Top 100 Contractors in PSC F999: Other Environmental Services, Studies, and Analytical Support, FY2025

Name: Top 100 Contractors in PSC F999: Other Environmental Services, Studies, and Analytical Support, FY2025
Creator: GovTribe
License: https://creativecommons.org/licenses/by/4.0/

Parent companies by net contract obligations Oct 1, 2024 – Sep 30, 2025 Code page on GovTribe

The top 10 won 76% of FY2025 PSC F999 contract dollars

Contract obligations: $4,453,882,475 Net of deobligations, by contracts coded PSC F999
Contractors: 604 Parent companies with an obligation
Largest contractor: Environmental Chemical Corporation $1.89 billion, 41.1% of obligations
Data as of: Oct 23, 2026

Contract actions from FPDS (SAM.gov). How the rankings work · Download all 100 rows as CSV · Free to reuse with credit to GovTribe (CC BY 4.0)

Full ranking

Rank	Contractor	Net obligations	Share	Trend
1	Environmental Chemical Corporation 3 awardees, including ECC Constructors LLC and ECC Environmental LLC Top agencies Army (Department of the Army) DHS (Department of Homeland Security) EPA (Environmental Protection Agency)	$1,888,460,173	41.1%	Rank history: #13 in FY2021, #19 in FY2022, #14 in FY2023 and #16 in FY2024; up 15 since FY2024.
2	Amentum Holdings, Inc. 5 awardees, including United Cleanup Oak Ridge LLC, Idaho Environmental Coalition LLC and Four Rivers Nuclear Partnership LLC Top agencies DOE (Department of Energy)	$940,188,327	20.5%	Rank history: not on the FY2021–FY2024 lists; new.
3	United Cleanup Oak Ridge LLC Top agencies DOE (Department of Energy)	$132,359,640	2.9%	Rank history: not on the FY2021–FY2022 lists, #1 in FY2023 and #1 in FY2024; down 2 since FY2024.
4	Guidehouse Inc. 2 awardees, including Aptim Federal Services, LLC and Aptim-Amentum Alaska Decommissioning LLC Top agencies DOE (Department of Energy) Army (Department of the Army) Navy (Department of the Navy)	$126,171,935	2.7%	Rank history: not on the FY2021–FY2023 lists and #7 in FY2024; up 3 since FY2024.
5	Hanford Laboratory Management and Integration LLC Top agencies DOE (Department of Energy)	$110,020,720	2.4%	Rank history: #9 in FY2021, #4 in FY2022, #6 in FY2023 and #5 in FY2024; unchanged since FY2024.
6	Idaho Environmental Coalition LLC 2 awardees Top agencies DOE (Department of Energy)	$89,822,360	2.0%	Rank history: not on the FY2021–FY2023 lists and #6 in FY2024; unchanged since FY2024.
7	BWX Technologies, Inc. 2 awardees, including Nuclear Fuel Services Inc. and Bwxt Nuclear Operations Group, Inc. Top agencies DOE (Department of Energy)	$65,570,356	1.4%	Rank history: not on the FY2021 list, #15 in FY2022, #3 in FY2023 and #8 in FY2024; up 1 since FY2024.
8	Hydrogeologic, Inc. Top agencies Army (Department of the Army) EPA (Environmental Protection Agency) USAF (Department of the Air Force)	$52,771,930	1.1%	Rank history: #4 in FY2021, #8 in FY2022, #7 in FY2023 and #10 in FY2024; up 2 since FY2024.
9	L3Harris Technologies, Inc. Through Bwxt Ordnance Tennessee, Inc. Top agencies DOE (Department of Energy)	$46,800,000	1.0%	Rank history: not on the FY2021–FY2024 lists; new.
10	Sevenson Environmental Services, Inc. Top agencies EPA (Environmental Protection Agency) Army (Department of the Army)	$42,225,145	0.9%	Rank history: #8 in FY2021, #2 in FY2022, #9 in FY2023 and #4 in FY2024; down 6 since FY2024.
11	West Valley Cleanup Alliance, LLC Top agencies DOE (Department of Energy)	$40,643,286	0.9%	Rank history: not on the FY2021–FY2024 lists; new.
12	Navarro Research and Engineering, Inc. Top agencies DOE (Department of Energy)	$39,023,059	0.8%	Rank history: #12 in FY2021, #13 in FY2022, #11 in FY2023 and #14 in FY2024; up 2 since FY2024.
