| Untapped Ventures | California |
| untapt, Inc. | New York |
| UNTeam | California |
| Untech | Delaware |
| Unthink.ai | Texas |
| Unthinkable Solutions, LLP | |
| Until Labs | |
| Untitled, LLC | Kentucky |
| Untold Branding, Inc. | |
| Untra Corporation | Pennsylvania |
| Untuck, LLC | |
| Unusual Ventures | California |
| Unvale | |
| Unvired, Inc. | Texas |
| Unwired Ltd | California |
| Unyte Health US, Inc. | |
| UO Solutions, LLC | |
| UP Aerospace, Inc. | Colorado |
| Up and Running Software, Inc. | Iowa |
| UP Creative, Inc. | |
| UP Digital Marketing | |
| Up Ideas | |
| Up North Computers | Alaska |
| Up Online Agency | |
| UP Partners | California |
| Up Time Technology | Washington |
| Up&Up | South Carolina |
| UP, Inc. | Florida |
| Up-N-Running Consulting, Inc. | Minnesota |
| up.net | Michigan |
| Upaya Social Ventures | |
| Upbound | Washington |
| UpBrainery Technologies | |
| UPC Capital Ventures | Colorado |
| UpCear | New York |
| UpCity | Illinois |
| UpCode Studios, LLC | |
| UpCodes | Texas |
| Upcom Technologies, Inc. | |
| UpContent | Pennsylvania |
| UpCounsel Technologies, Inc. | California |
| Upcraft Media, LLC | |
| Updata Partners | District of Columbia |
| UpDoer Technology | |
| Updox | Ohio |
| UpEquity | Texas |
| Upflex, Inc. | New York |
| Upfluence, Inc. | New York |
| Upfort | California |
| Upfront Software, Inc. | Maine |