| I Associate Consulting Limited | Professional & scientific | 2002 |
| I J Aesthetics Limited | Other services | 2020 |
| I M Dimsum Limited | Hospitality | 2024 |
| Ibuk Manchester Limited | Hospitality | 2025 |
| Ibuk Stratford Limited | Hospitality | 2025 |
| Ibuk Ventures Limited | Hospitality | 2024 |
| Icag Ltd. | Professional & scientific | 2021 |
| Icona Business Coaching Limited | Professional & scientific | 2012 |
| Idealisation Ltd | Construction | 2015 |
| Imanjanet Ltd | Health & social care | 2023 |
| Imrie Holdings Ltd | Real estate | 2024 |
| IN the 10% Ltd | Financial services | 2021 |
| INA Property Solutions Limited | Manufacturing | 2025 |
| Incognito Luxury Events Ltd | Hospitality | 2025 |
| Inexx Ltd | Wholesale & retail | 2025 |
| Infinity Residential Ltd | Real estate | 2018 |
| Ingenious Plumbing Limited | Households | 2023 |
| Inkling Creative Ltd | Administrative & support | 2015 |
| Innovate Smart Digital Limited | Other services | 2018 |
| Inspiring Healthcare Limited | Health & social care | 2022 |
| Intelligent Aero Ltd | Professional & scientific | 2024 |
| Invention Vault Limited | Information & communication | 2019 |
| Inventro Ltd | Transport & logistics | 2026 |
| Investech Next Ltd | Wholesale & retail | 2026 |
| IPJ Consulting Ltd | Information & communication | 2025 |
| ISA UK Development Ltd | Education | 2025 |
| IST Systems Ltd | Information & communication | 2004 |
| Ivernus Ltd | Information & communication | 2017 |
| IVY Cat Company Ltd | Administrative & support | 2019 |
| IVY Investment Properties Limited | Real estate | 2013 |
| Izgiz Ltd | Extraterritorial | 2010 |
| J C Financial Group Limited | Financial services | 2024 |
| J D Enforcement Ltd | Administrative & support | 2023 |
| J Hall Consultants Ltd | Professional & scientific | 2009 |
| J NEL Consulting Limited | Professional & scientific | 2015 |
| J.P. Dawkins Limited | Administrative & support | 1994 |
| J.P. Rees Developments Limited | Construction | 2010 |
| Jabot Soft Furnishings Limited | Wholesale & retail | 2002 |
| Jade Valley Limited | Extraterritorial | 2024 |
| JAH Landscapes Ltd | Administrative & support | 2022 |
| Jalso (Enterprises) Limited | Financial services | 1995 |
| Jazz Hands Performing Arts Ltd | Arts & recreation | 2025 |
| JB Spa Group Ltd | Other services | 2022 |
| Jedex Ltd | Administrative & support | 2011 |
| Jelly Beans Preschool Limited | Education | 2007 |
| Jenny Betts London Limited | Wholesale & retail | 2017 |
| Jewell Associates Limited | Administrative & support | 2019 |
| Jewell Building Contractors Limited | Construction | 2006 |
| JHB & Partners Ltd | Professional & scientific | 2025 |
| JHN Limited | Health & social care | 2014 |
| Jibran Ahmed Ltd | Professional & scientific | 2024 |
| JIG5AW Ltd | Professional & scientific | 2023 |
| Jina Beauty Limited | Other services | 2016 |
| JJM Building Services Limited | Construction | 2017 |
| Jjra Technologies Ltd | Information & communication | 2010 |
| JN Farnsworth Ltd | Professional & scientific | 2025 |
| Jnop Properties Ltd | Real estate | 2025 |
| Jodie Samantha Norville Ltd | Extraterritorial | 2025 |
| John Goldsmith Ltd | Wholesale & retail | 2020 |
| Johnson IT Consultants Limited | Information & communication | 2019 |
| JON Hills Sound Ltd | Manufacturing | 2018 |
| JP Estate Services Ltd | Administrative & support | 2025 |
| JPS Sound Limited | Information & communication | 2014 |
| JRL Properties Ltd | Real estate | 2018 |
| Jtew Trading Ltd | Professional & scientific | 2023 |
| JTF Design Limited | Administrative & support | 2025 |
| Junjun and Bricks Limited | Real estate | 2024 |
| Justconstruct Ltd | Construction | 2016 |
| JW4X4SUPPORT Ltd | Professional & scientific | 2019 |
| JZB Properties Ltd | Real estate | 2021 |
| K & M Roofing and Building Services Limited | Construction | 2008 |
| K P Rigging Services Ltd | Information & communication | 2015 |
| K S N Construction Ltd | Construction | 2016 |
| K W G Properties Ltd | Real estate | 2015 |
| K/J Tone Properties Ltd | Real estate | 2021 |
| K2 Consulting Partners Limited | Professional & scientific | 2014 |
| KA Property Portfolio Limited | Real estate | 2019 |
| Kaaly Ltd | Information & communication | 2012 |
| Kanapina Limited | Hospitality | 2017 |
| Kapre Lounge Limited | Wholesale & retail | 2015 |
| Karitci Joinery Solutions Limited | Construction | 2017 |
| Kazys Ltd | Health & social care | 2020 |
| Keltek Services Limited | Construction | 2011 |
| Kenjoy Home Services Ltd | Construction | 2026 |
| Key Wine Company Ltd. | Wholesale & retail | 2022 |
| Keystatus Limited | Administrative & support | 2002 |
| Keystone Property Consultancy Ltd | Real estate | 2018 |
| Khioni Ltd | Professional & scientific | 2022 |
| Kings Moving Group Ltd | Administrative & support | 2023 |
| Kingswood Stud Limited | Agriculture & fishing | 2019 |
| Kinnaird Medical Services Ltd | Health & social care | 2022 |
| Kleinkaap Ltd | Real estate | 2026 |
| KM Properties (U.K) Limited | Real estate | 2025 |
| Knights of Fulham Removals Ltd | Transport & logistics | 2016 |
| KOI & Water Gardens Limited | Wholesale & retail | 2006 |
| Konect Plus Ltd | Information & communication | 2014 |
| Korado (UK) Limited | Professional & scientific | 1998 |
| Kriek and Gibson Ltd | Professional & scientific | 2012 |
| Kriek and Gibson Properties Limited | Real estate | 2015 |
| Krispy Clean Limited | Administrative & support | 2019 |