A more thorough explanation:

Sponsorship disclosure is a legal requirement in the United States for radio and television stations to identify the sources of sponsored material. This includes any transmission for which money, service, or other valuable consideration is paid or promised to the station. Even political material and political sponsors must be identified.

The broadcaster must clearly identify sponsored material to viewers and fully disclose the true identity of the person or persons who sponsored the material. This extends to political material provided by an outside sponsor, even if it was provided without consideration. For campaign advertising, the material must identify both the source of the ad's funding and whether it was authorized by a particular candidate.

Enforcement of these laws is the responsibility of the Federal Communications Commission. Compliance is facilitated by requiring all employees involved in the production and dissemination of sponsored media to disclose information about their role to the broadcaster.

A political group pays a radio station to air an advertisement supporting a particular candidate. The radio station must clearly identify the advertisement as sponsored and disclose the true identity of the political group that paid for it. If the advertisement was longer than five minutes, the disclosure must be made both at the beginning and the end of the material.

This example illustrates how sponsorship disclosure applies to political material and the requirement for clear identification and disclosure of the sponsor's identity.