Claims-made vs occurrence. The one E&O distinction that matters most.

Every E&O insurance policy is either “claims-made” or “occurrence”. The difference determines what happens if a client sues you years after the engagement ended. Most cohort vendors issue claims-made policies (cheaper, but requires tail coverage at retirement). A few issue occurrence policies (more expensive, but the policy covers the event whenever the claim arises).

Claims-made policies

A claims-made policy covers claims made during the policy period, regardless of when the alleged error occurred. If a client sues you in 2026 about work you did in 2023, your 2026 claims-made policy covers it — but only if you had continuous coverage from 2023 to 2026 (the “retroactive date”) AND your current policy is active when the claim is filed.

The trap: when you retire or stop carrying E&O insurance, you have no active policy. A claim filed against you 2 years after you stopped practising has no coverage unless you bought tail coverage at retirement — an extended reporting period that maintains coverage for claims arising after the policy ends. Tail coverage typically costs 100-300% of the final annual premium, paid as a single lump sum at retirement.

Occurrence policies

An occurrence policy covers claims arising from events that occurred during the policy period, regardless of when the claim is filed. If you had occurrence coverage in 2023 and your client sues you in 2028 about 2023 work, the 2023 policy still covers it — even if you retired in 2024 and never bought any insurance again.

Occurrence policies are more expensive than claims-made because the insurer is on the hook indefinitely. Many E&O carriers no longer offer occurrence policies for professional liability — the form has largely shifted to claims-made since the 1980s. Allied health, social work, and counselling are professions where occurrence policies still exist; tech / SaaS / consultant E&O is almost universally claims-made.

Which form does each cohort vendor issue?

• NEXT: Claims-made (standard).
• Thimble: Claims-made; by-the-hour purchases are essentially per-engagement claims-made coverage.
• Insureon: Varies by carrier — most carriers in Insureon's panel issue claims-made E&O. Verify with the bound carrier.
• Hiscox: Primarily claims-made for US small-business E&O.
• The Hartford: Both forms available depending on profession. Allied health gets occurrence-form options; tech / consulting is claims-made.
• Embroker / Vouch / Coalition: Claims-made (standard for tech E&O).

Practical implications

1. If you're buying claims-made (most cohort vendors), maintain continuous coverage. A gap of even 30 days in coverage can leave you uncovered for past work claims that surface during the gap.
2. Budget for tail coverage at retirement. The cost is 100-300% of your final annual premium. Plan for it; don't be surprised.
3. If your profession offers occurrence-form options (allied health, some consulting), evaluate the lifetime cost. Occurrence may be cheaper over a 30-year career because you avoid the tail-coverage lump sum.
4. When switching carriers, transfer the retroactive date. Don't accept a new policy with a current-date retroactive date — you lose coverage for any past work.

Practical recommendation: Always ask your broker or carrier these three questions: (1) Is this policy claims-made or occurrence? (2) What is my retroactive date? (3) What does tail coverage cost if I retire from this policy? The answers determine your real long-term cost and risk profile, not the headline monthly premium.