| Itops Clothing Limited | Manufacturing | 2014 |
| Itopsec Ltd | Information & communication | 2004 |
| Itroger Tech AGN Ltd | Information & communication | 2025 |
| ITS Hygiene Ltd | Wholesale & retail | 2019 |
| ITS London Ltd | Wholesale & retail | 2019 |
| ITS Proper Jerk Limited | Hospitality | 2023 |
| ITS5OCLOCK Ltd | Real estate | 2024 |
| Itserv Limited | Information & communication | 2007 |
| Itsolenterprises Limited | Wholesale & retail | 2021 |
| Itsus Consulting Ltd | Information & communication | 2008 |
| Ittehad Traders Limited | Wholesale & retail | 2026 |
| Ityzer Ltd | Information & communication | 2025 |
| IUK Renovation and Trading Limited | Wholesale & retail | 2025 |
| Iulian Palade Ltd | Transport & logistics | 2016 |
| Iungo Care C.I.C. | Health & social care | 2019 |
| Iungo Solutions Limited | Information & communication | 2020 |
| IVA Stone Ltd | Construction | 2019 |
| Ivan&Ryan Transport Ltd | Construction | 2022 |
| Ivanbooks Limited | Wholesale & retail | 2025 |
| Ivandevelopment Ltd | Administrative & support | 2023 |
| Ivanovna SA Ltd | Information & communication | 2023 |
| Ivape Distribution Limited | Other services | 2018 |
| IVC Consultants Limited | Administrative & support | 2017 |
| Iver Smash Limited | Hospitality | 2023 |
| Iver Station Ltd | Wholesale & retail | 2018 |
| Iveron Media Group Ltd | Information & communication | 2026 |
| Iveston Property Ltd | Real estate | 2026 |
| IVF Clinics Limited | Professional & scientific | 2014 |
| Ivici Limited | Health & social care | 2020 |
| Iview Health Ltd | Information & communication | 2023 |
| Ivision Market Ltd | Financial services | 2021 |
| IVO Build Limited | Construction | 2015 |
| Ivonera Ltd | Education | 2025 |
| Ivor Holdings Limited | Real estate | 1950 |
| Ivor Thomas Funerals Limited | Other services | 2018 |
| Ivor Thomas Holdings Ltd | Financial services | 2026 |
| Ivorreece Limited | Information & communication | 2023 |
| Ivory and Sugar Ltd | Manufacturing | 2025 |
| Ivory Capital Group Ltd | Financial services | 2018 |
| Ivory Horizon Limited | Information & communication | 2024 |
| Ivory INK Crafts Limited | Wholesale & retail | 2025 |
| Ivory Properties Limited | Real estate | 2004 |
| Ivorysands Hospitality Limited | Hospitality | 2021 |
| IVP Logistic Ltd | Transport & logistics | 2016 |
| IVY Equestrian Limited | Agriculture & fishing | 2025 |
| IVY Lane (Macclesfield) Limited | Construction | 2019 |
| IVY Marketing Communications Limited | Professional & scientific | 2017 |
| IVY Solicitors Limited | Professional & scientific | 2016 |
| Ivychic Limited | Wholesale & retail | 2025 |
| Ivylane Residential Properties Ltd | Real estate | 2024 |
| IW Financials Ltd | Financial services | 2021 |
| Iwancareservices Ltd | Health & social care | 2025 |
| IWC Holdings Limited | Financial services | 2020 |
| Iweb Group Limited | Extraterritorial | 2019 |
| Iwingo.Io Ltd | Education | 2025 |
| IWS Online School Ltd | Education | 2023 |
| Iwtbad Ltd | Health & social care | 2021 |
| IXD Consultants Limited | Professional & scientific | 2013 |
| Ixion Developments Limited | Construction | 2007 |
| Ixion Holding PC | | 2018 |
| Ixion Projects Limited | Construction | 2016 |
| Ixorra Services Ltd | Wholesale & retail | 2021 |
| IY Innovation LLP | | 2025 |
| Iyad Cars Ltd | Wholesale & retail | 2025 |
| Iyatan Solutions Ltd | Wholesale & retail | 2025 |
| Iyaya Limited | Wholesale & retail | 2025 |
| IYC IDC Ltd | Professional & scientific | 2025 |
| IYH Group Ltd | Wholesale & retail | 2021 |
| IYI Investment Ltd | Wholesale & retail | 2018 |
| IYM 420 Ltd | Arts & recreation | 2020 |
| Iyuifh Ltd | Manufacturing | 2026 |
| Izdestiny Ltd | Wholesale & retail | 2020 |
| Izgi Ltd | Wholesale & retail | 2025 |
| IZI Electric Ltd | Administrative & support | 2023 |
| Izidor Ltd | Construction | 2015 |
| Izzy Holdings Ltd | Financial services | 2023 |
| Izzy Services (UK) Ltd | Extraterritorial | 2013 |
| Izzy’S MTM Ltd | Other services | 2023 |
| Iésous Ltd | Professional & scientific | 2024 |
| J & A.Leigh Limited | | 1953 |
| J & C Developments Ltd | Health & social care | 2008 |
| J & D Retail Ltd | Wholesale & retail | 2017 |
| J & H Stores Ltd | Wholesale & retail | 2017 |
| J & J Facilities Services Limited | Administrative & support | 2020 |
| J & J Properties (Rochdale) Ltd | Real estate | 2019 |
| J & J Taverns Ltd | Hospitality | 2019 |
| J & K Isca Ltd | Health & social care | 2023 |
| J & L Facades Limited | Construction | 2019 |
| J & L.V. Limited | Health & social care | 2008 |
| J & M Brothers Ltd | Construction | 2014 |
| J & M Industrial Services Limited | Administrative & support | 2017 |
| J & N Car Sales Limited | Wholesale & retail | 2020 |
| J & R Land Ltd | Professional & scientific | 2012 |
| J & R Salvage Recovery Ltd | Financial services | 2018 |
| J & S Art Publishing Ltd | Wholesale & retail | 2024 |
| J & T Taylor Enterprises Limited | Administrative & support | 2012 |
| J a 786 Developments Ltd | Construction | 2021 |
| J a Consultia Ltd | Professional & scientific | 2014 |
| J a Rewbridge Development Services Ltd | Professional & scientific | 2015 |
| J a S Groundcare Ltd | Administrative & support | 2021 |