| XML.com | California |
| XML.org | Massachusetts |
| XMLFox | Wisconsin |
| XMLWorks | Georgia |
| XMMS | Pennsylvania |
| XMPie, Inc. | New York |
| XMPP Standards Foundation | Colorado |
| XMPro | Texas |
| Xmultiple | California |
| XMW, Inc. | |
| Xn Ventures Management, LLC | Florida |
| Xnet Communications, Inc. | Georgia |
| XNet Information Systems, Inc. | Illinois |
| XNS Brand Consulting Angency | |
| XO Agency, LLC | Oregon |
| Xobee Networks, Inc. | California |
| Xobin, Inc. | Delaware |
| Xodus Medical, Inc. | Pennsylvania |
| Xoftsystems | California |
| XohoTech, Inc. | New York |
| XOi Technologies | Tennessee |
| Xojo, Inc. | Texas |
| Xola, Inc. | California |
| XOMA Corporation | California |
| Xometry | Maryland |
| Xona Microfluidics, Inc. | North Carolina |
| Xona Space Systems, Inc. | California |
| Xona Systems | Maryland |
| XonaSoftware, Inc. | Illinois |
| Xone Labs, Inc. | California |
| Xonicwave | California |
| Xonique | |
| Xontogeny, LLC | Massachusetts |
| Xoogler | |
| XOP Networks | Texas |
| XOR | California |
| XOR Security | Virginia |
| Xoran Technologies, Inc. | Michigan |
| Xorbix Technologies, Inc. | Wisconsin |
| Xorcom | Tennessee |
| Xored Software, Inc. | Texas |
| Xoriant | California |
| XORLabs, LLC | Arizona |
| XORTX Therapeutics, Inc. | |
| Xos Trucks | California |
| Xosomix, LLC | California |
| Xoxide.com | Arizona |
| Xoxzo, Inc. | |
| XP Pharma Consulting, LLC | |
| XP Power | California |