| Unacast | New York |
| Unagi | Delaware |
| UnaliWear, Inc. | Texas |
| Unanet | Virginia |
| Unanimous | Nebraska |
| Unbabel, Inc. | California |
| Unbound Commerce, Inc. | Massachusetts |
| Unbound ML, Inc. | |
| Unbound Security | New York |
| unboXt, Inc. | Georgia |
| Unbridled Creative Consulting & Design | Oregon |
| Unbxd, Inc. | California |
| Uncanny Consulting Services, LLC | |
| Uncap, Inc. | |
| Unchained Capital, Inc. | Texas |
| Unchained Commerce | |
| Unchained Labs | California |
| Unchartified, LLC | |
| Uncle Jake Media | North Carolina |
| Uncommn | |
| Uncommon Denominator, LLC | |
| Uncommon Innovation | |
| Uncork | Texas |
| Uncork Capital | California |
| Uncork Capital | |
| Uncorkd, Inc. | Illinois |
| Uncubed Studios | New York |
| Undefeated Creative, LLC | California |
| Underbit Technologies, Inc. | California |
| UnderConsideration, LLC | |
| UnderDefense | |
| Underdog Marketing Solutions | |
| Underscore VC | Massachusetts |
| Understanding Algebra by James Brennan | Idaho |
| Understanding Calculus | Illinois |
| Understory | |
| Undertone, Inc. | New York |
| Underwood Distributing Company | Michigan |
| Underwood Innovations, LLC | Illinois |
| Undetectable, LLC | Wyoming |
| Unearth Labs | Washington |
| Unee Labs | |
| UneeQ Digital Humans | Texas |
| Unetixs Vascular, Inc. | Rhode Island |
| UNETY Systems, Inc. | Illinois |
| UNFCU | |
| Unframed Digital | |
| Unfrl, LLC | Utah |
| Unfuddle, LLC | |
| Ungerboeck | Missouri |