No, I don't know. based on your question, did a little poking around. There are MANY people with a title that at least in part includes "Inspector General." I assume the contention that all are in SES refers to the top dog in each office, not the Assistants, Deputies, Deputy Assistants, or Principal Assistants.
Senior Executive Service Performance Review Board Membership
SES statutes (5 USC, Part-III, Subpart-B, Chapter-31) and protocol are outside of the various statutes that establish Inspectors General.
5 USC 3133 sets out Authorization of positions and authority for appointment (into SES). This particular statute does not, by law, etablish that all IG are SES.
It may be that all the various statutes that establish particular Offices of IG specify the head must be SES.
Oh, here is a statute passed by Congress that appears to establish that all IG are SES.
5 App. USC 6 - Authority of Inspector General
(d)Yeah, wow, convoluted and relies on numerous external references. Typical federal mishmash. They make big bucks creating then forcing everybody to navigate Byzantine rules.
(1)
(A) For purposes of applying the provisions of law identified in subparagraph (B)--
(i) each Office of Inspector General shall be considered to be a separate agency; and
(ii) the Inspector General who is the head of an office referred to in clause (i) shall, with respect to such office, have the functions, powers, and duties of an agency head or appointing authority under such provisions.(B) This paragraph applies with respect to the following provisions of title 5, United States Code:
(i) Subchapter II of chapter 35.
(ii) Sections 8335 (b), 8336, 8344, 8414, 8468, and 8425 (b).
(iii) All provisions relating to the Senior Executive Service (as determined by the Office of Personnel Management), subject to paragraph (2).(2) For purposes of applying section 4507 (b) of title 5, United States Code, paragraph (1)(A)(ii) shall be applied by substituting "the Council of the Inspectors General on Integrity and Efficiency (established by section 11 of the Inspector General Act) shall" for "the Inspector General who is the head of an office referred to in clause (i) shall, with respect to such office,".
5 USC 8335(b), 8336, 8344, 8414, 8468, and 8425 are about retirement, separation, and reassignment pay. All about the Benjamins.
5 USC 4507(b) - Awarding of ranks in the Senior Executive Service
More Benjamins for "Meritorious Executive" (20% bonus) and "Distinguished Executive" (35% bonus). Note too, being "an agency" for purposes of being in the federal government carries substantial power. Each OIG is an agency unto itself.
Not all agencies are covered by SES. Some have their own systems for creating unaccountable bureaucrats.
Senior level employees of several agencies are exempt from the SES but have their own senior executive positions; these include the Federal Bureau of Investigation, Central Intelligence Agency, Defense Intelligence Agency, National Security Agency, Transportation Security Administration, Federal Aviation Administration, Government Accountability Office, Members of the Foreign Service, and government corporations.
Note that none of those agencies is an OIG. Every OIG is under SES, and every (head) IG is in a managerial position. So yes, I would say all IG are in SES.
And OPM says:
In an agency covered by the Senior Executive Service (SES), SES positions include positions classified above GS-15 that include duties involving one or more of the functional criteria (executive or managerial) identified in law.
Totally unrelated to your question, I notice 5 App. USC 6 authorizes IG and others in every OIG to carry a firearm and to arrest w/o a warrant.
— I seem to recall reading somewhere the Inspectors General are all members of the SES. Do you know if that’s correct? —
No, I don’t know. based on your question, did a little poking around... Oh, here is a statute passed by Congress that appears to establish that all IG are SES.
5 App. USC 6 - Authority of Inspector General
**********************************************************************************
Well, thank you so much for the answer. SES needs to be dismantled — they think they are in charge—not POTUS. IIRC, this travesty was put into place during Carter Admin.