13	EA Engineering Science and Technology Inc. PBC Top agencies Army (Department of the Army) EPA (Environmental Protection Agency) Navy (Department of the Navy)	$30,267,349	0.7%	Rank history: #10 in FY2021, #11 in FY2022, #2 in FY2023 and #15 in FY2024; up 2 since FY2024.
14	Leidos Holdings, Inc. 4 awardees, including Leidos, Inc. Top agencies Army (Department of the Army) DHS (Department of Homeland Security) USAF (Department of the Air Force)	$29,198,358	0.6%	Rank history: #27 in FY2021, #18 in FY2022, #24 in FY2023 and #20 in FY2024; up 6 since FY2024.
15	Sustainment & Restoration Services, LLC Top agencies Army (Department of the Army) USAF (Department of the Air Force) HHS (Department of Health and Human Services)	$27,770,559	0.6%	Rank history: not on the FY2021–FY2023 lists and #79 in FY2024; up 64 since FY2024.
16	Tetra Tech, Inc. 13 awardees, including Tetra TECH EC, Inc. and Ard, Inc. Top agencies Army (Department of the Army) DOE (Department of Energy) USAID (US Agency for International Development)	$26,943,785	0.6%	Rank history: #15 in FY2021, #17 in FY2022, #19 in FY2023 and #19 in FY2024; up 3 since FY2024.
17	Southern Ohio Cleanup Company LLC Top agencies DOE (Department of Energy)	$26,751,447	0.6%	Rank history: not on the FY2021–FY2024 lists; up 166 since FY2024.
18	Bering Straits Native Corporation Through Paragon Professional Services LLC Top agencies Army (Department of the Army) DOE (Department of Energy)	$25,633,990	0.6%	Rank history: not on the FY2021–FY2024 lists; new.
19	Bristol Bay Native Corporation 7 awardees, including SES Civil and Environmental LLC, Aerostar Environmental and Construction LLC and Tekpro Support Services, LLC Top agencies Army (Department of the Army) USAF (Department of the Air Force) DOE (Department of Energy)	$24,593,635	0.5%	Rank history: not on the FY2021–FY2022 lists, #89 in FY2023 and #99 in FY2024; up 80 since FY2024.
20	Ashbritt Inc. Top agencies Army (Department of the Army)	$22,451,832	0.5%	Rank history: not on the FY2021–FY2024 lists; new.
21	Bay West LLC Top agencies Army (Department of the Army) USAF (Department of the Air Force)	$21,098,677	0.5%	Rank history: #47 in FY2021, #53 in FY2022, #21 in FY2023 and #22 in FY2024; up 1 since FY2024.
22	Cape Environmental Management Inc. 2 awardees, including Cape Remediation, LLC Top agencies EPA (Environmental Protection Agency) USAF (Department of the Air Force) Army (Department of the Army)	$17,770,798	0.4%	Rank history: #11 in FY2021, #12 in FY2022, #36 in FY2023 and #29 in FY2024; up 7 since FY2024.
23	AECOM 8 awardees, including AECOM Technical Services, Inc., URS Group, Inc. and AECOM International Inc. Top agencies EPA (Environmental Protection Agency) Army (Department of the Army) DOI (Department of the Interior)	$16,003,397	0.3%	Rank history: #1 in FY2021, #1 in FY2022 and not on the FY2023–FY2024 lists; returned.
24	Calista Corp 3 awardees, including Brice Engineering, LLC and Brice Solutions, LLC Top agencies Army (Department of the Army) DHS (Department of Homeland Security) USAF (Department of the Air Force)	$15,798,315	0.3%	Rank history: #61 in FY2021, #49 in FY2022 and not on the FY2023–FY2024 lists; returned.
25	Ducks Unlimited, Inc. Top agencies Army (Department of the Army)	$15,000,000	0.3%	Rank history: not on the FY2021–FY2024 lists; new.
26	Olgoonik Corporation Through FPM Remediations, Inc. Top agencies USAF (Department of the Air Force) Army (Department of the Army) DHS (Department of Homeland Security)	$14,303,599	0.3%	Rank history: not on the FY2021–FY2022 lists, #71 in FY2023 and #26 in FY2024; unchanged since FY2024.
27	Environmental Restoration LLC Top agencies EPA (Environmental Protection Agency)	$12,653,821	0.3%	Rank history: #23 in FY2021, #6 in FY2022, #12 in FY2023 and #32 in FY2024; up 5 since FY2024.
