| Heroshika Properties Ltd | Real estate | 2023 |
| Herstoryy CIC | Health & social care | 2024 |
| Heskform Limited | Households | 1999 |
| Hexpro Ltd | Information & communication | 2021 |
| Highline Corporate Limited | Professional & scientific | 2021 |
| Highprop Ventures Limited | Real estate | 2025 |
| Highview Prop Limited | Real estate | 2025 |
| Hirani Interiors Limited | Construction | 2022 |
| Hitopia Ltd | Professional & scientific | 2016 |
| HJ Fast Foods Ltd | Hospitality | 2021 |
| HM Profix Ltd | Construction | 2025 |
| Hobnika Limited | Wholesale & retail | 2015 |
| Hoffman Property Ltd | Real estate | 2018 |
| Hogbitz Ltd | Manufacturing | 2023 |
| Hoia Solutions Limited | Transport & logistics | 2016 |
| Holborn Notaries Ltd | Professional & scientific | 2016 |
| Hold Property Limited | Real estate | 2023 |
| Holloway Management Limited | Households | 2016 |
| Home and Office Automation Limited | Information & communication | 2017 |
| Home Like Heaven Ltd | Wholesale & retail | 2025 |
| Home Physio London Ltd | Health & social care | 2024 |
| Homecherry House RTM Company Limited | Households | 2010 |
| Homeglaze Home Improvements Ltd | Construction | 2011 |
| Homely Habitat Limited | Construction | 2025 |
| Homes by Jinal Ltd | Real estate | 2025 |
| Hope MED Limited | Wholesale & retail | 2013 |
| Horace and Grange Ltd | Households | 2026 |
| Horizon Capital Assets Limited | Real estate | 2012 |
| Horizon Computer Systems Limited | Information & communication | 1988 |
| Horizon Hartwig Limited | Professional & scientific | 2013 |
| Hornell Construction Limited | Construction | 2026 |
| House of Ee[N] Designs Limited | Real estate | 2025 |
| House of Hair Chigwell Limited | Other services | 2015 |
| House of Sarbloh Ltd | Manufacturing | 2025 |
| House Soul Ltd | Construction | 2023 |
| House to Home (London) Limited | Real estate | 2017 |
| HP Fast Food Ltd | Hospitality | 2024 |
| HPM Property Limited | Real estate | 2018 |
| Hrks Limited | Real estate | 2001 |
| Hs&Company Ltd | Wholesale & retail | 2024 |
| Hsbrands Limited | Wholesale & retail | 2022 |
| HSK Health Limited | Health & social care | 2013 |
| Huemun Clssiks Limited | Information & communication | 2020 |
| Hurst Property Holdings Limited | Real estate | 2024 |
| Hynte Limited | Education | 2012 |
| Hznszn Ltd | Wholesale & retail | 2026 |
| I & K Specialist Ltd | Construction | 2017 |
| I Basildon Properties Ltd | Real estate | 2022 |
| I Direct Independent Living Limited | Health & social care | 2014 |
| I M Investors Ltd | Real estate | 2025 |
| I&D Properties London Ltd | Real estate | 2023 |
| I.M.C.J Ltd | Construction | 2023 |
| ICM Tiles Ltd | Construction | 2024 |
| ID Construction Ltd | Construction | 2015 |
| Id-Vent Ltd | Construction | 2021 |
| Ideal Emart Ltd | Information & communication | 2007 |
| IG Gray Ltd | Construction | 2025 |
| Igadgetspro Limited | Wholesale & retail | 2026 |
| IGM Building Solutions Limited | Construction | 2016 |
| IJ Bansal Properties Ltd | Real estate | 2022 |
| IKE Okolie Ltd | Professional & scientific | 2025 |
| IKE Perissos Ltd | Professional & scientific | 2014 |
| Ilford Developments and Investments Ltd | Real estate | 2017 |
| Illyrian Logistics & Training Ltd | Transport & logistics | 2026 |
| Illyrian Logistics Ltd | Transport & logistics | 2024 |
| IM Groundworks Ltd | Construction | 2024 |
| Imaks Group Limited | Real estate | 2015 |
| Imani Food Products Limited | Manufacturing | 2015 |
| IMF Fixing ,Facade Construction Ltd | Construction | 2018 |
| Impact Implement Advisory Ltd | Professional & scientific | 2024 |
| Imperial ASK Line Ltd | Wholesale & retail | 2025 |
| Imperial Tuition Services Ltd | Education | 2014 |
| Inderjit Group Limited | Financial services | 2025 |
| India House Investments Ltd | Real estate | 2017 |
| Indian Kadai Ltd | Hospitality | 2017 |
| Indulgent Homes Limited | Wholesale & retail | 2025 |
| Infinity Project Management Limited | Construction | 2019 |
| Infriq Ltd | Information & communication | 2026 |
| ING Roofing Ltd | Manufacturing | 2019 |
| Ingham Healthcare Limited | Health & social care | 2004 |
| Inhouse Office Solutions Ltd | Real estate | 2019 |
| Innate Experiences Limited | Administrative & support | 2022 |
| Inner Cybin Limited | Wholesale & retail | 2022 |
| Inner Flows Collective Ltd | Professional & scientific | 2025 |
| Inspired by Islam | Professional & scientific | 2014 |
| Instant Transport Ltd | Wholesale & retail | 2021 |
| Insuresoft Ltd | Information & communication | 2025 |
| Integrated Care Services Group Ltd | Health & social care | 2023 |
| INTENSIVECARE24/7 Ltd | Health & social care | 2025 |
| International Football Club Limited | Financial services | 2022 |
| Intrasecure Group Ltd | Education | 2015 |
| Intrix Services (UK) Limited | Extraterritorial | 2008 |
| Invena UK Limited | Administrative & support | 2015 |
| Invicta Business and Accounting Services Limited | Professional & scientific | 2010 |
| ION Tudorel Ltd | Construction | 2024 |
| Ionda Ltd | Construction | 2020 |
| Ir&C Ltd | Information & communication | 2020 |
| Isha Healthcare Limited | Public administration | 2024 |
| Ishrathealthcare Ltd | Professional & scientific | 2011 |
| IT & MD Plumbing Ltd | Construction | 2024 |