£1m doesn't always mean £1m: the wording behind an insurance limit

Two policies can carry the same limit and behave nothing alike.

The number on the front is the easy part. The wording that decides how that number is applied is where things really matter, and it has been fought over in some of the largest insurance disputes on record.

Asbestos is where the aggregate limit earned its place in history, and a recent ruling shows how the mechanics work to this day. In February 2026 an Ohio appeals court decided Copeland Corporation v Travelers, a dispute over three liability policies written in the early 1980s, each carrying a $1m per-occurrence limit and a $3m aggregate. Travelers had paid $3m and argued the cover was exhausted: every asbestos claim traced back to a single decision to build compressors with asbestos gaskets, so on its reading that was one occurrence, one aggregate, spent.

The court disagreed. It held that each person's exposure was a separate occurrence, which meant the claims could reach $3m per occurrence up to the full $9m aggregate across the three policies. Roughly $6m turned on how the word "occurrence" met the limit.

That is why an aggregate limit is in place. The insurer agrees to pay per claim up to a point, then sets a ceiling on the total across the period. Which brings the whole thing back to the schedule in front of you.

Closer to home

And closer to home, on our side of the Pond, the same wording decides who gets paid in professional indemnity. In AIG Europe v Woodman, decided by the UK Supreme Court in 2017, a firm of solicitors held PI cover with a £3m limit for any one claim. Investors in overseas property developments in Turkey and Morocco lost money after the firm released their funds from escrow before it should have, and their combined claims ran well beyond £3m.

Whether they shared a single £3m limit or unlocked more came down to one line in the standard solicitors' wording, which treats claims arising from "a series of related matters or transactions" as one claim. The Supreme Court held that the Turkish investors' claims aggregated together, the Moroccan investors' claims aggregated together, but the two groups did not aggregate with each other. One clause decided how far a fixed pot of cover would stretch across a crowd of claimants.

Let’s forget history lessons for a moment

For a growing business the practical version is simpler but just as consequential. An aggregate limit is the total the insurer will pay across the policy year. Every claim draws from the same pot, and once it is empty, there can be no more pay-outs. An "any one claim" limit resets for each claim, so a bad run of several claims does not exhaust your cover in one go.

Professional indemnity is often written on an aggregate basis. Public liability is often written any one claim. Often, but not always.

Two PI quotes can both say "£1m limit" and behave nothing alike. Have two claims land in the same year and the aggregate one can run dry while the any one claim one keeps paying. Same headline, very different year.

So read the basis, not just the big number on the front. That's the bit that tells you what your cover actually does when you need it more than once.