28	Right Way Environmental Contractors, Inc. Top agencies Army (Department of the Army)	$12,510,751	0.3%	Rank history: not on the FY2021–FY2024 lists; new.
29	Eastern Research Group Inc. Top agencies EPA (Environmental Protection Agency) USDA (Department of Agriculture) GSA (General Services Administration)	$12,212,602	0.3%	Rank history: #49 in FY2021, #42 in FY2022, #25 in FY2023 and #17 in FY2024; down 12 since FY2024.
30	The Solution Foundry, LLC Top agencies USAF (Department of the Air Force) Army (Department of the Army)	$11,714,755	0.3%	Rank history: #40 in FY2021, #36 in FY2022, #40 in FY2023 and #36 in FY2024; up 6 since FY2024.
31	Parsons Corporation Through Parsons Government Services Inc. Top agencies Army (Department of the Army)	$11,514,380	0.3%	Rank history: not on the FY2021 list, #14 in FY2022, #55 in FY2023 and #38 in FY2024; up 7 since FY2024.
32	S&K Mission Support, LLC Top agencies DOE (Department of Energy)	$10,660,401	0.2%	Rank history: not on the FY2021–FY2023 lists and #68 in FY2024; up 36 since FY2024.
33	Environmental Rail Solutions Inc. Top agencies Army (Department of the Army)	$10,605,864	0.2%	Rank history: not on the FY2021 list, #47 in FY2022, #31 in FY2023 and #23 in FY2024; down 10 since FY2024.
34	Arcadis U.s., Inc. Top agencies Army (Department of the Army)	$9,460,388	0.2%	Rank history: not on the FY2021–FY2024 lists; up 171 since FY2024.
35	LDS Kemron JV 4 LLC Top agencies Army (Department of the Army)	$8,485,821	0.2%	Rank history: not on the FY2021–FY2024 lists; new.
36	Environmental Assessment Services, LLC Top agencies Army (Department of the Army) USAF (Department of the Air Force)	$7,728,269	0.2%	Rank history: not on the FY2021–FY2024 lists; up 80 since FY2024.
37	Bb&E, Inc. Top agencies NASA (National Aeronautics and Space Administration) USAF (Department of the Air Force) DOI (Department of the Interior)	$7,677,920	0.2%	Rank history: #48 in FY2021, #55 in FY2022, #60 in FY2023 and #48 in FY2024; up 11 since FY2024.
38	Environmental Compliance Consultants, Inc. Top agencies Army (Department of the Army)	$7,541,321	0.2%	Rank history: not on the FY2021–FY2024 lists; up 234 since FY2024.
39	Verina Consulting Group LLC Top agencies Army (Department of the Army)	$7,213,839	0.2%	Rank history: not on the FY2021–FY2022 lists, #92 in FY2023 and not on the FY2024 list; up 88 since FY2024.
40	Aec-Weston JV, LLC Top agencies Army (Department of the Army) DOI (Department of the Interior)	$7,049,518	0.2%	Rank history: not on the FY2021–FY2024 lists; up 189 since FY2024.
41	Global Science & Technology, LLC Top agencies Commerce (Department of Commerce)	$6,965,854	0.2%	Rank history: not on the FY2021 list, #61 in FY2022, #56 in FY2023 and #45 in FY2024; up 4 since FY2024.
42	Huntington Ingalls Industries, Inc. Through Newport News Nuclear Bwxt-Los Alamos LLC Top agencies DOE (Department of Energy)	$6,781,652	0.1%	Rank history: #51 in FY2021, #39 in FY2022, #39 in FY2023 and not on the FY2024 list; up 455 since FY2024.
43	HUI Huliau Technology Services LLC Top agencies Army (Department of the Army)	$6,659,638	0.1%	Rank history: not on the FY2021–FY2023 lists and #3 in FY2024; down 40 since FY2024.
44	GV Henson Creek LLC Top agencies DHS (Department of Homeland Security)	$6,658,663	0.1%	Rank history: not on the FY2021–FY2024 lists; new.
45	Battelle Memorial Institute Top agencies HHS (Department of Health and Human Services) EPA (Environmental Protection Agency) Navy (Department of the Navy)	$6,622,140	0.1%	Rank history: #29 in FY2021, not on the FY2022–FY2023 lists and #75 in FY2024; up 30 since FY2024.
46	JFL-WCS Partners LLC Through Waste Control Specialists LLC Top agencies DOE (Department of Energy)	$6,350,000	0.1%	Rank history: not on the FY2021–FY2022 lists, #59 in FY2023 and #31 in FY2024; down 15 since FY2024.
