Top 100 Contractors in PSC B510: Environmental Studies and Assessments, Jul 2025–Jun 2026

Name: Top 100 Contractors in PSC B510: Environmental Studies and Assessments, Jul 2025–Jun 2026
Creator: GovTribe

Parent companies by net contract obligations Jul 1, 2025 – Jun 30, 2026 Code page on GovTribe

The top 10 won 58% of PSC B510 contract dollars from July 2025 through June 2026

Contract obligations: $236,652,451 Net of deobligations, by contracts coded PSC B510
Contractors: 214 Parent companies with an obligation
Largest contractor: Amentum Holdings, Inc. $38.9 million, 15.0% of obligations
Data as of: Oct 14, 2026

Contract actions from FPDS (SAM.gov). How the rankings work · Download all 100 rows as CSV

Full ranking

Rank	Contractor	Net obligations	Share	Trend
1	Amentum Holdings, Inc. Through Amentum Services, Inc. Top agencies Army (Department of the Army)	$38,867,641	15.0%	Rank history: not on the FY2021–FY2023 lists, #36 in FY2024 and #1 in FY2025; unchanged since Jul 2024–Jun 2025.
2	Gulf South Research Corp Top agencies DHS (Department of Homeland Security) DOT (Department of Transportation) DOI (Department of the Interior)	$26,485,754	10.2%	Rank history: not on the FY2021–FY2022 lists, #41 in FY2023, not on the FY2024 list and #3 in FY2025; up 55 since Jul 2024–Jun 2025.
3	Vernadero Group Inc. Top agencies DHS (Department of Homeland Security) Army (Department of the Army) IBWC (International Boundary and Water Commission U.S.-Mexico)	$22,649,549	8.7%	Rank history: #95 in FY2021, not on the FY2022–FY2024 lists and #5 in FY2025; new, not ranked in Jul 2024–Jun 2025.
4	Hdr, Inc. 2 awardees, including HDR Environmental, Operations and Construction, Inc. Top agencies Navy (Department of the Navy)	$11,994,888	4.6%	Rank history: #83 in FY2021, #47 in FY2022, #31 in FY2023, #4 in FY2024 and #4 in FY2025; down 1 since Jul 2024–Jun 2025.
5	Eastern Research Group Inc. Top agencies EPA (Environmental Protection Agency) DOI (Department of the Interior)	$10,176,374	3.9%	Rank history: #2 in FY2021, #12 in FY2022, #13 in FY2023, #7 in FY2024 and #6 in FY2025; up 11 since Jul 2024–Jun 2025.
6	Tierra Right of Way Services Ltd Top agencies DHS (Department of Homeland Security)	$8,887,899	3.4%	Rank history: not on the FY2021–FY2024 lists and #28 in FY2025; new, not ranked in Jul 2024–Jun 2025.
7	Dawson Solutions LLC Top agencies DHS (Department of Homeland Security) USDA (Department of Agriculture)	$8,731,862	3.4%	Rank history: not on the FY2021–FY2022 lists, #22 in FY2023, #42 in FY2024 and #7 in FY2025; up 31 since Jul 2024–Jun 2025.
8	Tetra Tech, Inc. 4 awardees Top agencies EPA (Environmental Protection Agency) DOE (Department of Energy)	$8,727,213	3.4%	Rank history: #7 in FY2021, #2 in FY2022, #1 in FY2023, #3 in FY2024 and #2 in FY2025; down 6 since Jul 2024–Jun 2025.
9	ECO & Associates, Inc. Top agencies DHS (Department of Homeland Security)	$8,393,259	3.2%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
10	Jacobs Government Services Company Through Jacobs Engineering Group Inc. Top agencies Army (Department of the Army)	$5,465,312	2.1%	Rank history: not on the FY2021–FY2023 lists, #10 in FY2024 and #8 in FY2025; up 1 since Jul 2024–Jun 2025.
