| O'Reilly Hosptitaltiy Management MO | Accommodation & Food Services | 0 | — | A |
| O'ROURKE & SONS, INC. PA | Manufacturing | 0 | — | C |
| O'ROURKE WRECKING COMPANY OH | Construction | 0 | — | A |
| O'Shea Lumber Company PA | Wholesale Trade | 0 | — | A |
| O'Steen Brothers, Inc. FL | Construction | 0 | — | C |
| O'Sullivan Plumbing, Inc. IL | Construction | 0 | — | A |
| O(1) Labs Operating Corporation CA | Information & Media | 2 | $235,000 | — |
| O-AT-KA Milk Products NY | Manufacturing | 0 | — | F |
| O-I (Owens-Illinois, Inc./Owens-Brockway Glass Container, Inc.) TX | — | 0 | — | — |
| O-I Glass WA | Manufacturing | 0 | — | D |
| O.C. Jones & Sons, Inc. CA | Construction | 0 | — | F |
| O.C. McDonald Co., Inc. CA | Construction | 0 | — | D |
| O.C. Seacrets, Inc. MD | Accommodation & Food Services | 0 | — | C |
| O.C. Tanner Company UT | Manufacturing | 2 | $135,506 | — |
| O.C. Trucking, Inc. IA | Transportation & Warehousing | 0 | — | A |
| O.E.C. Shipping Los Angeles, Inc. CA | Professional & Technical Services | 2 | $63,000 | — |
| O.E.S. Equipment, LLC TX | Real Estate | 1 | $98,509 | — |
| O.Keller Tool Engineering MI | Manufacturing | 0 | — | A |
| O.L. Development, Inc. CA | Construction | 0 | — | F |
| O.L. Thompson Construction Co., Inc. SC | Construction | 0 | — | C |
| O.M.E Quality Services Inc FL | Construction | 0 | — | A |
| O.M.G Entertainment CA | Professional & Technical Services | 2 | $74,880 | — |
| O.P.E.N. America, Inc. dba: OpenWorks AZ | — | 0 | — | — |
| O.P.E.N. America,Inc DBA OpenWorks AZ | Administrative & Waste Services | 0 | — | A |
| O.P.H Laguna Hills, Inc. dba The Original Pancake House CA | — | 0 | — | — |
| O.P.H. - R.B., Inc., The Original Pancake House CA | — | 0 | — | — |
| O.P.I. Products Inc. CA | — | 0 | — | — |
| O.R. Builders Inc. CA | Construction | 0 | — | F |
| O.S. Kelly Company OH | Manufacturing | 0 | — | F |
| O.T. Neighoff & Sons, Inc. MD | Construction | 0 | — | D |
| O.W. Lee Co., Inc. CA | — | 0 | — | — |
| O.W. Lee, Inc. TX | Manufacturing | 0 | — | F |
| O/K International corp MA | Manufacturing | 0 | — | A |
| O1 Communications, Inc. CA | — | 0 | — | — |
| O2 TECHNOLOGIES INC CA | Professional & Technical Services | 8 | $90,250 | — |
| O2Cool Manufacturing, LLC TX | Manufacturing | 0 | — | A |
| O2M Technologies, LLC IL | Healthcare & Social Assistance | 1 | $69,576 | — |
| O3 TECHNOLOGY SOLUTIONS LLC NJ | Professional & Technical Services | 4 | $106,018 | — |
| O3 Technology Solutions, LLC NY | Professional & Technical Services | 2 | $92,248 | — |
| O3b Networks USA, LLC VA | Professional & Technical Services | 1 | $121,040 | — |
| O4 Fabrication LLC TX | Construction | 0 | — | A |
| o9 Solutions, Inc. TX | Professional & Technical Services | 26 | $10,961,071 | — |
| OA Both dba Schlenk Metallic Pigments MA | Wholesale Trade | 0 | — | A |
| OA HVAC services CA | Construction | 0 | — | A |
| OA Logistics CA | — | 0 | — | — |
| OA Logistics GA | — | 0 | — | — |
| OA MANUFACTURING INC WI | Manufacturing | 0 | — | A |
| Oa Valley Hospital District CA | Healthcare & Social Assistance | 0 | — | F |
| OACAA & OPAE OH | — | 0 | — | — |
| Oahu Air Conditioning Services, Inc HI | Construction | 0 | — | F |
