| Ignite Programme Partners Limited | Professional & scientific | 2025 |
| Ignite Wood Burners Ltd | Construction | 2022 |
| Ignitec Ltd | Professional & scientific | 2013 |
| Ignition Auto Hub Ltd | Wholesale & retail | 2025 |
| Ignition DG Limited | Professional & scientific | 2006 |
| Ignition Films Limited | Information & communication | 1999 |
| Ignition Heating Limited | Construction | 2013 |
| Ignition Heating Service & Repair Limited | Construction | 2021 |
| Igocare Limited | Health & social care | 2019 |
| Igocode Ltd | Information & communication | 2014 |
| Igoe Ltd | Extraterritorial | 2013 |
| IGP UK Contracts Limited | Administrative & support | 1992 |
| IH Creative Ltd | Professional & scientific | 2013 |
| IH Management Plus Ltd | Professional & scientific | 2014 |
| Ihator&Sons Limited | Wholesale & retail | 2018 |
| IHB Creative Studios Ltd | Information & communication | 2023 |
| Ihsan Tuition Ltd | Education | 2024 |
| Ihubwestbury Limited | Wholesale & retail | 2026 |
| II Quattrocento Limited | Hospitality | 2017 |
| Iinova Design Limited | Construction | 2017 |
| IJ Transport Ltd | Transport & logistics | 2024 |
| IJC Ltd | Manufacturing | 2018 |
| IJM Bristol Ltd | Hospitality | 2026 |
| IJM Consulting Limited | Professional & scientific | 2008 |
| Ikaya Construction Ltd | Construction | 2016 |
| Ikbristol Ltd | Real estate | 2024 |
| Iken Business Ltd | Information & communication | 1992 |
| Ikenna Limited | Health & social care | 2024 |
| Ikeos Ltd | Construction | 2025 |
| IKH Properties Ltd | Real estate | 2025 |
| Ikigai Holdings Limited | Financial services | 2023 |
| Ikioi Training Ltd | Other services | 2022 |
| Ikoyi (Management) Company Limited | Households | 1973 |
| Ikroop Kaur Ltd | Hospitality | 2025 |
| Iktomi Events Limited | Arts & recreation | 2018 |
| Iktomi Limited | Arts & recreation | 2018 |
| Iktomi Tickets Limited | Arts & recreation | 2022 |
| Ikue Limited | Information & communication | 2019 |
| Ikwiin Limited | Wholesale & retail | 2021 |
| IL Palio Property Group Limited | Real estate | 2023 |
| IL Piccolo Amico Ltd | Hospitality | 2026 |
| IL Tiramisu Limited | Wholesale & retail | 2026 |
| Ila-Connect Limited | Other services | 2018 |
| Ilakem Investments Ltd | Real estate | 2025 |
| Ildc Worldwide Holdings UK Limited | Financial services | 2021 |
| Iles Plumbing Ltd | Construction | 2025 |
| Iles Property Investments Ltd | Real estate | 2026 |
| Iletpro Holdings Ltd | Real estate | 2021 |
| Ilexa Limited | Professional & scientific | 2022 |
| Ilexzone Limited | Construction | 1983 |
| Ilievci Ltd | Transport & logistics | 2019 |
| Ilio Media Limited | Information & communication | 2011 |
| Iljc Limited | Health & social care | 2020 |
| Illidan Ltd | Administrative & support | 2015 |
| Illion Jewellery Ltd | Manufacturing | 2015 |
| Illora Limited | Information & communication | 2026 |
| Illuminate Engineering Ltd | Professional & scientific | 2023 |
| Illumination Electrical Services Ltd | Construction | 2016 |
| Illumineightbrand Ltd | Professional & scientific | 2024 |
| Illumo Digital Limited | Information & communication | 2023 |
| Illusioniq Limited | Information & communication | 2024 |
| Illusions Magic Bar Bristol Ltd | Hospitality | 2011 |
| Illustrate Ventures Ltd | Wholesale & retail | 2018 |
| ILM Bayan Limited | Real estate | 2019 |
| ILM Property Group Ltd | Construction | 2026 |
| ILO Limited | Wholesale & retail | 2021 |
| ILO Zyberi Renting Limited | Real estate | 2025 |
| Ilolta Limited | Administrative & support | 2019 |
| Ilyanco Ltd | Transport & logistics | 2018 |
| Ilyas Traders Ltd | Wholesale & retail | 2020 |
| IM Business Consulting Limited | Administrative & support | 2014 |
| IM Investigations (UK) Limited | Administrative & support | 2017 |
| Imachination Ltd | Manufacturing | 2022 |
| Image Cabin Limited | Professional & scientific | 2017 |
| Image Electrical Limited | Construction | 2017 |
| Image Holding (South West) Limited | Financial services | 2024 |
| Image Holdings (UK) Limited | Administrative & support | 2006 |
| Image Office Supplies Limited | Wholesale & retail | 1991 |
| Images by Buzz Ltd | Professional & scientific | 2019 |
| Imagicle Ltd | Information & communication | 2014 |
| Imagile Asset Management Limited | Administrative & support | 2016 |
| Imagile Group Limited | Extraterritorial | 2021 |
| Imagile Infrastructure Management Limited | Extraterritorial | 2021 |
| Imagile Limited | Administrative & support | 2016 |
| Imagile Support Services Limited | Administrative & support | 2016 |
| Imaginable Ltd | Manufacturing | 2011 |
| Imaginal Consulting International Limited | Professional & scientific | 2015 |
| Imaginary Astronaut Ltd | Professional & scientific | 2005 |
| Imaginatal Health Ltd | Health & social care | 2020 |
| Imaginatal Services Ltd | Health & social care | 2018 |
| Imagine Change Consulting Limited | Professional & scientific | 2024 |
| Imagine the Possibilities Ltd | Administrative & support | 2021 |
| Imagine This (Live) Limited | Arts & recreation | 2016 |
| Imagineering Futures Ltd | Administrative & support | 2021 |
| Imagineerium Ltd | Professional & scientific | 2021 |
| Imaginovation Fintech Solutions Group UK Limited | Information & communication | 2017 |
| Imahe UK Ltd | Other services | 2026 |
| Imai Solar Ltd | Energy | 2022 |
| Imanden Ltd | Information & communication | 2020 |
| Imanhood Limited | Health & social care | 2023 |