Top 100 Contractors in NAICS 621111: Offices of Physicians (except Mental Health Specialists), FY2022

Full ranking

Rank	Contractor	Net obligations	Share	Trend
1	Leidos Holdings, Inc. Through QTC Medical Services Inc. Top agencies VA (Department of Veterans Affairs) DHS (Department of Homeland Security) HHS (Department of Health and Human Services)	$935,812,494	31.7%	Rank history: #2 in FY2021, #1 in FY2023, #1 in FY2024 and #1 in FY2025; up 1 since FY2021.
2	UnitedHealth Group Incorporated Through Optumserve Health Services, Inc. Top agencies VA (Department of Veterans Affairs) DHA (Defense Health Agency) Army (Department of the Army)	$794,972,635	27.0%	Rank history: #3 in FY2021, #2 in FY2023, #2 in FY2024 and #2 in FY2025; up 1 since FY2021.
3	Maximus Inc. Through Veterans Evaluation Services, Inc. Top agencies VA (Department of Veterans Affairs)	$690,607,689	23.4%	Rank history: #5 in FY2021, #3 in FY2023, #4 in FY2024 and not on the FY2025 list; up 2 since FY2021.
4	Triwest Healthcare Alliance Corp Top agencies VA (Department of Veterans Affairs)	$110,342,006	3.7%	Rank history: #1 in FY2021, #5 in FY2023, #75 in FY2024 and not on the FY2025 list; down 3 since FY2021.
5	International Sos Government Medical Services, Inc. Top agencies Army (Department of the Army)	$31,730,708	1.1%	Rank history: not on the FY2021 list, #7 in FY2023, #18 in FY2024 and not on the FY2025 list; new.
6	Native Health Top agencies HHS (Department of Health and Human Services)	$25,816,853	0.9%	Rank history: #33 in FY2021, #27 in FY2023, #33 in FY2024 and #32 in FY2025; up 27 since FY2021.
7	The Chenega Corporation 3 awardees, including Chenega Tri-Services, LLC and Chenega Reliable Services LLC Top agencies Army (Department of the Army) Commerce (Department of Commerce) NSF (National Science Foundation)	$25,402,561	0.9%	Rank history: #6 in FY2021, #6 in FY2023, #8 in FY2024 and not on the FY2025 list; down 1 since FY2021.
8	Loyal Source Government Services LLC Top agencies VA (Department of Veterans Affairs)	$24,940,091	0.8%	Rank history: not on the FY2021 list, #4 in FY2023, #5 in FY2024 and #4 in FY2025; new.
9	Spectrum Healthcare Resources Incorporated Top agencies HHS (Department of Health and Human Services)	$7,276,114	0.2%	Rank history: #7 in FY2021 and not on the FY2023–FY2025 lists; down 2 since FY2021.
10	Eagle Global Scientific, LLC Top agencies HHS (Department of Health and Human Services) Army (Department of the Army)	$6,375,669	0.2%	Rank history: #9 in FY2021 and not on the FY2023–FY2025 lists; down 1 since FY2021.
11	Medicus Healthcare Solutions, LLC Top agencies VA (Department of Veterans Affairs) HHS (Department of Health and Human Services)	$6,300,581	0.2%	Rank history: #20 in FY2021, #8 in FY2023, #16 in FY2024 and #14 in FY2025; up 9 since FY2021.
12	Millbrook Support Services Inc. Top agencies VA (Department of Veterans Affairs)	$5,116,168	0.2%	Rank history: #59 in FY2021 and not on the FY2023–FY2025 lists; up 47 since FY2021.
13	Ansible Government Solutions LLC Top agencies VA (Department of Veterans Affairs)	$4,692,713	0.2%	Rank history: #17 in FY2021, #14 in FY2023, #42 in FY2024 and #33 in FY2025; up 4 since FY2021.
14	Avosys Technology, Inc. Top agencies USAF (Department of the Air Force)	$4,552,238	0.2%	Rank history: #10 in FY2021, #21 in FY2023, #17 in FY2024 and #16 in FY2025; down 4 since FY2021.
15	Heartbeat Health, Inc. Top agencies VA (Department of Veterans Affairs)	$4,114,850	0.1%	Rank history: not on the FY2021 list and not on the FY2023–FY2025 lists; new.
