An Archer MSA is a tax-exempt trust or custodial account that you set up with a U.S. financial institution (such as a bank or an insurance company) in which you can save money exclusively for future medical expenses. This account must be used in conjunction with a High Deductible Health Plan (HDHP). To be eligible for an Archer MSA, you must have an HDHP. An HDHP has a higher annual deductible than typical health plans and a maximum limit on the annual out-of-pocket medical expenses that you must pay for covered expenses.