| 1 | NAICS 541715Research and Development in the Physical, Engineering, and Life Sciences (Except Nanotechnology and Biotechnology) | 9,051 | 62,611 | $239.16B | LOCKHEED MARTIN CORP | ▸ |
| 2 | NAICS 541330Engineering Services | 7,677 | 79,179 | $204.54B | RTX CORP | ▸ |
| 3 | NAICS 524114Direct Health and Medical Insurance Carriers | 148 | 2,395 | $194.66B | OPTUM LABS TOPAZ INC | ▸ |
| 4 | NAICS 561210Facilities Support Services | 3,243 | 60,966 | $176.22B | HONEYWELL INTERNATIONAL INC | ▸ |
| 5 | NAICS 541512Computer Systems Design Services | 3,058 | 35,270 | $144.45B | BOOZ ALLEN HAMILTON HOLDING CORPORATION | ▸ |
| 6 | NAICS 541519Other Computer Related Services | 4,524 | 63,024 | $78.10B | LEIDOS HOLDINGS, INC. | ▸ |
| 7 | NAICS 541611Administrative Management and General Management Consulting Services | 5,412 | 45,851 | $66.48B | CHEMONICS INTERNATIONAL, INC. | ▸ |
| 8 | NAICS 541990All Other Professional, Scientific, and Technical Services | 7,207 | 29,430 | $60.53B | BATTELLE ENERGY ALLIANCE, LLC | ▸ |
| 9 | NAICS 541511Custom Computer Programming Services | 3,542 | 16,170 | $46.44B | GENERAL DYNAMICS CORP | ▸ |
| 10 | NAICS 541710Research and Development in the Physical, Engineering, and Life Sciences | 272 | 1,313 | $45.59B | LAWRENCE LIVERMORE NATIONAL SECURITY, LLC | ▸ |
| 11 | NAICS 488190Other Support Activities for Air Transportation | 726 | 10,236 | $33.00B | JACOBS ENGINEERING GROUP INC. | ▸ |
| 12 | NAICS 562910Remediation Services | 2,095 | 14,965 | $29.75B | JACOBS ENGINEERING GROUP INC. | ▸ |
| 13 | NAICS 561612Security Guards and Patrol Services | 931 | 20,044 | $27.14B | SECURITAS AB | ▸ |
| 14 | NAICS 621111Offices of Physicians (Except Mental Health Specialists) | 1,447 | 6,998 | $25.10B | LEIDOS HOLDINGS, INC. | ▸ |
| 15 | NAICS 541714Research and Development in Biotechnology (Except Nanobiotechnology) | 1,353 | 3,636 | $18.51B | ALLIANCE FOR ENERGY INNOVATION, LLC | ▸ |
| 16 | NAICS 541513Computer Facilities Management Services | 976 | 4,426 | $16.07B | LEIDOS HOLDINGS, INC. | ▸ |
| 17 | NAICS 481212Nonscheduled Chartered Freight Air Transportation | 242 | 6,364 | $15.66B | SPACE EXPLORATION TECHNOLOGIES CORP. | ▸ |
| 18 | NAICS 483111Deep Sea Freight Transportation | 155 | 8,382 | $14.75B | U.S. MARINE MANAGEMENT, LLC | ▸ |
| 19 | NAICS 518210Computing Infrastructure Providers, Data Processing, Web Hosting, and Related Services | 1,925 | 7,172 | $13.55B | LEIDOS HOLDINGS, INC. | ▸ |
| 20 | NAICS 511210Software Publishers | 1,988 | 11,706 | $12.90B | DELL TECHNOLOGIES INC. | ▸ |
| 21 | NAICS 481211Nonscheduled Chartered Passenger Air Transportation | 394 | 19,412 | $11.68B | PATRIOT TEAM | ▸ |
| 22 | NAICS 517110Wired Telecommunications Carriers | 289 | 18,336 | $11.22B | TYTO ATHENE, LLC | ▸ |
