| Xentaurs | California |
| Xentria | Illinois |
| Xentris Wireless, LLC | Illinois |
| Xequel Bio | Texas |
| Xeran | Massachusetts |
| Xerdict, LLC | New Jersey |
| Xeric Design Ltd | Nevada |
| Xerillion Corporation | Illinois |
| Xerion Advanced Battery Corporation | Ohio |
| Xerious Solutions | Louisiana |
| Xeris Pharmaceuticals, Inc. | Illinois |
| Xeris Pharmaceuticals, Inc. | |
| Xeroproject | District of Columbia |
| Xerostart | Kansas |
| XeroThera, Inc. | |
| Xerox Corporation | Connecticut |
| Xert Communications Corporation | Virginia |
| XESS Corporation | North Carolina |
| Xesto, Inc. | |
| Xetra Networks, Inc. | California |
| Xevo | Washington |
| xFact | Massachusetts |
| Xfactor.io | |
| Xfernet | California |
| Xfinion, Inc. | Virginia |
| Xfinity | Pennsylvania |
| XForms, LLC | |
| Xfund | California |
| XFX Technologies, Inc. | California |
| XG Ventures | California |
| Xgaming X-Arcade | Pennsylvania |
| XGen Pharmaceuticals DJB, Inc. | New York |
| Xgene Pharmaceutical, Inc. | |
| XGeniSys | Tennessee |
| XgenTech | New York |
| XHTMLJunction | California |
| Xi Computer | California |
| Xi Graphics, Inc. | Colorado |
| Xiacom, Inc. | New York |
| Xicomm, LLC | California |
| Xiconic Pharmaceuticals, LLC | |
| XID Software, Inc. | Texas |
| XIFIN, Inc. | California |
| Xigla Software | Florida |
| Xignite, Inc. | California |
| XII Medical, Inc. | California |
| Xilinx | California |
| Xilio Therapeutics, Inc. | Massachusetts |
| Xilis, Inc. | North Carolina |
| Xillent Studio | California |