47	Ciri Development Corporation 4 awardees, including North Wind General Contractors LLC, North Wind Site Services LLC and North Wind Resource Consulting LLC Top agencies DOI (Department of the Interior) Army (Department of the Army) DOE (Department of Energy)	$6,292,287	0.1%	Rank history: not on the FY2021 list, #5 in FY2022, #78 in FY2023 and #94 in FY2024; up 47 since FY2024.
48	Link Technologies Inc. Top agencies DOE (Department of Energy)	$6,267,000	0.1%	Rank history: #60 in FY2021, #62 in FY2022, #62 in FY2023 and #52 in FY2024; up 4 since FY2024.
49	Asgn Incorporated Through ECS Federal, LLC Top agencies Commerce (Department of Commerce)	$6,016,868	0.1%	Rank history: not on the FY2021–FY2023 lists and #63 in FY2024; up 14 since FY2024.
50	LMI Consulting, LLC Top agencies DHS (Department of Homeland Security) GSA (General Services Administration)	$5,967,108	0.1%	Rank history: not on the FY2021–FY2024 lists; up 108 since FY2024.
51	Bluestone Environmental Group, Inc. Top agencies Army (Department of the Army) EPA (Environmental Protection Agency) USDA (Department of Agriculture)	$5,911,250	0.1%	Rank history: not on the FY2021–FY2023 lists and #81 in FY2024; up 30 since FY2024.
52	Bluestone Interspec JV, LLC Top agencies Navy (Department of the Navy)	$5,710,907	0.1%	Rank history: not on the FY2021–FY2022 lists, #95 in FY2023 and #86 in FY2024; up 34 since FY2024.
53	Republic Services Inc. 3 awardees, including Environmental, Safety & Health Consulting Services, Inc. and NRC Gulf Environmental Services Inc. Top agencies Army (Department of the Army) Navy (Department of the Navy)	$5,645,560	0.1%	Rank history: not on the FY2021–FY2023 lists and #47 in FY2024; down 6 since FY2024.
54	Chemtex Environmental Laboratory, Inc. Top agencies EPA (Environmental Protection Agency)	$5,581,437	0.1%	Rank history: not on the FY2021 list, #99 in FY2022 and not on the FY2023–FY2024 lists; up 100 since FY2024.
55	Q & A Diversified LLC Top agencies Army (Department of the Army)	$5,527,747	0.1%	Rank history: not on the FY2021–FY2024 lists; up 69 since FY2024.
56	Bonner Analytical Testing Co Top agencies EPA (Environmental Protection Agency)	$5,505,500	0.1%	Rank history: not on the FY2021 list, #94 in FY2022 and not on the FY2023–FY2024 lists; up 45 since FY2024.
57	Seres-Arcadis SB JV, LLC Top agencies Army (Department of the Army)	$5,505,137	0.1%	Rank history: #70 in FY2021, #60 in FY2022, #74 in FY2023 and #30 in FY2024; down 27 since FY2024.
58	SOL Solutions LLC Top agencies Army (Department of the Army) Navy (Department of the Navy)	$5,400,207	0.1%	Rank history: not on the FY2021–FY2023 lists and #34 in FY2024; down 24 since FY2024.
59	CTI Environmental Inc Top agencies Army (Department of the Army)	$5,308,796	0.1%	Rank history: not on the FY2021–FY2024 lists; new.
60	Laubacker Enterprises, Inc. Top agencies Army (Department of the Army)	$4,898,000	0.1%	Rank history: not on the FY2021–FY2024 lists; new.
61	ICF International Inc. Through ICF Incorporated, L.L.C. Top agencies EPA (Environmental Protection Agency) DOI (Department of the Interior) USDA (Department of Agriculture)	$4,622,692	0.1%	Rank history: not on the FY2021–FY2023 lists and #43 in FY2024; down 18 since FY2024.
62	Skeo Solutions, Inc. Top agencies EPA (Environmental Protection Agency)	$4,504,433	0.1%	Rank history: #90 in FY2021, #22 in FY2022, #33 in FY2023 and #27 in FY2024; down 35 since FY2024.
63	Bhate Environmental Associates, Inc. Top agencies USAF (Department of the Air Force) Navy (Department of the Navy)	$4,316,435	0.1%	Rank history: #57 in FY2021, #52 in FY2022, #68 in FY2023 and #87 in FY2024; up 24 since FY2024.
