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5 U.S. Code § 8469 - Withholding of State income taxes

The Office shall, in accordance with this section, enter into an agreement with any State within 120 days of a request for agreement from the proper State official. The agreement shall provide that the Office shall withhold State income tax in the case of the monthly annuity of any annuitant who voluntarily requests, in writing, such withholding. The amounts withheld during any calendar quarter shall be held in the Fund and disbursed to the States during the month following that calendar quarter.
An annuitant may have in effect at any time only one request for withholding under this section, and an annuitant may not have more than two such requests in effect during any one calendar year.
Subject to subsection (b), an annuitant may change the State designated by that annuitant for purposes of having withholdings made, and may request that the withholdings be remitted in accordance with such change. An annuitant also may revoke any request of that annuitant for withholding. Any change in the State designated or revocation is effective on the first day of the month after the month in which the request or the revocation is processed by the Office, but in no event later than on the first day of the second month beginning after the day on which such request or revocation is received by the Office.
This section does not give the consent of the United States to the application of a statute which imposes more burdensome requirements on the United States than on employers generally, or which subjects the United States or any annuitant to a penalty or liability because of this section. The Office may not accept pay from a State for services performed in withholding State income taxes from annuities. Any amount erroneously withheld from an annuity and paid to a State by the Office shall be repaid by the State in accordance with regulations issued by the Office.
(e) For the purpose of this section—
the term “State” means a State, the District of Columbia, or any territory or possession of the United States; and
the term “annuitant” includes a survivor who is receiving an annuity from the Fund.