| HG Maddison Limited | Financial services | 2025 |
| HGM Property Investment Limited | Real estate | 2025 |
| HI GS Logistics Limited | Transport & logistics | 2016 |
| High Field (Worcs) Limited | Financial services | 2026 |
| High Lodge (2025) Ltd | Households | 2025 |
| High Lodge Court Limited | Real estate | 2011 |
| High Stile Living Ltd | Real estate | 2026 |
| High Stile Property Ltd | Real estate | 2025 |
| Highbase LRW Limited | Real estate | 2015 |
| Highbay Partitions Limited | Construction | 2013 |
| Hill 22 Limited | Wholesale & retail | 2022 |
| Hill Estates (Cardiff) Limited | Real estate | 2022 |
| Hillberry Facilities Management Limited | Administrative & support | 2020 |
| Hillfield Motor Company Limited | Wholesale & retail | 2009 |
| Hillgrove Nature Limited | Agriculture & fishing | 2021 |
| Hillhampton Developments Limited | Real estate | 2015 |
| Hills Wills Limited | Professional & scientific | 2016 |
| Hindlip Properties Limited | Real estate | 2017 |
| Hirst Consulting Limited | Professional & scientific | 2005 |
| HIT Strategy Limited | Professional & scientific | 2025 |
| Hive House Ltd | Public administration | 2024 |
| HJ Clinical Limited | Administrative & support | 2024 |
| HK Surveyors Ltd | Real estate | 2022 |
| HLW Independent Fostering Consultancy Ltd | Health & social care | 2010 |
| HMO Harmony Ltd | Real estate | 2023 |
| HNB Advisory Ltd | Professional & scientific | 2014 |
| Hodges Landscaping and Design Ltd | Administrative & support | 2026 |
| Hodgson Court Limited | Real estate | 2005 |
| Holdco Ltd | Professional & scientific | 2021 |
| Holy Smokes Media Ltd | Information & communication | 2022 |
| Holyrood House (Malvern) Management Company Limited | Households | 2023 |
| Homesure Limited | Real estate | 1949 |
| Homo Ludens Ltd | Arts & recreation | 2024 |
| Horalzer Ltd | Administrative & support | 2018 |
| Horizon Legacy Holdings Limited | Financial services | 2025 |
| Horizon Legacy Investments Limited | Real estate | 2025 |
| Hornbrook 006 Ltd | Financial services | 2021 |
| Hornbrook 007 Ltd | Financial services | 2021 |
| Hornbrook 008 Ltd | Financial services | 2021 |
| Hornbrook 009 Ltd | Financial services | 2021 |
| Hornbrook 010 Ltd | Financial services | 2021 |
| Hornbrook 011 Ltd | Financial services | 2021 |
| Hornbrook Holdings B LLP | | 2021 |
| Hornbrook Holdings C LLP | | 2021 |
| Horton Lane Ltd | Wholesale & retail | 2021 |
| Hotelshop Onbusiness Limited | Administrative & support | 2015 |
| Hovebooks Ltd | Wholesale & retail | 2016 |
| HOW Very Limited | Arts & recreation | 2016 |
| Hoxley Homes Ltd | Other services | 2022 |
| HPC Medical Services Ltd | Health & social care | 2021 |
| HSD Retail Ltd | Wholesale & retail | 2017 |
| HSL Leisure & Retail Limited | Manufacturing | 2012 |
| Huddington Property Management Limited | Extraterritorial | 2012 |
| Hughley Estates Limited | Real estate | 2022 |
| Hugwoo Ltd | Real estate | 2025 |
| Huins ENT Ltd | Health & social care | 2019 |
| Hummingbird Residences Ltd | Real estate | 2025 |
| Hunt Industries Limited | Manufacturing | 2016 |
| Hunt Industries Management Limited | Manufacturing | 2016 |
| Hunt Industries Property Limited | Manufacturing | 2016 |
| HUW Griffiths ENT Ltd | Health & social care | 2023 |
| Huzzah for Schools Ltd | Administrative & support | 2023 |
| Huzzah NW10 Ltd | Administrative & support | 2017 |
| Hydroloco Ltd | Wholesale & retail | 2018 |
| Hyetts Express Deliveries Ltd | Transport & logistics | 2002 |
| Hymix Limited | Manufacturing | 1986 |
| Hywel and Roar Limited | Professional & scientific | 2016 |
| I Candi Rocks Limited | Administrative & support | 2019 |
| I Really Love Limited | Arts & recreation | 2025 |
| I.P.T. Holdings Limited | Financial services | 2021 |
| I.P.T. Technology Limited | Manufacturing | 2007 |
| I.P.T. Technology Support LLP | | 2021 |
| Iact (IT ALL Comes Together) Limited | Information & communication | 2025 |
| IAN Flower Consulting Ltd | Professional & scientific | 2019 |
| IAN GEE Ltd | Health & social care | 2018 |
| Ibrahim Property Ltd | Real estate | 2024 |
| Icjm Family Co Ltd | Professional & scientific | 2025 |
| Ickara Limited | Administrative & support | 2019 |
| ICY Waters Consulting Limited | Professional & scientific | 2023 |
| ID Droitwich Limited | Hospitality | 2026 |
| Iddem Limited | Professional & scientific | 2023 |
| IDP Energy Limited | Professional & scientific | 2025 |
| Ienacurium Ltd | Administrative & support | 2024 |
| Ierc Holdings Limited | Administrative & support | 2020 |
| Illumination Events Limited | Administrative & support | 2022 |
| Illusion Studio Limited | Professional & scientific | 2017 |
| IM Performance Ltd | Professional & scientific | 2014 |
| Imcso Ltd | Administrative & support | 2024 |
| Imperator Services Group Ltd | Construction | 2020 |
| Impero Design Ltd | Professional & scientific | 2009 |
| Impossibleflying Ltd | Manufacturing | 2020 |
| Imre Group Ltd | Administrative & support | 2024 |
| Imre Holdings Limited | Administrative & support | 2021 |
| Imre Holiday Lettings Limited | Hospitality | 2021 |
| Imre Investments Limited | Administrative & support | 2021 |
| Imre Property Developments Limited | Construction | 2021 |
| Imre Property Investments Limited | Real estate | 2021 |
| IN Spite of Everything, YES Limited | Administrative & support | 2019 |
| In-House Design and Marketing Ltd | Administrative & support | 2017 |
| Incrementa Limited | Information & communication | 2021 |