5 U.S. Code § 8432d - Qualified Roth contribution program
(a) Definitions.— For purposes of this section—
(1) the term “qualified Roth contribution program” means a program described in paragraph (1) of section 402A(b) of the Internal Revenue Code of 1986 which meets the requirements of paragraph (2) of such section; and
(b) Authority To Establish.— The Executive Director shall by regulation provide for the inclusion in the Thrift Savings Plan of a qualified Roth contribution program, under such terms and conditions as the Board may prescribe.
(c) Required Provisions.— The regulations under subsection (b) shall include—
(1) provisions under which an election to make designated Roth contributions may be made—
(A) by any individual who is eligible to make contributions under section 8351, 8432 (a), 8440a, 8440b, 8440c, 8440d, or 8440e; and
(2) any provisions which may, as a result of enactment of this section, be necessary in order to clarify the meaning of any reference to an “account” made in section 8432 (f), 8433, 8434 (d), 8435, 8437, or any other provision of law; and