| X2C Limited | Information & communication | 2018 |
| Xcelerate Accounting Ltd | Professional & scientific | 2024 |
| Xercom Computer Services Limited | Information & communication | 1997 |
| Xitol Limited | Information & communication | 2023 |
| Xposure Visual Communications Ltd | Professional & scientific | 2002 |
| Xprt Care Ltd | Health & social care | 2023 |
| XPS Ltd | Extraterritorial | 2008 |
| Y3K Systems Limited | Information & communication | 2001 |
| Yachtline Limited | Financial services | 1999 |
| YAH DAH YAH DAH Limited | Professional & scientific | 2013 |
| Yantsi Business Systems Limited | Administrative & support | 2025 |
| Yaris Equestrian Limited | Manufacturing | 2013 |
| Yasmine Mcclory Foundation CIC | Agriculture & fishing | 2024 |
| Ybrd LLP | | 2023 |
| Yeardley Estates Ltd | Real estate | 2024 |
| Yellow Brick Road Estates Ltd | Real estate | 2024 |
| Yellow Brick Road Holdings Ltd | Financial services | 2024 |
| Yellow Brick Road Newark Ltd | Health & social care | 2024 |
| Yellow Brick Road Pump Farm Ltd | Health & social care | 2023 |
| Yellow Jacket Pest Control Ltd | Professional & scientific | 2023 |
| Yellow Kestrel Limited | Professional & scientific | 2025 |
| Yellowstone Energy Limited | Wholesale & retail | 2025 |
| Ymca Newark and Sherwood | Arts & recreation | 2018 |
| York House Group Limited | Professional & scientific | 2024 |
| York Pizza Ltd | Hospitality | 2026 |
| Yorkehouse Holdings Ltd | Real estate | 2014 |
| Yorkehouse Newark Limited | Real estate | 2022 |
| Yorkehouse Properties Ltd | Real estate | 2014 |
| Yototo Limited | Information & communication | 2020 |
| YOU CAN DO in the Community CIC | Education | 2019 |
| YOU CAN DO Sport Ltd | Education | 2018 |
| Your Essential Assistant Ltd | Administrative & support | 2022 |
| YOUR4LEGS Limited | Extraterritorial | 2022 |
| Yourow Logistics Limited | Arts & recreation | 2026 |
| YRD Haulage Limited | Transport & logistics | 2024 |
| Yupp.Beer Limited | Hospitality | 2019 |
| Yvonne N Ltd | Wholesale & retail | 2017 |
| YX Leisure & Gaming Limited | Professional & scientific | 2016 |
| Zakirrajput Limited | Manufacturing | 2025 |
| Zalema Ltd | Transport & logistics | 2017 |
| Zana Technology Limited | Information & communication | 2024 |
| ZAR Cars Ltd | Wholesale & retail | 2023 |
| Zavorsky Limited | Construction | 2025 |
| Zazees Ltd | Hospitality | 2023 |
| Zazz Cocktails Limited | Wholesale & retail | 2024 |
| Zemium Ltd | Public administration | 2018 |
| Zenas Top Nosh Limited | Hospitality | 2014 |
| Zenith & Vale Properties Limited | Real estate | 2025 |
| Zentec Limited | Professional & scientific | 1999 |
| Zerenity Ltd | Other services | 2021 |
| Zero DRY Time Sleaford Ltd | Other services | 2016 |
| Zest CTO Group Ltd | Information & communication | 2019 |
| Zest Group Property Ltd | Real estate | 2019 |
| Zest Partnership Limited | Professional & scientific | 2012 |
| Ziggypig Ltd | Wholesale & retail | 2026 |
| ZNC Projects Ltd | Arts & recreation | 2019 |
| Zombie Motorcycles Ltd | Wholesale & retail | 2023 |
| Zorawski Ltd | Transport & logistics | 2012 |