| Heidi Klein Limited | Wholesale & retail | 2001 |
| Helen Lynam Nutrition Ltd | Health & social care | 2013 |
| Helena Sullivan Revops 4 Recruitment Ltd | Professional & scientific | 2026 |
| Hello Sailor Ltd | Transport & logistics | 2024 |
| Hellyers Ltd | Real estate | 2025 |
| Hembu Ltd | Manufacturing | 2025 |
| Hestia Space Ltd | Professional & scientific | 2016 |
| HF Investment Properties Ltd | Real estate | 2022 |
| Hidden Productions Limited | Administrative & support | 2026 |
| High Lanes Partnership Limited | Real estate | 2010 |
| High Spirits Limited | Wholesale & retail | 2023 |
| Highclare Properties Limited | Real estate | 2016 |
| Highclare Property Holdings Limited | Real estate | 2017 |
| Highclere FH Ltd | Construction | 2024 |
| Highclere Hotel Limited | Hospitality | 2002 |
| Highclere House Holdings Ltd | Construction | 2024 |
| Highclere House Management Co. Ltd | Households | 2024 |
| Highmile Limited | Transport & logistics | 2018 |
| Highstreet & Commercial Holdings Limited | Real estate | 1994 |
| Highveld Homes Limited | Construction | 2022 |
| Hinman Associates Limited | Professional & scientific | 2010 |
| Hippisley Limited | Professional & scientific | 2012 |
| Hiprep Limited | Other services | 2014 |
| Hire Depot Limited | Administrative & support | 1994 |
| Hitnext Ltd | Information & communication | 2026 |
| Hkrsd Interiors Ltd | Construction | 2019 |
| HM Evans Consulting Limited | Professional & scientific | 2012 |
| HM GB (Wind) Ltd | Energy | 2020 |
| HM Hub Ltd | Professional & scientific | 2020 |
| HM Kier Ltd | Real estate | 2021 |
| Hmae 1 Ltd | Real estate | 2018 |
| Hmae Hillside Ltd | Real estate | 2019 |
| Hodson Construction Ltd | Construction | 2018 |
| Hoffman Europe Limited | Professional & scientific | 2000 |
| Hogan's Alley Limited | Arts & recreation | 2024 |
| Holly Business Systems Limited | Other services | 1995 |
| Home SYS Limited | Other services | 2022 |
| Homly Ltd | Real estate | 2018 |
| Hooked UP Creative Ltd | Administrative & support | 2022 |
| Hope Technical Developments Limited | Manufacturing | 1962 |
| Hopi Demattio Ltd | Information & communication | 2015 |
| Hornblower Services Limited | Construction | 1970 |
| Hotrocks Global Ltd | Wholesale & retail | 2023 |
| Hotrocks Jewellery UK Limited | Manufacturing | 2014 |
| Hotshots Sports Coaching Limited | Arts & recreation | 2001 |
| House 15 Limited | Other services | 2022 |
| HOW 2 Keep Youyr JOB Ltd | Extraterritorial | 2023 |
| Howell (Ascot) Properties Limited | Real estate | 1963 |
| HPB Developments Limited | Extraterritorial | 2015 |
| HSC Optivita UK I LP | | 2004 |
| HSC Optivita UK II LP | | 2005 |
| HSC Optivita UK III LP | | 2005 |
| HSC Optivita VII UK LP | | 2006 |
| HSC Optivita Viii UK LP | | 2006 |
| HSC Optivita X UK Limited Partnership | | 2007 |
| HSC Optivita XI UK Limited Partnership | | 2008 |
| HT Utilities Ltd | Professional & scientific | 2020 |
| Hugo James Ltd | Construction | 2024 |
| Hundred House Management Company Ltd | Households | 2018 |
| Hunter Lombard Property Group Ltd | Real estate | 2025 |
| Huntsbriar Care Group Ltd | Health & social care | 2025 |
| Huthwaite Hold Co II LLP | | 2022 |
| Huxley Bear Limited | Education | 2021 |
| Hydro Systems UK Limited | Wholesale & retail | 2004 |
| Hydrocarbon Capital Limited | Information & communication | 2013 |
| I Knowledge Consultancy Limited | Professional & scientific | 2011 |
| I.P. Generation Ltd | Information & communication | 2003 |
| Iain Mckenzie EP Ltd | Professional & scientific | 2019 |
| IAN Weiss Plumbing & Heating Limited | Construction | 2007 |
| Ianua Limited | Professional & scientific | 2024 |
| Icebear Limited | Extraterritorial | 1996 |
| Iconic Europe Limited | Construction | 2014 |
| Iconic Golf Group Ltd | Wholesale & retail | 2016 |
| ID8 360 Limited | Information & communication | 2022 |
| ID8 Retail Limited | Information & communication | 2023 |
| IDS Financial Consulting Limited | Other services | 2014 |
| IFF Personal Care Ltd | Manufacturing | 2023 |
| IFP Construction Limited | Hospitality | 2016 |
| IHD Care Ltd | Health & social care | 2017 |
| Ikoyi Realty Limited | Construction | 2022 |
| Illusion Plaster Ltd | Construction | 2026 |
| Imagion Ltd | Information & communication | 2020 |
| Impactful Leaders Limited | Professional & scientific | 2022 |
| Impartial Financial Advice Ltd | Financial services | 2019 |
| Improving Care Solutions Ltd | Professional & scientific | 2018 |
| IMS Hygiene Solutions Ltd | Wholesale & retail | 2020 |
| IN Style Ascot Ltd | Wholesale & retail | 2023 |
| IN Time Worldwide Express Limited | Transport & logistics | 2002 |
| Incognito Aesthetics Ltd | Health & social care | 2025 |
| Indent Systems Limited | Wholesale & retail | 2004 |
| Index Holdings Ltd | Professional & scientific | 2006 |
| Index House Limited | Real estate | 2005 |
| Indigo Asset Management Ltd | Real estate | 2011 |
| Indit Ltd | Real estate | 2019 |
| Indulgent Brands Ltd | Hospitality | 2023 |
| Inetex Limited | Information & communication | 2007 |
| Infant Apparel Ltd | Wholesale & retail | 2023 |
| Infinitech Worldwide Ltd | Professional & scientific | 2012 |
| Infiniti Finance Limited | Financial services | 1999 |
| Infiniti Roofing Ltd | Construction | 2025 |