| Westat, Inc. | Bethesda | MD | $1.93B |
| The Rand Corporation | Santa Monica | CA | $1.36B |
| National Opinion Research Center | Chicago | IL | $1.11B |
| Fors Marsh Group LLC | Arlington | VA | $1.11B |
| Mathematica Inc.Princeton, NJ · UEI T41EGEAK2L35 | Princeton | NJ | $961M |
| Mathematica Inc.Washington, DC · UEI UJMMR3K2CDK6 | Washington | DC | $497M |
| Family Health International | Durham | NC | $470M |
| Educational Testing Service | Princeton | NJ | $377M |
| Human Resources Research Organization (humrro) | Alexandria | VA | $279M |
| Vera Institute Of Justice, Inc. | Brooklyn | NY | $189M |
| International Aids Vaccine Initiative Inc. | New York | NY | $137M |
| MDRC | New York | NY | $77.5M |
| New South Associates, Inc. | Stone Mountain | GA | $60.3M |
| Fundacion Inciensa | La Union | SAN JOSE | $53.8M |
| Child Trends, Incorporated | Rockville | MD | $47.3M |
| Data Recognition Corporation | Maple Grove | MN | $35.1M |
| Public Health Institute | Oakland | CA | $31.3M |
| Morgan, Angel, Brigham & Associates L.L.C. | Washington | DC | $25M |
| Far Western Anthropological Research Group, Inc. | Davis | CA | $20.6M |
| North South Consulting Group LLC | Elizabethtown | KY | $19.5M |
| Mission Analytics Group, Inc. | San Francisco | CA | $18.7M |
| Brockington And Associates, Inc. | Atlanta | GA | $18.5M |
| Southeastern Archaeological Research, LLC | Orlando | FL | $18.5M |
| International Archaeology, LLC | Honolulu | HI | $17.7M |
| Activate Research Inc. | Washington | DC | $16.4M |
| Development Services Group, Inc. | Bethesda | MD | $15.5M |
| Human Services Research Institute | Cambridge | MA | $14.5M |
| Cognitive Performance Group Of Florida, LLC | Portsmouth | VA | $13.1M |
| Insignia Health, LLC | Portland | OR | $13M |
| Optimal Solutions Group, L.L.C | College Park | MD | $12.6M |
| The Center For Employment Security Education & Research Inc. | Washington | DC | $12.3M |
| Historical Research Associates, Inc. | Missoula | MT | $11.2M |
| Emendata LLC | San Francisco | CA | $10.1M |
| Protagonist Technology LLC | Washington | DC | $9.92M |
| Stratevarious Inc. | Grand Rapids | MI | $9.9M |
| Carley Technologies Inc. | Sewickley | PA | $7.77M |
| C4 Innovations LLC | Lexington | MA | $6.94M |
| Wapsi Valley Archaeology, Inc. | Anamosa | IA | $6.9M |
| The Institute For Cancer Research | Philadelphia | PA | $6.46M |
| Integrated Behavioral Health, Inc. | Irvine | CA | $6.43M |
| Chestnut Health Systems Inc. | Bloomington | IL | $5.82M |
| BNP Education Partners LLC | Denver | CO | $5.71M |
| G2 Archaeology | Reno | NV | $5.53M |
| Noguchi Memorial Institute For Medical Research | Accra | | $5.32M |
| Cultural Resource Analysts, Inc. | Lexington | KY | $4.89M |
| Rhodium Group LLC | New York | NY | $4.65M |
| Kairos Research LLC | Dayton | OH | $4.52M |
| Gramercy Research Group, L.L.C | Knightdale | NC | $4.51M |
| Pro-change Behavior Systems, Inc. | South Kingstown | RI | $4.08M |
| 361 Interactive LLC | Dayton | OH | $3.95M |
| Acsilabs, Inc. | San Diego | CA | $3.44M |
| The Fox Foundation Inc. | Tampa | FL | $3.41M |
| Long Term Strategy Group, LLC | Washington | DC | $2.97M |
| Polycharge America, Inc. | Tucson | AZ | $2.83M |
| Core Correctional Solutions, LLC | Akron | OH | $2.79M |
| American Transportation Research Institute Inc. | Washington | DC | $2.67M |
| Universitat St. Gallen | St. Gallen | | $2.62M |
| Policy Research Inc. | Troy | NY | $2.47M |
| Population Reference Bureau, Inc. | Washington | DC | $2.42M |
| Barron LLC | Gillette | WY | $2.41M |
| Vsgi LLC | Palm Coast | FL | $2.37M |
| Thresher Ventures, LLC | Arlington | VA | $2.32M |
| Acacia Heritage Consulting LLC | Austin | TX | $2.32M |
| Mari, LLC | Bentonville | VA | $2.24M |
| The National Bureau Of Asian Research | Seattle | WA | $2.18M |
| Convergent View Research & Consultancy Private Limited | New Delhi | | $2.18M |
| Donald William Walls | Denver | CO | $2.15M |
| Hudson Institute, Inc. | Washington | DC | $2.14M |
| Sentient Research | West Covina | CA | $2.11M |
| Advanced Analytical Consulting Group, Inc. | Wayland | MA | $2.08M |
| R G Research Group, Inc. | Los Alamitos | CA | $2.07M |
| American Indian Development Associates, LLC | Albuquerque | NM | $1.89M |
| The Conference Board, Inc. | New York | NY | $1.88M |
| Thomas Jefferson Institute For The Study Of World Politics | Washington | DC | $1.72M |
| The Campbell Collaboration A Non Profit Corp. | Philadelphia | PA | $1.61M |
| Challenge America | Carbondale | CO | $1.57M |
| Dfusion Inc. | Scotts Valley | CA | $1.56M |
| Applied Decision Science LLC | Cincinnati | OH | $1.54M |
| Pacific Forum International | Honolulu | HI | $1.54M |
| Baylor Research Institute | Dallas | TX | $1.46M |
| Middle East Media Research Institute Inc. | Washington | DC | $1.44M |
| DMG Four Corners Research, Inc. | Las Cruces | NM | $1.41M |
| Michigan Department Of Education | Lansing | MI | $1.33M |
| Parenthetic, LLC | Alexandria | VA | $1.29M |
| Liminal Esports LLC | Gates Mills | OH | $1.25M |
| Makefully LLC | Kansas City | MO | $1.25M |
| Mark A Cohen LLC | Nashville | TN | $1.13M |
| Szott Aaron | Bethesda | MD | $1.07M |
| Victoria University | Melbourne | | $1.06M |
| Lightcast, LLC | Moscow | ID | $1.04M |
| Judy Cooper | Plano | TX | $1.01M |
| Layla Kassem | Oak Park | IL | $961K |
| Brightfield Group LLC | Chicago | IL | $959K |
| Plus Alpha Research & Consulting, LLC | Arlington | VA | $950K |
| Elbow Kent | Madison | WI | $940K |
| Thayer LLC | Sterling | VA | $935K |
| Crain Anthony R | Potomac | MD | $934K |
| Center For Advanced Defense Studies, Inc. (the) | Washington | DC | $926K |
| Hoogalit, Inc. | Menlo Park | CA | $900K |
| Decision.partners Inc. | Pittsburgh | PA | $882K |
