Large companies aren't the same as individuals when it comes to insurance. If you have enough employees, and you're covering an relatively small risk, you don't need to /buy/ anything at all. You just self-insure and you save a ton of money relative to what an insurance company would charge for the same coverage.
I've worked at several large companies where almost all of the insurance (health, life, etc) was done on a self-insured basis, with an insurance company providing providing administrative oversight (validating claims) for a flat fee. (But not actually providing insurance coverage.) If necessary, a company can buy reinsurance to cover claims above some (very, very high) deductible, the same way that your insurance company does.
And the reason why large companies do this is that, in fact, they do get a lot more bang for the buck than any of their employees could as individual consumers.
I've worked at several large companies where almost all of the insurance (health, life, etc) was done on a self-insured basis, with an insurance company providing providing administrative oversight (validating claims) for a flat fee. (But not actually providing insurance coverage.) If necessary, a company can buy reinsurance to cover claims above some (very, very high) deductible, the same way that your insurance company does.
And the reason why large companies do this is that, in fact, they do get a lot more bang for the buck than any of their employees could as individual consumers.