| Heights Club Ltd | Arts & recreation | 2015 |
| HEIMDALL360 Ltd | Professional & scientific | 2014 |
| Helen Fallon Consulting Ltd | Administrative & support | 2026 |
| Henley Audio Ltd | Wholesale & retail | 2016 |
| Henley Designs Limited | Wholesale & retail | 1992 |
| Henley Pro Ltd | Wholesale & retail | 2017 |
| Herbert Hennessy Ltd | Professional & scientific | 2020 |
| Heritage of Industry Limited | Administrative & support | 1989 |
| Hexa Investments Limited | Real estate | 2025 |
| Hexis Consulting Ltd | Professional & scientific | 2024 |
| Hexlane Systems Ltd | Information & communication | 2026 |
| HGL & Sons Limited | Administrative & support | 2018 |
| HHM & C Property Ltd | Real estate | 2026 |
| Hickman Eadle Flooring Ltd | Construction | 2021 |
| High Lodge Farm Events Ltd | Arts & recreation | 2026 |
| Highways Supervision Ltd | Construction | 2017 |
| Hikari Systems Ltd | Information & communication | 2024 |
| Hill Coates Associates Ltd | Other services | 2016 |
| Hill Coates Capital Advisors Ltd | Financial services | 2026 |
| Hill's Distribution Limited | Wholesale & retail | 2023 |
| Hill's Mortgages Limited | Financial services | 2026 |
| Himanshu Cash&Carry Ltd | Wholesale & retail | 2026 |
| Hiskysat Limited | Information & communication | 2018 |
| HIT Away Sports Ltd | Manufacturing | 2023 |
| Hitact Intergrated Services Ltd | Wholesale & retail | 2025 |
| HK Integrated Solutions Ltd | Wholesale & retail | 2021 |
| HO Bioscience Consulting Ltd | Information & communication | 2025 |
| Hoch Consultancy Limited | Information & communication | 2025 |
| Holistic Grips Ltd | Manufacturing | 2023 |
| Holistic Security Ltd | Information & communication | 2024 |
| Holland and Devine Electrical Services Limited | Construction | 2021 |
| Holtram Trustees Ltd | Financial services | 2025 |
| Homes Investments and Properties Ltd | Real estate | 2023 |
| Homesafe Building & Construction Ltd | Construction | 2017 |
| Hope & Nova Ltd | Wholesale & retail | 2022 |
| Hope Cottage Freehold Residents Management Ltd | Households | 2025 |
| Hornesys Ltd | Construction | 2024 |
| Horticultural Trades Association(The) | Other services | 1920 |
| House of Beaux Ltd | Other services | 2020 |
| House of Creation Publishing Limited | Education | 2006 |
| House of Transformation | Other services | 2023 |
| Housewell Ltd | Administrative & support | 2015 |
| Housewell Properties Ltd | Administrative & support | 2023 |
| Howbery Builders Ltd | Construction | 2017 |
| HR Services SS Limited | Professional & scientific | 2015 |
| Hsic GP1 Limited | Financial services | 2012 |
| Hsic GP2 Limited | Financial services | 2012 |
| Hsic Holdings (GP) Limited | Real estate | 2022 |
| Hsic NO.2 GP Limited | Real estate | 2022 |
| Hsic NO.2 LP | | 2022 |
| Hsic NO.3 Limited | Real estate | 2021 |
| Hsic NO.4 GP Limited | Real estate | 2023 |
| Hsic NO.4 LP | | 2023 |
| Hsrr Ltd | Financial services | 2021 |
| HST Solutions Limited | Construction | 2024 |
| HSY Holdings Ltd | Financial services | 2021 |
| HT Consultants Ltd | Information & communication | 1997 |
| Hudor Capital Ltd | Information & communication | 2022 |
| Huey Games (Holdings) Ltd | Information & communication | 2016 |
| Hush Holiday Ltd | Real estate | 2024 |
| Hutchings Mockridge Limited | Real estate | 2024 |
| Hutton Music Limited | Arts & recreation | 2024 |
| HW Intelligence Ltd | Information & communication | 2026 |
| I Didcot Ltd | Information & communication | 2025 |
| I.A.K Cleaning Ltd | Administrative & support | 2021 |
| IAN and Jean Stockton Limited | Real estate | 2026 |
| IAN Davies Flooring Ltd | Construction | 2022 |
| Ibrahim & Rayan Technologies Ltd | Information & communication | 2014 |
| ICC Trans Ltd | Transport & logistics | 2016 |
| Ice Dance Events Adults Ltd | Arts & recreation | 2025 |
| ID Cloud Solutions Limited | Information & communication | 2016 |
| ID Scaffolding (Oxford) Ltd | Construction | 2025 |
| Idappcom Ltd. | Information & communication | 2009 |
| Ideapiece Ltd | Information & communication | 2017 |
| IDS Wealth Limited | Real estate | 2026 |
| IFW Logistics Ltd | Transport & logistics | 2021 |
| IL Plumbing & Heating Limited | Construction | 2024 |
| Ilumier Limited | Manufacturing | 2024 |
| Imagine Studios London UK Ltd | Professional & scientific | 2026 |
| Imperial Freight Solutions Limited | Transport & logistics | 2025 |
| Imperial Grill Ltd | Hospitality | 2020 |
| Imperial Maritime Consultants Limited | Professional & scientific | 2019 |
| Imperium Property Investments Ltd | Real estate | 2025 |
| Impregilo New Cross Limited | Construction | 2001 |
| Information International Ltd. | Information & communication | 1999 |
| Inhealthcare Limited | Information & communication | 2012 |
| Inox Hoses Global Limited | Manufacturing | 2023 |
| Inpar Solutions Limited | Information & communication | 2023 |
| Insight Control Solutions Limited | Professional & scientific | 2009 |
| Insightmedwrite Ltd | Health & social care | 2025 |
| Inspire Mentoring Ltd | Professional & scientific | 2019 |
| Inspired Market Research Ltd | Professional & scientific | 2012 |
| Inspired Toxicology Ltd | Professional & scientific | 2013 |
| Interactive Illusion Ltd | Information & communication | 2022 |
| International Financial Services Ltd | Financial services | 2023 |
| Intimate Spaces Ltd | Professional & scientific | 2023 |
| Invitrum Ltd | Wholesale & retail | 2025 |
| Ionforge.Ai Limited | Manufacturing | 2024 |
| Iquant Consultancy Ltd | Information & communication | 2025 |
| Iris Blinds Ltd | Construction | 2020 |