5 C.F.R. § 5101.103
(b) Prohibitions. A Commission member or other employee shall not engage in non-Federal employment or any other outside activity that:
(1) Involves the rendering of advice concerning any legal, accounting or economic matter, or any agricultural, mining, foreign currency market or other commodity-related matter, in which the Commission may be significantly interested, except that this prohibition shall not apply to a special Government employee unless the special Government employee:
(c) Prior approval for outside employment.