Captive insurance company
From ACT Wiki
1. Groups of companies - insurance.
A company that is part of a more general commercial group of companies, established primarily to insure the risks of its parent company and other companies in the group.
2. Groups of companies - insurance - wider ownership structures.
Similar companies with a limited range of customers - rather than being part of the general insurance market - but owned by a wider number of corporate shareholders than a single parent company.
The broader shareholder group would still be the primary customers of the captive insurance company.