A health savings account (HSA) is a tax-advantaged medical savings account available to taxpayers in the United States who are enrolled in a high-deductible health plan (HDHP). The funds contributed to an account are not subject to federal income tax at the time of deposit. Unlike a flexible spending account (FSA), HSA funds roll over and accumulate year to year if not spent. HSAs are owned by the individual, which differentiates them from company-owned health reimbursement arrangements (HRAs) that are an alternate tax-deductible source of funds paired with either HDHPs or standard health plans. HSA funds may currently be used to pay for qualified medical expenses at any time without federal tax liability or penalty. Beginning in early 2011, OTC (over-the-counter) medications cannot be paid with HSA dollars without a doctor's prescription. Withdrawals for non-medical expenses are treated very similarly to those in an individual retirement account (IRA) in that they may provide tax advantages if taken after retirement age, and they incur penalties if taken earlier. These accounts are a component of consumer-driven health care.