| Hanover Hill Management Company Limited | Real estate | 2019 |
| Hanover Systems Limited | Construction | 2007 |
| Harcourt Consulting Limited | Financial services | 2024 |
| Hardy Hotel Limited | Hospitality | 2016 |
| Hardy North Wales Limited | Real estate | 2014 |
| Harkin Capital Ltd | Financial services | 2025 |
| Harkin Property Ltd | Real estate | 2024 |
| Harmony Hair Studio Bangor Ltd | Other services | 2026 |
| Harris Salvage Ltd | Wholesale & retail | 2026 |
| Harrison Care Homes Bangor Ltd | Health & social care | 2024 |
| Harrison Care Homes Ltd | Health & social care | 2022 |
| Harvest Jacks Ltd | Hospitality | 2022 |
| Harvey & Rybak Limited | Extraterritorial | 2018 |
| Harvey Homes of Distinction Limited | Construction | 2000 |
| Hatty Limited | Financial services | 2006 |
| Haulfre Limited | Hospitality | 2025 |
| Haus Hotels Limited | Extraterritorial | 2017 |
| Haus of Deck Limited | Wholesale & retail | 2018 |
| Haven Crew Wear Ltd | Manufacturing | 2025 |
| Haworth Group Property Management Ltd | Households | 2025 |
| Hawthorne and Beechwood Management Company Ltd | Extraterritorial | 2021 |
| Hayho Enterprises Ltd | Hospitality | 2007 |
| Hcni Ltd | Health & social care | 2012 |
| Hcni Supported Living Limited | Health & social care | 2025 |
| Headland Management Limited | Extraterritorial | 2007 |
| Headline Productions Limited | Information & communication | 2014 |
| Headmasters Cuts Ltd | Other services | 2023 |
| Headrow House Leeds Limited | Construction | 2022 |
| Healing Hands Thai Massage Limited | Other services | 2023 |
| Health Infinity Limited | Financial services | 2024 |
| Health to Drive Ltd | Extraterritorial | 2019 |
| Healthcare Insurance (NI) Ltd | Financial services | 2012 |
| Heart Health Hub Ltd | Health & social care | 2025 |
| Heatherlea Fine Foods NI Limited | Manufacturing | 2010 |
| Heatherlea Retail Limited | Wholesale & retail | 2012 |
| Heatni Ltd | Wholesale & retail | 2023 |
| Heavenly Sound (UK) Limited | Manufacturing | 2018 |
| Hebog Environmental Limited | Professional & scientific | 2004 |
| Hedley Refrigeration Limited | Construction | 2025 |
| Hedyn CYF | Manufacturing | 2009 |
| Heffernan Commercial Property Valuations Ltd | Real estate | 2025 |
| Hefin Cannon Transport Limited | Transport & logistics | 2016 |
| Hehehope Limited | Real estate | 2023 |
| HEK Consulting Ltd | Professional & scientific | 2025 |
| Helensview Park Management Limited | Extraterritorial | 2007 |
| Helgrind Ltd | Arts & recreation | 2023 |
| Helixn Ltd | Information & communication | 2025 |
| Helping Hand Tutoring Ltd | Education | 2006 |
| Helping Hands (Northern Ireland) Ltd | Professional & scientific | 2013 |
| Heol Santes Helen Limited | Extraterritorial | 2007 |
| Herba-Chrisni Ltd | Arts & recreation | 2021 |
| Herb’S Courier Services Ltd | Transport & logistics | 2026 |
| Hercus Ltd | Extraterritorial | 2020 |
| Hermanas Rentals Limited | Real estate | 2025 |
| Herpetoloco Ltd | Wholesale & retail | 2025 |
| Hesk Developments Limited | Real estate | 2006 |
| Hestia Fire Protection Ltd | Professional & scientific | 2025 |
| Hezley Ltd | Real estate | 2019 |
| HH Administrative Services Limited | Information & communication | 2022 |
| HI Bangor Ltd | Hospitality | 2024 |
| High Flow Services Limited | Transport & logistics | 2019 |
| High Street Swansea Limited | Construction | 2021 |
| Highland First Management Company UK Limited | Real estate | 2023 |
| Highlife Rope Access Ltd | Construction | 2015 |
| Hightown Merchants Limited | Real estate | 1997 |
| Hilltop House 117 Hornsey Lane RTM Company Limited | Households | 2011 |
| Hine & Divine Limited | Other services | 2025 |
| Hlpro Ltd | Professional & scientific | 2024 |
| HMW Business Services Ltd | Professional & scientific | 2015 |
| Hobby and Games Ltd | Wholesale & retail | 2025 |
| Hogan (Asphalt) Ltd. | Manufacturing | 1979 |
| Hogan (Concrete) Ltd | Manufacturing | 1981 |
| Hogan (Construction) Ltd | Construction | 1983 |
| Hogan (Holdings) Ltd | Professional & scientific | 1983 |
| Holborn Villas Limited | Households | 1983 |
| Holdenhurst Road Bournemouth Limited | Construction | 2014 |
| Holdfast LAB Ltd | Information & communication | 2026 |
| Hollyhill Limited | Real estate | 2009 |
| Home of Heating Ltd | Construction | 2011 |
| Home Surveyors Limited | Extraterritorial | 2000 |
| Home-Start North Down | Health & social care | 1989 |
| Homelink Online Limited | Real estate | 2006 |
| HOMES2LETNI Ltd | Real estate | 2016 |
| Honeycomb Law CIC | Professional & scientific | 2020 |
| Hooters Car Wash Ltd | Administrative & support | 2025 |
| Horizon Design & Construction Ltd | Construction | 2020 |
| Horizon Financial LLP | | 2024 |
| Horner Pharmacy Limited | Wholesale & retail | 2005 |
| Horsesmouth Productions Limited | Information & communication | 2007 |
| Hospitality Accounting Solutions Ltd | Professional & scientific | 2016 |
| Hot Dogs Grooming London Limited | Other services | 2023 |
| House of Bars Ltd | Other services | 2022 |
| House of Hope Care Limited | Public administration | 2026 |
| House of Linen Hire Ltd | Other services | 2026 |
| House of Niyah Ltd | Hospitality | 2025 |
| House of ZEN (Sunderland) Limited | Hospitality | 2017 |
| House of ZEN LLP | | 2011 |
| Howson Quigg Property Group Limited | Real estate | 2024 |
| How’S DAD? SUT MAE DAD? CYF | Health & social care | 2024 |
| HQ Fit Ltd | Arts & recreation | 2022 |