A pool is a group of insurers or reinsurers through which particular types of risks (often of a substandard nature) are underwritten, with premiums, losses, and expenses shared in agreed ratios.
Pooling can also involve a group of organizations that form a shared risk pool. Pooling is an attractive alternative for insureds that are not large enough to legally or feasibly self-insure but that desire more control over their loss exposures as well as an opportunity to reduce their cost of risk, compared to a program written by a commercial insurer.