16	Acuity International LLC Top agencies Army (Department of the Army)	$4,073,701	0.1%	Rank history: not on the FY2021 list, #16 in FY2023, #21 in FY2024 and #9 in FY2025; new.
17	AB Staffing Solutions LLC Top agencies HHS (Department of Health and Human Services)	$3,719,163	0.1%	Rank history: #18 in FY2021, #20 in FY2023 and not on the FY2024–FY2025 lists; up 1 since FY2021.
18	Total Emergency Ambulatory Medicine LLP Top agencies VA (Department of Veterans Affairs)	$3,499,481	0.1%	Rank history: #11 in FY2021, #34 in FY2023, #53 in FY2024 and not on the FY2025 list; down 7 since FY2021.
19	Oklahoma State University Top agencies HHS (Department of Health and Human Services) DOJ (Department of Justice)	$3,377,864	0.1%	Rank history: #14 in FY2021, #17 in FY2023, #85 in FY2024 and not on the FY2025 list; down 5 since FY2021.
20	Dilligas Corp Top agencies VA (Department of Veterans Affairs)	$3,327,968	0.1%	Rank history: #13 in FY2021, #63 in FY2023 and not on the FY2024–FY2025 lists; down 7 since FY2021.
21	Prairie Band Health Services Inc. Top agencies HHS (Department of Health and Human Services)	$3,299,250	0.1%	Rank history: not on the FY2021 list, #29 in FY2023, #13 in FY2024 and #8 in FY2025; up 162 since FY2021.
22	Wellpath LLC Top agencies DOJ (Department of Justice)	$3,276,234	0.1%	Rank history: #24 in FY2021, #51 in FY2023 and not on the FY2024–FY2025 lists; up 2 since FY2021.
23	Nativearc, LLC Top agencies HHS (Department of Health and Human Services)	$3,169,505	0.1%	Rank history: not on the FY2021 list, #18 in FY2023, #30 in FY2024 and #74 in FY2025; new.
24	CHS Middle East LLC Through Acuity-Chs, LLC Top agencies WHS (DOD Washington Headquarters Service) Treasury (Department of the Treasury) DISA (Defense Information Systems Agency)	$3,121,893	0.1%	Rank history: #23 in FY2021, #19 in FY2023, #67 in FY2024 and not on the FY2025 list; down 1 since FY2021.
25	EGA Associates, LLC 2 awardees Top agencies VA (Department of Veterans Affairs)	$2,964,453	0.1%	Rank history: #34 in FY2021, #43 in FY2023, #31 in FY2024 and #24 in FY2025; up 9 since FY2021.
26	South Carolina State of 2 awardees, including Medical University Hospital Authority and Medical University of South Carolina The Top agencies VA (Department of Veterans Affairs)	$2,936,043	0.1%	Rank history: not on the FY2021 list and not on the FY2023–FY2025 lists; new.
27	Vetmed Group LLC Top agencies VA (Department of Veterans Affairs)	$2,928,756	0.1%	Rank history: #30 in FY2021, #11 in FY2023, #12 in FY2024 and #12 in FY2025; up 3 since FY2021.
28	Pinnacle Emergency Medical Group, PLLC Top agencies HHS (Department of Health and Human Services)	$2,854,620	0.1%	Rank history: #26 in FY2021, #66 in FY2023 and not on the FY2024–FY2025 lists; down 2 since FY2021.
29	Inrad, LLC Top agencies HHS (Department of Health and Human Services)	$2,851,750	0.1%	Rank history: #27 in FY2021, #47 in FY2023 and not on the FY2024–FY2025 lists; down 2 since FY2021.
30	Rielcad JV LLC Top agencies Army (Department of the Army)	$2,849,750	0.1%	Rank history: #85 in FY2021, #15 in FY2023, #32 in FY2024 and #29 in FY2025; up 55 since FY2021.
31	Market Services, Inc. Top agencies HHS (Department of Health and Human Services)	$2,698,625	0.1%	Rank history: #39 in FY2021, #38 in FY2023, #74 in FY2024 and not on the FY2025 list; up 8 since FY2021.
32	Medical Faculty Associates, Inc. Top agencies DHA (Defense Health Agency) DOS (Department of State)	$2,576,926	0.1%	Rank history: #25 in FY2021, #24 in FY2023, #35 in FY2024 and #69 in FY2025; down 7 since FY2021.
