| Yarnolds Limited | Professional & scientific | 1998 |
| Yarnolds Property Limited | Construction | 1998 |
| Yazsam Ltd | Professional & scientific | 2024 |
| Yelo Enterprises Ltd | Manufacturing | 2016 |
| Yeomanry Mews Property Management Ltd | Households | 2022 |
| Yorke Electrical Installations Limited | Construction | 2008 |
| Yorkshire Cuisine Limited | Extraterritorial | 2013 |
| YOU SAY Agency Limited | Professional & scientific | 2015 |
| Your Emerging Self Ltd | Professional & scientific | 2021 |
| Your GOB Ltd | Wholesale & retail | 2024 |
| Your Past Memories Limited | Administrative & support | 2017 |
| Your Stepping Stones Ltd | Professional & scientific | 2002 |
| Yours London Limited | Health & social care | 2024 |
| Yoyo Productions Limited | Information & communication | 1998 |
| YP Connexions Limited | Administrative & support | 2011 |
| YPL Halford Ltd | Real estate | 2022 |
| YPL Warwick Street Limited | Construction | 2014 |
| Ysrp Ltd | Professional & scientific | 2021 |
| Yukikazu UK Ltd | Hospitality | 2022 |
| Yuri Management Ltd | Professional & scientific | 2019 |
| Zandria Productions Ltd | Information & communication | 2023 |
| Zazaexclusive Ltd | Transport & logistics | 2025 |
| Zenith Tax Solutions Limited | Extraterritorial | 2008 |
| ZI Consultancy Limited | Professional & scientific | 2008 |
| Ziggy Services Ltd | Information & communication | 2025 |
| Zinc Group Limited | Financial services | 2008 |
| Zirgonium Limited | Information & communication | 2011 |
| Zone X Clothing Limited | Wholesale & retail | 2023 |