SCOTUS Curbs 'Pure Omissions' Lawsuits

In a 9-0 opinion, Justice Sonia Sotomayor wrote that such "pure omissions are not actionable" under the U.S. Securities and Exchange Commission's securities fraud rule known as Rule 10b-5. Instead, investors can bring such suits only when such omissions create "misleading half-truths."

The decision represents a narrow victory for infrastructure conglomerate Macquarie Infrastructure Corp., which is being sued by investor Moab Partners. Moab alleges Macquarie failed to disclose in its securities filings the risk that an international regulation of shipping fuel oil would have on the health of a subsidiary company that stored fuel oil.