| I M C Electrical Services Limited | Construction | 2026 |
| I M Thomas Limited | Real estate | 2015 |
| I P & D (Bacs) Limited | Administrative & support | 2003 |
| I R H Contractors Limited | Construction | 2002 |
| I R M Pratt Ltd | Professional & scientific | 2019 |
| I S Surveying Ltd | Professional & scientific | 2014 |
| I Scream Taco Company Ltd | Hospitality | 2015 |
| I Want Stuff Limited | Wholesale & retail | 2004 |
| I&I Traders Ltd. | Wholesale & retail | 2024 |
| I&J Domestic & Commercial Cleaning Limited | Administrative & support | 2016 |
| I&L Property Ltd | Real estate | 2015 |
| I&O Investments and Holdings Ltd | Real estate | 2024 |
| I'Merge Today Ltd | Professional & scientific | 2025 |
| I-Can Qualifications Limited | Education | 2008 |
| I-Contact Video Limited | Information & communication | 2000 |
| I-Play Soft Play Ltd | Health & social care | 2012 |
| I-Show Ltd | Construction | 2019 |
| I-Tech Systems Ltd | Information & communication | 2010 |
| I.B.S. Group Limited | Wholesale & retail | 1995 |
| I.C.S. & M. Limited | Information & communication | 2002 |
| I.D. Design (Bristol) Ltd | Professional & scientific | 2021 |
| I.D. Knapp Limited | Construction | 2004 |
| I.D.S. Refrigeration Limited | Wholesale & retail | 1997 |
| I.J. Mcgill Transport Limited | Transport & logistics | 1993 |
| I.M.G.C Limited | Information & communication | 2012 |
| I.M.O Earthworks and Haulage Ltd | Transport & logistics | 2026 |
| I.M.S Enterprises Limited | Wholesale & retail | 2019 |
| I.N. Plumbing Ltd | Construction | 2006 |
| I.T. Services Bristol Limited | Information & communication | 2004 |
| I3CAPITAL Holdings Ltd | Financial services | 2025 |
| I3CAPITAL Ltd | Financial services | 2022 |
| I3DATA Ltd | Information & communication | 2025 |
| I3NETZERO Ltd | Professional & scientific | 2022 |
| I3SECURE Holdings Ltd | Financial services | 2025 |
| IA Couriers Ltd | Transport & logistics | 2024 |
| IA Delivery Solutions Ltd | Transport & logistics | 2024 |
| Iain Dennis Associates Limited | Administrative & support | 2013 |
| Iain Dick Associates Limited | Construction | 2007 |
| Iain Packham Limited | Health & social care | 2013 |
| Iain Sutherland Couriers Limited | Transport & logistics | 2017 |
| Iakickzz Limited | Wholesale & retail | 2026 |
| IAM Chapters Limited | Other services | 2013 |
| IAM Learning Limited | Extraterritorial | 2012 |
| IAM Trading Limited | Information & communication | 2003 |
| IAM UK Chapter Ltd | Other services | 2015 |
| Iamoptical Ltd | Health & social care | 2017 |
| Iampro Limited | Education | 2019 |
| IAN Clark Electrical Ltd | Construction | 2018 |
| IAN Clark I.T. Limited | Information & communication | 1997 |
| IAN Ferguson Therapy Services Ltd. | Other services | 2026 |
| IAN Flint Building Ltd | Construction | 2013 |
| IAN Jones Ltd | Construction | 2012 |
| IAN Lamb Carpentry Ltd | Manufacturing | 2022 |
| IAN Payne Consulting Limited | Information & communication | 2025 |
| IAN Purnell Education Ltd | Education | 2017 |
| IAN Ramsden Consulting Limited | Real estate | 2004 |
| IAN Robert Wakley Ltd | Extraterritorial | 2023 |
| IAN S Ford Building Surveying & Planning Ltd | Professional & scientific | 2003 |
| IAN Saunders Agencies Limited | Other services | 2003 |
| IAN Stuart Mortgages Limited | Financial services | 2015 |
| IAN Wilhelm Usher Ltd | Extraterritorial | 2024 |
| IAN Williams (Holdings) Limited | Professional & scientific | 1941 |
| IAN Williams Limited | Construction | 1966 |
| IAN Winson Ltd | Health & social care | 2009 |
| Ian's Pet Supplies Ltd | Wholesale & retail | 2009 |
| Iandi Business Solutions Limited | Professional & scientific | 2014 |
| Ianus Ltd | Wholesale & retail | 2023 |
| IAP Kidz Limited | Arts & recreation | 2025 |
| IAP Talent Group Limited | Arts & recreation | 2023 |
| Ias-Solutions Ltd | Construction | 2025 |
| Iasc Services Limited | Manufacturing | 2018 |
| Iastudios Limited | Education | 2025 |
| Iatquo Limited | Education | 2014 |
| Iaugapril Ltd | Administrative & support | 2021 |
| IB Executive Travel Ltd | Transport & logistics | 2026 |
| IB Guide Pro Ltd | Education | 2025 |
| Ibbots 1 Ltd | Extraterritorial | 2021 |
| Ibex Gale Limited | Professional & scientific | 2013 |
| Ibex Solar and Piling Limited | Administrative & support | 2024 |
| Ibinhungry Limited | Water & waste | 2025 |
| Ibionix Limited | Information & communication | 2020 |
| Ibis Services Ltd | Households | 2023 |
| Ibitoye Medical Services Ltd | Health & social care | 2026 |
| Iblend Barbers Ltd | Other services | 2022 |
| Iboss CGN Limited | Other services | 2024 |
| Ibra Perfumery Ltd | Wholesale & retail | 2024 |
| IBS Expert Ltd | Information & communication | 2021 |
| IBT Online Limited | Professional & scientific | 2012 |
| Ibuild Homes (Bristol) Ltd | Construction | 2017 |
| Ibuild Players Close Ltd | Construction | 2025 |
| Ibuild Property Developments Ltd | Construction | 2021 |
| IC Carpentry & Building Limited | Construction | 2012 |
| Ic&M Ltd | Professional & scientific | 2012 |
| Ic-Visual LAB C.I.C. | Arts & recreation | 2013 |
| IC2 Security Ltd | Professional & scientific | 2017 |
| IC2MONITORING Ltd | Administrative & support | 2024 |
| Icaddie Invest Limited | Real estate | 2018 |
| Icaddie Ltd | Arts & recreation | 2012 |
| Icandy Aesthetics Ltd | Other services | 2019 |
| Icanique Limited | Manufacturing | 2010 |