Unlike a Flexible Spending Account (FSA), unused funds in a Health Savings Account (HSA) at year-end:

Explanation

HSA balances roll over indefinitely and belong to the account owner, who keeps them even when changing employers or health plans, so the account can grow over many years. An FSA, by contrast, is generally subject to a use-it-or-lose-it rule. HSA funds do not revert to the employer and are not taxed at a flat penalty rate simply for remaining in the account. Portability and rollover are key advantages of the HSA over the FSA.