America's Cup organizers have received applications from three groups planning to compete at the 34th edition of sailing's premier event in 2013.
The five-month entry period started Monday, and within several hours defending champion BMW Oracle Racing of San Francisco had filed its application.
Two other challenger syndicates also filed applications Monday, but organizers are keeping their identities confidential until the applications are verified.
The Challenger of Record, Italian syndicate Mascalzone Latino, had previously declared its intention to race.
The America's Cup, which is the oldest international competition in existence, will sail 22-meter wing-sailed catamarans for the first time in 2013.
BMW Oracle Racing won the America's Cup in February, completing a two-race sweep against Alinghi of Switzerland off the coast of Valencia, Spain.
The port for the 2013 event has not yet been determined, but the organizers are looking at bids from San Francisco, Valencia and Italy.