| Hussaf Limited | Extraterritorial | 2007 |
| Hussain Jafri Ltd | Health & social care | 2025 |
| Hustlejacks Ltd | Wholesale & retail | 2021 |
| HUT-3 Holdings Limited | Financial services | 2019 |
| Huwa Logistics Ltd | Transport & logistics | 2021 |
| Huxter Estates Ltd | Real estate | 2020 |
| Huyton Travel Limited | Transport & logistics | 1986 |
| Hvac Technologies Ltd | Professional & scientific | 2021 |
| Hvvd Limited | Construction | 2019 |
| HW Plumbing & Heating Limited | Construction | 2019 |
| Hwgolf Ltd | Other services | 2019 |
| HWR Homes Ltd | Real estate | 2026 |
| HXN Capital Ltd | Financial services | 2025 |
| Hy-Plas Holdings Limited | Professional & scientific | 2010 |
| Hyacinth Close Residents Association Limited | Households | 1998 |
| Hybrid Boot Camp Ltd | Arts & recreation | 2014 |
| Hybrid Constructions Ltd | Construction | 2020 |
| Hybrid Property Group Ltd | Real estate | 2021 |
| Hybrit Services Ltd | Information & communication | 2016 |
| Hycut UK Ltd | Manufacturing | 2012 |
| Hyderabadi Biryani Centre Ltd | Hospitality | 2024 |
| Hydracoat Ltd | Construction | 2025 |
| Hydramech Services Limited | Manufacturing | 2015 |
| Hydrocode Limited | Information & communication | 1992 |
| Hydrovation Group Limited | Professional & scientific | 2022 |
| Hydrus Services Limited | Professional & scientific | 2015 |
| Hygiplas (Containers) Limited | Extraterritorial | 1978 |
| HYK Holdings Ltd | Manufacturing | 2026 |
| Hylton Care Limited | Health & social care | 2016 |
| HYPERO2 Health Ltd | Health & social care | 2025 |
| Hyslop Ltd | Health & social care | 2008 |
| HYT Teaching Ltd | Other services | 2025 |
| I & E Haulage UK Limited | Transport & logistics | 2010 |
| I & M Northampton Limited | Financial services | 2024 |
| I -Doo-B-Doo Ltd. | Arts & recreation | 2012 |
| I AM JON Duncan Ltd | Arts & recreation | 2019 |
| I AM Virtual Assist Ltd. | Construction | 2017 |
| I and S Building Contractors Limited | Construction | 2017 |
| I B Brickwork Limited | Administrative & support | 2017 |
| I Clean Universal Limited | Administrative & support | 2024 |
| I Cook YOU Serve C.I.C. | Hospitality | 2022 |
| I DELIVER4U Ltd | Transport & logistics | 2025 |
| I E Foods Ltd | Hospitality | 2019 |
| I H M Limited | Information & communication | 2000 |
| I I Magik Ltd | Construction | 2017 |
| I Loaf YOU Ltd | Manufacturing | 2025 |
| I Love Claims Limited | Administrative & support | 2011 |
| I N Sheds Ltd | Manufacturing | 2011 |
| I P T Design Ltd | Administrative & support | 2007 |
| I Ward and Sons Restoration LLP | | 2014 |
| I&B Paravan Ltd | Construction | 2024 |
| I&M Property 2 Limited | Construction | 2018 |
| I&M Property Limited | Real estate | 2017 |
| I&W Service Ltd | Transport & logistics | 2025 |
| I&Z Decorating Ltd | Construction | 2026 |
| I-Ab Limited | Information & communication | 2008 |
| I-Can Marketing Ltd | Administrative & support | 2020 |
| I-Can Telecommunications Ltd | Administrative & support | 2022 |
| I-Freight Luongo Ltd | Transport & logistics | 2020 |
| I-Kompli Ltd | Administrative & support | 2024 |
| I-One Data Solutions Ltd | Information & communication | 2022 |
| I-Sell Marketing Ltd | Administrative & support | 2023 |
| I.A. MAY Limited | Construction | 2002 |
| I.B Food Service Ltd | Hospitality | 2026 |
| I.C Logistics Limited | Transport & logistics | 2024 |
| I.C.E.Courier Ltd | Construction | 2023 |
| I.D. Lloyd & Sons Limited | Construction | 2002 |
| I.G.Estates Limited | Real estate | 2004 |
| I.R.S. Holdings Limited | Manufacturing | 1997 |
| I.S.O.D.T Limited | Wholesale & retail | 2014 |
| I.T. Parts Limited | Professional & scientific | 2003 |
| I.T.P. Sales Limited | Manufacturing | 1974 |
| I25 Services Ltd | Wholesale & retail | 2025 |
| I2O Ltd. | Construction | 2013 |
| I3 Primary Care Network Limited | Health & social care | 2021 |
| I4LOGISTICS Ltd | Transport & logistics | 2018 |
| I81B4U Limited | Information & communication | 2020 |
| Iaasbiaem Ltd | Health & social care | 2018 |
| IAM Brickpro Ltd | Construction | 2025 |
| Iamadd Ltd | Information & communication | 2023 |
| IAN Bird Financial Planning Limited | Professional & scientific | 2016 |
| IAN Booth Property Services Ltd | Professional & scientific | 2016 |
| IAN Brodie Catering (PIG Roasting) Limited | Hospitality | 2001 |
| IAN Lovell Electrical Services Limited | Construction | 2013 |
| IAN Mooney Ltd | Construction | 2006 |
| IAN Reilly and Associates Limited | Health & social care | 2013 |
| IAN Stephens Consulting Limited | Professional & scientific | 2015 |
| IAN White Electrical Services Limited | Construction | 2010 |
| Iaru Furniture Limited | Manufacturing | 2019 |
| IB Contracting Ltd | Professional & scientific | 2016 |
| IB Kitchen Solutions Ltd | Construction | 2025 |
| IB Property Ltd | Real estate | 2019 |
| IBA Global Examinations Board Limited | Education | 2013 |
| Ibeans Technology Limited | Information & communication | 2021 |
| Ibifaka Limited | Wholesale & retail | 2025 |
| Ibiola & Co. Ltd | Health & social care | 2015 |
| Ibis Asset Holdings Ltd | Administrative & support | 2017 |
| Ibis BTL Properties Ltd | Real estate | 2025 |
| Ibis Group Ltd | Construction | 2018 |
| IBL Lighting Ltd | Administrative & support | 2007 |