11	University of California, Davis Top agencies EPA (Environmental Protection Agency)	$5,291,875	2.0%	Rank history: not on the FY2021–FY2023 lists, #23 in FY2024 and #9 in FY2025; down 6 since Jul 2024–Jun 2025.
12	Ardl Inc. Top agencies Army (Department of the Army)	$5,154,214	2.0%	Rank history: not on the FY2021 list, #39 in FY2022, #28 in FY2023, not on the FY2024 list and #32 in FY2025; up 21 since Jul 2024–Jun 2025.
13	Neptune and Company, Incorporated Top agencies DOE (Department of Energy)	$4,980,197	1.9%	Rank history: #61 in FY2021, #52 in FY2022, #18 in FY2023, #28 in FY2024 and #13 in FY2025; up 4 since Jul 2024–Jun 2025.
14	Dawson Mcg, Inc. Top agencies DHS (Department of Homeland Security)	$4,494,512	1.7%	Rank history: not on the FY2021–FY2024 lists and #12 in FY2025; new, not ranked in Jul 2024–Jun 2025.
15	Consolidated Safety Services Incorporated Top agencies EPA (Environmental Protection Agency)	$4,208,882	1.6%	Rank history: #9 in FY2021, #14 in FY2022, #15 in FY2023, #15 in FY2024 and #10 in FY2025; up 6 since Jul 2024–Jun 2025.
16	Golder Europe Service Centre SRL 2 awardees, including WSP USA Solutions Inc. and WSP Italia S.R.L. Top agencies DOE (Department of Energy) DOI (Department of the Interior) GSA (General Services Administration)	$3,559,823	1.4%	Rank history: not on the FY2021–FY2022 lists, #25 in FY2023, #18 in FY2024 and #14 in FY2025; down 10 since Jul 2024–Jun 2025.
17	Rmec Environmental Inc Top agencies Army (Department of the Army)	$3,419,660	1.3%	Rank history: not on the FY2021–FY2022 lists, #20 in FY2023, #17 in FY2024 and #16 in FY2025; down 3 since Jul 2024–Jun 2025.
18	AECOM 3 awardees, including Environmental Management & Planning Solutions LLC, AECOM Services, LLC and AECOM Italia S.P.A. Top agencies DOI (Department of the Interior) EOP (Executive Office of the President) Army (Department of the Army)	$2,980,854	1.1%	Rank history: #22 in FY2021, #5 in FY2022, #3 in FY2023, #12 in FY2024 and #30 in FY2025; down 11 since Jul 2024–Jun 2025.
19	Ciri Development Corporation Through North Wind Resource Consulting LLC Top agencies DOI (Department of the Interior)	$2,791,569	1.1%	Rank history: not on the FY2021–FY2022 lists, #27 in FY2023, not on the FY2024 list and #19 in FY2025; up 200 since Jul 2024–Jun 2025.
20	Southeastern Archaeological Research Inc. Top agencies Army (Department of the Army)	$2,469,182	1.0%	Rank history: #23 in FY2021, #35 in FY2022, #48 in FY2023, #54 in FY2024 and #15 in FY2025; up 4 since Jul 2024–Jun 2025.
21	MBK Engineers Top agencies DOI (Department of the Interior)	$2,467,103	1.0%	Rank history: #58 in FY2021, #69 in FY2022, #67 in FY2023, #13 in FY2024 and #53 in FY2025; up 50 since Jul 2024–Jun 2025.
22	Kemron Environmental Services Inc. Top agencies Army (Department of the Army)	$2,185,928	0.8%	Rank history: not on the FY2021–FY2023 lists, #2 in FY2024 and not on the FY2025 list; up 85 since Jul 2024–Jun 2025.
23	EA Engineering Science and Technology Inc. PBC Top agencies EPA (Environmental Protection Agency)	$1,925,763	0.7%	Rank history: not on the FY2021–FY2023 lists, #34 in FY2024 and #35 in FY2025; up 6 since Jul 2024–Jun 2025.
