Glossary

Market share

An insurer's portion of all premiums written in a given line, state and year, calculated by dividing its direct premiums written by the market total.

Also called: insurance market share, share of premiums, premium market share, homeowners market share

Market share is an insurer's slice of the premium in a defined market. The formula is its direct premiums written divided by the direct premiums written by all insurers for the same line, place and period. Say an insurer wrote $2 billion of homeowners premium in a state where all insurers together wrote $20 billion. Its market share is 10%.

The NAIC publishes the standard figures in its annual market share reports, by group, which combines affiliated companies. In the NAIC's 2025 data for homeowners multiple peril across the states and territories, State Farm Group held 18.67% and the ten largest groups together held 62.39%. State pictures differ: a company with a small national share can dominate one state, and an insurer of last resort can hold a large share when private carriers pull back.

Share shows who is growing or retreating and how concentrated the market is. It does not show who has the best price, service or financial strength, and a high share can reflect a company's age and agent network as much as its quality. It also moves with rates, because an increase raises premium even if the policy count is flat. Compare share with financial strength ratings and complaint data. See The 100 largest homeowners insurance companies in the U.S., 2025 and the largest home insurers in every state, 2025.

Last reviewed October 10, 2026

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Related terms

Direct premiums written The total premium on the policies an insurer issues itself in a period, counted when written and before any share is passed to reinsurers. NAIC The standard-setting group governed by the chief insurance regulators of the 50 states, D.C. and five U.S. territories, founded in 1871. Loss ratio The share of earned premium an insurer pays out or sets aside for claims, shown as a percentage and used to judge profitability and set rates. Reinsurance Insurance that an insurance company buys from other companies, which reimburse part of its claim payments, especially after a large disaster. FAIR plan A state pool, funded by the insurers doing business there, that sells basic property coverage to owners who cannot find it in the regular market. Residual market The state-created plans and pools that cover property owners the private market declines, as opposed to coverage insurers sell by choice.

Related guides

The largest home insurers in every state, 2025 The three largest homeowners insurance groups in each state and D.C. by 2025 premiums, with their market shares from NAIC data and what the patterns mean. The 100 largest homeowners insurance companies in the U.S., 2025 The NAIC's 2025 ranking of the 100 largest home insurance groups by premiums written, with market shares, what the top 10 hold and how to read size. How to use the NAIC complaint index to compare home insurers The complaint index compares an insurer's share of complaints with its share of premium. How to read 1.00, where states differ, and why small numbers mislead. What the NAIC does (and what it does not) The NAIC is the association of state insurance regulators. It writes model laws, runs filing systems and publishes homeowners data, but it does not regulate.

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