Audit sits at the sharp end of accountancy's risk spectrum: the work exists to be relied on by third parties, and when fraud or misstatement surfaces, the auditor's PI policy is where claimants look. Auditors are regulated accountants first – so everything in our accountant insurance guide applies – but audit work changes the underwriting, the limits you should carry, and who will insure you.
What insurance does an auditor need?
Professional indemnity – at audit-appropriate limits. Statutory audit requires registration (via ICAEW, ICAS or ACCA as Recognised Supervisory Bodies), and registered auditors must comply with their body's PII regulations – ICAEW's participating-insurer and approved-wording regime, with minimums of £2m any-one-claim above £800k fee income (2.5× income, £250k floor below). But audit claims scale with the audited entity, not your fee: failure-to-detect-fraud allegations are a defining exposure, and firms auditing anything of size routinely carry limits well above the regulatory floor. Retroactive cover (six years under ICAEW wording) matters acutely because audit claims emerge slowly.
Also: employers' liability, cyber (audit files are dense with client financial data), legal expenses/regulatory-investigation cover (FRC and body investigations are their own cost even when no claim follows), and management liability for audit-firm principals.
How much does it cost?
Audit rates toward the top of the accountancy range – within the profession's broad 0.3%–1.5% of fee income band, audit and insolvency sit in the medium-to-high risk tier, with corporate finance and listed-entity work rating hardest. A small firm with a modest audit book should expect PI premiums meaningfully above a compliance-only practice of the same size; claims history and audit-client profile (regulated entities, charities, pension schemes) drive rating. Minimum premiums apply.
Comparison of providers
Audit PI is broker territory:
| Provider | Type | Notable features |
|---|---|---|
| Specialist accountancy-PI brokers (PI Expert, professionalindemnity.co.uk et al.) | Brokers | Access across the qualifying-insurer panel; wordings matched to RSB requirements; audit-book presentation expertise |
| Gallagher | Broker | Dedicated accountants' practice with risk-management support |
| Lockton / Howden | Global brokers | For larger firms and listed-entity auditors |
| ICPA scheme | Association | AXA-backed compliant cover for smaller practices – check audit-work eligibility for your book |
Direct online insurers are generally unsuitable once statutory audit is in the work split; several exclude or heavily restrict it.
Reviews and expert ratings
Broker-placed market: consumer review scores don't discriminate usefully. Which? and Fairer Finance don't rate this niche. The quality gates: your RSB's participating-insurer list, approved wording compliance, and the broker's experience presenting audit books to underwriters.
Key takeaway
Treat the regulatory minimum as a floor, not a target – audit exposure scales with the entities you sign off, and buying limits against your largest engagement is the sober approach. Present your audit book transparently at renewal (client sectors, fee concentrations, quality-review history), keep retroactive cover continuous when switching insurers, and add regulatory-investigation cover: in audit, the investigation often arrives before any claim does.
Sources
- icaew.com/regulation/professional-indemnity-insurance
- professionalindemnity.co.uk/professions/accountants/ (risk tiering; rates)
- icpa.org.uk (requirements guides)
- See also our accountant insurance guide for the body-by-body formulas