| Xzibit Motors Ltd | Wholesale & retail | 2021 |
| XĪN and Voltaire Limited | Manufacturing | 2017 |
| Y and S London Ltd | Health & social care | 2017 |
| Y Creative Limited | Professional & scientific | 2013 |
| Y Delivery Ltd | Other services | 2023 |
| Y K S Investment Property Ltd | Real estate | 2025 |
| Y&A Capital Limited | Health & social care | 2023 |
| Y&E WU Ltd | Hospitality | 2020 |
| Y2B Properties C.I.C. | Other services | 2019 |
| Y2K Entertainment Music & Arts Ltd | Professional & scientific | 2014 |
| Y2K Music Arts & Culture CIC | Health & social care | 2025 |
| Y2K Vehicle Movements Ltd | Transport & logistics | 2025 |
| YA Capital Investment Ltd | Real estate | 2020 |
| Yabe Limited | Information & communication | 2015 |
| Yago Ltd | Wholesale & retail | 2025 |
| Yaha Consultancy Limited | Health & social care | 2016 |
| YAM Property Consulting 13 Briggate Limited | Real estate | 2025 |
| Yamato Engineering Co. Ltd | Manufacturing | 2018 |
| Yamimoto Limited | Wholesale & retail | 2015 |
| Yamkwad Enterpise Limited | Administrative & support | 2024 |
| Yammy.Jewellery Ltd | Wholesale & retail | 2024 |
| YAN ZE KJ Ltd. | Wholesale & retail | 2025 |
| Yantrix Ltd | Education | 2026 |
| Yanyan Trading Ltd | Wholesale & retail | 2022 |
| Yardley Heating Services Limited | Construction | 2008 |
| Yaruba Limited | Other services | 2021 |
| YAS Property Holdings Ltd | Real estate | 2022 |
| Yash Universal UK Ltd | Information & communication | 2026 |
| Yashtech Data Solutions UK Ltd | Information & communication | 2015 |
| Yask Furniture Factory Limited | Manufacturing | 2004 |
| Yaska Farah Ltd | Health & social care | 2024 |
| Yasmeen Trading Ltd | Financial services | 2024 |
| Yasmina's Closets Limited | Wholesale & retail | 2024 |
| Yasrob Ltd | Real estate | 2021 |
| YASSIN03 Ltd | Real estate | 2022 |
| Yatou Capital Limited | Financial services | 2025 |
| Yaus Property Ltd | Real estate | 2021 |
| Yazanmia Limited | Health & social care | 2020 |
| YB & FS Solutions UK Ltd | Wholesale & retail | 2023 |
| Ybmb Ltd | Education | 2023 |
| YBR Developments Limited | Real estate | 2021 |
| YCM Consulting Limited | Professional & scientific | 2008 |
| YE Olde Bullring Tavern Ltd | Hospitality | 2025 |
| YEH Dosti Ltd | Hospitality | 2022 |
| Yelai Holdings Ltd | Real estate | 2024 |
| Yelai Ltd | Wholesale & retail | 2022 |
| Yelda Kitchen Ltd | Hospitality | 2026 |
| Yellow Balloon Properties Limited | Real estate | 2021 |
| Yellow Leaf Consulting Ltd | Professional & scientific | 2014 |
| Yellow Line Taxis Ltd | Transport & logistics | 2018 |
| Yellow Vista Ltd | Financial services | 2023 |
| Yellowchairproperties Limited | Real estate | 2023 |
| Yenomy Ltd | Construction | 2025 |
| YEO Holdings Limited | Financial services | 2019 |
| YEP Clean Ltd | Administrative & support | 2019 |
| YES Chef Magazine Limited | Manufacturing | 2006 |
| YES Wefix Limited | Other services | 2026 |
| Yesac & Nixium Limited | Information & communication | 2016 |
| Yesagain Group Ltd | Wholesale & retail | 2025 |
| Yesagain Ltd | Information & communication | 2022 |
| Yeshmn Limited | Wholesale & retail | 2025 |
| Yesss Conservatories Ltd | Extraterritorial | 2025 |
| Yetunde Asif Limited | Manufacturing | 2026 |
| YEW Tree Marketing Ltd | Administrative & support | 2025 |
| Yexle Limited | Information & communication | 2019 |
| YI XIN MO Ltd. | Wholesale & retail | 2025 |
| YI Yang LI Ltd. | Wholesale & retail | 2025 |
| Yieldcompass Limited | Real estate | 2017 |
| Yimi Ltd | Information & communication | 2017 |
| YIN Feng Zhang Ltd. | Wholesale & retail | 2025 |
| Ying Feng Qian Ltd. | Wholesale & retail | 2025 |
| Ying GE LIU Ltd. | Wholesale & retail | 2025 |
| Yings Management Limited | Hospitality | 2023 |
| Yjun KJ Ltd. | Wholesale & retail | 2025 |
| YK FAN Ltd. | Wholesale & retail | 2025 |
| YKS Trading Ltd | Hospitality | 2016 |
| Ylfpublishing Ltd | Professional & scientific | 2024 |
| Ymca South Midlands Limited | Hospitality | 1992 |
| YMT Solutions Ltd | Wholesale & retail | 2021 |
| YO Fast Ltd | Wholesale & retail | 2025 |
| YO Takeaway Ltd | Hospitality | 2023 |
| Yo-Foodie Limited | Hospitality | 2021 |
| Yofoodie Service Ltd | Hospitality | 2023 |
| Yoga Yoga Spa Limited | Health & social care | 2025 |
| Yogalily Studio Ltd | Education | 2024 |
| Yogo Cairns Ltd | Real estate | 2023 |
| Yokebuild Limited | Real estate | 1982 |
| Yoko Comfort Property LLP | | 2021 |
| Yoko Property Investments LLP | | 2021 |
| Yoko Property Ltd | Real estate | 2019 |
| Yolobro Ltd | Real estate | 2020 |
| Yolomarts Limited | Wholesale & retail | 2023 |
| Yomak Properties Limited | Real estate | 2020 |
| Yong an JU Ltd | Real estate | 2023 |
| Yong YG KJ Ltd. | Wholesale & retail | 2025 |
| Yong YI WU Ltd. | Wholesale & retail | 2025 |
| Yonne Consulting Ltd | Information & communication | 2025 |
| YOO to a TEE Ltd | Wholesale & retail | 2025 |
| York City Properties 2 Limited | Hospitality | 2021 |
| York City Properties Limited | Hospitality | 2008 |