| Atkinson, Andelson, Loya, Ruud & Romo CA | Professional & Technical Services | 0 | — | C |
| Atkinson, Andelsonm Loya, Ruud & Romo CA | Professional & Technical Services | 0 | — | A |
| Atkinsons' Market ID | Retail Trade | 0 | — | C |
| AtkinsRealis US Nuclear ID | Administrative & Waste Services | 0 | — | A |
| AtkinsRealis US Nuclear SC | Administrative & Waste Services | 0 | — | A |
| AtkinsRealis US Nuclear - Albuquerque NM | Administrative & Waste Services | 0 | — | A |
| AtkinsRealis US Nuclear - Oak Ridge TN | Administrative & Waste Services | 0 | — | A |
| AtkinsRealis US Nuclear - Richland WA | Professional & Technical Services | 0 | — | A |
| AtkinsRealis USA Inc. FL | Professional & Technical Services | 14 | $115,653 | — |
| AtkinsRéalis US Nuclear Roll-Up TN | Administrative & Waste Services | 0 | — | A |
| AtkinsRéalis USA Inc. FL | Professional & Technical Services | 2 | $131,875 | — |
| Atkore AR | Manufacturing | 0 | — | A |
| Atkore AZ | Manufacturing | 0 | — | A |
| Atkore CA | Manufacturing | 0 | — | F |
| Atkore CO | Manufacturing | 0 | — | F |
| Atkore FL | Manufacturing | 0 | — | A |
| Atkore GA | Manufacturing | 0 | — | D |
| Atkore IL | Manufacturing | 0 | — | A |
| Atkore IN | Manufacturing | 0 | — | F |
| Atkore KY | Manufacturing | 0 | — | D |
| Atkore MA | Manufacturing | 0 | — | F |
| Atkore MO | Manufacturing | 0 | — | F |
| Atkore NM | Manufacturing | 0 | — | D |
| Atkore NY | Manufacturing | 0 | — | D |
| Atkore OR | Manufacturing | 0 | — | F |
| Atkore PA | Manufacturing | 0 | — | F |
| Atkore SC | Manufacturing | 0 | — | C |
| Atkore TX | Manufacturing | 0 | — | C |
| Atkore UT | Manufacturing | 0 | — | F |
| Atkore WA | Transportation & Warehousing | 0 | — | A |
| Atkore WI | Manufacturing | 0 | — | F |
| Atkore - Unistrut MI | Manufacturing | 0 | — | D |
| Atkore Inc MI | Manufacturing | 0 | — | F |
| Atkore Management LLC IL | Manufacturing | 5 | $159,780 | — |
| Atkore Plastics Southeast SC | — | 0 | — | — |
| ATL Construction Inc MA | Construction | 0 | — | A |
| ATL Crown Perimeter GA | Accommodation & Food Services | 0 | — | F |
| ATL GA Staffing GA | Administrative & Waste Services | 0 | — | A |
| ATL Technology UT | Manufacturing | 0 | — | A |
| Atlan Inc DE | Professional & Technical Services | 1 | $170,000 | — |
| Atlanta GA | Transportation & Warehousing | 0 | — | A |
| Atlanta Attachment Company GA | — | 0 | — | — |
| Atlanta Beverage Company GA | Wholesale Trade | 0 | — | F |
| Atlanta Bonded Warehouse Corporation GA | Transportation & Warehousing | 0 | — | A |
| Atlanta Bonded Warehouse Corporation MS | Transportation & Warehousing | 0 | — | A |
| Atlanta Bonded Warehouse Corporation SC | Transportation & Warehousing | 0 | — | A |
| Atlanta Bonded Warehouse Corporation TX | Transportation & Warehousing | 0 | — | A |
| Atlanta Casework Systems GA | Manufacturing | 0 | — | D |
| Atlanta Commercial Millworks GA | Manufacturing | 0 | — | F |
| Atlanta Commercial Tire GA | Retail Trade | 0 | — | C |