Each year the Office of Personnel Management (OPM) sends SSA a file to be verified and matched against the Master Earnings File (MEF) and Employer Information File (EIF). OPM will match SSA's tax return records with OPM's records on disability retirees under age 60, disabled adult child survivors, certain retirees in receipt of a supplemental benefit under the Federal Employees Retirement System (FERS), and certain annuitants receiving a discontinued service retirement benefit under the Civil Service Retirement System (CSRS). By law, these annuitants and survivors are limited in the amount they can earn and still retain benefits paid to them. OPM will use the SSA data to determine continued eligibility for benefits.