24	Environmental Testing and Consulting, Inc. Top agencies Army (Department of the Army)	$1,759,547	0.7%	Rank history: not on the FY2021 list, #27 in FY2022, #30 in FY2023, #30 in FY2024 and #21 in FY2025; up 1 since Jul 2024–Jun 2025.
25	Pb&A / CSS JV, Llc. Top agencies EPA (Environmental Protection Agency)	$1,717,319	0.7%	Rank history: not on the FY2021 list, #6 in FY2022, #7 in FY2023, #40 in FY2024 and not on the FY2025 list; up 17 since Jul 2024–Jun 2025.
26	Environmental Science Corporation Top agencies Army (Department of the Army)	$1,660,351	0.6%	Rank history: #36 in FY2021, #36 in FY2022, #46 in FY2023, #62 in FY2024 and #25 in FY2025; up 26 since Jul 2024–Jun 2025.
27	Avid Core LLC Top agencies DHS (Department of Homeland Security)	$1,634,791	0.6%	Rank history: not on the FY2021–FY2022 lists, #35 in FY2023, #37 in FY2024 and #24 in FY2025; up 1 since Jul 2024–Jun 2025.
28	Pond & Company Top agencies USAF (Department of the Air Force)	$1,516,045	0.6%	Rank history: not on the FY2021–FY2024 lists and #26 in FY2025; new, not ranked in Jul 2024–Jun 2025.
29	R Ward & Associates Inc. Top agencies Army (Department of the Army)	$1,446,581	0.6%	Rank history: not on the FY2021–FY2024 lists and #31 in FY2025; new, not ranked in Jul 2024–Jun 2025.
30	Horsley Witten Group, Inc. Top agencies EPA (Environmental Protection Agency)	$1,291,599	0.5%	Rank history: #12 in FY2021, #41 in FY2022, #40 in FY2023, #32 in FY2024 and #38 in FY2025; up 49 since Jul 2024–Jun 2025.
31	LG2 Environmental Solutions, Inc. Top agencies Army (Department of the Army)	$1,281,044	0.5%	Rank history: #20 in FY2021, #57 in FY2022, #49 in FY2023, #69 in FY2024 and #27 in FY2025; up 31 since Jul 2024–Jun 2025.
32	Ocean Associates Inc. Top agencies Commerce (Department of Commerce)	$1,262,815	0.5%	Rank history: not on the FY2021–FY2023 lists, #76 in FY2024 and #48 in FY2025; up 12 since Jul 2024–Jun 2025.
33	Environmental Assessment Services, LLC Top agencies Army (Department of the Army)	$1,247,287	0.5%	Rank history: not on the FY2021–FY2024 lists and #29 in FY2025; up 99 since Jul 2024–Jun 2025.
34	Chugai Technos Corporation Top agencies Navy (Department of the Navy)	$1,171,794	0.5%	Rank history: not on the FY2021–FY2024 lists and #45 in FY2025; up 40 since Jul 2024–Jun 2025.
35	Green Water Solutions, LLC Top agencies IBWC (International Boundary and Water Commission U.S.-Mexico)	$1,080,247	0.4%	Rank history: not on the FY2021–FY2024 lists and #39 in FY2025; new, not ranked in Jul 2024–Jun 2025.
36	Star Geoenvironmental LLC Top agencies Army (Department of the Army)	$1,054,384	0.4%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
37	Global Consulting Inc. Top agencies HHS (Department of Health and Human Services)	$990,371	0.4%	Rank history: #67 in FY2021, #73 in FY2022, #65 in FY2023, #53 in FY2024 and #41 in FY2025; down 5 since Jul 2024–Jun 2025.
38	Blue World Research Institute Inc. Top agencies DOI (Department of the Interior)	$948,524	0.4%	Rank history: #24 in FY2021, #72 in FY2022, #16 in FY2023, #38 in FY2024 and #40 in FY2025; up 2 since Jul 2024–Jun 2025.
