| Howling Husky Ltd | Wholesale & retail | 2024 |
| Hoxton Capital Consultancy Ltd | Financial services | 2017 |
| HPC Classics Limited | Wholesale & retail | 2019 |
| HR Trading Post Ltd | Wholesale & retail | 2025 |
| HRD Investments Limited | Real estate | 2019 |
| HSF Investments Limited | Real estate | 2016 |
| Hsgdental Limited | Health & social care | 2026 |
| HSH Sales and Lettings Limited | Real estate | 2016 |
| Hudson Financial Solutions Limited | Financial services | 2021 |
| Huggett Home Improvements Ltd | Construction | 2026 |
| Hugh Page Holdings Ltd | Financial services | 2024 |
| Hugh Page Investments Ltd | Financial services | 2024 |
| Human Design With Livy Ltd | Professional & scientific | 2022 |
| Humanist Live Ltd | Information & communication | 2023 |
| Humberside Decorative Supplies Limited | Wholesale & retail | 1983 |
| Humphrey & Co Accountants LLP | | 2021 |
| Humphrey & Co Audit Services Limited | Professional & scientific | 2016 |
| Humphrey Trustees Limited | Professional & scientific | 1997 |
| Hungry Monk Management Ltd | Households | 2023 |
| Hunnypot Corner Day Nursery LLP | | 2019 |
| Hunt Commercial Property (Sussex) Ltd | Real estate | 2023 |
| Hunt Commercial Property Ltd | Real estate | 2013 |
| Hunt Frame Lettings Ltd | Real estate | 2017 |
| HUNTING4 Limited | Health & social care | 2015 |
| Hunts Automotive Ltd | Wholesale & retail | 2026 |
| Hussain Hale Clinic Limited | Health & social care | 2023 |
| HUW Oliphant EYE Surgery Limited | Health & social care | 2022 |
| HUX Investments Limited | Real estate | 2017 |
| HW Electrical & Building Services Ltd | Construction | 2017 |
| HW Event Management Limited | Other services | 2018 |
| HW Investment Properties Limited | Real estate | 2022 |
| Hybs Services Ltd | Transport & logistics | 2022 |
| Hyde Gardens Management Ltd | Real estate | 2014 |
| Hyde Gardens Residents Association Limited | Real estate | 1997 |
| Hydehead Limited | Real estate | 1985 |
| Hydehead Properties Limited | Real estate | 2018 |
| Hylands Accounting Ltd | Professional & scientific | 2002 |
| I AM SO Many Things Ltd | Arts & recreation | 2017 |
| I Dent Limited | Wholesale & retail | 2011 |
| I G Halus Ltd | Health & social care | 2015 |
| I Love to Buy Local Limited | Other services | 2020 |
| I.D.E.A (Southern) Limited | Administrative & support | 2024 |
| I.D.I. Metal Fabrications Limited | Manufacturing | 2002 |
| I.D.P. Safety Services Limited | Professional & scientific | 2003 |
| I2W Ltd. | Information & communication | 2021 |
| Iain RAE (PM) Ltd | Wholesale & retail | 2026 |
| Iain RAE Limited | Construction | 2017 |
| IAN Bruce Limited | Administrative & support | 2012 |
| IAN J Cooke Limited | Construction | 2002 |
| IAN Reeve MED Services Ltd | Health & social care | 2022 |
| Ibid Property Sales Ltd | Real estate | 2014 |
| ICA Electrical Engineering Services Ltd | Construction | 2017 |
| Ican Consultants Limited | Construction | 2015 |
| Icatcha Media Limited | Manufacturing | 2020 |
| Ice Smart Repairs Ltd | Wholesale & retail | 2025 |
| Ice-Cream Hatch Ltd | Wholesale & retail | 2026 |
| Iceiba Ltd | Information & communication | 2019 |
| Icon Roofs Limited | Construction | 2013 |
| ICR Investments Limited | Real estate | 2022 |
| Icto U.K. Ltd | Information & communication | 2017 |
| IDB Holdings Ltd | Real estate | 2017 |
| Ideas 4 Living Ltd | Health & social care | 2002 |
| Identity Papers Ltd | Wholesale & retail | 2013 |
| Idre Project Engineering Ltd | Mining & quarrying | 2015 |
| Ifitstuff Ltd | Information & communication | 2008 |
| Iford Consulting Limited | Professional & scientific | 2025 |
| Ig-Tech Limited | Information & communication | 2024 |
| Iges Distribution Limited | Financial services | 2021 |
| Iges Power Ltd | Construction | 2023 |
| Iges Technology Limited | Financial services | 2021 |
| Iges Water UK Limited | Construction | 2019 |
| Ignitho Technologies UK Limited | Information & communication | 2013 |
| Ihdental Limited | Health & social care | 2021 |
| Ihrb Trading Limited | Professional & scientific | 2011 |
| IKC Investments Limited | Real estate | 2016 |
| IL & Co Limited | Health & social care | 2004 |
| Illustrae Ltd | Information & communication | 2025 |
| ILY Property UK Ltd | Real estate | 2025 |
| IMG Alchemy Ltd | Other services | 2020 |
| Immaddition Ltd | Extraterritorial | 2022 |
| Immense Scaffolding Limited | Construction | 2023 |
| Immerse Flooring Ltd | Construction | 2021 |
| Imogen Finance LLP | | 2008 |
| Impact Global Emission Solutions Limited | Other services | 2011 |
| Impactology Limited | Professional & scientific | 2018 |
| Imperial GAS & Power Ltd | Energy | 2021 |
| Imperial Groundworks and Construction Ltd | Construction | 2023 |
| Imperial Merchant & Other Services Ltd | Other services | 2023 |
| Imperial Parks Limited | Professional & scientific | 2022 |
| Imperium Housing Solutions Ltd | Real estate | 2025 |
| Imperium Sussex Holdings Limited | Real estate | 2021 |
| Impetus Recruitment Limited | Administrative & support | 2025 |
| Impromptu Shakespeare Ltd | Education | 2018 |
| IMS Consult Limited | Professional & scientific | 2013 |
| IN & OUT Supermarket Ltd | Wholesale & retail | 2024 |
| IN East London Ltd | Financial services | 2020 |
| IN House Home Care Ltd | Health & social care | 2025 |
| IN Situ Limited | Wholesale & retail | 2007 |
| In-Align Orthodontics Ltd | Wholesale & retail | 2019 |
| Inappropriate Media Ltd | Information & communication | 2024 |