Senate Bill 403 aims to regulate online credit card contributions for campaign finance in Wisconsin. The bill prohibits political committees, conduits, or political parties from accepting credit card contributions made via the Internet unless the contributor provides the credit card verification value or code, and the billing address associated with the card is located in the United States. An exception is made for U.S. citizens living abroad; if their credit card billing address is outside the U.S., they must provide a mailing address in the U.S. that corresponds to their voter registration.

Additionally, the bill mandates that the treasurer of each political entity maintain records of contributors' names and addresses for reporting purposes. It also establishes a penalty for financial institutions that process online credit card contributions without adhering to the verification requirements, imposing a forfeiture equal to the total amount of such contributions. This legislation seeks to enhance transparency and accountability in campaign financing by ensuring that contributions are properly verified.