| Abbreviation | Definition |
|---|---|
| PROH.MK | Proton Holdings, BHD |
| PROH.PK | Proone Holdings, Inc. |
| PROV | Provident Financial Holding, Inc. |
| PROX | Proxim, Inc. |
| PRPS | Power Plus Corporation |
| PRRC | Precision Response Corporation |
| PRRR | Pioneer RailWay Corporation |
| PRRR | Pioneer RailWay Corporation (de-listed) |
| PRSF | Portal Software, Inc. |
| PRSF | Portal Software, Incorporated (de-listed) |
| PRSF | Portal Software, Incorporated (de-listed) |
| PRSI | Portsmouth Square, Inc. |
| PRSI | Portsmouth Square, Incorporated (de-listed) |
| PRSI | Portsmouth Square, Incorporated (de-listed) |
| PRSM | Prism Group Inc |
| PRSM | Prism Group Incorporated (de-listed) |
| PRSM | Prism Group Incorporated (de-listed) |
| PRSP | Prosperity Bancshares, Inc. |
| PRSPP | Prosperity Bancshares Inc |
| PRSPP | Prosperity Bancshares Incorporated Preferred (de-listed) |