| Isherwood Holdings Ltd | Real estate | 2025 |
| ISI Investments Ltd | Financial services | 2015 |
| Isis Solutions UK Limited | Administrative & support | 2008 |
| Isla and BOE Ltd | Wholesale & retail | 2021 |
| Islamic Monetary Ltd | Other services | 2023 |
| Islandfortress Ltd | Information & communication | 2022 |
| Isle of Wight Events Ltd | Wholesale & retail | 2022 |
| Ismaeel Trading Limited | Wholesale & retail | 2024 |
| Ismart Hub Ltd | Wholesale & retail | 2023 |
| Ismatadar Limited | Health & social care | 2020 |
| Ismk Services Limited | Households | 2025 |
| Ismw Limited | Information & communication | 2022 |
| ISO Build Ltd | Construction | 2020 |
| ISO Group Holdings Ltd | Real estate | 2026 |
| Isosurface Limited | Information & communication | 2019 |
| Ispg Technology UK Limited | Administrative & support | 2020 |
| Isra Travels Ltd | Wholesale & retail | 2025 |
| Isrh Ltd | Health & social care | 2018 |
| Istanbul Bolton Ltd | Hospitality | 2026 |
| Istanbul Heyside Ltd | Hospitality | 2021 |
| Istanbul Restaurant Bolton Limited | Hospitality | 2025 |
| Istanbul Restaurant Derby Limited | Hospitality | 2022 |
| Istyle Ecom Ltd | Wholesale & retail | 2026 |
| Istyle NW Ltd | Wholesale & retail | 2016 |
| IT Access Ltd | Information & communication | 2021 |
| IT Bargainz Ltd | Wholesale & retail | 2024 |
| IT Field Consulting Limited | Information & communication | 2021 |
| IT Training Consultants Ltd | Information & communication | 2018 |
| IT VIZ Consultants Ltd | Information & communication | 2026 |
| It's HRZ Ltd | Wholesale & retail | 2026 |
| Itactive Limited | Professional & scientific | 2002 |
| Italia Engineering Import & Export Ltd | Wholesale & retail | 2018 |
| Italia to Go Ltd | Hospitality | 2019 |
| Italiano Chicken Limited | Hospitality | 2020 |
| Italiano Cibo Limited | Hospitality | 2019 |
| Italiano Westhoughton Limited | Hospitality | 2025 |
| ITC Project Services Limited | Construction | 2014 |
| Itech Construction Ltd | Construction | 2020 |
| Itechtraders Ltd | Wholesale & retail | 2024 |
| Itek (Bolton) Limited | Manufacturing | 1998 |
| Ithreaditmyway Ltd | Manufacturing | 2023 |
| ITL Academia Limited | Health & social care | 2026 |
| Itotech Ltd | Professional & scientific | 2016 |
| ITS Always Sunny Ltd | Other services | 2025 |
| Iultra Ltd | Wholesale & retail | 2021 |
| IUS Traders Ltd | Wholesale & retail | 2025 |
| Ivape Kraze Limited | Wholesale & retail | 2022 |
| Ives Digital Limited | Information & communication | 2026 |
| Ivinter Management Consultancy Limited | Professional & scientific | 2023 |
| Ivoire Food Ltd | Wholesale & retail | 2021 |
| IVY Transport Limited | Transport & logistics | 2024 |
| Ivypark Investments Limited | Real estate | 2021 |
| IWM Locum Ltd | Health & social care | 2024 |
| IWR Customer Journeys Limited | Professional & scientific | 2020 |
| Ixia Legal Limited | Professional & scientific | 2006 |
| Ixura Investments Limited | Financial services | 2023 |
| IY Foods Ltd | Hospitality | 2026 |
| IY Optical Limited | Health & social care | 2009 |
| Iyanuoluwa Media Ltd | Information & communication | 2025 |
| IYP Finance Limited | Administrative & support | 2016 |
| Iypatel Properties Ltd | Real estate | 2024 |
| Iyzb Ltd | Wholesale & retail | 2025 |
| IZ Properties & Lettings Ltd | Real estate | 2025 |
| Izfin Ltd | Professional & scientific | 2023 |
| IZMIR35 Ltd | Hospitality | 2025 |
| Izubizu Ltd | Administrative & support | 2016 |
| Izzy's Grill & Go Ltd | Hospitality | 2026 |
| J & B Estates Ltd | Real estate | 2025 |
| J & D Fenn Limited | Construction | 2018 |
| J & J Car Sales Ltd | Wholesale & retail | 2016 |
| J & J Property Partners Ltd | Real estate | 2025 |
| J & M Consultants Developments Ltd | Professional & scientific | 2025 |
| J & N Cars Limited | Wholesale & retail | 2015 |
| J & N Cleaning Services Ltd | Administrative & support | 2022 |
| J & N Cleaning Services NW Ltd | Administrative & support | 2024 |
| J & P Deliveries Holdings Ltd | Professional & scientific | 2020 |
| J & S Seddon (Building) Limited | Construction | 1989 |
| J & S Takeaway Limited | Hospitality | 2026 |
| J a Alfa Limited | Health & social care | 2011 |
| J a Dootson Limited | Professional & scientific | 2003 |
| J a Leach Investments Ltd | Other services | 1984 |
| J a T Brickwork Ltd | Construction | 2025 |
| J and J Wilson Holdings Limited | Financial services | 2020 |
| J Arnold Transport Ltd | Transport & logistics | 2018 |
| J B Adedokun Limited | Health & social care | 2011 |
| J B Civils Ltd | Construction | 2015 |
| J B Legal Services Ltd | Administrative & support | 2003 |
| J Bawden Ltd | Transport & logistics | 2023 |
| J Birkett Holdings Limited | Administrative & support | 2023 |
| J Brooks Property Ltd | Real estate | 2016 |
| J Broughton Therapies Limited | Health & social care | 2021 |
| J Burbidge Consultancy Limited | Professional & scientific | 2016 |
| J C Structural Solutions Limited | Professional & scientific | 2007 |
| J C Transport (N West) Limited | Transport & logistics | 2025 |
| J Clayton Limited | Information & communication | 2021 |
| J Controls Limited | Construction | 2008 |
| J Court Scaffolding Limited | Construction | 2005 |
| J Cullen Construction Limited | Construction | 2013 |
| J Curliss Electrical Ltd | Construction | 2017 |
| J D Construction (NW) Limited | Construction | 2006 |