[rbultje]

The affordable care act specifies that 80% of premiums must be spent on medical expenses. If not, the consumer gets a rebate at the end of the year.

See e.g. https://www.investopedia.com/terms/m/medical-cost-ratio.asp

[odysseus]

Note that this rule doesn't apply to the very large employers that self-insure.

Refer to: https://fas.org/sgp/crs/misc/R42735.pdf

[falcor84]

Interesting, I never heard of this. Then isn't this just the smoking gun to explain why it seems health insurers in the US are apparently so cool with skyrocketing healthcare costs, which then increase the 20%?

[coverage1]

The calculation for ACA is based on a three year average of low MCR, so you wouldn't get rebate solely due to a year of decreased medical loss