The U.S. Supreme Court has finally clarified when the statute of limitations starts on federal securities lawsuits, an issue last addressed 20 years ago.

Until the high court’s ruling last month, appellate courts had taken various views on exactly when the clock starts ticking for such claims. For that reason alone, says Jonathan Youngwood, a litigation partner at the law firm Simpson Thatcher, the decision is welcome. “Whether you’re a defendant or a plaintiff, it’s good to know what the rules are,” he says.

Jaclyn Jaeger is a freelance contributor to Compliance Week after working for the company for 15 years. She writes on a wide variety of topics, including ethics and compliance, risk management, legal,...