| Inbest Ltd | Wholesale & retail | 2015 |
| Increment Labs Ltd | Manufacturing | 2024 |
| Indigo Operations Ltd | Arts & recreation | 2011 |
| Indy Investments Ltd | Real estate | 2019 |
| Infinity M Ltd | Construction | 2017 |
| Infitech Solutions Limited | Professional & scientific | 2009 |
| Infocode Ltd | Information & communication | 2018 |
| Infolex Services Limited | | 1977 |
| Infuse Taste Studio Limited | Professional & scientific | 2025 |
| Inhomelux Ltd | Wholesale & retail | 2022 |
| INK Heads SMP Limited | Other services | 2025 |
| Inkanddots Ltd | Information & communication | 2015 |
| Inkonkoni Limited | Administrative & support | 2010 |
| Inkrediblestudiosuk Ltd | Information & communication | 2012 |
| Innerdrive Golf Limited | Arts & recreation | 2023 |
| Innovation Automotive (UK) Ltd | Wholesale & retail | 2018 |
| Innovative Home Marketing Ltd | Real estate | 2022 |
| Inovision Consulting Limited | Information & communication | 2018 |
| Inspiration & Energy Ltd | Administrative & support | 2004 |
| Instameds Limited | Health & social care | 2020 |
| Intdev Connect UK Limited | Information & communication | 2021 |
| Integral Psychology Limited | Health & social care | 2024 |
| Integrated Community Health Impact Ltd | Health & social care | 2026 |
| Intellect Study Abroad Ltd | Education | 2022 |
| Intelvision Media Limited | Professional & scientific | 2024 |
| Intermezzo Music Ltd | Arts & recreation | 2018 |
| International Board of Technical Professionals Limited | Information & communication | 2025 |
| Intershez Company Limited | Real estate | 1969 |
| Intt Nalliah Limited | Wholesale & retail | 2017 |
| Intuconstruction Limited | Construction | 2017 |
| Intutrade Limited | Wholesale & retail | 2017 |
| Invatek Ltd | Manufacturing | 2010 |
| Inventsports Limited | Wholesale & retail | 2018 |
| Ioan Sucila Limited | Construction | 2022 |
| IOT Help Ltd | Information & communication | 2017 |
| IPY 2019 Ltd | Transport & logistics | 2019 |
| Iraq Bakeries Limited | Manufacturing | 2020 |
| IRK Accountancy Services Ltd | Professional & scientific | 2015 |
| Irrupt Digital Ltd | Professional & scientific | 2024 |
| Isis House Management Limited | Households | 1983 |
| Islanders Healthcare Limited | Health & social care | 2021 |
| Islanders Vets Ltd | Professional & scientific | 2016 |
| Isu-K Consulting Ltd | Professional & scientific | 2025 |
| IT Service Solutions Limited | Information & communication | 2002 |
| IT Services New Malden Ltd | Information & communication | 2026 |
| Itchy Feet Adventures Limited | Arts & recreation | 2018 |
| Itec Avents Limited | Professional & scientific | 2015 |
| Iter Nostrum Ltd | Wholesale & retail | 2016 |
| Iterra Explorer Ltd | Administrative & support | 2017 |
| Ivora Properties Ltd | Real estate | 2026 |
| Ivyan Limited | Other services | 2022 |
| Izabela Couture Ltd | Manufacturing | 2019 |
| J & S Property Solutions Ltd | Real estate | 2023 |
| J a Building and Maintenance Limited | Construction | 2015 |
| J and C Proctor Limited | Information & communication | 2007 |
| J Ferreira Handyman Limited | Construction | 2025 |
| J George Properties Ltd | Real estate | 2026 |
| J Walsh Ltd | Construction | 2022 |
| J&G Empire Limited | Real estate | 2025 |
| J&J Motors LDN Limited | Wholesale & retail | 2025 |
| J&J Wellcare Ltd | Health & social care | 2025 |
| J&M Demolition Services Ltd. | Construction | 2015 |
| J&Mscaffolding Limited | Construction | 2014 |
| J&P Home Bento Ltd | Hospitality | 2018 |
| J&R Electric Ltd | Construction | 2021 |
| J'Leo Svue Ltd | Professional & scientific | 2022 |
| J2A IT Limited | Information & communication | 2026 |
| Jack's Building Service Limited | Construction | 2005 |
| Jada Networks Limited | Wholesale & retail | 2022 |
| Jalcyon Ltd | Wholesale & retail | 2021 |
| Jamal Restaurant Ltd | Hospitality | 2025 |
| Jamie Lorenzet Carpentry Ltd | Manufacturing | 2024 |
| Jane Curtis Events Limited | Professional & scientific | 2023 |
| Jannake Ananyaah Limited | Health & social care | 2014 |
| Jardine Care Limited | Health & social care | 2010 |
| JAS Medical Ltd | Professional & scientific | 2014 |
| Jasuja Advisory Limited | Professional & scientific | 2025 |
| Jasuja Property Investments Limited | Real estate | 2021 |
| JAY Properties(Southwest) Ltd | Real estate | 2022 |
| JB Cleaning Companhia Ltd | Administrative & support | 2024 |
| JBR Forte Ltd | Wholesale & retail | 2024 |
| JCJ Sales Limited | Wholesale & retail | 2024 |
| JDI Global Ltd | Transport & logistics | 2018 |
| JDM Construction Management Limited | Administrative & support | 2018 |
| Jean Stanford Holidays Limited | Administrative & support | 1995 |
| Jefferies Care Services Limited | Health & social care | 2010 |
| Jefferies Group Limited | Health & social care | 2021 |
| Jefferies Live in Care Services Ltd | Health & social care | 2024 |
| Jefferies Property Investment Limited | Real estate | 2015 |
| Jenin UK Trading Company Ltd | Wholesale & retail | 2011 |
| Jenkco Maritime Ltd | Professional & scientific | 2024 |
| Jenny Chippy Ltd | Hospitality | 2023 |
| Jer-Orla Ltd | Health & social care | 2011 |
| Jesus Disciples' Community Church | Education | 2009 |
| JEY Products Ltd | Wholesale & retail | 2024 |
| Jeyama Optics Ltd | Health & social care | 2023 |
| JFZ Jewellery Ltd | Wholesale & retail | 2025 |
| JH F&B Ltd | Hospitality | 2026 |
| JH Therapy and Education Ltd. | Education | 2012 |
| Jiejie Travel Limited | Administrative & support | 2024 |