| IFS Capital Ltd | Real estate | 2025 |
| Iftinchi Trans Ltd | Transport & logistics | 2022 |
| Igbems Ltd | Construction | 2023 |
| Ignite Productions Limited | Administrative & support | 2016 |
| Ijeh Services Ltd | Administrative & support | 2020 |
| IMA Services Limited | Construction | 2019 |
| Immp Limited | Construction | 2014 |
| IMO State Daughters Association Limited | Other services | 2018 |
| Impact Through Partnership Ltd | Education | 2021 |
| Imperial Maintenance Solutions Limited | Construction | 2015 |
| Imzzysheating&Plumbing Ltd | Construction | 2025 |
| Inca Trade Limited | Water & waste | 2005 |
| Increase Properties Services Ltd | Real estate | 2019 |
| Infection Prevention Compliance Ltd | Professional & scientific | 2025 |
| Infinite Auto Ltd | Manufacturing | 2020 |
| Insightful Inclusion Limited | Health & social care | 2024 |
| Inspired by Climate Evolution Ltd | Professional & scientific | 2020 |
| Integral UFH Limited | Construction | 2017 |
| Investpal Ltd | Information & communication | 2017 |
| IQ Fire Solutions Ltd | Construction | 2008 |
| IR Group Estates Ltd | Real estate | 2019 |
| IRG Housing Ltd | Professional & scientific | 2025 |
| Ironcore Ltd | Wholesale & retail | 2023 |
| ITF Tech Ltd | Information & communication | 2014 |
| IVD Construction Ltd | Construction | 2018 |
| IVD Maintenance Limited | Construction | 2024 |
| IVM Logistic Ltd | Transport & logistics | 2022 |
| Izzet Leaking Ltd | Water & waste | 2023 |
| J & B Contractors Limited | Construction | 2003 |
| J & G Associates Limited | Wholesale & retail | 2007 |
| J & R Service Station Ltd | Wholesale & retail | 2010 |
| J B J Pallets Essex Limited | Manufacturing | 2022 |
| J C M Heating & Plumbing Ltd | Construction | 2017 |
| J L Plumbing Limited | Construction | 2017 |
| J S Lowrie Haulage Limited | Water & waste | 2014 |
| J&E Logistics Ltd | Transport & logistics | 2015 |
| J&L Communications Ltd | Information & communication | 2024 |
| J.P. Fallon Limited | Professional & scientific | 2014 |
| J54 Properties Limited | Real estate | 2021 |
| Jade Global Developments Ltd | Construction | 2015 |
| Jade Global FM Ltd | Construction | 2014 |
| Jade Global Group Ltd | Construction | 2019 |
| Jade Global Interiors Ltd | Households | 2015 |
| Jade Global Lofts & Extensions Ltd | Construction | 2019 |
| Jade Global Mechanical & Electrical Ltd | Construction | 2015 |
| Jade Global Supplies Ltd | Wholesale & retail | 2014 |
| Jafn Limited | Real estate | 2018 |
| James Howgate Consultancy Ltd | Real estate | 2025 |
| Jara Properties Limited | Real estate | 1997 |
| Jardin DE Beauté Ltd | Other services | 2025 |
| Jax's Taxi's Ltd | Transport & logistics | 2018 |
| Jaxx Pavement Engineering Ltd | Construction | 2024 |
| Jaxx Site Investigations Ltd | Construction | 2024 |
| Jay's Gems Limited | Health & social care | 2025 |
| Jays Engineering Services Limited | Professional & scientific | 2023 |
| JB Drains and Gutters Ltd | Other services | 2019 |
| JCL Financial Ltd | Financial services | 2025 |
| JD Capital Holdings Ltd | Financial services | 2023 |
| Jelani Limited | Health & social care | 2014 |
| Jessikare Ltd | Health & social care | 2022 |
| Jessop Investments Limited | Real estate | 2018 |
| Jessop Truck OFF Limited | Hospitality | 2025 |
| JHG Bespoke Furniture Limited | Construction | 2018 |
| Jilon Solutions Ltd | Real estate | 2016 |
| JJM Roofing Ltd | Construction | 2018 |
| JK Tunes and Chords Ltd | Information & communication | 2018 |
| JL Purchase Holdings Limited | Extraterritorial | 2018 |
| JLA Prestige Cleaning Services Ltd | Administrative & support | 2026 |
| JM Inn Ltd | Hospitality | 2025 |
| JNS Products Limited | Real estate | 2018 |
| Johnson Services Limited | Construction | 2001 |
| Johnston Training Ltd | Transport & logistics | 2025 |
| Jojo Hair Ltd | Other services | 2020 |
| JON Ovel Consultancy Ltd | Construction | 2014 |
| Joreto Limited | Education | 2024 |
| JRC Engineering Consultants Limited | Professional & scientific | 2025 |
| JS Sandford Construction Limited | Construction | 2021 |
| JT Truck Repairs Ltd | Wholesale & retail | 2020 |
| Jules ET LIS Limited | Health & social care | 2004 |
| Jules Travel Ltd | Administrative & support | 2019 |
| Julzs Limited | Health & social care | 2019 |
| Just the Look Corporation Ltd | Wholesale & retail | 2025 |
| Just the Look Enterprise Limited | Wholesale & retail | 2025 |
| Justlyn Consultancy Services Limited | Professional & scientific | 2012 |
| Justwarmth Limited | Construction | 2014 |
| JW Electricians (Essex) Limited | Construction | 2026 |
| JWB Properties Limited | Real estate | 2018 |
| Jwpt Limited | Arts & recreation | 2022 |
| K & T Consults Ltd | Professional & scientific | 2020 |
| K Sims Plumbing & Heating Limited | Construction | 2015 |
| K&O Jointing Ltd | Construction | 2017 |
| K.A.M Roofing and Building Services Limited | Construction | 2023 |
| K.S.Wharf Commercials Limited | Transport & logistics | 2009 |
| K1 Barber Limited | Administrative & support | 2010 |
| KA Lexius Cargo Ltd | Transport & logistics | 2019 |
| KAB Management Ltd | Transport & logistics | 2014 |
| Kadir Ltd | Hospitality | 2015 |
| Kairos Aevum Ltd | Wholesale & retail | 2024 |
| Kairosconsult Ltd | Information & communication | 2023 |
| Kanvas Kove Studio Ltd | Arts & recreation | 2026 |