The Securities Litigation Uniform Standards Act precludes the maintenance -- in state or federal court -- of class actions alleging state law violations but premised on deception "in connection with the purchase or sale of a covered security." A covered security is a security listed on one of the national securities exchanges or issued by investment companies registered by the SEC. The question that came before the Second Circuit is whether a document that was not a covered security became a covered security because it was attached to a document that was a covered security. The district court held that it became a covered security. On appeal, the Second Circuit held that it did not and vacated the District Court's order with orders to remand the case to the New York County Supreme Court.
The decision in Ring v. AXA Investment, Inc.
can be found here