| Ipso Facto Limited | Wholesale & retail | 2023 |
| Ipsum (UK) Limited | Construction | 2011 |
| IQ Global Investments Limited | Real estate | 2007 |
| IQ Heating and GAS Ltd | Construction | 2026 |
| IQ House & Home Ltd | Real estate | 2024 |
| IQ Property & Space Solutions Ltd | Real estate | 2026 |
| IQ Scientific Limited | Wholesale & retail | 2026 |
| IQ Stars Ltd | Construction | 2025 |
| Iqbal Consultancy Ltd | Professional & scientific | 2026 |
| Iqbal Solutions Ltd | Transport & logistics | 2016 |
| Iqonique Consultancy Limited | Professional & scientific | 2019 |
| Iquda Ltd | Information & communication | 1999 |
| IR Consulting Limited | Financial services | 2015 |
| IR Logistics Ltd | Transport & logistics | 2025 |
| IR Optical Services Ltd | Extraterritorial | 2025 |
| IR Signature Holdings Ltd | Other services | 2025 |
| IR Wright Ltd | Hospitality | 2022 |
| Irad Ltd | Health & social care | 2025 |
| Iraj Estates Limited | Real estate | 2024 |
| Iram BI Ltd | Professional & scientific | 2024 |
| Iranian Monarchist Solidarity Centre Limited | Other services | 2026 |
| Ireach Trading Ltd | Wholesale & retail | 2024 |
| Ireos Ltd | Administrative & support | 2024 |
| Ireset Ltd | Wholesale & retail | 2025 |
| Irfan Ecom Ltd | Wholesale & retail | 2025 |
| Irfani Ltd | Wholesale & retail | 2025 |
| Irfarajpoot Ltd | Wholesale & retail | 2025 |
| Irhaa Sana Foods Limited | Hospitality | 2023 |
| Irina Chlubek Limited | Other services | 2012 |
| Iris Blue Gifts Ltd | Wholesale & retail | 2014 |
| Iris Building & Services Ltd | Construction | 2019 |
| Iris Elite Dance Company Ltd. | Professional & scientific | 2019 |
| Iris Health Services Limited | Other services | 2021 |
| Iris Holdings 3 Limited | Health & social care | 2025 |
| Iris Trading Ltd | Hospitality | 2019 |
| Irma Group Ltd | Hospitality | 2017 |
| Iron APE Clothing Ltd. | Manufacturing | 2015 |
| Iron Bone Inc. Ltd | Wholesale & retail | 2022 |
| Iron Made Limited | Arts & recreation | 2024 |
| Iron Maidens (Nottingham) Limited | Administrative & support | 2005 |
| Iron Monkey Events Limited | Information & communication | 2018 |
| Ironcrest IT Limited | Information & communication | 2025 |
| Ironhq Ltd | Wholesale & retail | 2025 |
| Ironing Centre (Nottingham) Limited | Other services | 2006 |
| Irons Trading Ltd | Wholesale & retail | 2023 |
| Ironside Joinery Limited | Manufacturing | 2021 |
| Ironville Properties Ltd | Real estate | 2019 |
| Ironwebclub Ltd | Administrative & support | 2019 |
| Irony Creative Ltd | Construction | 2023 |
| IRR Devco Ltd | Extraterritorial | 2025 |
| Irubber Limited | Manufacturing | 2008 |
| Irufa Ltd | Health & social care | 2021 |
| Irvine Design Ltd | Professional & scientific | 2022 |
| Irving Junior Walters Ltd | Extraterritorial | 2025 |
| Irwin Family Developments Limited | Extraterritorial | 2019 |
| IS Analytics and Project Services Ltd | Information & communication | 2024 |
| IS Holdings Ltd | Administrative & support | 2016 |
| IS This Love Ltd | Professional & scientific | 2024 |
| IS Wave Limited | Wholesale & retail | 2026 |
| IS3 Ltd | Information & communication | 2016 |
| ISA Apartments Limited | Extraterritorial | 2024 |
| Isa-Lea Limited | Other services | 1932 |
| Isaac Fraser Limited | Professional & scientific | 2026 |
| Isaac Reliable Solutions Ltd | Wholesale & retail | 2024 |
| Isaacbrawn Engineering Ltd | Professional & scientific | 2023 |
| Isaacs Recruit Ltd | Administrative & support | 2025 |
| Isabel Transport Ltd | Transport & logistics | 2019 |
| Isabelle Meira Limited | Wholesale & retail | 2019 |
| Isaiah Active Ltd | Wholesale & retail | 2024 |
| Isaiah's Daughter Limited | Wholesale & retail | 2018 |
| Isaksen Developments Ltd | Information & communication | 2023 |
| Iscb NDT Ltd | Professional & scientific | 2025 |
| ISE Plumbing and Heating Ltd | Construction | 2019 |
| Isegoria Publishing C.I.C. | Information & communication | 2021 |
| Isero Limited | Administrative & support | 2010 |
| Iset Solutions Limited | Wholesale & retail | 2017 |
| Iset UK Fire and Security Distribution Ltd | Wholesale & retail | 2022 |
| Ishak Practices Ltd | Health & social care | 2007 |
| Ishak Properties Ltd | Construction | 2005 |
| Ishani Investments Ltd | Financial services | 2018 |
| Ishmael/Maliz Criminal Defence Investigation Ltd | Administrative & support | 2015 |
| Ishtar Consultants Ltd | Professional & scientific | 2023 |
| Ishtiaq & Sons Properties Ltd | Real estate | 2022 |
| ISI Bidco Limited | Financial services | 2021 |
| Isibindi Ltd | Information & communication | 2025 |
| Isla and Theo Properties Ltd | Real estate | 2022 |
| Isla Holdings Limited | Real estate | 2025 |
| Isla Investment & Property Services Ltd | Construction | 2014 |
| Isla Investments Ltd | Construction | 2019 |
| Isla Travel Ltd | Administrative & support | 2018 |
| Islam Development Limited | Real estate | 2025 |
| Islamic Centre Nottingham | Other services | 1976 |
| Islamic Marriage Solutions Ltd | Other services | 2021 |
| Island Community Haven CIC | Agriculture & fishing | 2020 |
| Island Hvac Systems Ltd | Wholesale & retail | 2018 |
| Island Properties Nottm Ltd | Hospitality | 2013 |
| Island Vibes Ltd | Construction | 2014 |
| Islano Limited | Professional & scientific | 2020 |
| Isle of MAN Sales Limited | Wholesale & retail | 1987 |
| ISM UK Group Limited | Education | 2020 |