Upon termination of a given policy, the amount of premium collected minus the amount paid out in claims is the insurer's underwriting profit on that policy. Underwriting performance is measured by something called the "combined ratio", which is the ratio of expenses/losses to premiums. A combined ratio of less than 100% indicates an underwriting profit, while anything over 100 indicates an underwriting loss. A company with a combined ratio over 100% may nevertheless remain profitable due to investment earnings.
NerdWallet compared quotes from these insurers in ZIP codes across the country. Rates are for policies that include liability, collision, comprehensive, and uninsured/underinsured motorist coverages, as well as any other coverage required in each state. Our “good driver” profile is a 40-year-old with no moving violations and credit in the “good” tier.