Portability of Benefits for Nonappropriated Fund Employees Act of 1990

Portability of Benefits for Nonappropriated Fund Employees Act of 1990 - Entitles employees of nonappropriated fund instrumentalities of the Department of Defense (DOD) and Coast Guard who transfer, after December 31, 1986, to civil service positions within DOD or the Coast Guard to credit for their service for such instrumentality when computing the length of service to determine: (1) the order of retention in a reduction in force; (2) eligibility for a periodic step increase; and (3) the amount of accrued annual leave.

Requires the annual, sick, and home leave credited to such an employee to be transferred to the civil service employing agency. Requires the annual, sick, and home leave of an employee holding a civil service position within DOD or the Coast Guard who transfers to a nonappropriated fund position within such an instrumentality to be transferred to the employing entity. Authorizes the Secretary of Defense and the Secretary of Transportation, as appropriate, to compensate the gaining entity for the leave transferred. Provides that movement from a civil service position to a nonappropriated fund instrumentality position is not a separation from service for purposes of receiving a lump-sum payment for accumulated and accrued annual leave in the case of an employee whose annual leave is so transferred.

Authorizes the Office of Personnel Management (OPM) to prescribe regulations which provide for the application of provisions relating to grade and pay retention to employees of such instrumentalities who move to civil service positions within DOD or the Coast Guard.

Provides that the pay rate for an employee of a nonappropriated fund instrumentality who is moved involuntarily to a similar position within the civil service system shall be set at a rate which is not less than the employee's existing rate of basic pay in the nonappropriated fund system and not above the maximum for the grade, except as may be provided for under such regulations prescribed by OPM relating to grade and pay retention.

Authorizes OPM to prescribe regulations under which certain DOD and Coast Guard employees subject to the Civil Service Retirement System (CSRS) or the Federal Employees' Retirement System (FERS) who have moved to a nonappropriated fund position within DOD or the Coast Guard may elect to retain coverage under such retirement systems, as applicable.

Authorizes OPM to prescribe regulations under which certain employees of nonappropriated fund instrumentalities of DOD or the Coast Guard who are vested participants in a nonappropriated fund retirement system and have moved to a civil service system position within DOD or the Coast Guard may elect to remain covered during any subsequent Government employment by the retirement system applicable to the employee's current or most recent employment in the nonappropriated fund system.

Revises the definition of "annuitant" to allow nonappropriated fund employees of DOD or the Coast Guard who move to civil service positions within such entities and elect to remain covered by a nonappropriated fund retirement system to participate in the Federal Employees Health Benefits Program when they retire.

Outlines provisions governing: (1) participation in the Thrift Savings Plan by individuals electing to remain subject to CSRS or FERS; and (2) pay deductions and contributions for individuals electing to remain covered by a retirement system established for nonappropriated fund employees.