| Abbreviation | Definition |
|---|---|
| ONCOZ | On Command Corporation |
| ONCR | Oncor, Inc. |
| ONDI | Ontrack Data International, Inc. |
| ONDS | OnDisplay |
| ONEA | One and Only, Inc. |
| ONEL | Onelink Communication, Inc. |
| ONEM | OneMain.Com, Inc. |
| ONES | Onesource Information Service |
| ONEV | One Voice Technologies |
| ONFC | Oneida Financial Corporation |
| ONHN | OnHealth Network Corporation |
| ONHN | OnHealth Network Corporation (de-listed) |
| ONHN | OnHealth Network Corporation (de-listed) |
| ONINE | Online Innovation, Inc. |
| ONMC | Omninet Media.Com, Inc. |
| ONMH | Omni Medical Holdings, Inc. |
| ONPR | One Price Clothing Stores |
| ONPT | On Point Technology Systems, Inc. |
| ONSB | Old North State Bank |
| ONSE | OnSite Energy Corporation |