The U.S. Supreme Court’s decision yesterday in Merrill Lynch v. Manning clarified the scope of federal jurisdiction under the Exchange Act in certain important respects, but also left open critical issues that may arise in future cases.  Although the Court rejected federal jurisdiction in resolving the sole issue that was before it, the Court also stated that federal courts might well have jurisdiction over state law claims that “necessarily raise” substantial issues under federal law.

The decision, however, provides little guidance as to how that standard may be applied. Future cases involving securities trading, and the extensive body of federal regulation governing that activity, may well require future courts to determine that issue.