I've been reading about the history of insurance to understand how we got here. Here's a quick story from one insurance book.
There once was a membership association called the American Insurance Underwriters (AIU). The AIU acted as an agent for member insurance companies in international markets. Each member insurance company held a percentage of the AIU pool by which payments and liabilities were assigned.
In the 1960s, an insurance company and AIU member bid on a contract to insure a large church in Boston. But the insurance company didn't bid the insurance like everyone else. Instead, the underwriting team created a tailored contract with its own rate calculations, "rather than the standard forms and prices other (AIU) insurers had agreed to use."
The incumbent insurer was not pleased: