What happens to money left in a HSA at the end of the year?

If you have money left in a health savings account (HSA) at the end of the year, that money can stay, and continue to grow, right where it is. It will simply roll over to the next year. Unlike other types of medical expense savings accounts, HSAs are not subject to a "use it or lose it" provision that would require you to forfeit or use up the money in the account by the end of the year. Your HSA allows you to build up funds that can be used to pay your medical expenses now, in the near future, or even in your retirement.