39	Swca Incorporated Top agencies DOI (Department of the Interior)	$923,834	0.4%	Rank history: not on the FY2021–FY2023 lists, #29 in FY2024 and #57 in FY2025; down 8 since Jul 2024–Jun 2025.
40	WSP USA Environment & Infrastructure Inc. Top agencies DHS (Department of Homeland Security) DOI (Department of the Interior)	$923,269	0.4%	Rank history: not on the FY2021–FY2022 lists, #96 in FY2023, not on the FY2024 list and #95 in FY2025; new, not ranked in Jul 2024–Jun 2025.
41	Chloeta Holdings LLC Top agencies USDA (Department of Agriculture)	$896,128	0.3%	Rank history: not on the FY2021–FY2023 lists, #75 in FY2024 and #44 in FY2025; up 28 since Jul 2024–Jun 2025.
42	Marstel-Day, LLC Top agencies DOI (Department of the Interior) USAF (Department of the Air Force)	$878,651	0.3%	Rank history: #88 in FY2021, #58 in FY2022, #47 in FY2023, #77 in FY2024 and #49 in FY2025; up 24 since Jul 2024–Jun 2025.
43	Mtsa II JV LLC Top agencies DHS (Department of Homeland Security)	$864,775	0.3%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
44	Hawaii International Environmental Services Inc. Top agencies Army (Department of the Army)	$847,856	0.3%	Rank history: not on the FY2021–FY2024 lists and #46 in FY2025; up 71 since Jul 2024–Jun 2025.
45	Quaternary Resource Investigations, L.L.C. Top agencies GSA (General Services Administration)	$791,926	0.3%	Rank history: #91 in FY2021, #23 in FY2022, #24 in FY2023, #43 in FY2024 and not on the FY2025 list; up 33 since Jul 2024–Jun 2025.
46	Semanticbits LLC Through ICF Incorporated, L.L.C. Top agencies DOI (Department of the Interior) DOT (Department of Transportation) USDA (Department of Agriculture)	$657,185	0.3%	Rank history: not on the FY2021–FY2023 lists, #45 in FY2024 and not on the FY2025 list; down 5 since Jul 2024–Jun 2025.
47	Paleowest LLC Top agencies Army (Department of the Army)	$631,886	0.2%	Rank history: #99 in FY2021, not on the FY2022–FY2023 lists, #94 in FY2024 and #37 in FY2025; up 8 since Jul 2024–Jun 2025.
48	American Resources Group Ltd Top agencies USDA (Department of Agriculture)	$626,577	0.2%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
49	S C & A Inc. Top agencies DOE (Department of Energy) NRC (Nuclear Regulatory Commission)	$554,559	0.2%	Rank history: #54 in FY2021, not on the FY2022–FY2023 lists, #35 in FY2024 and #36 in FY2025; down 19 since Jul 2024–Jun 2025.
50	Kfs, LLC Top agencies Army (Department of the Army)	$548,147	0.2%	Rank history: not on the FY2021–FY2024 lists and #22 in FY2025; down 15 since Jul 2024–Jun 2025.
51	ASM Affiliates Inc. Top agencies DOI (Department of the Interior)	$545,000	0.2%	Rank history: not on the FY2021 list, #63 in FY2022, not on the FY2023 list, #74 in FY2024 and not on the FY2025 list; up 130 since Jul 2024–Jun 2025.
52	Ironwood Consulting Inc. Top agencies DOI (Department of the Interior)	$519,145	0.2%	Rank history: not on the FY2021–FY2024 lists and #55 in FY2025; up 18 since Jul 2024–Jun 2025.
53	Minatoishi Palumbo Architects, Inc. Top agencies Army (Department of the Army)	$503,285	0.2%	Rank history: not on the FY2021–FY2023 lists, #1 in FY2024 and #74 in FY2025; up 39 since Jul 2024–Jun 2025.
