5 U.S.C. § 8475
Investment policies
The Board shall develop investment policies under section 8472(f)(1) of this title which provide for—
(1)
prudent investments suitable for accumulating funds for payment of retirement income; and
(2)
low administrative costs.
(Added Pub. L. 99–335, title I, § 101(a) , June 6, 1986 , 100 Stat. 581 .)