HSA Investment Services You may choose to potentially grow your savings for future health care costs by investing some of your money in mutual funds. Once you reach the designated balance for your HSA, known as the investment threshold, you can invest a portion of your savings. Investment Guidelines The following guidelines apply when you invest some of your HSA funds: When you make a transfer to your investment account, the amount of the transfer cannot bring the balance of your HSA below your investment threshold. The minimum amount you may transfer to your investment account is $100. You can't make payments for qualified medical expense directly from your investment account. If you wish to use funds from your investment account to make payments, you'll have to transfer funds from your investments back into your HSA.