| Hrjdev Ltd | Information & communication | 2026 |
| Hronis Ltd | Water & waste | 2024 |
| HS & LS Group Ltd | Professional & scientific | 2014 |
| HS Foodie Ltd | Wholesale & retail | 2024 |
| HS Music CIC | Education | 2024 |
| HS Plastering Ltd | Construction | 2023 |
| HS Sandhu Limited | Real estate | 2018 |
| Hsgfintech Consulting Limited | Other services | 2019 |
| HSK Food and Wine Limited | Wholesale & retail | 2021 |
| HSP Engineering Solutions Ltd | Information & communication | 2010 |
| HSR Group Ltd | Professional & scientific | 2016 |
| HST Travels Limited | Extraterritorial | 2025 |
| Htt&C Ltd | Education | 2024 |
| Huaan PAY Ltd | Information & communication | 2021 |
| Hudson's Court Management Limited | Households | 2014 |
| Huesandtonesuk Ltd | Other services | 2024 |
| Hugh Marsh @Chocolate Peach Ltd | Hospitality | 2021 |
| Hughenden Court Management Company Limited | Administrative & support | 1988 |
| Hughenden Holdings Limited | Financial services | 2016 |
| Hughenden Properties Limited | Real estate | 2018 |
| Hughenden Property Ltd | Real estate | 2026 |
| Hughenden Valley Pharma Limited | Wholesale & retail | 2003 |
| Hughenden Villagestore Ltd | Wholesale & retail | 2022 |
| Hugo Volrath Ltd | Professional & scientific | 2025 |
| Humayoun Scripting Ltd | Information & communication | 2025 |
| Humphries & Hastie Limited | Manufacturing | 2017 |
| Hungry HUT H/W Limited | Hospitality | 2021 |
| Hungry Services Ltd | Hospitality | 2018 |
| Hungry Yasmine Ltd | Manufacturing | 2025 |
| Hunter Bowden Limited | Professional & scientific | 2009 |
| Hunter Rose Developments Ltd | Construction | 2023 |
| Hunter's Solicitors LLP | | 2013 |
| Hunts Office Furniture & Interiors Limited | Administrative & support | 1996 |
| Huntsman Air Sports Ltd | Wholesale & retail | 2016 |
| Hurco Europe Limited | Manufacturing | 1982 |
| Hurco Holdings Limited | Professional & scientific | 1982 |
| Hurlstone Associates Limited | Professional & scientific | 2009 |
| Hurrah! Ltd | Information & communication | 2012 |
| Hurryin Limited | Transport & logistics | 2020 |
| Hurst Property Management Limited | Households | 2023 |
| Hussain Properties Limited | Real estate | 2002 |
| Hussaini Services Ltd | Information & communication | 2024 |
| Hussar Group Ltd | Construction | 2015 |
| Hutchinson & Dibley Limited | Manufacturing | 1966 |
| HUW Consultancy Limited | Extraterritorial | 2022 |
| HVK Group Limited | Extraterritorial | 2021 |
| HW Halal Meat Limited | Wholesale & retail | 2018 |
| Hwbidco Ltd | Administrative & support | 2012 |
| HWC Investment Ltd | Real estate | 2022 |
| Hwrufc Supporters Ltd | Arts & recreation | 2016 |
| Hwss Ltd | Hospitality | 2024 |
| Hydro Navitas Solutions Ltd. | Wholesale & retail | 2015 |
| Hydrokem Aerosols Limited | Manufacturing | 1979 |
| Hydrotec Overseas Limited | Water & waste | 2015 |
| Hydrotecint Limited | Financial services | 2025 |
| Hygge Clothing Limited | Administrative & support | 2015 |
| Hygge Europe Limited | Administrative & support | 2015 |
| Hygge Fashion Limited | Administrative & support | 2015 |
| Hygge Retail Limited | Administrative & support | 2015 |
| Hygiene Direct Limited | Wholesale & retail | 2011 |
| Hyper Media Limited | Professional & scientific | 2017 |
| Hyrons Court Management Limited | Households | 1992 |
| Hyrora Talent Ltd | Administrative & support | 2025 |
| Hyyper Energy Solutions Ltd | Professional & scientific | 2012 |
| HZ Entertainment Berkshire Ltd | Arts & recreation | 2018 |
| HZK Media Limited | Wholesale & retail | 2010 |
| I AM Chief Ltd | Health & social care | 2019 |
| I C Shaw Consulting Limited | Professional & scientific | 2010 |
| I CAN Smell Burning Ltd | Professional & scientific | 2023 |
| I Count Limited | Professional & scientific | 2004 |
| I F M Insurance Brokers (Midlands) Ltd | Financial services | 1991 |
| I F M Select Holdings Limited | Financial services | 2018 |
| I H Group Holdings Ltd | Wholesale & retail | 2017 |
| I Lettings Limited | Real estate | 2016 |
| I Shopfitting Ltd | Construction | 2017 |
| I&S Security Ltd | Financial services | 2022 |
| I-Vine Tech Ltd | Information & communication | 2024 |
| I-Vine Training Ltd | Information & communication | 2023 |
| I.C. Electrical Contractors Limited | Construction | 2001 |
| I.E.A Properties Ltd | Real estate | 2025 |
| I.J. Plant Co. Ltd. | Wholesale & retail | 2000 |
| I.L. Beeks (High Wycombe) Limited | Construction | 1965 |
| I4 Consultancy and Design Limited | Professional & scientific | 2002 |
| IA Cyber Store Ltd | Wholesale & retail | 2026 |
| Iameko Ltd | Wholesale & retail | 2018 |
| Iamtajir Limited | Wholesale & retail | 2026 |
| Iamzf Ltd | Wholesale & retail | 2025 |
| IAN Rowe Foundation | Education | 2012 |
| IAN Watson Agencies Limited | Wholesale & retail | 2011 |
| Iancm Limited | Construction | 2011 |
| Ibassline Limited | Information & communication | 2013 |
| IBE Management Limited | Professional & scientific | 2005 |
| Ibex Alliance Ltd | Professional & scientific | 2025 |
| Ibgc Bosphorous Ltd | Professional & scientific | 2020 |
| Ibip Limited | Professional & scientific | 2013 |
| Ibis Integrated Bindery Systems Limited | Manufacturing | 1999 |
| IBO Centre Ltd | Hospitality | 2022 |
| IBU Trading Ltd | Wholesale & retail | 2025 |
| Icarus Theatre Collective & Cultural Services Ltd | Wholesale & retail | 2010 |
| Icarus' Othello Ltd | Wholesale & retail | 2013 |