen Inc. v. Connecticut Retirement Plans & Trust Funds (No. 11-1085) (“Amgen”). In the past two years, the Supreme Court has heard no less than five appeals arising from securities class actions.

Amgen requires the Court to reconsider its own landmark decision in Basic Inc. v. Levinson, 485 U.S. 224 (1988), adopting a rebuttable classwide presumption of reliance based on the “fraud-on-the-market” (“FOTM”) theory. The FOTM theory assumes that the market price of securities traded in an efficient market reflects all publicly-available information, including any material misrepresentations. Twenty-five years later, the parties in Amgen ask the Court to resolve whether, in such a case, a district court must (1) “require proof of materiality” concerning the challenged statements and/or (2) “allow the defendant to present evidence rebutting the applicability of the fraud-on-the-market theory” before certifying a class under Fed. R. Civ. P. 23(b)(3). To fully understand the import of these questions, some background on the relevant concepts is helpful.

(more…)