54	Ecoquants LLC Top agencies DOI (Department of the Interior)	$500,000	0.2%	Rank history: not on the FY2021–FY2022 lists, #94 in FY2023, not on the FY2024 list and #56 in FY2025; new, not ranked in Jul 2024–Jun 2025.
55	Hydrogeologic, Inc. Top agencies EPA (Environmental Protection Agency)	$456,449	0.2%	Rank history: not on the FY2021–FY2023 lists, #59 in FY2024 and #50 in FY2025; down 1 since Jul 2024–Jun 2025.
56	Heliotech Top agencies EPA (Environmental Protection Agency)	$442,756	0.2%	Rank history: not on the FY2021–FY2024 lists and #61 in FY2025; up 135 since Jul 2024–Jun 2025.
57	Raven Environmental Services, Inc. Top agencies USDA (Department of Agriculture)	$439,814	0.2%	Rank history: not on the FY2021–FY2024 lists and #60 in FY2025; up 77 since Jul 2024–Jun 2025.
58	Ecological Associates, Inc. Top agencies Army (Department of the Army)	$415,148	0.2%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
59	Watercourse Engineering, Inc. Top agencies DOI (Department of the Interior)	$400,000	0.2%	Rank history: not on the FY2021–FY2023 lists, #89 in FY2024 and #47 in FY2025; down 8 since Jul 2024–Jun 2025.
60	ERO Resources Corporation Top agencies DOI (Department of the Interior)	$380,111	0.1%	Rank history: not on the FY2021 list, #60 in FY2022, #39 in FY2023, #46 in FY2024 and #64 in FY2025; new, not ranked in Jul 2024–Jun 2025.
61	Copperhead Environmental Consulting Inc. Top agencies USDA (Department of Agriculture)	$368,700	0.1%	Rank history: not on the FY2021 list, #66 in FY2022, #63 in FY2023, #97 in FY2024 and not on the FY2025 list; up 74 since Jul 2024–Jun 2025.
62	Historical Research Associates, Inc. Top agencies DOI (Department of the Interior)	$351,597	0.1%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
63	Seva EHS Inc Top agencies DLA (Defense Logistics Agency)	$317,610	0.1%	Rank history: not on the FY2021–FY2025 lists; up 21 since Jul 2024–Jun 2025.
64	I-2-I Solutions, Inc. Top agencies IBWC (International Boundary and Water Commission U.S.-Mexico)	$316,520	0.1%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
65	HDR and Tehama Joint Venture Top agencies USAF (Department of the Air Force)	$314,904	0.1%	Rank history: not on the FY2021–FY2024 lists and #65 in FY2025; new, not ranked in Jul 2024–Jun 2025.
66	AECOM Technical Services, Inc. Top agencies DOI (Department of the Interior)	$305,217	0.1%	Rank history: not on the FY2021–FY2023 lists, #5 in FY2024 and #54 in FY2025; down 58 since Jul 2024–Jun 2025.
67	Mabbett & Associates, Inc. Top agencies VA (Department of Veterans Affairs)	$300,548	0.1%	Rank history: #39 in FY2021, #33 in FY2022, not on the FY2023 list, #55 in FY2024 and #59 in FY2025; down 14 since Jul 2024–Jun 2025.
68	Kgsne JV II LLC Top agencies EPA (Environmental Protection Agency)	$300,080	0.1%	Rank history: not on the FY2021 list, #10 in FY2022, #17 in FY2023, #22 in FY2024 and #11 in FY2025; down 56 since Jul 2024–Jun 2025.
69	I.w. Tremont Co. Inc. Top agencies EPA (Environmental Protection Agency)	$295,734	0.1%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
70	TDA Research, Inc. Top agencies Navy (Department of the Navy)	$295,592	0.1%	Rank history: not on the FY2021–FY2024 lists and #68 in FY2025; new, not ranked in Jul 2024–Jun 2025.
