The country's biggest TV networks — ABC, CBS, NBC and Fox — have sued Locast, a streaming service that transmits their broadcasts for free, in federal court in New York.

The companies said in the suit, filed Wednesday, that Locast is violating their copyrights and asked for its service to be shut down. Locast has held that under the law, it is allowed to stream the networks without paying them because it is a nonprofit.

The networks are suing because Locast threatens their business model, and they say that Locast is acting on behalf of Dish and AT&T, which owns DirecTV. Cable and satellite TV companies pay TV stations; the TV stations then pay the networks, which are owned by Walt Disney Co., CBS Corp., Comcast Corp and Fox Corp.