64	Williams Construction & Cabinetry, Inc. Top agencies USDA (Department of Agriculture)	$4,228,500	0.1%	Rank history: not on the FY2021–FY2024 lists; new.
65	Potomac-Hudson Engineering Inc Top agencies DOE (Department of Energy)	$4,226,335	0.1%	Rank history: not on the FY2021–FY2023 lists and #71 in FY2024; up 6 since FY2024.
66	Noblis, Inc. Top agencies USAF (Department of the Air Force)	$4,222,912	0.1%	Rank history: not on the FY2021 list, #86 in FY2022, #88 in FY2023 and not on the FY2024 list; up 89 since FY2024.
67	Research Planning, Inc. Top agencies Commerce (Department of Commerce)	$4,084,918	0.1%	Rank history: not on the FY2021–FY2023 lists and #70 in FY2024; up 3 since FY2024.
68	Industrial Economics Inc. Top agencies DOE (Department of Energy) Commerce (Department of Commerce) EPA (Environmental Protection Agency)	$4,023,624	0.1%	Rank history: #95 in FY2021, #66 in FY2022, #51 in FY2023 and #56 in FY2024; down 12 since FY2024.
69	Genwest Systems Inc. Top agencies Commerce (Department of Commerce)	$3,841,649	0.1%	Rank history: #43 in FY2021, #51 in FY2022, #61 in FY2023 and not on the FY2024 list; up 79 since FY2024.
70	Enhanced Environmental & Emergency Services Inc. Top agencies Navy (Department of the Navy)	$3,785,088	0.1%	Rank history: not on the FY2021–FY2024 lists; up 82 since FY2024.
71	Ahtna-Arcadis 8(A) JV, LLC Top agencies Army (Department of the Army) USAF (Department of the Air Force)	$3,706,051	0.1%	Rank history: not on the FY2021–FY2022 lists, #30 in FY2023 and #53 in FY2024; down 18 since FY2024.
72	Cape-Weston JV1 LLC Top agencies Army (Department of the Army)	$3,655,672	0.1%	Rank history: not on the FY2021–FY2023 lists and #25 in FY2024; down 47 since FY2024.
73	Ayuda Arcadis 8A Joint Venture LLC Top agencies Army (Department of the Army) USAF (Department of the Air Force)	$3,602,749	0.1%	Rank history: #33 in FY2021, #73 in FY2022, #82 in FY2023 and #51 in FY2024; down 22 since FY2024.
74	Perikin Enterprises LLC Top agencies Army (Department of the Army)	$3,540,413	0.1%	Rank history: not on the FY2021–FY2022 lists, #80 in FY2023 and not on the FY2024 list; up 75 since FY2024.
75	Fpm-Aecom JV1 2 awardees, including Fpm-Aecom JV2 Top agencies DOE (Department of Energy) Army (Department of the Army) USAF (Department of the Air Force)	$3,503,404	0.1%	Rank history: not on the FY2021–FY2022 lists, #16 in FY2023 and #33 in FY2024; down 42 since FY2024.
76	Environmental Incentives, Inc. Top agencies USAID (US Agency for International Development)	$3,428,121	0.1%	Rank history: not on the FY2021–FY2023 lists and #95 in FY2024; up 19 since FY2024.
77	Signature Science, LLC Top agencies DFAS (Defense Finance and Accounting Service)	$3,375,037	0.1%	Rank history: not on the FY2021–FY2024 lists; up 46 since FY2024.
78	Koman ECO Ageiss JV LLC Top agencies USAF (Department of the Air Force) Army (Department of the Army)	$3,305,423	0.1%	Rank history: not on the FY2021–FY2024 lists; up 55 since FY2024.
79	Dawson Solutions LLC Through Laukoa Environmental Solutions, Inc. Top agencies DHS (Department of Homeland Security) USAF (Department of the Air Force) Army (Department of the Army)	$3,269,869	0.1%	Rank history: not on the FY2021–FY2022 lists, #69 in FY2023 and #9 in FY2024; down 70 since FY2024.
80	The Aleut Corporation 3 awardees, including Aleut Technical Services, LLC, Aleut Services, LLC and Aleut Environmental Remediation, LLC Top agencies EPA (Environmental Protection Agency) Army (Department of the Army)	$3,225,685	0.1%	Rank history: #58 in FY2021, not on the FY2022 list, #97 in FY2023 and not on the FY2024 list; returned.
81	Azura Consulting LLC Top agencies Commerce (Department of Commerce)	$3,117,608	0.1%	Rank history: not on the FY2021 list, #88 in FY2022, #73 in FY2023 and #77 in FY2024; down 4 since FY2024.