71	OCH JV Top agencies EPA (Environmental Protection Agency)	$294,106	0.1%	Rank history: #66 in FY2021, not on the FY2022–FY2024 lists and #69 in FY2025; up 17 since Jul 2024–Jun 2025.
72	S&K Mission Support, LLC Top agencies USDA (Department of Agriculture)	$283,836	0.1%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
73	Bluestone Environmental Group, Inc. Top agencies Army (Department of the Army)	$281,690	0.1%	Rank history: not on the FY2021 list, #83 in FY2022, #73 in FY2023, not on the FY2024 list and #67 in FY2025; up 16 since Jul 2024–Jun 2025.
74	New South Associates, Inc. Top agencies DOI (Department of the Interior)	$270,336	0.1%	Rank history: not on the FY2021–FY2024 lists and #72 in FY2025; up 133 since Jul 2024–Jun 2025.
75	Oneida Environmental, LLC Top agencies Navy (Department of the Navy)	$267,601	0.1%	Rank history: not on the FY2021–FY2024 lists and #70 in FY2025; up 16 since Jul 2024–Jun 2025.
76	SES Inc. Top agencies USDA (Department of Agriculture)	$266,300	0.1%	Rank history: not on the FY2021–FY2024 lists and #76 in FY2025; up 19 since Jul 2024–Jun 2025.
77	Al Department Environmental Management Top agencies NASA (National Aeronautics and Space Administration)	$265,000	0.1%	Rank history: not on the FY2021–FY2024 lists and #71 in FY2025; up 161 since Jul 2024–Jun 2025.
78	DAV Energy Solutions, Inc. Top agencies Army (Department of the Army)	$259,000	0.1%	Rank history: not on the FY2021–FY2024 lists and #75 in FY2025; up 133 since Jul 2024–Jun 2025.
79	Research Triangle Institute Top agencies DOI (Department of the Interior)	$257,606	0.1%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
80	Cherokee Nation Through Cherokee Nation Environmental Solutions, L.L.C. Top agencies Army (Department of the Army)	$254,217	0.1%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
81	Avanti Corporation Top agencies DOI (Department of the Interior)	$251,667	0.1%	Rank history: not on the FY2021–FY2022 lists, #90 in FY2023 and not on the FY2024–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
82	Alaska Biomap, Inc. Top agencies DOI (Department of the Interior)	$250,435	0.1%	Rank history: not on the FY2021–FY2024 lists and #80 in FY2025; up 46 since Jul 2024–Jun 2025.
83	Environmental Science Services Inc. Top agencies Army (Department of the Army)	$248,856	0.1%	Rank history: not on the FY2021–FY2024 lists and #33 in FY2025; down 49 since Jul 2024–Jun 2025.
84	Advista Top agencies DOS (Department of State)	$248,711	0.1%	Rank history: not on the FY2021–FY2024 lists and #77 in FY2025; new, not ranked in Jul 2024–Jun 2025.
85	Rock Leaf Water Environmental LLC Top agencies USDA (Department of Agriculture)	$244,745	0.1%	Rank history: not on the FY2021–FY2024 lists and #78 in FY2025; up 21 since Jul 2024–Jun 2025.
86	Bromgrove Limited Top agencies USAF (Department of the Air Force)	$243,882	0.1%	Rank history: not on the FY2021–FY2024 lists and #88 in FY2025; up 36 since Jul 2024–Jun 2025.
87	Deloitte 2 awardees, including Deloitte & Touche LLP Top agencies DOI (Department of the Interior)	$238,217	0.1%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
88	Hsg, LLC Top agencies DOI (Department of the Interior)	$236,598	0.1%	Rank history: #78 in FY2021, not on the FY2022–FY2024 lists and #79 in FY2025; up 157 since Jul 2024–Jun 2025.
