| Xdobo Ltd | Extraterritorial | 2022 |
| XH Construction Ltd | Construction | 2024 |
| XIA Properties Limited | Real estate | 2025 |
| XP Tavern Ltd | Hospitality | 2023 |
| Xpro 44 | Education | 2023 |
| Xservus Limited | Information & communication | 2015 |
| Xylon Installations Limited | Construction | 2014 |
| Y & R Enterprises Ltd | Real estate | 1988 |
| Yaar Hospitality Limited | Hospitality | 2025 |
| Yabirk Limited | Construction | 2025 |
| Yadah Projects Ltd | Construction | 2017 |
| Yagoo Ltd | Extraterritorial | 2020 |
| Yaldham Estate Management Limited | Real estate | 2014 |
| Yannis I.T.S (London) Ltd | Real estate | 2006 |
| Yapper Ventures Ltd | Administrative & support | 2020 |
| Yara Solutions Ltd | Information & communication | 2024 |
| Yarainvestments Ltd | Households | 2018 |
| Yashenterprise Limited | Hospitality | 2015 |
| Yasmeen London Limited | Wholesale & retail | 2020 |
| Yaura Limited | Wholesale & retail | 2017 |
| Yavaconstruct Ltd | Real estate | 2011 |
| Yaya Joy Limited | Wholesale & retail | 2023 |
| YD Sports Ltd | Education | 2019 |
| Yeahhh MAN ENT. Ltd | Manufacturing | 2018 |
| Yediceriler Limited | Extraterritorial | 2024 |
| Yehwot Limited | Information & communication | 2020 |
| Yellow FOX IT Ltd | Information & communication | 2024 |
| YES Cleaning and Property Services Ltd | Real estate | 2024 |
| YES Cleaning Ltd | Administrative & support | 2024 |
| Yeye MI Ltd | Manufacturing | 2025 |
| Yfla Limited | Wholesale & retail | 2019 |
| YGS Group Ltd | Education | 2016 |
| Yhian Limited | Wholesale & retail | 2008 |
| Yian Ltd | Other services | 2025 |
| Yimt Food Ltd | Hospitality | 2024 |
| Ylle Ltd. | Wholesale & retail | 2024 |
| YM Corporation Europe Ltd | Wholesale & retail | 2024 |
| Ymevents Ltd | Administrative & support | 2021 |
| Yobe Ltd | Real estate | 2022 |
| Yojo Limited | Transport & logistics | 2025 |
| Yokea Limited | Health & social care | 2022 |
| Yonder Studio Ltd | Manufacturing | 2019 |
| Yonder.Living Ltd | Wholesale & retail | 2014 |
| Yorkhouse Care Homes Ltd | Health & social care | 2017 |
| Yorkmoor Beckenham Grove Ltd | Administrative & support | 2005 |
| Youhelp BG | Health & social care | 2009 |
| Young Vibrant Ltd | Public administration | 2018 |
| Your Business Machine Ltd | Information & communication | 2024 |
| Your Clever Business Solutions Ltd | Other services | 2016 |
| Your Office Ltd | Real estate | 2007 |
| Youth Enterprise Ltd | Administrative & support | 2026 |
| Yuju Place Limited | Health & social care | 2024 |
| Yuma Properties Ltd | Real estate | 2025 |
| Yummy Little Belly (Food) Ltd | Manufacturing | 2025 |
| Yummy Little Belly (Growww) Ltd | Information & communication | 2025 |
| Yummy Little Belly Ltd | Information & communication | 2025 |
| YXL Property Investments Ltd | Real estate | 2021 |
| Zabco Homes Ltd | Real estate | 2024 |
| Zaborsky Services Limited | Manufacturing | 2024 |
| ZAC Lodges Limited | Hospitality | 2017 |
| Zacks Car Wash Ltd | Wholesale & retail | 2025 |
| Zacks Properties Ltd | Real estate | 2021 |
| Zaimi AGA Ltd | Wholesale & retail | 2024 |
| Zainab Medical Ltd | Health & social care | 2022 |
| Zandra Healthcare Ltd | Health & social care | 2011 |
| Zapfantech Ltd | Professional & scientific | 2020 |
| Zapp Acoustics Ltd | Construction | 2013 |
| Zaribelle Homes Ltd | Real estate | 2025 |
| Zarita's Choice Ltd | Wholesale & retail | 2024 |
| Zasbi Limited | Arts & recreation | 2016 |
| ZAU Medical Services Ltd | Professional & scientific | 2018 |
| Zayed Limited | Health & social care | 2013 |
| Zaza Barbers Limited | Other services | 2017 |
| Zazen Media Limited | Information & communication | 2006 |
| Zazi Holdings Limited | Real estate | 2026 |
| ZC Polaris Limited | Transport & logistics | 2022 |
| ZD Builders Ltd | Construction | 2016 |
| ZEN Realty UK Limited | Administrative & support | 2017 |
| Zenia Pharmaceuticals Limited | Wholesale & retail | 2016 |
| Zenith International Ventures Group Ltd | Wholesale & retail | 2025 |
| Zenithgold Limited | Real estate | 1981 |
| Zentara Living Ltd | Real estate | 2026 |
| Zenviro Ltd | Wholesale & retail | 2026 |
| Zeriyah Ltd | Information & communication | 2023 |
| Zero Degree Films LLP | | 2023 |
| Zero Mileage Property Ltd | Real estate | 2021 |
| Zeromileage Publishing Limited | Information & communication | 2025 |
| Zeromileage the Label Limited | Information & communication | 2023 |
| Zeus Cloud Ltd | Information & communication | 2014 |
| Zeus of London Limited | Wholesale & retail | 2016 |
| Zeus Property Ltd | Real estate | 2015 |
| ZH Analytics Ltd | Information & communication | 2024 |
| ZH Assests Management Ltd | Real estate | 2026 |
| ZH Assets Ltd | Real estate | 2026 |
| ZH Electrical Solutions Ltd | Construction | 2023 |
| ZH Property Services Ltd | Construction | 2012 |
| Zhaal Limited | Wholesale & retail | 2024 |
| Zheng Property Ltd | Real estate | 2026 |
| Zheng Qian 008 Ltd | Hospitality | 2026 |
| Zimdet Services Limited | Other services | 2006 |