A Health Reimbursement Arrangement is an employer account that they can fund to pay for qualified medical expenses. The benefit of an HRA for an employer is that they pay for expenses that are eligible and actually incurred (up to whatever limit is set by the employer’s plan). An HRA can be used with any kind of health insurance (low or high deductible). When an employee is terminated, none of the money earmarked for that employee goes with the employee. it is returned to the Employer. The HSA is an account owned by the individual and funds can be carried forward and is portable, giving much more flexibility to the individual employee.
Source: Publication 969 (2018), Health Savings Accounts and Other Tax-Favored Health Plans.