| ProjectGrid | Ohio |
| Projections Research, Inc. | Pennsylvania |
| ProjectLocker, LLC | Georgia |
| ProjectManagementSoftware.com | Texas |
| ProjectManager.com | Texas |
| Projectmates, Inc. | Texas |
| ProjectMatrix, Inc. | Ohio |
| Projector PSA, Inc. | Massachusetts |
| Projector SuperStore, LLC | Arizona |
| ProjectorScreen.com | New Jersey |
| Projects Unlimited, Inc. | Ohio |
| ProjectSpace | Ohio |
| ProjectST | Washington |
| ProjectThunder.com, Inc. | California |
| ProjectToolbelt | California |
| Projecturf, LLC | California |
| Projectworks | California |
| Projectxyz | Alabama |
| Projekt15 | |
| Projekt202, LLC | Texas |
| ProJenX | New York |
| Projetech, Inc. | Ohio |
| ProjX, Inc. | Oregon |
| ProjX360 | |
| ProKanban.org | |
| ProKarma, Inc. | Oregon |
| Prokaryotics, Inc. | New Jersey |
| Prokeep, Inc. | Louisiana |
| ProKidney Corporation | North Carolina |
| PROKOMA Corporation | California |
| ProLance IT | |
| Prolap Web, LLC | |
| Proleadsoft | |
| Proleo, LLC | |
| Proletariat, Inc. | Massachusetts |
| Proliant Biologicals, LLC | Iowa |
| Proliant Health & Biologicals | Iowa |
| Prolifagen, Inc. | |
| Prolific Machines, Inc. | California |
| Prolific Studio | |
| Prolific Technologies, Inc. | Missouri |
| Prolifics | California |
| Prolink Computer, Inc. | California |
| ProLink IT Solutions | Utah |
| ProLink Systems | California |
| ProLinks Marketing & Web Services | Texas |
| Prolog Ventures | Missouri |
| Prologic Technology Systems, Inc. | Texas |
| ProLynx, Inc. | California |
| Prolytix | Vermont |