33	State of California Controllers Office 2 awardees, including The Regents of the University of California. San Francisco and University of California, Davis Top agencies HHS (Department of Health and Human Services) VA (Department of Veterans Affairs)	$2,567,363	0.1%	Rank history: #50 in FY2021, #48 in FY2023 and not on the FY2024–FY2025 lists; up 17 since FY2021.
34	Chickasaw Business Solutions, LLC Top agencies USAF (Department of the Air Force)	$2,477,382	0.1%	Rank history: not on the FY2021 list, #25 in FY2023, #37 in FY2024 and #36 in FY2025; new.
35	CHG Healthcare Services Inc. Through CHG Companies, Inc. Top agencies HHS (Department of Health and Human Services) DOJ (Department of Justice)	$2,466,934	0.1%	Rank history: #95 in FY2021, #28 in FY2023, #27 in FY2024 and not on the FY2025 list; up 60 since FY2021.
36	Vision Technology Inc. Top agencies Army (Department of the Army)	$2,457,114	0.1%	Rank history: #65 in FY2021, #30 in FY2023 and not on the FY2024–FY2025 lists; up 29 since FY2021.
37	Ghost RX Inc. Top agencies VA (Department of Veterans Affairs)	$2,394,846	0.1%	Rank history: #29 in FY2021, #9 in FY2023 and not on the FY2024–FY2025 lists; down 8 since FY2021.
38	Bay Area Anesthesia LLC Top agencies HHS (Department of Health and Human Services)	$2,328,124	0.1%	Rank history: #92 in FY2021, #13 in FY2023, #24 in FY2024 and #44 in FY2025; up 54 since FY2021.
39	Acuity-Chs, LLC Top agencies WHS (DOD Washington Headquarters Service) Treasury (Department of the Treasury)	$2,301,411	0.1%	Rank history: not on the FY2021 list, not on the FY2023 list, #22 in FY2024 and #21 in FY2025; up 70 since FY2021.
40	Nationwide Healthcare Solutions, LLC Top agencies Army (Department of the Army)	$2,250,394	0.1%	Rank history: #35 in FY2021, #22 in FY2023, #40 in FY2024 and #39 in FY2025; down 5 since FY2021.
41	University System of Maryland 3 awardees, including University of Maryland Diagnostic Imaging Specialists, P. A. and University of Maryland Neurology Associates Pa Top agencies VA (Department of Veterans Affairs)	$2,055,314	0.1%	Rank history: #19 in FY2021, #58 in FY2023, #43 in FY2024 and not on the FY2025 list; down 22 since FY2021.
42	American Correctional Healthcare, Inc. Top agencies DOJ (Department of Justice)	$1,903,098	0.1%	Rank history: not on the FY2021 list, not on the FY2023–FY2024 lists and #93 in FY2025; new.
43	Katmai Integrated Solutions, LLC Top agencies Army (Department of the Army)	$1,882,860	0.1%	Rank history: #46 in FY2021 and not on the FY2023–FY2025 lists; up 3 since FY2021.
44	U.s. Federal Solutions, Inc. Top agencies DHA (Defense Health Agency)	$1,752,700	0.1%	Rank history: #54 in FY2021, #32 in FY2023, #46 in FY2024 and not on the FY2025 list; up 10 since FY2021.
45	Sentrillion Corporation Through Altos Federal Group Inc. Top agencies CSOSA (Court Services and Offender Supervision Agency)	$1,743,800	0.1%	Rank history: #51 in FY2021, #72 in FY2023 and not on the FY2024–FY2025 lists; up 6 since FY2021.
46	Call Solutions, LLC Top agencies VA (Department of Veterans Affairs)	$1,668,800	0.1%	Rank history: #58 in FY2021, #45 in FY2023, #78 in FY2024 and #42 in FY2025; up 12 since FY2021.
47	Keith Van Meter & Associates (A Professional Medical Corporation) Top agencies VA (Department of Veterans Affairs)	$1,661,536	0.1%	Rank history: #36 in FY2021 and not on the FY2023–FY2025 lists; down 11 since FY2021.
48	Heart of America Indian Center, Inc. Top agencies HHS (Department of Health and Human Services)	$1,657,515	0.1%	Rank history: not on the FY2021 list and not on the FY2023–FY2025 lists; up 60 since FY2021.
