| keystone Electronics NY | Manufacturing | 0 | — | F |
| Keystone Excavators, Inc. FL | Construction | 0 | — | F |
| Keystone Foam PA | Manufacturing | 0 | — | D |
| Keystone Food Products Inc. PA | — | 0 | — | — |
| KEYSTONE FOODS LLC AL | Manufacturing | 0 | — | F |
| KEYSTONE FOODS LLC GA | Manufacturing | 0 | — | F |
| KEYSTONE FOODS LLC KY | Manufacturing | 0 | — | F |
| Keystone Foods/Tyson Foods AL | — | 0 | — | — |
| Keystone Forging Co. PA | Manufacturing | 0 | — | F |
| Keystone Friction Hinge Co PA | Manufacturing | 0 | — | F |
| Keystone Fruit and Vegetable Co. Inc. CA | Agriculture & Forestry | 0 | — | A |
| Keystone Generating Station PA | Utilities | 0 | — | A |
| Keystone Hospitality LLC PA | Administrative & Waste Services | 0 | — | F |
| Keystone Human Services PA | Healthcare & Social Assistance | 0 | — | A |
| Keystone Independence Management PA | Administrative & Waste Services | 0 | — | F |
| Keystone Industries NJ | Manufacturing | 0 | — | D |
| Keystone Iron and Metal Co., Inc PA | Wholesale Trade | 0 | — | A |
| Keystone Landfill, Inc. PA | Administrative & Waste Services | 0 | — | F |
| Keystone Lodging CO | — | 0 | — | — |
| Keystone Masonry WA | Construction | 0 | — | F |
| KEYSTONE MEMORIALS, INC GA | Manufacturing | 0 | — | F |
| Keystone MFG Company PA | Manufacturing | 0 | — | F |
| Keystone Millwork, Inc. TX | Manufacturing | 0 | — | A |
| Keystone Natural Holdings CO | Manufacturing | 0 | — | F |
| Keystone Natural Holdings NJ | Manufacturing | 0 | — | D |
| Keystone Natural Holdings PA | Manufacturing | 0 | — | F |
| Keystone Nursing Care Center Inc IA | Healthcare & Social Assistance | 0 | — | A |
| Keystone Peer Review Organization FL | — | 0 | — | — |
| Keystone Peer Review Organization (KEPRO) PA | — | 0 | — | — |
| Keystone Petroleum Equipment, LTD PA | Wholesale Trade | 0 | — | A |
| Keystone Plastics NJ | Manufacturing | 0 | — | F |
| Keystone Plus Construction Corp. DC | Construction | 0 | — | A |
| Keystone Potato Products LLC PA | Manufacturing | 0 | — | F |
| Keystone Powdered Metal Co COVID19 NC | — | 0 | — | — |
| Keystone Powdered Metal Company NC | Manufacturing | 0 | — | B |
| Keystone Powdered Metal Company PA | Manufacturing | 0 | — | F |
| Keystone Precision & Engineering, Inc. MA | Manufacturing | 0 | — | F |
| Keystone Profiles LTD PA | Manufacturing | 0 | — | F |
| Keystone Protein PA | Manufacturing | 0 | — | F |
| Keystone Quality Transport Company DE | Transportation & Warehousing | 0 | — | F |
| Keystone Quality Transport Company MD | Transportation & Warehousing | 0 | — | F |
| Keystone Quality Transport Company PA | Transportation & Warehousing | 0 | — | D |
| Keystone Resort CO | — | 0 | — | — |
| Keystone Resort-Update CO | — | 0 | — | — |
| Keystone Ridge Designs PA | Manufacturing | 0 | — | F |
| KEYSTONE RURAL HEALTH CENTER PA | Healthcare & Social Assistance | 4 | $1,837,817 | — |
| Keystone RV Company IN | Manufacturing | 0 | — | D |
| Keystone RV Company OR | Manufacturing | 0 | — | F |
| Keystone RV Crossroads IN | Manufacturing | 0 | — | F |
| Keystone RV Dutchmen IN | Manufacturing | 0 | — | C |
