| 1 | CH2M HILL PLATEAU REMEDIATION COMPANY | $7,065,250,860 | 1 | $7,065,250,860 | Jun 19, 2008 | Department of Energy |
| 2 | SAVANNAH RIVER MISSION COMPLETION, LLC | $4,498,271,567 | 9 | $499,807,952 | May 05, 2026 | Department of Energy |
| 3 | FLUOR-BWXT PORTSMOUTH LLC | $4,464,785,978 | 1 | $4,464,785,978 | Aug 16, 2010 | Department of Energy |
| 4 | UCOR LLC | $3,900,788,934 | 1 | $3,900,788,934 | Apr 29, 2011 | Department of Energy |
| 5 | CENTRAL PLATEAU CLEANUP COMPANY, LLC | $3,264,172,218 | 8 | $408,021,527 | Oct 01, 2024 | Department of Energy |
| 6 | UNITED CLEANUP OAK RIDGE LLC | $2,544,767,270 | 1 | $2,544,767,270 | May 17, 2023 | Department of Energy |
| 7 | IDAHO ENVIRONMENTAL COALITION LLC | $1,657,305,176 | 1 | $1,657,305,176 | Oct 01, 2023 | Department of Energy |
| 8 | HYDROGEOLOGIC, INC. | $993,905,153 | 130 | $7,645,424 | Sep 24, 2026 | Environmental Protection … |
| 9 | CH2M HILL BWXT WEST VALLEY, LLC | $990,004,958 | 1 | $990,004,958 | Jul 01, 2011 | Department of Energy |
| 10 | SEVENSON ENVIRONMENTAL SERVICES, INC. | $966,301,419 | 38 | $25,428,985 | Mar 17, 2026 | Department of Defense |
| 11 | EA ENGINEERING, SCIENCE, AND TECHNOLOGY, IN… | $965,931,846 | 188 | $5,137,935 | Sep 26, 2027 | Environmental Protection … |
| 12 | NAVARRO RESEARCH AND ENGINEERING, INC. | $787,778,121 | 15 | $52,518,541 | Dec 01, 2025 | Department of Energy |
