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5 U.S. Code § 6365 - Contributions of annual leave

An employee may, by written application to the Leave Bank Board, request that a specified number of hours be transferred from the annual leave account of such employee to the leave bank established by such agency.
An employee may state a concern and desire to aid a specified proposed leave recipient or a leave recipient in the application filed under paragraph (1).
Upon approving an application under subsection (a), the employing agency of the leave contributor may transfer all or any part of the number of hours requested for transfer, except that the number of hours so transferred may not exceed the limitations under paragraph (2).
In any one leave year, a leave contributor may contribute no more than a total of one-half of the amount of annual leave such contributor would be entitled to accrue during the leave year in which the contribution is made.
A leave contributor who is projected to have annual leave that otherwise would be subject to forfeiture at the end of the leave year under section 6304(a) may contribute no more than the number of hours remaining in the leave year (as of the date of the contribution) for which the leave contributor is scheduled to work and receive pay.
The Leave Bank Board of a leave contributor may waive the limitations under subsection (b)(2). Any such waiver shall be in writing.
The Office of Personnel Management shall prescribe regulations establishing an open enrollment period during which an employee may contribute leave under subsection (a) for a leave year.