82	Gulf South Research Corp Top agencies Navy (Department of the Navy) OSD (Office of the Secretary of Defense) USAF (Department of the Air Force)	$2,995,777	0.1%	Rank history: not on the FY2021–FY2024 lists; up 32 since FY2024.
83	Gryphon Environmental, LLC Top agencies USAF (Department of the Air Force) Army (Department of the Army)	$2,948,889	0.1%	Rank history: not on the FY2021–FY2024 lists; up 62 since FY2024.
84	Energysolutions, LLC Top agencies Army (Department of the Army)	$2,947,890	0.1%	Rank history: not on the FY2021–FY2024 lists; new.
85	Weston Solutions Holdings, Inc. 2 awardees, including Weston Solutions Inc. Top agencies Army (Department of the Army) EPA (Environmental Protection Agency)	$2,928,709	0.1%	Rank history: #20 in FY2021, #29 in FY2022, #49 in FY2023 and not on the FY2024 list; up 57 since FY2024.
86	Ardl Inc. Top agencies Army (Department of the Army) EPA (Environmental Protection Agency)	$2,925,037	0.1%	Rank history: #31 in FY2021, not on the FY2022 list, #66 in FY2023 and not on the FY2024 list; up 207 since FY2024.
87	Ch2M Hill, Inc. Top agencies EPA (Environmental Protection Agency)	$2,872,881	0.1%	Rank history: not on the FY2021 list, #83 in FY2022, not on the FY2023 list and #50 in FY2024; down 37 since FY2024.
88	Ones Plexus Joint Venture LLC Top agencies Army (Department of the Army)	$2,841,700	0.1%	Rank history: not on the FY2021–FY2024 lists; new.
89	Renova-Sovereign Joint Venture Top agencies Army (Department of the Army)	$2,832,658	0.1%	Rank history: #64 in FY2021, #75 in FY2022 and not on the FY2023–FY2024 lists; up 54 since FY2024.
90	Sundance Consultants, LLC 3 awardees, including Sundance EA Associates II and Sundance - EA Alliance, LLC Top agencies Navy (Department of the Navy) Army (Department of the Army)	$2,808,910	0.1%	Rank history: not on the FY2021–FY2024 lists; up 27 since FY2024.
91	Marstel-Day, LLC Top agencies Navy (Department of the Navy) DOI (Department of the Interior)	$2,743,075	0.1%	Rank history: not on the FY2021 list, #93 in FY2022, #58 in FY2023 and not on the FY2024 list; up 115 since FY2024.
92	Research Triangle Institute Top agencies EPA (Environmental Protection Agency) Commerce (Department of Commerce)	$2,727,360	0.1%	Rank history: not on the FY2021–FY2024 lists; up 34 since FY2024.
93	Cape Fear Analytical, LLC Top agencies EPA (Environmental Protection Agency)	$2,696,266	0.1%	Rank history: not on the FY2021–FY2024 lists; new.
94	Catawba Teapec LLC Top agencies DOE (Department of Energy)	$2,648,722	0.1%	Rank history: not on the FY2021–FY2024 lists; new.
95	The Chenega Corporation 3 awardees, including Chenega Reliable Services LLC and C2 Alaska, LLC Top agencies Army (Department of the Army) DOI (Department of the Interior)	$2,611,545	0.1%	Rank history: not on the FY2021–FY2024 lists; new.
96	Ecodit LLC Top agencies USAID (US Agency for International Development)	$2,608,874	0.1%	Rank history: not on the FY2021–FY2024 lists; new.
97	Credere Associates, LLC Top agencies Army (Department of the Army)	$2,583,110	0.1%	Rank history: #55 in FY2021 and not on the FY2022–FY2024 lists; up 160 since FY2024.
98	Northrop Grumman Systems Corporation Through Alliant Techsystems Operations LLC Top agencies Army (Department of the Army)	$2,574,217	0.1%	Rank history: not on the FY2021–FY2024 lists; up 95 since FY2024.
99	Ahtna Solutions, LLC Top agencies USAF (Department of the Air Force) Commerce (Department of Commerce)	$2,557,673	0.1%	Rank history: not on the FY2021 list, #48 in FY2022, not on the FY2023 list and #83 in FY2024; down 16 since FY2024.
100	Claene Group LLC Top agencies Army (Department of the Army)	$2,548,344	0.1%	Rank history: not on the FY2021–FY2024 lists; up 36 since FY2024.

