| Harrop Ltd | Health & social care | 2012 |
| Harry GRT Ltd | Wholesale & retail | 2018 |
| Harry's News Ltd | Wholesale & retail | 2017 |
| Hartwell Design & Build Limited | Construction | 2003 |
| Harvest Haven TW1 Ltd | Wholesale & retail | 2024 |
| Harvey's Bakehouse Ltd | Wholesale & retail | 2023 |
| Hasegawa Ltd | Health & social care | 2024 |
| Havenmove Property Management Limited | Households | 1986 |
| Havok Media Ltd | Information & communication | 2025 |
| Hawk Management (UK) Limited | Education | 1998 |
| Hawk Management Group Limited | Extraterritorial | 2016 |
| Hawton Business Park Limited | Real estate | 2024 |
| Hayes Medical Consultancy Ltd | Health & social care | 2010 |
| Haygo Holding Limited | Financial services | 2021 |
| Haygo Limited | Construction | 2021 |
| Haymarket Consumer Media Ltd. | Information & communication | 1981 |
| Haymarket Group Limited | Professional & scientific | 1993 |
| Haymarket Media Group Ltd. | Information & communication | 1932 |
| Haymarket Medical Publications Ltd. | Information & communication | 1980 |
| Haymarket Publishing Services Limited | Professional & scientific | 1964 |
| Haymarket UK2 Limited | Administrative & support | 2008 |
| Haymarket Worldwide Limited | Professional & scientific | 1965 |
| Hazel Data Services Ltd | Extraterritorial | 2022 |
| Hazel Keech Singh Consulting Limited | Professional & scientific | 2025 |
| HCO Ltd | Wholesale & retail | 2003 |
| HCO Nominee Limited | Extraterritorial | 2025 |
| HD PAY Services Ltd | Administrative & support | 2022 |
| Healing Touch Limited | Health & social care | 2023 |
| Healthwatch Richmond Ltd. | Other services | 2013 |
| Heart Twickenham CIC | Other services | 2014 |
| Heat Sauna Ltd | Health & social care | 2025 |
| Heathfield Partners Limited | Real estate | 2012 |
| Heathrow Premium Chauffeurs Ltd | Transport & logistics | 2023 |
| Heatrun Ltd | Construction | 2022 |
| Heavenly Dish (London) Limited | Hospitality | 2017 |
| Hecuk Limited | Professional & scientific | 2018 |
| Heddway Ltd | Professional & scientific | 2023 |
| Hedone Spa Ltd | Other services | 2025 |
| Hedson Facades Limited | Construction | 2021 |
| Hedson Group Ltd | Financial services | 2018 |
| Hedson Rail Limited | Construction | 2013 |
| Hei-Uk Ltd | Education | 2025 |
| Helene Dollie Ltd | Professional & scientific | 2023 |
| Helios Properties UK Ltd | Real estate | 2007 |
| Helix Learning Trust Ltd | Education | 2025 |
| Hempstead Properties Limited | | 1960 |
| Henebery Homes Ltd | Real estate | 2025 |
| Henebery Ltd | Real estate | 2024 |
| Henry James Design and Build Limited | Construction | 2022 |
| Henry Prideaux & Associates Ltd | Professional & scientific | 2012 |
| Heritage of London Ltd | Administrative & support | 2016 |
| Heritage People Limited | Administrative & support | 2026 |
| Heritage Trade Limited | Construction | 2017 |
| Heritage-Construction-Group Limited | Construction | 2026 |
| Hero Food Group Ltd | Hospitality | 2020 |
| Hevercourt Limited | Health & social care | 2017 |
| HEX Technology Group Ltd | Professional & scientific | 2021 |
| Hfcs Consulting Ltd | Information & communication | 2017 |
| HGS Rail Ltd | Construction | 2025 |
| HH Beauty London Ltd | Other services | 2026 |
| Hhip Limited | Information & communication | 2009 |
| HI Growth Ltd | Professional & scientific | 2021 |
| High 5 Safety Ltd | Professional & scientific | 2025 |
| High Care Clinic Ltd | Health & social care | 2016 |
| High House Creative Limited | Professional & scientific | 2019 |
| High-Tech Scientific Investments Limited | Financial services | 2002 |
| Highlight Inventory Services Limited | Administrative & support | 2010 |
| Higrow Limited | Wholesale & retail | 2015 |
| Hill View House Management Company Limited | Real estate | 1998 |
| Hillfoot Ltd | Professional & scientific | 2021 |
| Hillside Land & Property Limited | Real estate | 2019 |
| Himalayan Pink Salt Company Ltd | Wholesale & retail | 2025 |
| Hint of Italy Ltd | Hospitality | 2019 |
| Hirenum.Us Ltd | Wholesale & retail | 2026 |
| Hiro Hiro Limited | Other services | 2019 |
| Hiro Hiro Nails Limited | Other services | 2022 |
| Hkic Ltd | Professional & scientific | 2022 |
| HLJ Consulting Limited | Professional & scientific | 2014 |
| HMC Enterprises Limited | Professional & scientific | 2003 |
| Hoang Properties Ltd | Real estate | 2023 |
| Hobbs-Devaney Plumbing & Heating Ltd | Construction | 2025 |
| Hollister Consulting Limited | Professional & scientific | 2017 |
| Hollow Mountain Films Ltd | Information & communication | 2022 |
| Holly Road Property Management Ltd | Real estate | 2016 |
| Hollygrove Flooring Company Limited | Wholesale & retail | 1972 |
| Hollys Kitchen Ltd | Hospitality | 2023 |
| Holton Heath Ltd | Real estate | 2025 |
| HOM Group Ltd | Hospitality | 2022 |
| Home Stop Limited | Wholesale & retail | 2011 |
| Homebaked Gift Company Limited | Hospitality | 2015 |
| Homemade Curries Ltd | Hospitality | 2018 |
| Homeroots Spices Ltd | Wholesale & retail | 2026 |
| Homshtag Ltd | Wholesale & retail | 2025 |
| Honeyguide Limited | Information & communication | 2020 |
| Honour Advisory Ltd | Professional & scientific | 2025 |
| Hoopr Ltd | Information & communication | 2025 |
| Hope and Play Ltd | Health & social care | 2007 |
| Horatio Court Residents Association Limited | Households | 1998 |
| Horizon House Management Limited | Households | 2019 |
| Horizon Strategy Research Limited | Professional & scientific | 2024 |