3 HSA Rules You Really Need to Know
Health savings accounts (HSAs) aren't necessarily as well-known as long-term savings plans like IRAs and 401(k)s. That's actually a shame because HSAs are loaded with tax benefits.
HSA contributions are tax-free, and funds that aren't withdrawn right away can be invested for added growth. Investment gains in an HSA are tax-free, as are withdrawals to cover qualifying medical expenses. There can also be steep penalties for removing funds from an HSA for non-medical purposes.
Source Fool.com