This depends heavily on the age and wage of the employee. For a typical 20-something developer making $100k, the monthly cost for a good HMO might be peanuts at ~$300/mo., a mere 4% overhead.

But for the 60-year-old hourly line worker making $40k, whose wife and two kids are also covered by the plan (thanks union!), a good HMO might cost upwards of $2000/mo., an almost 50% overhead. [0]

For a PPO, the numbers would be even higher.

[0]: https://www.calchoice.com/FormPdfStreamer.aspx?FormId=6601&E...

I will admit that I am definitely skewing this towards the HN demographic, and that it's different in other industries as you point out.