31 U.S.C. § 9502

In this chapter— (1) “Government pension plan”— (A) means a pension, annuity, retirement, or similar plan (except a plan covered under the Employee Retirement Income Security Act of 1974 ( 29 U.S.C. 1001 et seq.) or a plan or program financed by contributions required under chapter 21 or 22 of the Internal Revenue Code of 1986 ( 26 U.S.C. 3101 et seq., 3201 et seq.)) established or maintained by an agency, for any of its officers or employees, regardless of the number of participants covered by the plan; and (B) includes— (i) the Civil Service Retirement System. (ii) the Coast Guard Retirement System. (iii) the Commissioned Corps of the Public Health Service Retirement System. (iv) the Farm Credit District Retirement Plans. (v) the Federal Home Loan Bank Board Retirement Systems. (vi) the Federal Home Loan Mortgage Corporation Plan. (vii) the Federal Reserve Employees Retirement Plans. (viii) the Foreign Service Retirement and Disability System. (ix) judicial plans. (x) the Military Retirement System. (xi) the National Oceanic and Atmospheric Administration Retirement System. (xii) nonappropriated fund plans. (xiii) the Tennessee Valley Authority Retirement System. (2) “plan year” means the calendar, policy, or fiscal year chosen by the Government pension plan on which the records of the plan are kept.