5 U.S.C. § 7351: Gifts to superiors

(a) An employee may not—(1) solicit a contribution from another employee for a gift to an official superior; (2) make a donation as a gift or give a gift to an official superior; or (3) accept a gift from an employee receiving less pay than himself. (b) An employee who violates this section shall be subject to appropriate disciplinary action by the employing agency or entity. (c) Each supervising ethics office (as defined in section 7353(d)(1)) is authorized to issue regulations implementing this section, including regulations exempting voluntary gifts or contributions that are given or received for special occasions such as marriage or retirement or under other circumstances in which gifts are traditionally given or exchanged.