| Ironbird Aerial Cinematography Ltd | Professional & scientific | 2013 |
| Ironshore Global (SPV 001) Limited | Real estate | 2016 |
| Ironwood Horizons Limited | Administrative & support | 2025 |
| Irose Limited | Wholesale & retail | 2025 |
| Irton Southport Limited | Professional & scientific | 2021 |
| Irvings Law Limited | Professional & scientific | 2017 |
| Irwell Property Management & Solutions Limited | Hospitality | 2026 |
| Irwin Plant and Equipment Services (UK) Ltd | Administrative & support | 2009 |
| Irwin Property Holdings Ltd | Real estate | 2026 |
| Iryo Communications Limited | Professional & scientific | 2011 |
| IS Agri UK Ltd | Agriculture & fishing | 2025 |
| IS Construction (Liverpool) Limited | Construction | 2025 |
| ISA Inspire Ltd | Transport & logistics | 2020 |
| ISA.SY1 Ltd | Other services | 2025 |
| Isaac Mini Mart Ltd | Other services | 2020 |
| Isaac’S Group Ltd | Transport & logistics | 2023 |
| Isabella’S Closet Ltd | Wholesale & retail | 2019 |
| ISC Capital Limited | Real estate | 2018 |
| Isc-Care Limited | Health & social care | 2020 |
| Isensing UK Ltd | Information & communication | 2019 |
| Iservo Limited | Administrative & support | 2016 |
| Isestate Limited | Real estate | 2025 |
| ISF Properties Limited | Real estate | 2025 |
| ISG Hospitality Ltd | Administrative & support | 2025 |
| Isha Health Ltd | Health & social care | 2018 |
| Isha.S Enterprise Ltd | Real estate | 2025 |
| Ishara Holdings Limited | Wholesale & retail | 2026 |
| Ishtar Estates Ltd | Real estate | 2025 |
| Isis Export Limited | Transport & logistics | 2010 |
| Isishealing Ltd | Health & social care | 2023 |
| Iskin Clinic Ltd | Transport & logistics | 2020 |
| Isla Events Ltd | Other services | 2020 |
| Isladore Limited | Construction | 2019 |
| Islam & Co Ltd | Professional & scientific | 2013 |
| Islamic Touch Ltd. | Wholesale & retail | 2018 |
| Island Dwellings Ltd | Real estate | 2025 |
| Island Emporiums Ltd | Wholesale & retail | 2025 |
| Island Hemp Farm Limited | Agriculture & fishing | 2018 |
| Islands Brow SPV Ltd | Real estate | 2025 |
| Islemount Limited | Professional & scientific | 2014 |
| ISM Property Management Limited | Real estate | 2022 |
| ISM Sports Limited | Other services | 2019 |
| Isnn Investment Properties Limited | Financial services | 2017 |
| Isocal (UK) Limited | Manufacturing | 1992 |
| Isocial Work Ltd | Health & social care | 2025 |
| Isoldetap Ltd | Wholesale & retail | 2025 |
| Isoo Marketing Ltd | Administrative & support | 2015 |
| Ispace Developments Ltd | Construction | 2007 |
| ISS Security Ltd | Administrative & support | 2022 |
| Issa Associates Ltd | Real estate | 2018 |
| Issa.Bella Brows and Lashes Ltd | Other services | 2025 |
| Issla Limited | Wholesale & retail | 2020 |
| Issueair Limited | Construction | 1999 |
| Istanbloom Ltd | Wholesale & retail | 2020 |
| Istanbul BBQ & Bistro Limited | Hospitality | 2017 |
| Istay Global Ltd | Hospitality | 2023 |
| Istore Brothers Limited | Information & communication | 2026 |
| ISW Northwest Ltd | Health & social care | 2016 |
| IT Answers (UK) Limited | Information & communication | 2004 |
| IT IS UN Limited | Arts & recreation | 2016 |
| IT Solutions Sphere Ltd | Information & communication | 2025 |
| IT Support North West Limited | Information & communication | 2013 |
| IT Systems Ltd | Information & communication | 2024 |
| IT WAS ALL a Dream Limited | Financial services | 2019 |
| IT Wink Limited | Information & communication | 2026 |
| It's a Kinda Magic Ltd | Hospitality | 2026 |
| It's Just for ME Ltd | Wholesale & retail | 2021 |
| ITA7411 Ltd | Real estate | 2014 |
| Itacon Ltd | Information & communication | 2021 |
| Ital UK Impex Ltd | Wholesale & retail | 2026 |
| Italbeit UK Limited | Manufacturing | 2025 |
| Italian Concept Limited | Hospitality | 2022 |
| Italian Pizza 574 Ltd | Hospitality | 2025 |
| Italy a & H Ltd | Hospitality | 2022 |
| Itcbcs Ltd | Professional & scientific | 2024 |
| Iter Digital Limited | Information & communication | 2022 |
| ITG Enterprises Ltd | Wholesale & retail | 2015 |
| ITG Web Ltd | Information & communication | 2017 |
| Ithaca Holdings (UK) Limited | Financial services | 2025 |
| ITL Enstitute Ltd | Information & communication | 2025 |
| Itopians Limited | Information & communication | 2021 |
| Itprotaxfree Ltd | Wholesale & retail | 2024 |
| Itros Ltd | Professional & scientific | 2024 |
| Itss Consultancy UK Ltd | Professional & scientific | 2025 |
| Itug Ltd | Administrative & support | 2016 |
| It’S Real Logistic Ltd | Health & social care | 2022 |
| It’S Sooper Limited | Construction | 2019 |
| Iulian Transport Ltd | Transport & logistics | 2019 |
| Iulirom Ltd | Wholesale & retail | 2019 |
| Iuly and Beny Limited | Wholesale & retail | 2022 |
| IVA Tucker One Trading Limited | Agriculture & fishing | 2015 |
| IVA Tucker Three Trading Limited | Agriculture & fishing | 2015 |
| Ivaa Group UK Ltd | Wholesale & retail | 2025 |
| Ivanhoe Management Limited | Real estate | 2001 |
| Ivanhoe Real Estate Ltd | Real estate | 2019 |
| Ivanhoe Road Management Limited | Households | 1998 |
| Ivcata VI Ltd | Information & communication | 2021 |
| Ivcc | Professional & scientific | 2008 |
| Ivebeenletdown.Com Ltd | Extraterritorial | 2014 |
| IVF 2.0 Limited | Health & social care | 2018 |