Health Savings Account acronym. HSAs may be opened by employees who enroll in a HDHP. Employees can put money in an HSA, up to an annual limit, using pre-tax dollars. Employers may also contribute funds to these accounts within the prescribed limit. HSA funds may be used to pay for medical expenses, and no tax is owed on funds withdrawn from an HSA to pay for medical expenses. HSAs are individually owned and the account remains with an employee after employment ends.