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Insurance glossary
What is E&S (excess and surplus lines) insurance?
A plain-English definition for wholesale insurance producers, and for the retail producers they work with.
Excess and surplus lines (E&S) insurance, also called surplus lines, is coverage written by non-admitted insurers for risks the standard admitted market will not or cannot cover. Typical E&S risks are new or emerging, distressed, unique, or need more capacity than standard insurers offer. It is placed through a licensed surplus lines broker.
How it works.
The U.S. property and casualty market has two segments: the standard (admitted) market and the surplus lines (non-admitted) market. A risk usually reaches E&S after the retail agent finds no fit in the admitted market; most states require that search to be documented. A licensed surplus lines broker then places it with an eligible non-admitted insurer.
Surplus lines insurers have freedom of rate and form, so terms and pricing can be tailored to the risk. In exchange, policyholders are generally not protected by state guaranty funds if the insurer fails. WSIA reports surplus lines was a $143.3 billion market in 2025, about 12.9% of all U.S. property and casualty premium and roughly 27.5% of commercial lines.
Why it matters to wholesale producers.
E&S is the core of most wholesale books. When admitted carriers tighten appetite, as WSIA describes in market cycles, more business flows to E&S and retail producers need wholesalers more. Those are the moments when retail producers are most open to a new wholesale relationship.
For retail producers: E&S is how you keep a client whose risk the standard market declined, such as a vacant building, a startup with no loss history or a property in a catastrophe-prone area.
Related terms.
On ProducerSpark.
Sources (opened October 23, 2026): WSIA: An introduction to the surplus lines insurance market (2026); NAIC: Surplus lines; NAIC: Glossary of insurance terms. General information, not legal or tax advice. Requirements vary by state.
Questions.
Is E&S insurance regulated?
Yes, differently from the admitted market. Surplus lines insurers must be licensed in their home state or country and deemed eligible by the insured's home state, and surplus lines brokers are licensed and regulated by states.
Why is it called surplus lines?
It covers the surplus of risks that the standard admitted market declines or does not fit.
Does E&S cover personal lines?
Mostly it covers commercial risks, but it can include personal lines such as homeowners coverage in catastrophe-prone areas.