WASHINGTON, Dec 21 (Reuters) - The U.S. Federal Communications Commission (FCC) on Wednesday proposed a $300 million fine against an auto warranty robocall campaign, the largest-ever penalty proposed by the agency over unwanted calls.

The FCC said that in the scheme run by two California men via their Sumco Panama company and other entities, more than 5 billion apparently illegal robocalls were made to more than half a billion phone numbers during a three-month span in 2021 "using pre-recorded voice calls to press consumers to speak to a 'warranty specialist' about extending or reinstating their car’s warranty." (Reporting by David Shepardson; Editing by Mark Porter)