89	Johnson, Mirmiran & Thompson, Inc. Top agencies GSA (General Services Administration)	$224,153	0.1%	Rank history: not on the FY2021–FY2022 lists, #66 in FY2023, #78 in FY2024 and #86 in FY2025; up 13 since Jul 2024–Jun 2025.
90	Environmental Cost Management, Inc. Top agencies DOI (Department of the Interior)	$220,948	0.1%	Rank history: not on the FY2021 list, #97 in FY2022, not on the FY2023 list, #85 in FY2024 and #73 in FY2025; down 17 since Jul 2024–Jun 2025.
91	Swift River Versar JV Top agencies Navy (Department of the Navy)	$220,617	0.1%	Rank history: #45 in FY2021, #38 in FY2022, #44 in FY2023, #24 in FY2024 and #81 in FY2025; down 65 since Jul 2024–Jun 2025.
92	Atkinsrealis USA Inc. Top agencies DOI (Department of the Interior)	$215,245	0.1%	Rank history: not on the FY2021–FY2024 lists and #83 in FY2025; new, not ranked in Jul 2024–Jun 2025.
93	Vanasse Hangen Brustlin Inc. Top agencies DOI (Department of the Interior)	$213,154	0.1%	Rank history: not on the FY2021–FY2024 lists and #84 in FY2025; new, not ranked in Jul 2024–Jun 2025.
94	Solv LLC Top agencies DOI (Department of the Interior)	$209,252	0.1%	Rank history: not on the FY2021–FY2022 lists, #61 in FY2023, not on the FY2024 list and #85 in FY2025; up 85 since Jul 2024–Jun 2025.
95	Aerialzeus, LLC Top agencies DOI (Department of the Interior)	$195,000	0.1%	Rank history: not on the FY2021–FY2024 lists and #87 in FY2025; new, not ranked in Jul 2024–Jun 2025.
96	Blue Yonder Inc. Through TRC Environmental Corporation Top agencies EPA (Environmental Protection Agency)	$189,950	0.1%	Rank history: not on the FY2021–FY2024 lists and #90 in FY2025; up 14 since Jul 2024–Jun 2025.
97	Water, Civil and Environmental Incorporated Top agencies USDA (Department of Agriculture)	$188,680	0.1%	Rank history: not on the FY2021–FY2025 lists; up 1 since Jul 2024–Jun 2025.
98	Cultural Resource Analysts, Inc. Top agencies DOT (Department of Transportation)	$186,905	0.1%	Rank history: not on the FY2021–FY2024 lists and #92 in FY2025; new, not ranked in Jul 2024–Jun 2025.
99	Relife SPA Through Relife Recycling S.R.L. Top agencies Army (Department of the Army)	$185,854	0.1%	Rank history: not on the FY2021–FY2025 lists; up 15 since Jul 2024–Jun 2025.
100	Ivl, Institut FÜR Vegetationskunde UND Landschaftsökologie H. Schott UND Partner Landschaftsökologen Top agencies Army (Department of the Army)	$178,050	0.1%	Rank history: not on the FY2021–FY2024 lists and #93 in FY2025; new, not ranked in Jul 2024–Jun 2025.

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100 of 214 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 $259 million 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. 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.
Period: the trailing 12 months end with the last month that ended at least 90 days ago, because the Department of Defense reports its contract actions to FPDS about 90 days late. The list is rebuilt each night.
Rank changes compare with Jul 2024–Jun 2025. "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.
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 B510 contractors in Jul 2025–Jun 2026?

1. Amentum Holdings, Inc. ($38.9M), 2. Gulf South Research Corp ($26.5M), 3. Vernadero Group Inc. ($22.6M), 4. Hdr, Inc. ($12M), 5. Eastern Research Group Inc. ($10.2M), 6. Tierra Right of Way Services Ltd ($8.89M), 7. Dawson Solutions LLC ($8.73M), 8. Tetra Tech, Inc. ($8.73M), 9. ECO & Associates, Inc. ($8.39M), 10. Jacobs Government Services Company ($5.47M).

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