According to the United States Office of Government Ethics:
Some ethics provisions that apply to executive branch employees apply differently to an employee who qualifies as a “special Government employee” (SGE), or do not apply at all.
Congress created the SGE category in 1962 when it revised the criminal conflict of interest statutes. Congress recognized the need to apply appropriate conflict of interest restrictions to experts, consultants, and other advisers who serve the Government on a temporary basis. On the other hand, Congress also determined that the Government cannot obtain the expertise it needs if it requires experts to forego their private professional lives as a condition of temporary service. Since 1962, the SGE category has been used in a number of statutes and regulations as a means of tailoring the applicability of some restrictions.
As defined in 18 U.S.C. § 202, an SGE is an officer or employee who is retained, designated, appointed, or employed to perform temporary duties, with or without compensation, for not more than 130 days during any period of 365 consecutive days. The SGE category should be distinguished from other categories of individuals who serve executive branch agencies but who are not employees, such as independent contractors (who are generally not covered by the ethics laws and regulations at all). Also, although many SGEs serve as advisory committee members, not all members of advisory committees are SGEs.
The following lists have been obtained from various agencies, of their list of SGEs.
Defense Intelligence Agency
DIA Special Government Employees, requested 11/15/13 [31 Pages, 14.2MB]
Federal Bureau of Investigation
FBI Special Government Employees, requested 11/15/13 [4 Pages, 0.9MB]