Category: Claims handling · Reviewed by Jake Leat, Associate Director · Last reviewed 2026-06-11
Other-insurance clause analysis is the technical exercise of construing and applying the “other insurance” provisions in two or more responsive policies to determine which insurer pays, in what order, and in what proportions.
Most non-marine policies contain an “other insurance” clause attempting to control how the policy interacts with any other insurance covering the same loss. These clauses come in three principal forms — escape, excess and rateable proportion — and produce dramatically different outcomes depending on how they conflict with the equivalent clauses in the other responsive policies.
The analysis matters because the operative clause determines, in fact, which insurer bears the loss. A landlord with overlapping property cover and a tenant’s named-insured cover may find that one insurer escapes entirely (escape clause), while another pays in full (no other-insurance clause or escape only); the choice is driven by the wording.
The principles are developed by case law and contract construction:
The judicial approach is to construe each clause in its context, identify any conflict and then resolve the conflict by an established hierarchy:
The analysis is highly technical and the outcomes can be counter-intuitive.
Other-insurance clauses are routinely overlooked by handlers at FNOL but become critical at the coverage analysis stage. A complete analysis runs through:
First, identify all responsive policies. This may include the insured’s own multiple policies, the insured’s contractual counterparties’ policies (where the insured is a co-insured), parent or group policies, and historic policies for long-tail exposures.
Second, locate the other-insurance clause in each. The clause is typically in the conditions section, with terms like “Other Insurance”, “Contribution” or “Co-insurance”.
Third, classify each clause:
Fourth, apply the resolution hierarchy.
Fifth, calculate the resulting allocation.
In practice, modern professional indemnity, D&O and cyber wordings increasingly contain “excess” clauses designed to preserve the insurer’s position as a follow market behind other covers. This is particularly common in personal D&O policies (where the company D&O is intended to be primary) and in personal cyber policies (where the company cyber is intended to be primary).
Modern property and liability wordings frequently use rateable-proportion clauses, producing more predictable contribution outcomes.
The analysis is documented in the coverage opinion. Where the analysis produces a counter-intuitive outcome (one insurer paying the entire loss while another with apparent cover pays nothing), the reasoning needs careful explanation to underwriting management and reinsurers.
“Pro rata by limit” — proportional contribution by reference to each policy’s limit (the most common method).
“Pro rata by independent liability” — proportional contribution by reference to each policy’s independent exposure to the loss (less common; used where limits diverge sharply from exposure).
“Maximum loss” — each insurer pays up to its share of the loss, capped at its policy limit.
“Layered” other-insurance clauses — clauses that distinguish between primary and excess covers, producing different rules for each.
“Specific carve-outs” — clauses that exclude specific types of cover from the other-insurance analysis (for example, statutory motor cover or employers’ liability cover that must respond regardless).
A FTSE-listed company’s directors face a $5m derivative claim. The directors are covered by three policies: the company D&O programme (£20m, with a rateable-proportion other-insurance clause); the parent group’s Side A D&O policy (£10m, with an “excess of all other insurance” clause); and a personal D&O cover taken by one of the directors at her own cost (£2m, with an escape clause stating that the policy does not respond if any other cover is in force).
Analysis: the personal policy’s escape clause is engaged because both the company D&O and the parent Side A respond. The personal policy escapes entirely; it pays nothing. The Side A excess clause is engaged because the company D&O responds. The company D&O is the primary cover and responds in full up to its £20m limit. The Side A acts as excess above the company D&O — but since the claim is only $5m (approximately £4m), it does not reach the Side A. Outcome: company D&O pays the claim entirely; the Side A and personal D&O policies pay nothing.
This is the typical “tower architecture” outcome of carefully drafted other-insurance clauses: the cover responds in the designed order, with backups available only when the primary is exhausted.
By Matt Bartlett, Director, on 2026-06-11. Next review: 2026-12-11.
This entry is part of the Apex Insurance Wiki. Last reviewed by Matt Bartlett on 2026-06-11. Apex Insurance Brokers Limited, FCA FRN 724952, Companies House 07014570. Not regulated advice — consult your broker on your specific position.
Apex Insurance Brokers serves UK professional services firms and commercial businesses. Call 0117 325 0027, email hello@apexinsurancebrokers.co.uk, or request a quotation.
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