49	Minneapolis Radiology Associates, Ltd. Top agencies VA (Department of Veterans Affairs)	$1,655,795	0.1%	Rank history: #41 in FY2021, #44 in FY2023, #41 in FY2024 and #47 in FY2025; down 8 since FY2021.
50	Frontline National LLC Top agencies Army (Department of the Army) USAF (Department of the Air Force) USDA (Department of Agriculture)	$1,648,477	0.1%	Rank history: #37 in FY2021, not on the FY2023 list, #76 in FY2024 and #66 in FY2025; down 13 since FY2021.
51	Vergence LLC Top agencies Army (Department of the Army)	$1,631,110	0.1%	Rank history: not on the FY2021 list and not on the FY2023–FY2025 lists; new.
52	Avera Health 2 awardees, including Avera Mckennan and Wagner Community Memorial Hospital Top agencies VA (Department of Veterans Affairs) Army (Department of the Army)	$1,589,930	0.1%	Rank history: #31 in FY2021, #42 in FY2023 and not on the FY2024–FY2025 lists; down 21 since FY2021.
53	Metropolitan Medical LLC Top agencies USDA (Department of Agriculture)	$1,500,000	0.1%	Rank history: not on the FY2021 list, #36 in FY2023, #44 in FY2024 and not on the FY2025 list; new.
54	Lowcountry Surgery Center, LLC Top agencies VA (Department of Veterans Affairs)	$1,445,847	<0.1%	Rank history: not on the FY2021 list and not on the FY2023–FY2025 lists; new.
55	Jade Wolf Operations, LLC Top agencies VA (Department of Veterans Affairs)	$1,399,837	<0.1%	Rank history: #52 in FY2021, #10 in FY2023, #28 in FY2024 and #27 in FY2025; down 3 since FY2021.
56	Sterling Medical Corporation Top agencies VA (Department of Veterans Affairs)	$1,370,113	<0.1%	Rank history: #49 in FY2021, not on the FY2023 list, #19 in FY2024 and not on the FY2025 list; down 7 since FY2021.
57	MCV Associated Physicians Top agencies VA (Department of Veterans Affairs)	$1,357,510	<0.1%	Rank history: #53 in FY2021 and not on the FY2023–FY2025 lists; down 4 since FY2021.
58	University of Minnesota Physicians Top agencies VA (Department of Veterans Affairs)	$1,303,292	<0.1%	Rank history: #12 in FY2021, #62 in FY2023, not on the FY2024 list and #63 in FY2025; down 46 since FY2021.
59	Clinovators LLC Top agencies VA (Department of Veterans Affairs)	$1,224,621	<0.1%	Rank history: #60 in FY2021 and not on the FY2023–FY2025 lists; up 1 since FY2021.
60	Sequoyah Staffing Agency, LLC Top agencies HHS (Department of Health and Human Services)	$1,215,252	<0.1%	Rank history: #21 in FY2021, #12 in FY2023, #14 in FY2024 and #18 in FY2025; down 39 since FY2021.
61	Cherokee Nation Mission Solutions, L.L.C. Top agencies Army (Department of the Army)	$1,127,193	<0.1%	Rank history: #43 in FY2021 and not on the FY2023–FY2025 lists; down 18 since FY2021.
62	Medstar Health, Inc. Through Radamerica II, LLC Top agencies VA (Department of Veterans Affairs)	$1,121,696	<0.1%	Rank history: #42 in FY2021 and not on the FY2023–FY2025 lists; down 20 since FY2021.
63	DAX Safety & Staffing Solutions, LLC Top agencies VA (Department of Veterans Affairs) HHS (Department of Health and Human Services)	$1,100,432	<0.1%	Rank history: not on the FY2021 list, #50 in FY2023, #29 in FY2024 and #54 in FY2025; up 323 since FY2021.
64	University of Louisville Top agencies VA (Department of Veterans Affairs)	$1,041,145	<0.1%	Rank history: #83 in FY2021, #99 in FY2023 and not on the FY2024–FY2025 lists; up 19 since FY2021.
65	Vascular Radiology Associates II Top agencies VA (Department of Veterans Affairs)	$1,038,917	<0.1%	Rank history: #82 in FY2021, #83 in FY2023 and not on the FY2024–FY2025 lists; up 17 since FY2021.
