| Ice Cubed Property Finance Limited | Financial services | 2017 |
| Ice Cubed Real Estate Limited | Real estate | 2007 |
| Icentia Limited | Manufacturing | 2018 |
| Icer Consulting Limited | Professional & scientific | 2011 |
| Iciea Limited | Real estate | 2003 |
| Icon Project Management (York) Limited | Professional & scientific | 2012 |
| Iconic Drinks Limited | Hospitality | 2012 |
| Iconiqem Group Limited | Administrative & support | 2021 |
| Iconiqem Limited | Manufacturing | 2021 |
| Iconiqem Properties Limited | Real estate | 2022 |
| Iconiqem Services Limited | Administrative & support | 2010 |
| ID Homes (Galtres) Ltd | Real estate | 2020 |
| ID Homes (York) Ltd | Real estate | 2014 |
| ID Sauce Limited | Professional & scientific | 2026 |
| ID3AS-COMPANY Limited | Other services | 2011 |
| Idea Training Ltd | Professional & scientific | 2012 |
| Ideal Developments Limited | Professional & scientific | 1964 |
| Ideal Homes (UK) Limited | Extraterritorial | 1972 |
| Ideal Homes Anglia Limited | Extraterritorial | 1972 |
| Ideal Homes Central Limited | Professional & scientific | 1956 |
| Ideal Homes Holdings Limited | Construction | 1934 |
| Ideal Homes Limited | Professional & scientific | 1929 |
| Ideal Homes Midlands Limited | Extraterritorial | 1962 |
| Ideal Homes North West Limited | Professional & scientific | 1919 |
| Ideal Homes Northern Limited | Extraterritorial | 1931 |
| Ideal Homes Scotland Limited | Extraterritorial | 1937 |
| Ideal Homes Services Limited | Extraterritorial | 1972 |
| Ideal Homes Southern Limited | Professional & scientific | 1962 |
| Ideal Hygiene Limited | Wholesale & retail | 2022 |
| Ideal Marble and Granite Limited | Construction | 2002 |
| Ideas and Solutions Limited | Professional & scientific | 2003 |
| Ideas Projects Limited | Professional & scientific | 2011 |
| Identi Bidco Limited | Financial services | 2024 |
| Identi Lower Midco Limited | Financial services | 2024 |
| Identi Midco Limited | Financial services | 2024 |
| Identi Topco Limited | Financial services | 2024 |
| Identicare Limited | Wholesale & retail | 2020 |
| Idle Hound Productions Limited | Professional & scientific | 2020 |
| Idonis Ltd | Manufacturing | 2014 |
| IDR Home Limited | Professional & scientific | 2018 |
| Idyllic Stays Ltd | Hospitality | 2021 |
| Iestyn Davies Enterprises Limited | Arts & recreation | 2010 |
| IFA Virtual PA Ltd | Administrative & support | 2023 |
| IGA Automotive Limited | Wholesale & retail | 2023 |
| IGA Holdings Limited | Professional & scientific | 2017 |
| IGA Property Limited | Real estate | 2021 |
| IGL Technologies Limited | Wholesale & retail | 2018 |
| Igniyte Ltd | Information & communication | 2009 |
| IHC Property Limited | Real estate | 2016 |
| IIC Technologies Limited | Professional & scientific | 1992 |
| Iilex Limited | Professional & scientific | 2018 |
| IJH Design Ltd | Professional & scientific | 2011 |
| IJR Assets Management Ltd | Professional & scientific | 2026 |
| Ikcss Ltd | Information & communication | 2009 |
| Ikliving Ltd | Real estate | 2026 |
| IKM Limited | Professional & scientific | 2013 |
| Ikrecords Productions Ltd. | Other services | 2014 |
| IL Paradiso (West Yorkshire) Ltd | Hospitality | 2020 |
| ILBA24 Limited | Professional & scientific | 2017 |
| ILC-UK01 Ltd | Wholesale & retail | 2025 |
| Iles (York) Limited | Real estate | 1954 |
| Illingworths Group Ltd | Financial services | 2020 |
| Illuminate Lighting Ltd | Administrative & support | 2016 |
| ILO Events Ltd | Professional & scientific | 2023 |
| ILUMIN8 Training Limited | Education | 2017 |
| Imaginarium FS Limited | Other services | 2014 |
| Imaging and Property Ltd | Real estate | 2025 |
| Imago Trading Limited | Wholesale & retail | 2007 |
| Imandar Limited | Professional & scientific | 2016 |
| IMC Dental Ltd | Health & social care | 2025 |
| IMC Enviro Ltd | Water & waste | 2018 |
| Imdc Limited | Hospitality | 2025 |
| Imetria Ltd | Professional & scientific | 2013 |
| Imex Investments Limited | Real estate | 2020 |
| IMG Property Limited | Professional & scientific | 2007 |
| Imhotek Consulting Ltd | Information & communication | 2014 |
| Imlee Spice (York) Ltd | Hospitality | 2018 |
| Immersive Tours Limited | Administrative & support | 2015 |
| Immingham Outflow Limited | Extraterritorial | 2001 |
| IMP Manufacturing Ltd | Manufacturing | 2022 |
| Impact Communications Limited | Professional & scientific | 2007 |
| IMPACT1 (Yorkshire) Ltd | Arts & recreation | 2022 |
| Impellier Limited | Professional & scientific | 2020 |
| Imperial (Felling) LLP | | 2012 |
| Imperial Work Surfaces Limited | Manufacturing | 2020 |
| Imperialt Limited | Hospitality | 2021 |
| Imperious Games Ltd | Information & communication | 2025 |
| Imperium Flotech Limited | Information & communication | 2017 |
| Implex Commissioning Ltd | Professional & scientific | 2024 |
| Implex Critical Services Ltd | Professional & scientific | 2022 |
| Improve Skills Ltd | Education | 2023 |
| Impulse Branding & Web Ltd | Professional & scientific | 2012 |
| IMS Blast Resistant Buildings Ltd | Manufacturing | 2013 |
| IMS Construct Ltd | Manufacturing | 2022 |
| IMS Energy Ltd | Manufacturing | 2018 |
| Imssc KUN Ltd | Information & communication | 2025 |
| Imssc Ltd | Information & communication | 2024 |
| IN Bloom Guitars Limited | Wholesale & retail | 2025 |
| IN Bloom PR and Marketing Ltd | Professional & scientific | 2025 |
| IN Camera Productions Limited | Information & communication | 1993 |