| Ideal Upholstery Ltd | Wholesale & retail | 2013 |
| Identity Care Housing Ltd | Health & social care | 2020 |
| Idrive YOU Limited | Transport & logistics | 2016 |
| Idsw Assessments Limited | Information & communication | 2016 |
| Idylic Choice Care Limited | Health & social care | 2024 |
| IE Security Management Limited | Information & communication | 2022 |
| Iffifli Ltd | Administrative & support | 2025 |
| IG FM Administration Limited | Professional & scientific | 2022 |
| IG Pharma Ltd | Wholesale & retail | 2019 |
| Igenio Ltd | Wholesale & retail | 2014 |
| Ignite Catering Equipment Ltd | Wholesale & retail | 2018 |
| IGW Photography Ltd | Professional & scientific | 2026 |
| IH Property Group Ltd | Real estate | 2026 |
| IHC Tooling Ltd | Professional & scientific | 2024 |
| IK (Nelson) Properties Ltd | Real estate | 2017 |
| Ilham Tech Ltd | Information & communication | 2024 |
| Imaan Beauty Secrets Limited | Other services | 2018 |
| Image Solutions (NW) Ltd | Manufacturing | 2026 |
| IMK Holdings Ltd | Financial services | 2020 |
| Impact Plastic Solutions Ltd | Construction | 2024 |
| Impact Textiles B.V. | | 1992 |
| Imperial Health Service Ltd | Health & social care | 2017 |
| Imperial Roots Furniture Limited | Wholesale & retail | 2026 |
| Imran Transport Limited | Transport & logistics | 2019 |
| Imransardar Ltd | Wholesale & retail | 2025 |
| In-Situ-In-Place | Arts & recreation | 2012 |
| Inago Limited | Health & social care | 2011 |
| Incredible Growth 001 Ltd | Administrative & support | 2025 |
| Incredible Growth 002 Ltd | Administrative & support | 2025 |
| Incredible Growth 003 Ltd | Administrative & support | 2025 |
| Incredible Growth 004 Ltd | Administrative & support | 2025 |
| Incredible Growth Solutions Limited | Professional & scientific | 2015 |
| Indcane Limited | Other services | 2020 |
| Independent Access Inspections Group Ltd | Construction | 2022 |
| Independent Sewing Machines Limited | Manufacturing | 2004 |
| Indigio Services S1.6 Limited | Other services | 2020 |
| Indigo Plus Ltd | Wholesale & retail | 2022 |
| Indigo Services Part Limited | Other services | 2020 |
| Indulgepass Limited | Information & communication | 2025 |
| Indus Comforts Limited | Wholesale & retail | 2026 |
| Industrious Brickwork Ltd | Construction | 2025 |
| Infectacheck Limited | Professional & scientific | 2010 |
| Infinity Innovators Ltd | Professional & scientific | 2022 |
| Infra Communications Ltd | Information & communication | 2025 |
| Infra Fire and Security Ltd | Administrative & support | 2025 |
| Ingustu Couriers Ltd | Transport & logistics | 2025 |
| Innermind Limited | Health & social care | 2013 |
| Inno Growth Limited | Professional & scientific | 2023 |
| Innovative Lubricants Limited | Professional & scientific | 2012 |
| Innovative Outdoor Products Limited | Manufacturing | 1983 |
| Inputx Ltd | Information & communication | 2025 |
| Insight Innovators Ltd | Information & communication | 2023 |
| Inspiring Investments Limited | Information & communication | 2012 |
| Integrationale Care Ltd | Health & social care | 2023 |
| International Association Alienated Parents Society CIC | Other services | 2026 |
| International Cargo and Travel Ltd | Transport & logistics | 2019 |
| Interp Ltd | Wholesale & retail | 2017 |
| Interwood Furniture UK Limited | Wholesale & retail | 2019 |
| Intu Care Ltd | Health & social care | 2024 |
| Invigorate Aesthetics & Beauty Limited | Other services | 2018 |
| Invyso Ltd | Information & communication | 2023 |
| IP Property Investments NW Limited | Real estate | 2019 |
| IP Sign Services Ltd | Professional & scientific | 2023 |
| IQ Vehicle Replacement Limited | Administrative & support | 2023 |
| Iqsofas Limited | Wholesale & retail | 2025 |
| Irwell Vehicle Solutions Ltd | Administrative & support | 2017 |
| IS IT a Claim Ltd | Extraterritorial | 2011 |
| ISH Autos Ltd | Wholesale & retail | 2025 |
| Ishb Consultancy Ltd | Information & communication | 2024 |
| Islam UN Ltd | Administrative & support | 2024 |
| Isobel Horn Consulting Limited | Other services | 2015 |
| Isobel Interiors Limited | Professional & scientific | 2024 |
| Isra Couriers Limited | Transport & logistics | 2022 |
| Issa Furniture Ltd | Wholesale & retail | 2025 |
| Istock Global Ltd | Wholesale & retail | 2008 |
| Italian Cutz Limited | Other services | 2022 |
| Itea Services Limited | Information & communication | 2025 |
| ITW Properties Limited | Real estate | 2024 |
| IZU Property Ltd | Real estate | 2025 |
| J & J Closures Limited | Manufacturing | 1996 |
| J & R Gases Limited | Manufacturing | 1999 |
| J & R UK Plant Hire Limited | Construction | 2009 |
| J a S Wholesales Meat Limited | Wholesale & retail | 2021 |
| J E Accountancy Ltd | Professional & scientific | 2011 |
| J West Property Holdings Limited | Real estate | 2025 |
| J&J Auto Services Solihull Ltd | Wholesale & retail | 2021 |
| J.A.Bowes Commissioning & Project Management Solutions Ltd | Professional & scientific | 2017 |
| J.E. Hartley Holdings Limited | Financial services | 2023 |
| J.S Building Solutions Ltd | Construction | 2019 |
| Jaanam 1 Limited | Hospitality | 2026 |
| Jack Baker Carpets LLP | | 2022 |
| JAG Inspection Limited | Professional & scientific | 2010 |
| Jake Business Solutions Ltd | Administrative & support | 2009 |
| Jakes Perfume Parlour Ltd | Wholesale & retail | 2022 |
| James Thornber Limited | Financial services | 2019 |
| James White Building Contractors Ltd | Construction | 2024 |
| James White Construction Ltd | Construction | 2019 |
| Jamia Rehmania Razwiyyah | Professional & scientific | 2012 |
| JAN Business Consultancy Ltd | Professional & scientific | 2012 |
| Jands Property Services Limited | Real estate | 1991 |