Apportionment is a method for splitting a claim amount when more than one policy or insurer covers the same risk.
Insurance mechanics
When multiple insurers respond to the same loss, each policy is usually obligated for part of the payment. The split is often based on:
- total limit and retention,
- policy priority,
- pro-rata sharing language,
- or policy-specific triggers.
Claims workflow
Claims handlers first identify all potentially collectible policies, then compare wording on priority of coverage, exclusions, and per-risk terms. After confirming overlaps, loss payment is allocated so no insurer pays more than its contractual share.
Underwriting perspective
Overlapping coverages can create coordination risk and double coverage disputes. Underwriters use prior apportionment cases to tighten wording, especially for clients with layered limits.
Example
A warehouse has both a primary property policy and an excess policy for the same fire loss. The total repair bill is $900,000. If the primary limit is $500,000 and excess attaches at $500,000, the primary insurer pays first and the excess insurer covers the remainder if applicable.