Category: Comparative markets · Reviewed by Jake Leat, Associate Director · Last reviewed 2026-06-05
The US professional indemnity (PI) market — known domestically as errors and omissions (E&O) insurance — is one of the largest professional liability markets in the world, written predominantly through the admitted state-regulated carriers, surplus lines specialists, and the London market via Lloyd’s coverholders.
Category: Comparative insurance markets Also known as: US E&O market, US professional liability market Jurisdiction / Domicile: United States (state-by-state regulation) Regulator: State insurance departments, coordinated through the National Association of Insurance Commissioners (NAIC) Related concepts: professional indemnity insurance, Lloyd’s of London, surplus lines
The US professional indemnity (PI) market refers to the writing of professional liability cover — referred to in the United States as errors and omissions (E&O) — for lawyers, accountants, architects, engineers, technology firms, financial advisers, medical professionals (where written as medical malpractice it forms a discrete sub-market) and miscellaneous professional services. The market comprises both admitted carriers, regulated by the insurance department of each state, and non-admitted surplus lines insurers writing risks that the admitted market declines or cannot accommodate.
According to NAIC market share data, the US “other liability — claims-made” line, which captures the bulk of E&O business, generates direct written premium of tens of billions of US dollars annually. Lawyers’ professional liability and medical malpractice are reported separately under their own lines of business.
US insurance is regulated at state level under the McCarran-Ferguson Act 1945, which preserved state regulatory authority over the business of insurance. Each of the fifty states maintains its own insurance code and department; the NAIC coordinates model laws and uniform reporting. Surplus lines placements are governed by the Nonadmitted and Reinsurance Reform Act (NRRA) within the Dodd-Frank Wall Street Reform and Consumer Protection Act 2010, which channels regulation to the insured’s home state.
Admitted E&O carriers — including AIG, Chubb, Travelers, CNA, Hartford, Liberty Mutual and Berkshire Hathaway specialty units — file rates and forms with state regulators and write standard professional risks. Complex, high-limit, or unusual risks (large law firms, technology errors and omissions for software-as-a-service businesses, miscellaneous professional liability for emerging professions) typically flow to the surplus lines market, where carriers such as Markel, RSUI, Beazley USA and Lloyd’s syndicates operating through coverholders write on non-admitted paper. Limits commonly range from US$1m for small professional firms to towers of US$100m or more for the largest accounting and law firm placements.
For UK brokers, the US PI market is the principal alternative to London for very large or complex professional risks with US exposure. London continues to lead on cross-border professional liability, particularly for international law firms and multinational consultancy groups, and Lloyd’s surplus lines presence (see Lloyd’s New York office) gives UK syndicates direct access. A UK insured with US subsidiaries will frequently have a primary admitted US E&O policy issued by a US carrier, with excess layers placed at Lloyd’s or in the company market in London.
A UK-headquartered international law firm with offices in New York and California arranges its global professional indemnity programme. The US tower is structured with a primary US$10m layer written by a US admitted carrier (Chubb), excess layers from US surplus lines carriers, and the top layers placed at Lloyd’s of London through a broker with US capability. The London-led portion provides difference-in-conditions cover for non-US engagements and unifies the global limit.
This entry is part of the Apex Insurance Wiki. Last reviewed by Matt Bartlett on 2026-06-05. Next review: 2026-12-05.
Apex Insurance Brokers Limited. Authorised and regulated by the Financial Conduct Authority, FRN 724952. Registered in England and Wales, Companies House 07014570. This entry provides general information about UK insurance concepts and is not regulated advice. Consult your insurance broker on your specific position.
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