| National Healthcare Corporation TN | Healthcare & Social Assistance | 0 | — | F |
| National HealthCare Corporation VA | Healthcare & Social Assistance | 0 | — | F |
| National HealthCare Corportation TN | Healthcare & Social Assistance | 0 | — | A |
| National Healthcare Investors AL | Healthcare & Social Assistance | 0 | — | F |
| National Healthcare of Mt. Vernon d/b/a Crossroads Community Hospital IL | Healthcare & Social Assistance | 0 | — | F |
| National Healthcare Professionals LLC IL | Administrative & Waste Services | 1 | $95,000 | — |
| National Healthcare Solutions, Inc. TX | Finance & Insurance | 1 | $89,190 | — |
| National Healthcare/Cool Springs TN | Healthcare & Social Assistance | 0 | — | F |
| National Healthplex, Inc. NY | Healthcare & Social Assistance | 0 | — | F |
| National Heat Treat TX | Manufacturing | 0 | — | A |
| National Heathcare Associates ME | Healthcare & Social Assistance | 0 | — | F |
| National Heritage Academies MI | Educational Services | 0 | — | A |
| National Hispanic Medical Association DC | Other Services | 1 | $80,850 | — |
| National Holding Company IL | Transportation & Warehousing | 0 | — | A |
| National Hose + Accessory TX | Manufacturing | 0 | — | F |
| National Hospitalist Services, PC LA | Administrative & Waste Services | 17 | $222,328 | — |
| National Hot Rod Association CA | Arts & Entertainment | 0 | — | C |
| National Housing Trust DC | Professional & Technical Services | 1 | $98,800 | — |
| National Hybrid, Inc. NY | — | 0 | — | — |
| National Indemnity Company NE | Finance & Insurance | 3 | $106,311 | — |
| National Industrial Concepts TN | Manufacturing | 0 | — | A |
| National Industrial Maintenance MI | Administrative & Waste Services | 0 | — | A |
| National Industrial Maintenance, Inc. IN | Administrative & Waste Services | 0 | — | C |
| National Industrial Supply MI | Manufacturing | 0 | — | A |
| National Infantry Museum Foundation GA | Arts & Entertainment | 0 | — | A |
| National Information Solutions Cooperative ND | Professional & Technical Services | 3 | $82,961 | — |
| National Inspection and Consultants FL | Professional & Technical Services | 0 | — | A |
| National Inspection Services, LLC LA | Professional & Technical Services | 0 | — | A |
| National Institute of Aerospace VA | — | 0 | — | — |
| National Institute of Aerospace Associates VA | Professional & Technical Services | 2 | $102,606 | — |
| National Institutes of Health, HHS MD | Professional & Technical Services | 138 | $110,372 | — |
| National Instrument LLC MD | Manufacturing | 0 | — | A |
| National Instruments Corporation TX | Professional & Technical Services | 10 | $151,988 | — |
| National Integrated Industries, Inc. CT | Manufacturing | 0 | — | F |
| National Interiors Inc NY | Construction | 0 | — | A |
| NATIONAL INTERSTATE INSURANCE PA | Transportation & Warehousing | 0 | — | F |
| National Inventors Hall of Fame OH | Educational Services | 0 | — | A |
| National Jet Company Inc MD | Manufacturing | 0 | — | F |
| National Jewish Health CO | Healthcare & Social Assistance | 1 | $70,000 | C |
| National labor strategies NJ | Administrative & Waste Services | 0 | — | F |
| National League of Cities Services DC | Other Services | 0 | — | A |
| National Liability & Fire Insurance Company CT | Finance & Insurance | 1 | $575,000 | — |
| National Life Insurance Company VT | Finance & Insurance | 9 | $151,833 | — |
| National Lloyds-American Summit - NLASCO Services TX | — | 0 | — | — |
| National Louis University IL | Educational Services | 1 | $53,045 | — |
| National Lutheran Community Services VA | Healthcare & Social Assistance | 0 | — | F |
| National Machine Group DBA NMG Aerospace OH | Manufacturing | 0 | — | F |
| National Machine Products AL | Wholesale Trade | 0 | — | A |
| NATIONAL MACHINERY & FABRICATION SC | Manufacturing | 0 | — | A |
| National Machinery LLC OH | Manufacturing | 0 | — | C |
