Every insurance company, or underwriting company, that's licensed to conduct business in a given state is issued an NAIC number, which is short for National Association of Insurance Commissioners. No two companies share the same number.
The number has traditionally been five digits in length, but not always. Gerber Life Insurance Company's NAIC number is eight digits long, for example. Nevertheless, the numbers serve as a company identification code that the NAIC organization is responsible for assigning. This is a U.S.-based organization consisting of state government officials who regulate the conduct of insurance companies and agents in their state or territory or the District of Columbia, with the goal of protecting insurance consumers.
For license plates renewals of motorized vehicles, an NAIC number is generally required. It's located on most automobile insurance cards, perhaps in the upper-right corner. Optionally, the number is usually listed on insurance companies' websites.
The NAIC has a Consumer Information Source to help consumers locate reputable insurance companies by using the NAIC number. On the NAIC's website, consumers can use the CIS to enter an insurance company's name or its NAIC number to find information about the insurer, such as any closed consumer complaints against it, and licensing and financial data.