Other Insurance Clause

An other insurance clause is a provision found in nearly every liability and property policy that dictates how coverage coordinates when two or more policies apply to the same claim. Insurers include it to prevent a policyholder from collecting twice for one loss and to allocate responsibility among carriers. The three common flavors are pro rata (each policy pays its proportional share), excess (the policy pays only after other coverage is used up), and escape (the policy pays nothing when other insurance exists). Because the wording controls who pays first and how much, it is one of the most litigated sections in commercial insurance.

For a small-business buyer, this matters most when you are named on someone else's policy or you carry overlapping coverage. If you are listed as an additional insured on a general contractor's policy while also holding your own CGL, the two policies' other-insurance clauses decide which pays first. This is exactly why upstream parties demand primary and noncontributory wording — it overrides the default pro rata sharing so your policy responds first and does not seek contribution from theirs. Misaligned clauses can leave a business paying out of pocket while carriers argue.

A practical nuance: when two policies both claim to be excess (a so-called mutually repugnant conflict), many courts disregard the competing clauses and force the insurers to share the loss anyway. Related doctrines such as horizontal vs. vertical exhaustion and stacking of limits further shape the outcome. Always read the clause type before assuming a policy will respond, and use endorsements to make the coordination explicit rather than relying on the default language.