66	Hanford Occupational Healthcare and Wellness Inc. Top agencies DOE (Department of Energy)	$1,035,719	<0.1%	Rank history: #47 in FY2021 and not on the FY2023–FY2025 lists; down 19 since FY2021.
67	All Valley Imaging, L.l.c Top agencies HHS (Department of Health and Human Services)	$1,027,032	<0.1%	Rank history: not on the FY2021 list, #31 in FY2023, #38 in FY2024 and #77 in FY2025; up 384 since FY2021.
68	Giacare Inc. Top agencies Army (Department of the Army)	$1,017,419	<0.1%	Rank history: #61 in FY2021 and not on the FY2023–FY2025 lists; down 7 since FY2021.
69	Wichita Radiological Group Pa Top agencies VA (Department of Veterans Affairs)	$1,009,300	<0.1%	Rank history: #69 in FY2021, #60 in FY2023, #60 in FY2024 and #62 in FY2025; unchanged since FY2021.
70	Tribal Providers PLLC Top agencies HHS (Department of Health and Human Services)	$997,160	<0.1%	Rank history: not on the FY2021 list, not on the FY2023 list, #71 in FY2024 and not on the FY2025 list; new.
71	SI2 LLC Top agencies VA (Department of Veterans Affairs)	$994,755	<0.1%	Rank history: not on the FY2021 list, #86 in FY2023, not on the FY2024 list and #68 in FY2025; new.
72	Watanabe Enterprises LLC Top agencies VA (Department of Veterans Affairs)	$983,362	<0.1%	Rank history: #100 in FY2021, #64 in FY2023, #86 in FY2024 and #71 in FY2025; up 28 since FY2021.
73	Shelin, Agrawal, and Hyer, PLLC Top agencies USAF (Department of the Air Force)	$975,883	<0.1%	Rank history: #72 in FY2021, #55 in FY2023, #69 in FY2024 and #70 in FY2025; down 1 since FY2021.
74	Northstar Anesthesia of Michigan, PLLC Top agencies VA (Department of Veterans Affairs)	$975,572	<0.1%	Rank history: not on the FY2021 list and not on the FY2023–FY2025 lists; new.
75	Circulatory Services Inc. Top agencies VA (Department of Veterans Affairs)	$957,310	<0.1%	Rank history: #70 in FY2021, #61 in FY2023, not on the FY2024 list and #67 in FY2025; down 5 since FY2021.
76	Emory University Top agencies VA (Department of Veterans Affairs)	$946,303	<0.1%	Rank history: not on the FY2021 list, #56 in FY2023, #77 in FY2024 and not on the FY2025 list; up 407 since FY2021.
77	Assurgent Medical Staffing LLC Top agencies VA (Department of Veterans Affairs)	$944,409	<0.1%	Rank history: #63 in FY2021, #23 in FY2023, #34 in FY2024 and #34 in FY2025; down 14 since FY2021.
78	Appddictionstudio Limited Liability Company Top agencies USAF (Department of the Air Force) Army (Department of the Army)	$918,710	<0.1%	Rank history: not on the FY2021 list and not on the FY2023–FY2025 lists; up 28 since FY2021.
79	Department of Medicine Medical Service Group At the Suny Health Science Center At Syracuse Inc. Top agencies VA (Department of Veterans Affairs)	$918,005	<0.1%	Rank history: #94 in FY2021, #74 in FY2023 and not on the FY2024–FY2025 lists; up 15 since FY2021.
80	Atims, LLC Top agencies VA (Department of Veterans Affairs)	$907,638	<0.1%	Rank history: #76 in FY2021 and not on the FY2023–FY2025 lists; down 4 since FY2021.
81	Brigham & Womens Hospital Inc Through The General Hospital Corporation Top agencies HHS (Department of Health and Human Services)	$886,368	<0.1%	Rank history: not on the FY2021 list, #37 in FY2023 and not on the FY2024–FY2025 lists; up 48 since FY2021.
82	Health Carousel, LLC Through Next Medical Staffing LLC Top agencies VA (Department of Veterans Affairs)	$884,927	<0.1%	Rank history: #73 in FY2021, #67 in FY2023, #64 in FY2024 and not on the FY2025 list; down 9 since FY2021.
83	Tech62 Inc. Top agencies VA (Department of Veterans Affairs)	$871,278	<0.1%	Rank history: #75 in FY2021, #53 in FY2023, #54 in FY2024 and #60 in FY2025; down 8 since FY2021.