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100 of 604 contractors listed here. See the rest on GovTribe.

How this ranking works

Source: every contract action FPDS records (as published on SAM.gov) in the period, as GovTribe received it.
Amounts are net obligations: what was obligated, less what was deobligated. Shares are of $4.59 billion obligated before deobligations, so they never pass 100%.
Parent companies: each action counts under the ultimate parent its award record names, or under the awardee when it names none, so no dollar counts twice. An awardee whose own actions mostly name no parent, and that no other company's actions name as their parent, rolls up its SAM.gov registration's chain of parent companies: it counts under the first company there that other companies' actions name as their parent, or under the parent most of a company's own actions name, whichever comes first; with neither, under the highest company in the chain with federal contracts of its own. Joint ventures stay companies of their own. Parents of the same name (Inc., LLC and the like aside) count as one company, since FPDS records a company's parent under more than one UEI over time. GovTribe corrects a few parents and names by hand; see the corrections.
Fiscal year 2025 ran Oct 1, 2024 – Sep 30, 2025. The Department of Defense reports its contract actions to FPDS about 90 days late, so a fiscal year is ranked once they're in, in February, and the list doesn't change after.
Rank changes compare with FY2024. "New" marks a company outside that period's top 500, and "Returned" one of those that was on an earlier fiscal year's list.
Rank lines show each company's rank on every fiscal year's list since FY2021, #1 at the top, on a scale that gives the top of the list more room. A dashed stretch spans years it wasn't on the list. The step from FY2024 takes the color of the rank change beside it.
Placeholder recipients FPDS uses when it names no company ("Miscellaneous Foreign Contractors" and the like) aren't ranked.

Quick answers

Who were the top 10 PSC F999 contractors in FY2025?

1. Environmental Chemical Corporation ($1.89B), 2. Amentum Holdings, Inc. ($940M), 3. United Cleanup Oak Ridge LLC ($132M), 4. Guidehouse Inc. ($126M), 5. Hanford Laboratory Management and Integration LLC ($110M), 6. Idaho Environmental Coalition LLC ($89.8M), 7. BWX Technologies, Inc. ($65.6M), 8. Hydrogeologic, Inc. ($52.8M), 9. L3Harris Technologies, Inc. ($46.8M), 10. Sevenson Environmental Services, Inc. ($42.2M).

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