The Supreme Court has again steered clear of an international dispute over the treasure salvaged from a 19th century shipwreck.

The justices on Monday rejected appeals from the deep-sea explorers who found the wreck of a sunken Spanish galleon and Peru, both of which objected to court rulings awarding the treasure to Spain. In February, Spain took possession of 17 tons of silver coins and other artifacts estimated in 2007 to be worth $500 million.

Odyssey Marine Exploration has lost every round in federal court in its effort to hold on to the treasure it found when it discovered the wreck, believed to be the Nuestra Senora de las Mercedes, off Portugal's Atlantic coast near the Straits of Gibraltar. The ship was sunk in 1804.