Top 100 Contractors in NAICS 621: Ambulatory Health Care Services, FY2025
Parent companies by net contract obligations Oct 1, 2024 – Sep 30, 2025 Code page on GovTribe
The top 10 won 74% of FY2025 NAICS 621 contract dollars
Ranking facts
- Contract obligations
- $12,339,729,805 Net of deobligations, by contracts coded NAICS 621 or a code under it
- Contractors
- 2,242 Parent companies with an obligation
- Largest contractor
- Leidos Holdings, Inc. $2.78 billion, 20.8% of obligations
- Data as of
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 | $2,780,375,008 | |||
| 2 | $2,537,091,985 | |||
| 3 | $2,033,102,251 | |||
| 4 | $760,621,210 | |||
| 5 |
Fresenius Medical Care Holdings Inc.
|
$693,260,402 | ||
| 6 | $536,028,127 | |||
| 7 | $163,742,087 | |||
| 8 |
Laboratory Corporation of America Holdings
|
$141,928,303 | ||
| 9 |
KBR Wyle Services LLC
|
$125,413,993 | ||
| 10 |
American Medical Response West
|
$102,208,595 | ||
| 11 | $75,328,559 | |||
| 12 |
US Renal Care Inc.
Top agencies
|
$60,025,522 | ||
| 13 | $51,139,225 | |||
| 14 | $50,230,307 | |||
| 15 | $49,601,984 | |||
| 16 | $48,385,232 | |||
| 17 |
Roche Holdings Inc.
Top agencies
|
$47,975,879 | ||
| 18 | $43,094,284 | |||
| 19 | $41,303,107 | |||
| 20 | $39,268,029 | |||
| 21 | $35,515,348 | |||
| 22 | $34,775,819 | |||
| 23 | $34,454,229 | |||
| 24 | $34,419,922 | |||
| 25 | $29,905,153 | |||
| 26 | $29,880,694 | |||
| 27 | $28,986,155 | |||
| 28 |
Vetmed Group LLC
|
$28,951,516 | ||
| 29 |
Luke & Associates Inc.
Top agencies
|
$27,782,959 | ||
| 30 |
City of NY
Top agencies
|
$24,718,534 | ||
| 31 | $24,630,911 | |||
| 32 | $24,505,388 | |||
| 33 | $23,980,971 | |||
| 34 | $23,913,089 | |||
| 35 | $22,828,843 | |||
| 36 | $21,261,940 | |||
| 37 | $20,983,438 | |||
| 38 | $20,486,836 | |||
| 39 | $19,154,399 | |||
| 40 | $18,118,015 | |||
| 41 | $17,830,866 | |||
| 42 |
Acuity International LLC
|
$16,711,872 | ||
| 43 |
Aleknagik Technology, LLC
Top agencies
|
$16,307,850 | ||
| 44 | $16,213,517 | |||
| 45 | $15,706,405 | |||
| 46 | $15,611,296 | |||
| 47 | $15,284,606 | |||
| 48 | $14,655,969 | |||
| 49 |
Crassociates, Inc.
Top agencies
|
$13,765,096 | ||
| 50 |
Dilligas Corp
Top agencies
|
$13,607,526 | ||
| 51 | $13,551,934 | |||
| 52 |
Transox Inc.
Top agencies
|
$12,953,042 | ||
| 53 | $12,627,529 | |||
| 54 |
CG Services LLC
Top agencies
|
$12,397,727 | ||
| 55 | $12,307,032 | |||
| 56 |
Prairie Quest, Inc.
Top agencies
|
$12,169,617 | ||
| 57 | $12,003,842 | |||
| 58 | $11,946,550 | |||
| 59 | $11,754,534 | |||
| 60 | $11,751,750 | |||
| 61 | $11,645,670 | |||
| 62 | $11,461,265 | |||
| 63 | $11,443,449 | |||
| 64 | $11,263,494 | |||
| 65 |
Avosys Technology, Inc.
Top agencies
|
$10,933,789 | ||
| 66 | $10,832,485 | |||
| 67 | $10,429,388 | |||
| 68 | $10,223,191 | |||
| 69 | $9,741,364 | |||
| 70 | $9,731,194 | |||
| 71 |
T3I, Inc.
Top agencies
|
$9,583,404 | ||
| 72 | $9,456,610 | |||
| 73 | $9,440,024 | |||
| 74 |
Aims-Usgp JV LLC
Top agencies
|
$9,431,454 | ||
| 75 | $9,208,194 | |||
| 76 | $9,089,156 | |||
| 77 | $8,614,952 | |||
| 78 |
Reef Systems Corp
|
$8,376,520 | ||
| 79 |
Forensic Drug & Alcohol Testing LLC
|
$8,370,366 | ||
| 80 | $8,256,945 | |||
| 81 |
EGA Associates LLC
Top agencies
|
$8,047,765 | ||
| 82 | $7,836,079 | |||
| 83 | $7,500,000 | |||
| 84 | $7,493,968 | |||
| 85 | $7,472,738 | |||
| 86 | $7,414,652 | |||
| 87 | $7,234,455 | |||
| 88 | $7,039,209 | |||
| 89 | $7,033,630 | |||
| 90 |
Dalmor LLC
Top agencies
|
$6,720,652 | ||
| 91 | $6,618,514 | |||
| 92 |
Wellpath LLC
Top agencies
|
$6,565,788 | ||
| 93 | $6,561,863 | |||
| 94 |
Magellan Federal Inc.
|
$6,283,755 | ||
| 95 | $6,241,924 | |||
| 96 | $6,161,931 | |||
| 97 | $5,968,053 | |||
| 98 | $5,947,258 | |||
| 99 |
Tempus AI, Inc.
Top agencies
|
$5,734,095 | ||
| 100 | $5,715,672 |
Show 75 more
100 of 2,242 contractors listed here. See the rest on GovTribe.
Rankings for the codes under NAICS 621
| Code | Net obligations | Largest contractor |
|---|---|---|
| 6211 Offices of Physicians | $8,561,348,532 | Leidos Holdings, Inc. |
| 6214 Outpatient Care Centers | $1,931,203,895 | Fresenius Medical Care Holdings Inc. |
| 6219 Other Ambulatory Health Care Services | $844,209,583 | American Medical Response West |
| 6215 Medical and Diagnostic Laboratories | $554,380,249 | Laboratory Corporation of America Holdings |
| 6213 Offices of Other Health Practitioners | $357,260,852 | KBR Wyle Services LLC |
| 6216 Home Health Care Services | $66,274,513 | Warrior Service Company LLC |
| 6212 Offices of Dentists | $25,052,182 | Akicita Cyber LLC |
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 $13.4 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 NAICS 621 contractors in FY2025?
1. Leidos Holdings, Inc. ($2.78B), 2. UnitedHealth Group Incorporated ($2.54B), 3. Maximus Federal Services, Inc. ($2.03B), 4. Loyal Source Government Services LLC ($761M), 5. Fresenius Medical Care Holdings Inc. ($693M), 6. Davita Inc. ($536M), 7. Valor Healthcare Inc. ($164M), 8. Laboratory Corporation of America Holdings ($142M), 9. KBR Wyle Services LLC ($125M), 10. American Medical Response West ($102M).
On GovTribe
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