Erica P. John Fund, Inc. v. Halliburton Co.

The Erica P. John Fund (plaintiff), representing purchasers of Halliburton (defendant) stock, alleged Halliburton made misrepresentations inflating its stock price in violation of § 10(b) of the Securities and Exchange Act, and sought class certification relying on the fraud-on-the-market presumption of reliance established in Basic Inc. v. Levinson; the district court and court of appeals denied class certification because the plaintiffs could not prove loss causation, the link between the misrepresentation and an actual economic loss.