| High Circle Limited | Administrative & support | 2024 |
| High Gables Consulting Limited | Professional & scientific | 2025 |
| High Holly Consultancy Ltd | Other services | 2008 |
| Highcrest Investments Limited | Professional & scientific | 2003 |
| Highgate Asset Management (Holdings) Limited | Financial services | 2013 |
| Highgate Asset Management Limited | Professional & scientific | 2007 |
| Highgate Developments (UK) Limited | Real estate | 2009 |
| Highgate JV Developments Limited | Real estate | 2015 |
| Highgate Real Estate Holdings Limited | Real estate | 2014 |
| Highgate Real Estate UK Limited | Real estate | 2008 |
| Highstone Car Company Limited | Wholesale & retail | 2013 |
| Hillside Homes Loughton Ltd | Real estate | 2025 |
| Hillstone Investment Group Limited | Real estate | 2024 |
| HIM Collections Ltd | Manufacturing | 2022 |
| Himawari Works Ltd | Manufacturing | 2026 |
| Hippodrome Property Limited | Construction | 2017 |
| Hira Homes Ltd | Real estate | 2017 |
| Hire Power Contracts Limited | Transport & logistics | 1988 |
| Hitik Solutions Ltd | Information & communication | 2013 |
| HK EPP Ltd | Real estate | 2023 |
| Hksr Holdings Ltd | Real estate | 2022 |
| Hlpc UK Limited | Administrative & support | 2018 |
| HM Developments Two Limited | Construction | 2023 |
| HM Management Services Ltd | Professional & scientific | 2026 |
| HMP Management Limited | Construction | 1987 |
| HMS Ganges Management Company Limited | Real estate | 2019 |
| HOE Street Dental Surgery Limited | Health & social care | 2011 |
| Hoecroft Homes Limited | Real estate | 2016 |
| Holden Simmons Limited | Administrative & support | 2016 |
| Holiday 2 Go Ltd | Administrative & support | 2020 |
| Holistic Therapy Covent Garden Ltd | Other services | 2023 |
| Hollybush Gardens Developments Ltd | Real estate | 2023 |
| Hollybush Lakes Limited | Financial services | 2021 |
| Holt Renovations Ltd | Construction | 2014 |
| Homage Media Limited | Arts & recreation | 2022 |
| Home Sold NOW Limited | Real estate | 2026 |
| Homebumpkins Childcare Ltd | Health & social care | 2023 |
| Homes by Holmes Limited | Wholesale & retail | 2012 |
| Homes of Holloway Ltd | Real estate | 2026 |
| Homes R US Development Limited | Real estate | 2021 |
| Hometrend Limited | Extraterritorial | 2002 |
| Honeymaker Limited | Professional & scientific | 2009 |
| Hong Hong (UK) Limited | Health & social care | 2006 |
| Honiton Developments Limited | Construction | 2017 |
| Hopkins and Barnard Developments Limited | Construction | 2020 |
| Horizon Evergreen Limited | Construction | 2000 |
| Horizon Haven Holdings Ltd | Real estate | 2023 |
| Horizons Digital Ltd | Financial services | 2026 |
| Horne’S Building Services Ltd | Construction | 2024 |
| Hornsey Grenville Property Limited | Real estate | 2022 |
| Hoti Home Improvements Ltd | Construction | 2021 |
| House of El-Shaddai International | Other services | 2001 |
| House of Hundredtags Ltd | Wholesale & retail | 2024 |
| Household Shop Ltd | Wholesale & retail | 2019 |
| Housingconnections Limited | Administrative & support | 2000 |
| Howard Wise Properties Limited | Other services | 2018 |
| Howard's and Company (Brentwood) Limited | Construction | 1957 |
| Howick & Brooker Partnership Limited | Real estate | 2000 |
| Howlin' Music Limited | Information & communication | 1979 |
| Hoxton Barbers Ltd | Other services | 2024 |
| HR Arron Ltd | Wholesale & retail | 2023 |
| Hsat Management Limited | Professional & scientific | 2017 |
| HTM Health Limited | Health & social care | 2025 |
| HUB52 Limited | Households | 2014 |
| Hubb Creative Limited | Professional & scientific | 2023 |
| Hubb Media Ltd | Professional & scientific | 2025 |
| Huck Holdings PVT Ltd | Financial services | 2024 |
| Hunter Biscuit & Wolf Limited | Hospitality | 2021 |
| Hunterstone Investments Ltd | Information & communication | 2011 |
| Hunts Waste Management Ltd | Water & waste | 2018 |
| Huxley Gardens Ltd | Construction | 2018 |
| Huzcorse Property Co.Limited | Real estate | 1964 |
| Hydragold Limited | Hospitality | 1985 |
| Hydro Aesthetics Ltd | Health & social care | 2023 |
| Hygieia Wellness Ltd | Health & social care | 2025 |
| Hygienaclad Ltd | Extraterritorial | 2008 |
| Hygreen Energy Limited | Other services | 2022 |
| Hyper Recruitment Solutions Ltd | Administrative & support | 2011 |
| I & Z Construction Limited | Construction | 2023 |
| I Create My Story Ltd | Information & communication | 2023 |
| I H a Media Limited | Wholesale & retail | 2014 |
| I Hate HR Ltd | Administrative & support | 2022 |
| I M Lunae Ltd | Real estate | 2025 |
| I Organise Ltd | Real estate | 2023 |
| I W F F Ltd | Arts & recreation | 2019 |
| I&C Enterprise Ltd | Transport & logistics | 2019 |
| I-Smart Care Limited | Education | 2013 |
| IA Delivery Ltd | Transport & logistics | 2023 |
| Iadopt Limited | Other services | 2010 |
| IAN Cousins Limited | Manufacturing | 2015 |
| IAN Steinberg Limited | Professional & scientific | 2015 |
| IB Joinery Limited | Construction | 2018 |
| Ib&Ilg Investment Ltd | Real estate | 2024 |
| Ibab Consulting Ltd | Professional & scientific | 2020 |
| Ibin Ltd | Professional & scientific | 2018 |
| IC Retail Property Ltd | Administrative & support | 2019 |
| Ice Computer Solutions Limited | Information & communication | 2010 |
| Iconized Customs Limited | Administrative & support | 2023 |
| Iconshield Limited | Administrative & support | 2005 |
| IDA Partners Ltd | Professional & scientific | 2026 |