Coinsurer

You buy a house, and you need insurance. So you purchase insurance and receive a primary policy.

But let’s say you want additional insurance, because you bought a really, really big house. Some insurance companies might not want to write too large of a policy, so you might need a second provider to offer insurance to cover the balance of the required policy. This second party is the coinsurer.

It’s pretty uncommon in U.S. housing, but it can be a common practice in commercial real estate. Also some states force the use of coinsurers to spread out risk in the event of a massive claim.