'Any one claim' vs 'aggregate' PI limits: which basis is stronger?

Reviewed by Apex Insurance Brokers · Last reviewed 2026-08-05

What the limit of indemnity actually means

Every professional indemnity (PI) policy carries a limit of indemnity: the most the insurer will pay. The headline number, such as £1m, £2m or £5m, tells you only half the story. The basis on which that number applies is what decides how far it stretches when things go wrong more than once.

There are two common bases in the UK market. Understanding the difference matters most in a bad year, when one problem produces several claims, or several unrelated clients bring separate complaints in the same twelve months.

Any one claim vs aggregate: the comparison

A worked illustration. Suppose you hold a £2m limit and, in one policy year, three unrelated clients each bring a claim that settles for £1.5m. On an any-one-claim basis, the £2m is available in full to each claim, so all three are covered. On an aggregate basis, the £2m is the total for the year: the first claim consumes most of it, and there is little or nothing left for the second and third. The uninsured balance falls back on the firm.

That is the whole point of the distinction. Any-one-claim cover protects you against claim frequency. Aggregate cover does not.

So any-one-claim is always better?

For strength of protection at a given figure, yes. But there is nuance worth knowing before you assume aggregate cover is inadequate.

Many aggregate policies include a reinstatement: the limit is topped back up, once or a set number of times, after a claim erodes it. An "aggregate plus one reinstatement" effectively doubles the pot available across the year, narrowing the gap with any-one-claim cover. Whether a reinstatement applies, how many times, and at what cost, are all things to check on the schedule rather than assume.

Cost is the other factor. All else being equal, any-one-claim cover exposes the insurer to more, so it is generally priced accordingly. Aggregate cover, particularly with a reinstatement, can be a sensible balance for firms whose risk profile makes a cluster of large, simultaneous claims unlikely. The right answer depends on your work, your client base and, often, on what your regulator requires.

Not sure which basis your current policy uses? Ask us to check it →

Don't forget defence costs

The basis of the limit interacts with how defence and investigation costs are treated, and this quietly affects how much cover you really have.

• Costs in addition: defence costs are paid on top of the limit of indemnity, so legal spend does not eat into the money available to settle the claim.
• Costs inclusive: defence costs come out of the limit, reducing what is left for damages.

A generous-looking any-one-claim limit on a costs-inclusive basis can be less protective than it appears, because a hard-fought claim can burn a large share of the limit on legal fees before a penny reaches the claimant. Read the basis and the costs treatment together, not in isolation.

How UK professions differ

The basis is not always a free choice. Several regulators and professional bodies set minimum PI terms, and some specify the basis directly. The detail below reflects the general position; always check the current rules that apply to your firm, as minimum terms are periodically revised.

Solicitors. Firms regulated by the Solicitors Regulation Authority (SRA) must hold PI meeting the SRA Minimum Terms and Conditions. These require cover on an each and every claim (any-one-claim) basis, with a minimum limit that depends on how the firm is structured, and they restrict how far the policy can exclude or reduce cover. This is one of the most prescriptive PI regimes in the UK.

Chartered surveyors. Firms regulated by the Royal Institution of Chartered Surveyors (RICS) must comply with the RICS minimum policy wording, which for most firms requires cover on an each-and-every-claim basis, subject to certain permitted aggregate limits for specific exposures. RICS also sets minimum limits linked to firm turnover.

Accountants. Firms regulated by bodies such as ICAEW and ACCA are subject to PII regulations that set minimum limits, commonly geared to fee income. These regimes have historically permitted cover on an aggregate basis, often coupled with a requirement for reinstatement or for the limit to apply per claim above a threshold. The precise requirement is set by the relevant institute's regulations.

Architects. Registration with the Architects Registration Board (ARB) and membership of the RIBA require architects to hold "adequate and appropriate" PI cover, but they do not mandate a single fixed basis in the way the SRA does; the level and basis are judged against the practice's exposure.

Everyone else. For consultants, IT professionals, engineers, marketing agencies, recruiters and the many professions with no compulsory PI regime, the basis is a commercial decision. Here it pays to think about how your work could generate several claims at once, for example a single flawed piece of advice replicated across many clients, and to weigh that against price.

How to choose the right basis for your firm

• Check what you must have. If a regulator mandates a basis, that is your floor, not your ceiling.
• Think about correlated risk. Could one error, one template, one systemic mistake spawn many claims? If so, any-one-claim cover, or a healthy reinstatement, matters more.
• Read the costs treatment. "Costs in addition" preserves the limit for settlements; "costs inclusive" does not.
• Present your business fairly. Under the Insurance Act 2015, commercial policyholders owe a duty of fair presentation of the risk. Accurate answers on the proposal help ensure the policy responds when you need it.

Common questions

Is "any one claim" the same as "each and every claim"?

Yes. The two phrases are used interchangeably in UK PI wordings. Both mean the full limit is available for each separate claim, rather than shared across all claims in the policy year.

Does a reinstatement make an aggregate limit as good as any-one-claim?

Not quite, but it narrows the gap. A reinstatement tops the limit back up a set number of times after erosion. An aggregate limit with reinstatement gives more room across a bad year than a plain aggregate, but it is still capped, whereas any-one-claim cover is not limited by claim frequency.

How do I tell which basis my policy is on?

Look at the policy schedule and the limit-of-indemnity wording. It will state either "any one claim" / "each and every claim" or "in the aggregate", and separately whether defence costs are inclusive of, or in addition to, the limit. If it is unclear, your broker can confirm it for you.

Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority (FRN 724952). This guide is general information, not advice on a specific policy or a substitute for reading your policy wording.