| Howarth Enterprises Ltd | Financial services | 2026 |
| HR Upscale Ltd | Professional & scientific | 2020 |
| HRC Media Ltd | Arts & recreation | 2019 |
| HSY Investment UK Ltd | Real estate | 2017 |
| Hub E-Com Logistics Ltd | Wholesale & retail | 2020 |
| Hubl Holdings Ltd | Real estate | 2018 |
| HUD Developments Limited | Construction | 2017 |
| Hugo Hansell Design Limited | Professional & scientific | 2015 |
| Hundens House Ltd | Real estate | 2017 |
| Hurley House (Teddington) Residents Association Limited | Households | 1971 |
| Hyera Ltd | Professional & scientific | 2014 |
| Hymn Technology Ltd. | Wholesale & retail | 1996 |
| I Finkemeyer Limited | Information & communication | 2011 |
| I. J. Design Ltd | Construction | 2015 |
| Ice Clean Limited | Administrative & support | 2020 |
| Ichauffeur Limited | Transport & logistics | 2005 |
| Ichauffeur Worldwide Limited | Financial services | 2017 |
| Icoe Technology Ltd | Health & social care | 2019 |
| Icon Coffee House Ltd | Hospitality | 2021 |
| Idrak Agentic Systems Limited | Information & communication | 2026 |
| IEC Projects Limited | Administrative & support | 2020 |
| IG Property International Ltd | Real estate | 2016 |
| Igneous Software Limited | Information & communication | 2005 |
| IKG Accountants Limited | Professional & scientific | 2008 |
| ILI Dent Limited | Manufacturing | 2020 |
| Ilifessential Ltd | Wholesale & retail | 2020 |
| IM + IM Construction Ltd | Construction | 2023 |
| Impactic Volunteers Limited | Administrative & support | 2022 |
| Imperial Design Limited | Arts & recreation | 2002 |
| Imperial Hampton Limited | Real estate | 2012 |
| IN the Scenes Ltd | Arts & recreation | 2021 |
| IN5 Investments Limited | Real estate | 2018 |
| Incoterm Limited | Information & communication | 2025 |
| Increasing Wellbeing Limited | Health & social care | 2021 |
| Indefinite Property Freedom Limited | Real estate | 2019 |
| Industry Standard Studio Limited | Professional & scientific | 2023 |
| INFIN8 Investments Ltd | Extraterritorial | 2016 |
| Infinity Homz Ltd | Real estate | 2019 |
| Ingram House Residents Association Limited | Households | 1977 |
| Injury Smart Training Academy Ltd | Education | 2025 |
| Inmo Dent Limited | Health & social care | 2021 |
| Innershift Ltd | Real estate | 2017 |
| Innovation Interiors Limited | Construction | 2004 |
| Insight IT Consultancy Limited | Information & communication | 2011 |
| Inspired Hub Limited | Administrative & support | 2019 |
| Inspired Spaces Design Limited | Other services | 2015 |
| Integrity Healthcare Consulting Limited | Professional & scientific | 2014 |
| Interact CC Global Ltd | Administrative & support | 2024 |
| Interact CC Ltd | Administrative & support | 2011 |
| Interact CC Trustees Ltd | Professional & scientific | 2023 |
| Interact North West Limited | Professional & scientific | 2012 |
| Interact South East Ltd | Professional & scientific | 2017 |
| Interactive Marketing Ltd | Extraterritorial | 2014 |
| International Investment & Underwriting Limited | Professional & scientific | 2004 |
| Intuitive Events Ltd | Administrative & support | 2009 |
| Intuitive Festive Events Limited | Arts & recreation | 2025 |
| Invesprop Ltd | Real estate | 2018 |
| Invest Globally Ltd | Professional & scientific | 2022 |
| Investsmart Properties Ltd | Real estate | 2016 |
| Investuz Group Ltd | Real estate | 2023 |
| Invite Property Ltd | Real estate | 2023 |
| Iolite Investments Ltd | Extraterritorial | 2017 |
| Iridium Services Limited | Transport & logistics | 2025 |
| Iroko Securities Limited | Financial services | 2002 |
| IS Dreambig Investment Ltd | Extraterritorial | 2018 |
| Isabella Trading Corporation Limited | Wholesale & retail | 2013 |
| Island Locks Limited | Other services | 2006 |
| Isode Limited | Information & communication | 2002 |
| IST Property Portfolio Limited | Real estate | 2025 |
| IT Moves Limited | Wholesale & retail | 2012 |
| Ithentic Leadership Consulting Ltd | Professional & scientific | 2026 |
| Ithmar Ltd | Financial services | 2014 |
| Ivory & Co Hygienist Ltd | Health & social care | 2026 |
| Izzaxis Ltd | Real estate | 2018 |
| J & Kang Co Ltd | Wholesale & retail | 2020 |
| J B School Improvement Services Limited | Extraterritorial | 2011 |
| J P Food & Wines Ltd | Wholesale & retail | 2016 |
| J&R Roofing Solutions Ltd | Construction | 2026 |
| J'Ouvert Unified MAS Bands Incorporated Ltd | Education | 2023 |
| J. Altmann Limited | Households | 1960 |
| J. Griffiths Ltd | Construction | 2015 |
| J.J.C.Investment Company Limited | Real estate | 1955 |
| Jacc Investments | Extraterritorial | 2021 |
| Jack Cube Ltd | Manufacturing | 2016 |
| Jackets Fields Property Investments Limited | Real estate | 2018 |
| Jadi Living Ltd | Real estate | 2019 |
| James Bain Investments Limited | Financial services | 2023 |
| James DU Cann Limited | Information & communication | 1993 |
| James Lewis Engineering Solutions Ltd | Wholesale & retail | 2019 |
| James Lewis Limited | Administrative & support | 2004 |
| Jammm Holdings Ltd | Real estate | 2017 |
| Janaminhas Ltd | Health & social care | 2014 |
| Janlar Designs Ltd | Manufacturing | 2015 |
| Jardina Property Ltd | Real estate | 2018 |
| Jargone Marketing Limited | Professional & scientific | 2021 |
| Jarm Property Investment Ltd | Real estate | 2018 |
| Jason & Wendy's Properties Ltd | Real estate | 2019 |
| Jatk Fitness Ltd | Health & social care | 2024 |
| Javerick Group Ltd | Real estate | 2019 |
| JB Investment Group Ltd | Financial services | 2024 |