| 23 | NAICS 541690Other Scientific and Technical Consulting Services | 3,176 | 12,649 | $10.42B | KELLY SERVICES, INC. | ▸ |
| 24 | NAICS 562211Hazardous Waste Treatment and Disposal | 557 | 49,827 | $9.97B | JACOBS ENGINEERING GROUP INC. | ▸ |
| 25 | NAICS 541614Process, Physical Distribution, and Logistics Consulting Services | 722 | 122,942 | $9.79B | DEPLOYED RESOURCES LLC | ▸ |
| 26 | NAICS 561720Janitorial Services | 3,227 | 19,418 | $8.41B | DIDLAKE INC | ▸ |
| 27 | NAICS 811219Other Electronic and Precision Equipment Repair and Maintenance | 2,687 | 21,609 | $8.22B | RTX CORP | ▸ |
| 28 | NAICS 561990All Other Support Services | 2,025 | 8,144 | $7.99B | LOCKHEED MARTIN CORP | ▸ |
| 29 | NAICS 541810Advertising Agencies | 298 | 1,833 | $7.97B | DDB CHICAGO INC. | ▸ |
| 30 | NAICS 622110General Medical and Surgical Hospitals | 564 | 16,494 | $7.60B | NAPHCARE LLC | ▸ |
| 31 | NAICS 624230Emergency and Other Relief Services | 192 | 517 | $7.46B | RAPID DEPLOYMENT INC | ▸ |
| 32 | NAICS 611519Other Technical and Trade Schools | 618 | 2,494 | $6.69B | MANAGEMENT & TRAINING CORPORATION | ▸ |
| 33 | NAICS 522390Other Activities Related to Credit Intermediation | 30 | 122 | $6.32B | NELNET SERVICING LLC | ▸ |
| 34 | NAICS 541620Environmental Consulting Services | 2,247 | 16,870 | $6.13B | TETRA TECH, INC. | ▸ |
| 35 | NAICS 541211Offices of Certified Public Accountants | 248 | 2,830 | $6.13B | DIGNARI LLC | ▸ |
| 36 | NAICS 722310Food Service Contractors | 582 | 5,909 | $6.06B | SODEXO MANAGEMENT INC. | ▸ |
| 37 | NAICS 561320Temporary Help Services | 1,045 | 19,029 | $5.58B | LOYAL SOURCE GOVERNMENT SERVICES LLC | ▸ |
| 38 | NAICS 541720Research and Development in the Social Sciences and Humanities | 1,007 | 4,164 | $5.47B | LOCKHEED MARTIN CORP | ▸ |
| 39 | NAICS 621511Medical Laboratories | 771 | 8,645 | $5.42B | WALGREEN CO. | ▸ |
| 40 | NAICS 517410Satellite Telecommunications | 375 | 6,393 | $5.27B | LEONARDO SPA | ▸ |
| 41 | NAICS 541310Architectural Services | 1,139 | 11,961 | $5.14B | BL HARBERT INTERNATIONAL LLC | ▸ |
| 42 | NAICS 561422Telemarketing Bureaus and Other Contact Centers | 57 | 129 | $5.00B | MAXIMUS FEDERAL SERVICES, INC. | ▸ |
| 43 | NAICS 562119Other Waste Collection | 450 | 1,578 | $4.68B | ECC CONSTRUCTORS LLC | ▸ |
| 44 | NAICS 611430Professional and Management Development Training | 3,725 | 14,776 | $4.49B | JACOBS ENGINEERING GROUP INC. | ▸ |
| 45 | NAICS 623110Nursing Care Facilities (Skilled Nursing Facilities) | 1,770 | 17,273 | $4.40B | MIDLAND NAMPA HEALTHCARE LLC | ▸ |
| 46 | NAICS 517919All Other Telecommunications | 555 | 3,540 | $4.37B | PERATON INC. | ▸ |
| 47 | NAICS 541618Other Management Consulting Services | 1,135 | 3,384 | $4.35B | THE MITRE CORPORATION | ▸ |
| 48 | NAICS 541612Human Resources Consulting Services | 736 | 3,249 | $4.30B | DELOITTE FINANCIAL ADVISORY SERVICES LLP | ▸ |