| Impeccable Procurement Solutions Ltd | Professional & scientific | 2016 |
| Imperial Auction Services Ltd | Wholesale & retail | 2019 |
| Imperial Spice NW Ltd | Hospitality | 2025 |
| Imperial Vehicle Solutions Ltd | Wholesale & retail | 2023 |
| Important Snacks Limited | Hospitality | 2018 |
| Imran & Hanif Planning & Design Limited | Professional & scientific | 2018 |
| IMS Inns Ltd | Hospitality | 2019 |
| Imsai Limited | Professional & scientific | 2025 |
| IN Events Productions Ltd | Arts & recreation | 2026 |
| IN House Fitting Ltd | Construction | 2015 |
| IN the Vintage Closet Ltd | Wholesale & retail | 2020 |
| In-Line Ltd | Construction | 2016 |
| Inc. Design Limited | Professional & scientific | 1993 |
| Inc. Promotions Limited | Extraterritorial | 2013 |
| Inclusion Solutions (North West) Limited | Education | 2013 |
| Increase Properties Ltd | Real estate | 2019 |
| Independent Games Limited | Information & communication | 2020 |
| Independent Homes (North West) Limited | Real estate | 2001 |
| Independent Homes NO8 SPV Limited | Real estate | 2023 |
| Independent Landlords Group Ltd | Real estate | 2020 |
| India Chef Limited | Hospitality | 2018 |
| Indie LIT Ltd | Construction | 2022 |
| Indigo Bloom Ltd | Wholesale & retail | 2026 |
| Indigo Electrical Services (London) Limited | Construction | 2016 |
| Indigo Mech Ltd | Construction | 2024 |
| Industria Systems UK Limited | Information & communication | 2013 |
| Industrial Decontamination Services (UK) Ltd | Water & waste | 2026 |
| Industrial Reclamation and Salvage Limited | Water & waste | 2002 |
| Infinity Carpentry Limited | Construction | 2014 |
| Infinity Ortho Ltd | Wholesale & retail | 2023 |
| Infofusion Limited | Information & communication | 2025 |
| Inform Finance Limited | Financial services | 2025 |
| Informed Financial Advice Limited | Extraterritorial | 2009 |
| INFRASTRUCTURE4DATA Limited | Administrative & support | 2015 |
| ING Design Limited | Professional & scientific | 2013 |
| Inglenorth Ltd | Construction | 1999 |
| Ingram Contractors (International) Ltd | Manufacturing | 2025 |
| Initial Kitchens Limited | Wholesale & retail | 2021 |
| Inkjet Direct Ltd | Wholesale & retail | 2008 |
| Inleaf (Franchising) Limited | Administrative & support | 2016 |
| Inleaf Group Limited | Professional & scientific | 2022 |
| Inleaf Ltd | Administrative & support | 2013 |
| Innova Nursing Solutions Limited | Health & social care | 2017 |
| Innovate Concepts Ltd | Construction | 2018 |
| Innovate Groundworks & Civil Engineering Limited | Construction | 2024 |
| Innovation Chemicals Limited | Manufacturing | 2019 |
| Innovo Global Talent Ltd | Administrative & support | 2023 |
| Inquizitive Ltd | Arts & recreation | 2004 |
| Inscape Interiors Limited | Construction | 2002 |
| Insight Coatings Ltd | Administrative & support | 2019 |
| Inspirational Financial Planning Ltd | Professional & scientific | 2009 |
| Inspire 2 Grow Ltd | Professional & scientific | 2015 |
| Install Solar Panels Limited | Construction | 2022 |
| Instyle Clothing Limited | Wholesale & retail | 2020 |
| Integral Catering Engineers Limited | Manufacturing | 2014 |
| Integrated Development Solutions Limited | Real estate | 2000 |
| Integrated System Control Limited | Information & communication | 2005 |
| Interact IT Limited | Information & communication | 2011 |
| Interactive Management Limited | Households | 2002 |
| Intercounty Homes Limited | Real estate | 2012 |
| Intergrow International Ltd | Professional & scientific | 2024 |
| Interim Consultancy Services NW Ltd | Professional & scientific | 2025 |
| Interim Employment Limited | Administrative & support | 2016 |
| Interim Property Management Ltd | Real estate | 2022 |
| Interimengineering Limited | Construction | 2015 |
| Interiors Outlet Limited | Wholesale & retail | 2018 |
| International AID Trust | Wholesale & retail | 2001 |
| Inti Innovations Ltd | Professional & scientific | 2012 |
| Intrack Sound and Light Limited | Arts & recreation | 2015 |
| Intuitive Interim & Executive Search Ltd | Administrative & support | 2010 |
| Inuvera Ltd | Information & communication | 2024 |
| Investech Capital Management Limited | Financial services | 2002 |
| Investment Group Developments Ltd | Construction | 2021 |
| Investment Principles Limited | Extraterritorial | 2013 |
| Invew Limited | Professional & scientific | 2008 |
| Invew Telecom Limited | Information & communication | 2014 |
| Invictus Dance Events Limited | Arts & recreation | 2025 |
| ION Groundwork Ltd | Construction | 2018 |
| IP Man's Cuisine Ltd | Hospitality | 2019 |
| Ipati-Constantinescu Healthcare Services Ltd | Health & social care | 2019 |
| IPJ Holdings Limited | Financial services | 2024 |
| Iprs Aeromed Limited | Health & social care | 2001 |
| Iprs Group Limited | Financial services | 2002 |
| Iprs Health Limited | Wholesale & retail | 1995 |
| Iprs Limited | Extraterritorial | 2002 |
| Iprs Medical Transport Services Limited | Extraterritorial | 2022 |
| Iprs Mediquipe Limited | Manufacturing | 2002 |
| Ipsum Drainage Solutions Limited | Water & waste | 2013 |
| Ipsum Group Limited | Financial services | 2017 |
| Ipsum Power (ICP) Limited | Professional & scientific | 2005 |
| Ipsum Power (Licensed Networks) Limited | Administrative & support | 2009 |
| Ipsum Power (Midlands) Limited | Construction | 2018 |
| Ipsum Power (North West) Limited | Construction | 2008 |
| Ipsum Power (OHL) Limited | Construction | 2012 |
| Ipsum Power (Private Networks) Limited | Construction | 2000 |
| Ipsum Power (Training Services) Limited | Construction | 2011 |
| Ipsum Power (Trydan) Holdco Limited | Construction | 2016 |
| Ipsum Power (Trydan) Limited | Construction | 1989 |
| Ipsum Survey Solutions Limited | Water & waste | 2011 |
| Ipsum Utilities Limited | Financial services | 2018 |