| Yamurchata Limited | Other services | 2026 |
| Yang Chao TAO Ltd | Hospitality | 2024 |
| Yang LI Limited | Hospitality | 2019 |
| Yani Cuts Ltd | Other services | 2023 |
| Yardley Homes Ltd | Construction | 2021 |
| Yatton Health Ltd | Wholesale & retail | 2023 |
| YAU Brothers & Co Limited | Wholesale & retail | 1984 |
| Yavington Holdings Ltd | Financial services | 2019 |
| YB Delivery 2022 Ltd | Transport & logistics | 2022 |
| YE Property Holdings (UK) Limited | Real estate | 2026 |
| Yeah! Burger Limited | Hospitality | 2014 |
| Yeargate Investments NO 1 | Financial services | 2025 |
| Yeargate Investments NO 2 | Financial services | 2025 |
| Yeargate Investments NO 3 | Financial services | 2025 |
| Yeargate Investments NO 4 | Financial services | 2025 |
| Yeargate Investments NO 5 | Financial services | 2025 |
| Yeargate Investments NO 6 | Financial services | 2025 |
| Yeargate Investments NO 7 | Financial services | 2025 |
| Yeargate Limited | Construction | 1983 |
| Yeargate SPV Limited | Real estate | 2015 |
| Yeko Limited | Wholesale & retail | 2023 |
| Yellow Brock Road Limited | Households | 2022 |
| Yellow Car Wash Limited | Other services | 2020 |
| Yellow Door (Solent) | Health & social care | 2005 |
| Yellow Electrical and Property Services Limited | Construction | 2006 |
| Yellow Mountain Martial Arts Ltd | Wholesale & retail | 2022 |
| Yellow Photography Limited | Professional & scientific | 1998 |
| Yelloweye Consultancy Ltd | Professional & scientific | 2020 |
| Yellownotepad Limited | Administrative & support | 2021 |
| Yelwal Limited | Wholesale & retail | 2017 |
| Yemite Kitchen Ltd | Hospitality | 2025 |
| YES Event Services Limited | Manufacturing | 2016 |
| YES Mush Ltd | Wholesale & retail | 2021 |
| Yeskay Ltd | Professional & scientific | 2015 |
| Yewtree Workshops Ltd | Wholesale & retail | 2015 |
| YFB Marketing Ltd | Real estate | 2013 |
| YFT Logistics Limited | Administrative & support | 2009 |
| YGF Southampton Limited | Hospitality | 2025 |
| Ygochi Limited | Real estate | 2023 |
| Yinksyem Wellbeing Ltd | Health & social care | 2024 |
| Yipin Noodle Bar Limited | Hospitality | 2026 |
| YKM Ltd | Transport & logistics | 2024 |
| YKS & YKS Healthcare Limited | Health & social care | 2013 |
| Ymca Fairthorne Group | Other services | 2001 |
| Ymca Fairthorne Housing | Real estate | 2011 |
| YO Capital Ltd | Real estate | 2019 |
| YO Network Services Limited | Information & communication | 2013 |
| YO Telecom Limited | Information & communication | 2013 |
| YO! ENG Ltd | Education | 2023 |
| Yoga Sanctuary Southampton Limited | Education | 2011 |
| Yogis United Limited | Extraterritorial | 2015 |
| Yoho Cleaning Ltd | Administrative & support | 2026 |
| Yolo Wealth Management Ltd | Professional & scientific | 2019 |
| Yolomic Ltd. | Financial services | 2014 |
| YOMIYOMI2 Limited | Health & social care | 2024 |
| Yongap Care Limited | Health & social care | 2025 |
| Yorkshire Energy Contract Solutions Limited | Professional & scientific | 2011 |
| Yortex Limited | Real estate | 2023 |
| YOU ARE Salon Limited | Other services | 2025 |
| YOU Have IT Maid Ltd | Administrative & support | 2021 |
| YOU Massage Therapy Limited | Health & social care | 2015 |
| YOU Therapy Centre Ltd | Health & social care | 2019 |
| Youbuntu CIC | Education | 2025 |
| Younas & Sons Limited | Real estate | 2015 |
| Young Acorn Accountancy Limited | Professional & scientific | 2025 |
| Young Chef Young Waiter Limited | Hospitality | 2019 |
| Young Explorers (Southampton) Limited | Health & social care | 2019 |
| Young People's Wellbeing Service Ltd. | Health & social care | 2000 |
| Youngs Financial Planning Ltd | Financial services | 2018 |
| Youngs Welding and Fabrication Limited | Construction | 2019 |
| Youngtoo Travel Ltd | Administrative & support | 2024 |
| Younity Ltd | Health & social care | 2019 |
| Your Arena Ltd | Wholesale & retail | 2024 |
| Your Best Friend's Friend Limited | Other services | 2005 |
| Your Best Home Ideas Ltd | Wholesale & retail | 2019 |
| Your Best Ltd | Professional & scientific | 2019 |
| Your Brand Matters Ltd | Professional & scientific | 2015 |
| Your Finance Today Limited | Financial services | 2009 |
| Your Garden Built Ltd | Construction | 2023 |
| Your Gardens Hampshire Ltd | Professional & scientific | 2021 |
| Your Haus/Uk Ltd | Construction | 2023 |
| Your Home Sold Guaranteed UK Ltd | Real estate | 2020 |
| Your Key Space Ltd | Administrative & support | 2021 |
| Your Lead Machine Limited | Administrative & support | 2018 |
| Your Next Property Limited | Real estate | 2025 |
| Your Office Sidekick Ltd | Administrative & support | 2024 |
| Your Online Convenience Store Ltd | Wholesale & retail | 2025 |
| Your Own Energy Ltd | Energy | 2011 |
| Your Stay Solutions Ltd | Real estate | 2017 |
| Your Store Andover Limited | Transport & logistics | 2019 |
| Your Systems Ltd | Administrative & support | 2018 |
| Your Unique Print Ltd | Administrative & support | 2017 |
| Your-Q Limited | Professional & scientific | 2014 |
| Yourenergy Nutrition Limited | Professional & scientific | 2020 |
| Yours Financially Ltd | Financial services | 2003 |
| Yours Financially Support Services Limited | Financial services | 2006 |
| Youth and Families Matter | Health & social care | 2008 |
| YOUTH4YOUTH Group Limited | Information & communication | 2014 |
| Yoya Beauty Ltd | Other services | 2021 |
| YPM Properties Limited | Real estate | 2023 |