White list states maintain a list of insurance companies that can use unauthorized insurers to provide specialized or supplemental coverage, known as surplus lines insurance.

Surplus lines insurance protects against a financial risk that is too high for a regular insurance company to take on. Surplus line insurance can be used by companies or purchased individually. Unlike normal insurance, this insurance can be bought from an insurer not licensed in the insured’s state. However, the surplus lines insurer requires a license in the state where it is based.