| Hertfordshire Plumbing Company Limited | Construction | 2018 |
| Herts Holdings Ltd | Real estate | 2022 |
| Herts Property Maintenance Ltd | Households | 2018 |
| Heta Design Limited | Construction | 2016 |
| Hetal Limited | Financial services | 2021 |
| Hexagon Motor Company Ltd | Wholesale & retail | 2014 |
| Hgnl (Berkhamsted) Limited | Construction | 2025 |
| Hgnl (Pulborough) Limited | Construction | 2025 |
| Hgnl (Reigate) Limited | Construction | 2025 |
| Hgnl (Woking) Limited | Construction | 2025 |
| Hgnl CHD Ltd | Professional & scientific | 2025 |
| HGP Projects Limited | Construction | 2022 |
| HHE Sport Horses Ltd | Arts & recreation | 2025 |
| Hi-Tec Controls Limited | Construction | 1995 |
| High Lines Gallery LLP | | 2025 |
| High Technology Glazing Ltd. | Manufacturing | 2012 |
| High Technology Ventures Ltd | Professional & scientific | 2017 |
| Higham Freehold Ltd | Real estate | 2020 |
| Hillcroft Films Ltd | Information & communication | 2014 |
| Hills Licensing Limited | Professional & scientific | 2012 |
| Hireitall.Com Ltd | Administrative & support | 2008 |
| Hiss and Shake Records Limited | Information & communication | 2021 |
| Hivings Consultancy Ltd | Professional & scientific | 2018 |
| Hivings Holdings Ltd | Real estate | 2025 |
| Hj&B Properties Limited | Real estate | 2018 |
| HK Premier Properties Ltd | Real estate | 2024 |
| HNL Maidstone Limited | Construction | 2018 |
| HO Dynasty Limited | Other services | 2023 |
| Holistic Interiors Limited | Professional & scientific | 2023 |
| Holland & Harris Limited | Arts & recreation | 2001 |
| Hollie Warren Ltd. | Professional & scientific | 2025 |
| Holly Spring Limited | Other services | 2019 |
| Hollystone Estates Ltd | Real estate | 2025 |
| Hollywood Collectibles Ltd | Wholesale & retail | 2026 |
| Holwood (Fleet) Limited | Real estate | 2003 |
| Homedirect UK Trading Ltd | Wholesale & retail | 2011 |
| Homesline Limited | Construction | 2023 |
| Homo Shapiens Ltd | Professional & scientific | 2015 |
| Honest Safety Ltd | Administrative & support | 2025 |
| Hope Psychiatry Limited | Health & social care | 2020 |
| Horvath Gardening Ltd | Administrative & support | 2023 |
| Hot Mess Productions Limited | Arts & recreation | 2023 |
| House of Carpets (Uxbridge) Limited | Wholesale & retail | 2003 |
| House of Rora Limited | Construction | 2023 |
| House of Treetments Ltd | Other services | 2020 |
| HOW to Sing Ltd | Information & communication | 2010 |
| HOW U Develop Ltd | Professional & scientific | 2021 |
| Howard Commercial Interior Design Limited | Professional & scientific | 2018 |
| Howards Gate Management Company Limited | Real estate | 2003 |
| Hoys Bloodstock Limited | Agriculture & fishing | 2018 |
| HPS Property Matters Ltd | Construction | 2021 |
| Hsaa Imports Ltd | Wholesale & retail | 2025 |
| Hsoc Home Maintenance Ltd | Construction | 2021 |
| Hsoc the Roofing Company Ltd | Construction | 2022 |
| Hssd Limited | Administrative & support | 2010 |
| HTS Property Services Ltd | Construction | 2022 |
| Hubpro Limited | Administrative & support | 2015 |
| Hucha Group Ltd | Hospitality | 2024 |
| Hucha Ltd | Administrative & support | 2022 |
| Hudoma Ltd | Wholesale & retail | 2020 |
| Humdrum Skin Limited | Extraterritorial | 2023 |
| Hundred Acre Gardens Limited | Administrative & support | 2021 |
| Hungry Flames Ltd | Hospitality | 2025 |
| Hurlingham Stretch Tents Ltd | Administrative & support | 2016 |
| Hurlingham Tents Limited | Administrative & support | 2024 |
| Hush Social Limited | Hospitality | 2019 |
| Hyde & Myers Plumbing and Heating Limited | Construction | 2016 |
| HZZ Limited | Professional & scientific | 2015 |
| I-Dream Kitchens Limited | Manufacturing | 2022 |
| I.N.C Artists Ltd | Administrative & support | 2013 |
| I2IDEAS Limited | Professional & scientific | 2008 |
| I3A Solutions Limited | Information & communication | 2015 |
| Iceberg Medical Limited | Professional & scientific | 2007 |
| Icfonow Ltd | Administrative & support | 2016 |
| ID Greenstar Solutions Limited | Financial services | 2026 |
| Ideal Heating & Construction Ltd | Construction | 2022 |
| Identity Services UK Ltd | Administrative & support | 2017 |
| IDR Insolve Limited | Other services | 2021 |
| IDR Legal Limited | Professional & scientific | 2021 |
| IDR Worldwide Limited | Other services | 2011 |
| Ifillya Ltd | Wholesale & retail | 2023 |
| Ifnnwhen Ltd | Professional & scientific | 2023 |
| Iglass (UK) Limited | Construction | 2012 |
| Ignite Invest Ltd | Professional & scientific | 2004 |
| Ihmc Ltd | Wholesale & retail | 2016 |
| II Sun Limited | Information & communication | 2026 |
| Iibu Limited | Education | 2011 |
| Ijss Properties Limited | Real estate | 2026 |
| Image Link Chesham Limited | Manufacturing | 2005 |
| IMC Systems Limited | Information & communication | 1999 |
| Immedia Imaging Limited | Real estate | 2002 |
| Impact Matrix Ltd | Administrative & support | 2025 |
| IN Season Film and TV Ltd | Hospitality | 2024 |
| Inclusive Communication Solutions Ltd | Education | 2024 |
| Indigokrafts Private Limited | Wholesale & retail | 2015 |
| Inertia Mechanical Ltd | Construction | 2024 |
| Infeco Construction Ltd | Construction | 2025 |
| Infinite Housing Limited | Construction | 2004 |
| Infinity Property Ltd | Real estate | 2021 |
| Influential PMO Limited | Professional & scientific | 2024 |