84	Mayo Clinic Top agencies DOJ (Department of Justice)	$829,697	<0.1%	Rank history: #88 in FY2021, #73 in FY2023 and not on the FY2024–FY2025 lists; up 4 since FY2021.
85	White Mountain Radiology, P.L.L.C. Top agencies HHS (Department of Health and Human Services)	$818,521	<0.1%	Rank history: #96 in FY2021 and not on the FY2023–FY2025 lists; up 11 since FY2021.
86	Prosperitus Solutions LLC Top agencies Army (Department of the Army)	$803,632	<0.1%	Rank history: #84 in FY2021 and not on the FY2023–FY2025 lists; down 2 since FY2021.
87	WJM Professional Services LLC Top agencies VA (Department of Veterans Affairs) Army (Department of the Army)	$788,266	<0.1%	Rank history: not on the FY2021 list, #39 in FY2023, #83 in FY2024 and #7 in FY2025; up 381 since FY2021.
88	Vision Quest Solutions Inc. Top agencies HHS (Department of Health and Human Services)	$778,680	<0.1%	Rank history: not on the FY2021 list and not on the FY2023–FY2025 lists; new.
89	Clark. Narvarte & Vicks A Professional Corporation O'neill Top agencies VA (Department of Veterans Affairs)	$761,575	<0.1%	Rank history: #93 in FY2021, #70 in FY2023, not on the FY2024 list and #79 in FY2025; up 4 since FY2021.
90	Xrad Tele-Services Inc. Top agencies DHA (Defense Health Agency)	$761,277	<0.1%	Rank history: #48 in FY2021 and not on the FY2023–FY2025 lists; down 42 since FY2021.
91	TDY Medical Staffing Inc. Top agencies VA (Department of Veterans Affairs)	$742,048	<0.1%	Rank history: #28 in FY2021, #40 in FY2023, #61 in FY2024 and #52 in FY2025; down 63 since FY2021.
92	Cardiopulmonary Support Services, LLC Top agencies VA (Department of Veterans Affairs)	$735,299	<0.1%	Rank history: not on the FY2021 list, #59 in FY2023, #49 in FY2024 and not on the FY2025 list; up 15 since FY2021.
93	Johnsons Consulting LLC Top agencies DLA (Defense Logistics Agency) Army (Department of the Army)	$727,712	<0.1%	Rank history: not on the FY2021 list, #82 in FY2023 and not on the FY2024–FY2025 lists; up 27 since FY2021.
94	Nevada Emergency Care Top agencies HHS (Department of Health and Human Services)	$695,230	<0.1%	Rank history: not on the FY2021 list and not on the FY2023–FY2025 lists; up 118 since FY2021.
95	Pittman Consulting Group, LLC Top agencies Army (Department of the Army)	$675,650	<0.1%	Rank history: #89 in FY2021 and not on the FY2023–FY2025 lists; down 6 since FY2021.
96	Posterity Group LLC Top agencies VA (Department of Veterans Affairs)	$673,399	<0.1%	Rank history: not on the FY2021 list, #68 in FY2023, #95 in FY2024 and not on the FY2025 list; up 14 since FY2021.
97	University of Washington Top agencies HHS (Department of Health and Human Services)	$665,588	<0.1%	Rank history: not on the FY2021 list, #35 in FY2023 and not on the FY2024–FY2025 lists; new.
98	Locum Inc. Top agencies SSA (Social Security Administration)	$662,537	<0.1%	Rank history: not on the FY2021 list, not on the FY2023 list, #87 in FY2024 and #91 in FY2025; up 25 since FY2021.
99	Four Winds Staffing LLC Top agencies HHS (Department of Health and Human Services)	$638,000	<0.1%	Rank history: not on the FY2021 list, #46 in FY2023, #57 in FY2024 and #37 in FY2025; new.
100	Comprehensive Occupational Medical Services, P.C. Top agencies DOI (Department of the Interior) Army (Department of the Army)	$620,592	<0.1%	Rank history: #55 in FY2021 and not on the FY2023–FY2025 lists; down 45 since FY2021.

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 $2.95 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. 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 2022 ran Oct 1, 2021 – Sep 30, 2022. 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 FY2021. "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 FY2021 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