The U.S. Supreme Court signaled interest in a case that could affect how much leverage oil companies have to change their leases with tens of thousands of independent service station owners.

The justices asked the Justice Department for advice on a bid by Massachusetts gas station owners to sue Shell Oil Co. and Motiva Enterprises LLC. A group of station owners say Shell and Motiva used rent increases to try to end their franchise arrangements so the companies could take over operation of the stations.

The case, should the high court agree to hear it, could shape the rights of the 75,000 independent service station owners in the U.S. at a time of fluctuating gasoline prices and near-record oil company profits.

The case centers on the U.S. Petroleum Marketing Practices Act, a 1978 law that gave independent station owners more power in their dealings with oil companies. The station owners are suing under provisions in the law barring improper lease terminations.

Shell and Motiva contend the station owners can't invoke those provisions because they accepted new lease terms and continued to operate their franchises.