Viacom's lawyers said in court papers that the company dropped the M2 name in 1999 and called the channel "MTV2."

M2 Software, however, continued to press for monetary damages and a cut of Viacom's profits attributable to the trademark infringement, as allowed by federal law.

A federal district court in 2004 accepted a compromise proposal from Viacom and issued an injunction barring Viacom from using M2 or "M2: Music Television" in the future.

But the district court and the 9th U.S. Circuit Court of Appeals ruled that M2 Software wasn't entitled to damages or a portion of Viacom's profits because it hadn't shown that the infringement was intentional.

M2 Software appealed to the Supreme Court, arguing that federal law does not always require that trademark infringment be intentional for a trademark holder to seek a portion of profits.

The Supreme Court's decision lets stand the appeals court's ruling.