I work for a PEO -- Professional Employer Organization -- and that's essentially what we do. Clients that come onboard with a co-employment contract for their employees. We pay their employees, our clients pay us and we become the employer (in most states though laws are always changing). This means we have 90k employees that help us negotiate some pretty good rates for Benefit plans. It's actually a pretty decent way for a smaller company to offer benefits to their employees that are competitive to larger companies.

We do try to take on companies of a minimum size (10+ employees) but sometimes end up taking on companies with 2 or 3 employees because the owner forecasts explosive growth -- which never happens. All that said, it's a freaking battle with the carriers every year to try to keep the increases at a lower rate. Also, we have "rate buckets" where we place clients according to risk and past medical history of its employees. It still tends to work out better than if they would attempt to get insurance on their own.