| XRF Scientific UK Ltd | Extraterritorial | 2015 |
| Xtraspace Solutions Limited | Administrative & support | 2003 |
| XY Huang Limited | Administrative & support | 2013 |
| Y & K Medical Limited | Health & social care | 2021 |
| Y&C Catering Ltd | Hospitality | 2023 |
| Y-Prime UK Ltd | Information & communication | 2019 |
| Y1 Group Holdings Ltd | Financial services | 2025 |
| Y1 Group Limited | Financial services | 2018 |
| Y1 Sport Limited | Manufacturing | 2015 |
| Y123 Projects Limited | Real estate | 2023 |
| Y3 Recruit Limited | Administrative & support | 2017 |
| Yaka UK Property Limited | Real estate | 2018 |
| Yalla Thrive Ltd | Education | 2025 |
| Yamara Limited | Real estate | 2026 |
| Yandall Consultancy Limited | Professional & scientific | 2026 |
| Yandar Trading Limited | Wholesale & retail | 2025 |
| Yara Restaurant Delivery Ltd | Hospitality | 2025 |
| Yashan Ltd | Real estate | 2021 |
| Yasmin Sung Limited | Professional & scientific | 2026 |
| Yates & Birdsey Properties Ltd | Real estate | 2026 |
| Yates Bar Limited | Hospitality | 2025 |
| Yates Estates (MCR) Ltd | Real estate | 2022 |
| Yates Groundwork Ltd | Construction | 2020 |
| Yates Legal Limited | Professional & scientific | 2022 |
| YAY YAY (NW) Ltd | Wholesale & retail | 2025 |
| YB Business Transformation Consulting Limited | Professional & scientific | 2023 |
| YC Aesthdent Limited | Health & social care | 2026 |
| Yedd Consulting Limited | Professional & scientific | 2022 |
| Yellow Atlas Consulting Limited | Information & communication | 2020 |
| Yellow Bolts Limited | Financial services | 2016 |
| Yellow Delaney Communications Limited | Administrative & support | 2000 |
| Yellows and Greens Ltd | Wholesale & retail | 2024 |
| Yelonne Jewellery Ltd | Wholesale & retail | 2026 |
| Yering London Ltd | Financial services | 2017 |
| YES Bebe Ltd | Information & communication | 2016 |
| YEW Tree Farm Fraser Homes Limited | Construction | 2026 |
| Yindeo Limited | Administrative & support | 2012 |
| Yipiyap Limited | Education | 2012 |
| YL Group Ltd | Real estate | 2024 |
| YM Capital Management Ltd | Information & communication | 2025 |
| YM Home Limited | Construction | 2021 |
| YMW Consultancy Limited | Professional & scientific | 2025 |
| YO IPR Ltd | Extraterritorial | 2013 |
| Yoganidra.Love Limited | Other services | 2026 |
| Yogberries Limited | Wholesale & retail | 2010 |
| Yogberries Timperley Ltd | Wholesale & retail | 2024 |
| Yolo Estate Ltd. | Construction | 2022 |
| Yolo PAY Limited | Financial services | 2022 |
| Yolo Shop Ltd | Wholesale & retail | 2021 |
| Yoong Medical Limited | Health & social care | 2013 |
| York Lodge Developments Limited | Construction | 2017 |
| York Road (Sale) Management Company Limited | Real estate | 2002 |
| Yorkshire Spin Galvanising Limited | Manufacturing | 1992 |
| Young & Butt Limited | Professional & scientific | 1995 |
| Young Flooring Ltd | Construction | 2021 |
| Young Margaret Ltd | Wholesale & retail | 2019 |
| Young Village Ltd | Real estate | 2013 |
| Youproductive Limited | Other services | 2013 |
| Your Business Limited | Professional & scientific | 1998 |
| Your Cyber Coach Limited | Professional & scientific | 2024 |
| Your Feedback Limited | Professional & scientific | 2025 |
| Your Green & Co. Ltd | Hospitality | 2019 |
| Your Life Time IS Limited | Professional & scientific | 2020 |
| Your Logistics Company EOT Trustee Limited | Professional & scientific | 2024 |
| Your Logistics Company Ltd | Transport & logistics | 2014 |
| Yourbi Limited | Information & communication | 2024 |
| Yourcasa Development Limited | Real estate | 2016 |
| Youropay Limited | Administrative & support | 2010 |
| YPO Pennine Chapter | Other services | 2026 |
| YPO Pennine Gold Chapter | Other services | 2026 |
| YRM Medical Ltd | Health & social care | 2024 |
| YSR Beauty Ltd | Other services | 2019 |
| YTT Ltd | Real estate | 2018 |
| YU FAN Manchester Limited | Hospitality | 2025 |
| Yubhas Technologies Ltd | Information & communication | 2015 |
| Yun's Kitchen Limited | Hospitality | 2018 |
| Yungbaum Properties Limited | Real estate | 2021 |
| Yusuf DCP Ltd | Health & social care | 2023 |
| YY Investment Company Limited | Real estate | 2019 |
| YY YU Ltd | Real estate | 2019 |
| Yzma 00434534 Ltd | Manufacturing | 1947 |
| Z & D Rentals Ltd | Real estate | 2022 |
| Z & O Consultancy Ltd | Professional & scientific | 2023 |
| Z + F UK Properties Limited | Real estate | 2009 |
| Z a Investments (MCR) Ltd | Real estate | 2025 |
| Z J Bathrooms & Tiling Ltd | Construction | 2026 |
| Z Medical Limited | Health & social care | 2016 |
| Z Professionals Limited | Professional & scientific | 2020 |
| Z&L Homes Ltd | Construction | 2025 |
| Z-Tech Mobiles Limited | Wholesale & retail | 2017 |
| Z1NC Ltd | Administrative & support | 2019 |
| Zaabs Ltd | Health & social care | 2025 |
| Zachary Sophia Real Estate Limited | Real estate | 2025 |
| Zacollie Ltd | Construction | 2022 |
| Zaek Dent Ltd | Health & social care | 2017 |
| Zageno Ltd. | Wholesale & retail | 2020 |
| Zahn UK Management Ltd | Information & communication | 2024 |
| Zahra Eyecare Services Ltd | Health & social care | 2022 |
| Zaidi Estates Investments Limited | Real estate | 2024 |
| Zaira-Rose Ltd | Hospitality | 2026 |