| ID | Name | Type |
|---|---|---|
| #10588 | Optical Illusions | Z |
| #10589 | Optimal Group | Z |
| #10590 | Optimus Software | Z |
| #10591 | Options International | Z |
| #10592 | Opus Supplies Ltd | P |
| #10593 | Orange Enterprizes | Z |
| #10594 | Orange Software | Z |
| #10595 | Orb | ? |
| #10596 | Orbis Publishing Ltd | Z |
| #21563 | Orbit Data | Z |
| #18368 | Orbyte | P |
| #18306 | Orbyte Software | P |
| #10597 | Orc | ? |
| #10598 | Organism | ? |
| #10599 | Origin Systems Inc | P |
| #10600 | Original Computers Associaton | Z |
| #10601 | Original Soft | Z |
| #10602 | Orijon Software | Z |
| #10603 | Orin Soft | Z |
| #10604 | Orion Data Ltd | Z |