| Hopworth Limited | Real estate | 2024 |
| Hoque & Choudhury (GB) Limited | Hospitality | 2016 |
| Horndale Construction Limited | Construction | 2006 |
| Horndale Ltd | Construction | 2018 |
| Horse & Groom Limited | Hospitality | 2005 |
| Horsepitality Limited | Health & social care | 2019 |
| Horstmann Controls Limited | Extraterritorial | 1978 |
| Horstmann Group Limited | Professional & scientific | 2010 |
| Horticultural Ltd | Wholesale & retail | 2016 |
| HORTON465 Limited | Administrative & support | 2019 |
| Hosay Building Services Ltd | Construction | 2013 |
| Hoskin Homes Property Group Ltd | Financial services | 2020 |
| Hospitality Allergen Support UK Limited | Hospitality | 2021 |
| Hoss Enterprises Limited | Wholesale & retail | 2002 |
| Hostile Environment Training Limited | Education | 2013 |
| Hot Diggerty Dogs Ltd | Hospitality | 2020 |
| Hotpot Community CIC | Hospitality | 2025 |
| Hotzone Technologies Ltd | Professional & scientific | 2009 |
| House 2 Home Services Limited | Construction | 2006 |
| Howard Holiday Homes Limited | Hospitality | 2017 |
| Howard Road Ltd | Real estate | 2021 |
| Howezat Ltd | Extraterritorial | 2020 |
| Hoyland Homes (Southern) Ltd | Real estate | 2012 |
| HPW Architecture Ltd | Professional & scientific | 1998 |
| HR Solutions 4 Business Limited | Administrative & support | 2012 |
| HS Plumbing & Electrical Ltd | Construction | 2025 |
| Hsmh Ltd | Transport & logistics | 2013 |
| HUE Hub Ltd | Manufacturing | 2024 |
| Hugh Freedom Ltd | Financial services | 2025 |
| Hughes Construction Services (Southern) Ltd | Professional & scientific | 2009 |
| Humain Consulting Limited | Professional & scientific | 2026 |
| Hunter Estate Management Limited | Real estate | 2006 |
| Hunter Medical Recruitment Limited | Administrative & support | 2023 |
| Hurco Food Ltd | Hospitality | 2025 |
| Hursley Cafe Limited | Hospitality | 2020 |
| Hursley Contractors Limited | Agriculture & fishing | 2015 |
| Hursts Properties (South) Ltd | Real estate | 2024 |
| Husband Collection Services Ltd | Administrative & support | 2009 |
| Husky Carpentry Limited | Construction | 2020 |
| Hutaccomm.Com. Ltd | Real estate | 2001 |
| HWB (ARK) Limited | Financial services | 2023 |
| HWB (GH) Limited | Financial services | 2023 |
| HWB (GMB) Limited | Financial services | 2023 |
| HWB (JA) Limited | Financial services | 2023 |
| HWB (JF) Limited | Financial services | 2023 |
| HWB (MC) Limited | Financial services | 2023 |
| HWB (MJ) Limited | Financial services | 2023 |
| HWB (TMY) Limited | Financial services | 2023 |
| HWB Holdings Limited | Professional & scientific | 2002 |
| HY Podiatry Limited | Health & social care | 2013 |
| Hybrid Legal Limited | Professional & scientific | 2013 |
| Hybridity Technology Ltd | Information & communication | 2023 |
| Hyde Abbey House Limited | Construction | 2020 |
| Hyde Management Group Ltd | Professional & scientific | 2021 |
| Hygeia House Limited | Professional & scientific | 2025 |
| Hygge Associates Limited | Professional & scientific | 2023 |
| Hyse Ltd | Wholesale & retail | 2021 |
| I & S Fixings Limited | Construction | 2011 |
| I G I Developments Limited | Extraterritorial | 2006 |
| I Group Ltd | Financial services | 2017 |
| I Newton Investments Ltd | Real estate | 2021 |
| I.C.U Fire and Security Ltd | Administrative & support | 2025 |
| I4 Facilities Limited | Administrative & support | 2024 |
| I4 Group Limited | Financial services | 2021 |
| I4 Projects Limited | Construction | 1995 |
| IAC Acoustic Company UK Limited | Manufacturing | 2016 |
| IAN Wall Furniture Restoration Ltd | Other services | 2018 |
| IBL Realisations Limited | Information & communication | 1999 |
| Icare Health and Hospitality Services Ltd | Administrative & support | 2022 |
| ICD Partnership Limited | Education | 2017 |
| Icechip Limited | Extraterritorial | 2009 |
| Icon X Limited | Administrative & support | 2026 |
| Ideaengineai Ltd | Information & communication | 2025 |
| Identity Construction Ltd | Wholesale & retail | 2009 |
| Identity Labs Consultancy Limited | Other services | 2017 |
| IDR London Limited | Health & social care | 2016 |
| IDS Ingegneria DEI Sistemi (UK) Limited | Manufacturing | 2002 |
| IDW Design Limited | Professional & scientific | 2013 |
| Ignis Bidco Limited | Administrative & support | 2015 |
| Ignis Holdco Limited | Professional & scientific | 2017 |
| Ignis Midco Limited | Professional & scientific | 2017 |
| Ignis Topco Limited | Financial services | 2017 |
| Ihch Consulting Limited | Information & communication | 2013 |
| Iilsa Ltd | Wholesale & retail | 2023 |
| IJM Power Limited | Professional & scientific | 2011 |
| Ikew Limited | Information & communication | 2020 |
| Illuminance Ltd | Agriculture & fishing | 2023 |
| ILS Network (UK) Ltd | Administrative & support | 2010 |
| IM Healthcare Limited | Health & social care | 2012 |
| Imagevox Ltd | Administrative & support | 2019 |
| Imaginacts Entertainment Ltd | Arts & recreation | 2019 |
| Imagine Recruitment Resources Limited | Professional & scientific | 2023 |
| Imaging Blueprint Limited | Information & communication | 2013 |
| IME Lifting Solutions Ltd | Information & communication | 2017 |
| Imperial Square (Finchley) Management Limited | Households | 2014 |
| Impulse 24 Limited | Professional & scientific | 2007 |
| IN the Dog House Retreat Ltd | Other services | 2026 |
| Incat Crowther (UK) LLP | | 2014 |
| Incat Crowther Limited | Professional & scientific | 2014 |
| Inclusion Diversity (UK) Ltd | Other services | 2015 |