| Abbreviation | Definition |
|---|---|
| NZYM | Synthetech, Inc. |
| OAIS | Oasis Resorts International |
| OAKC | Oakhurst Company, Inc. |
| OAKF | Oak Hill Financial, Inc. |
| OAKR | Oakridge Energy, Inc. |
| OAKS | River Oaks Furniture, Inc. |
| OAKT | Oak Technology, Inc. |
| OAOT | Orthogonalized Atomic Orbital Technology Solutions, Inc. |
| OATS | Wild Oats Markets, Inc. |
| OBAS | Optibase, LTD. |
| OBCI | Ocean Bio Chemical, Inc. |
| OBGLF | Oil Baltija Group, LTD. |
| OBIE | Obie Media Corporation |
| OBJE | Obscene Jeans Corp. |
| OBJS | Objectshare, Inc. |
| OBJX | Interactive Objects, Inc. |
| OBTK | Obducat, A. B. (delisted) |
| OBTY | Orbit Technologies, Inc. (delisted) |
| OCAS | Ohio Casualty Corporation |
| OCCF | Optical Cable Corporation |