| ICA Business Services Limited | Professional & scientific | 2012 |
| Ideal Transport Limited | Transport & logistics | 2004 |
| IFA Investment Solutions Limited | Professional & scientific | 2007 |
| IGD Accounting Services Limited | Professional & scientific | 2009 |
| Ikechidumebi Evergreen Limited | Real estate | 2026 |
| Ikigai Consultancy Ltd | Professional & scientific | 2023 |
| Imperial Drainage Ltd | Water & waste | 2020 |
| Inclusive Learning for ALL Limited | Education | 2022 |
| Independent Safes Limited | Administrative & support | 2006 |
| Indian Zest Ltd | Hospitality | 2023 |
| Indigenous Music Ltd | Information & communication | 2024 |
| Indigenous Records Ltd | Information & communication | 2026 |
| Infasys Ltd | Information & communication | 2025 |
| Ingram Enterprises Limited | Wholesale & retail | 2004 |
| Innersculpt Retreats Limited | Hospitality | 2025 |
| Insight Advisory Limited | Professional & scientific | 2009 |
| International Passenger Protection Limited | Financial services | 1990 |
| Intervention Healthcare Ltd | Health & social care | 2011 |
| Invisible INK Limited | Professional & scientific | 2003 |
| IT Solutions Technology Limited | Information & communication | 2024 |
| Itsoy Ltd | Hospitality | 2021 |
| J & F Christian Community UK Limited | Information & communication | 2024 |
| J & G Consultants Ltd | Professional & scientific | 2011 |
| J & R Mechanical Services Limited | Professional & scientific | 2018 |
| J Burrows Services Limited | Construction | 2026 |
| J R Smart Finance Ltd | Financial services | 2024 |
| J W Designs Ltd | Professional & scientific | 2026 |
| Jabrik & Floon Ltd | Administrative & support | 2014 |
| Jack Holland Fitness Limited | Education | 2021 |
| Jack James Marketing Ltd | Professional & scientific | 2020 |
| Jackson Hickey Ltd | Professional & scientific | 2019 |
| JAE Accountancy Ltd | Professional & scientific | 2015 |
| James Lombard Limited | Administrative & support | 2013 |
| Jamie Fitz Pro Development Ltd | Administrative & support | 2026 |
| Jays Medical Limited | Professional & scientific | 2014 |
| JBA Accounting Ltd | Professional & scientific | 2020 |
| JCE Contracts Ltd | Professional & scientific | 2013 |
| Jcqs Ltd | Administrative & support | 2013 |
| JD 2026 Ltd | Real estate | 2025 |
| JEM Planning Ltd | Professional & scientific | 2026 |
| Jennifer Anderson Limited | Professional & scientific | 2017 |
| Jenningsconsulting Ltd | Professional & scientific | 2022 |
| Jenoastore Ltd | Wholesale & retail | 2022 |
| JL Homes and Properties Ltd | Real estate | 2015 |
| JLF Sunbeds Ltd | Other services | 2025 |
| JLG Electrical Solutions Limited | Manufacturing | 2020 |
| JLR Surveying Services Ltd | Construction | 2022 |
| Jlus Properties Ltd | Households | 2022 |
| JMS Contracts Ltd | Construction | 2015 |
| John Charles Goldsmith Limited | Construction | 2010 |
| Johnat Limited | Wholesale & retail | 2012 |
| Join Rivers Limited | Professional & scientific | 2013 |
| Jollof Express Limited | Hospitality | 2021 |
| Jonikas Limited | Construction | 2008 |
| Jordan Buchanan Limited | Other services | 2009 |
| JP Chauffeurs Ltd | Transport & logistics | 2019 |
| JRC Pathology Ltd | Health & social care | 2018 |
| Jska Limited | Professional & scientific | 2002 |
| Jubilee Assets Limited | Real estate | 2020 |
| Jugo Strategy Ltd | Professional & scientific | 2025 |
| Juliet Golf Limited | Construction | 2016 |
| JUP Property Ltd | Real estate | 2021 |
| Just the Key Properties Ltd | Professional & scientific | 2023 |
| JWA Associates Ltd | Information & communication | 2019 |
| K D Flooring Limited | Construction | 2005 |
| K Thom Properties Ltd | Real estate | 2022 |
| K Thom Property Holdings Ltd | Real estate | 2022 |
| KAJ Fitness Limited | Arts & recreation | 2025 |
| Kandy Jewellery Ltd | Wholesale & retail | 2013 |
| Kanini Software Solutions UK Ltd | Information & communication | 2024 |
| Kapstan Recruitment Ltd | Administrative & support | 2020 |
| Katie Rose Hair & Beauty Ltd | Other services | 2019 |
| Kdrti Limited | Transport & logistics | 2014 |
| Keenoir Ltd | Manufacturing | 2013 |
| Kemela Livings Limited | Real estate | 2025 |
| Kempwood CBS Limited | Construction | 2018 |
| Kentwest Developments Ltd | Construction | 2022 |
| Kentwest Property Group Ltd | Real estate | 2022 |
| KF & LF Properties Ltd | Real estate | 2025 |
| Kindhive Social Technology Ltd | Other services | 2023 |
| Kindly Properties Ltd | Hospitality | 2012 |
| Kindwell Group Limited | Administrative & support | 2020 |
| Kindwell Limited | Information & communication | 2009 |
| Kingsway Lifts Limited | Construction | 2012 |
| Kirk Developments Limited | Construction | 2017 |
| Kirk Vallis Ltd | Administrative & support | 2016 |
| Kiruna and Co Consultants Limited | Financial services | 2019 |
| Kiruna and Co Consulting 2 Ltd | Real estate | 2024 |
| Kitashi Ltd | Information & communication | 2024 |
| Kitchen Cafe Bistro Ltd | Hospitality | 2024 |
| Kite Lights Limited | Administrative & support | 2008 |
| Knfm Limited | Financial services | 2003 |
| Knitzu Studio Ltd | Manufacturing | 2025 |
| Kotori Research Ltd | Professional & scientific | 2022 |
| Kovaci Contractors Ltd | Construction | 2021 |
| Kronus Software (Research and Development) Limited | Professional & scientific | 1998 |
| Krubera Group Ltd | Administrative & support | 2015 |
| KS Service Group Ltd | Administrative & support | 2026 |
| Kssm Group Ltd | Real estate | 2025 |
| Kurdo Driving School Ltd | Education | 2017 |