According to https://www.investopedia.com/articles/personal-finance/090814/pros-and-cons-health-savings-account-hsa.asp , you'll get taxed if you withdraw the moneys before 65. Which sorta defeats it use as bridge coverage, assuming that you don't enroll in social security until you're 67. (I.e., that only gives you 2 years of coverage.) Seems like HSAs are not really worth the trouble; you may as well just stick the money in your bank account or some equally fungible asset.