| International Trading Co. Limited | Extraterritorial | 2006 |
| Internet Sales Drive Limited | Information & communication | 2012 |
| Intouchpr Limited | Wholesale & retail | 2010 |
| INTUNE24 Limited | Financial services | 2024 |
| Invest in Bricks Limited | Real estate | 2015 |
| Investment Hub Ltd | Real estate | 2018 |
| Ionut Capra Ltd | Transport & logistics | 2020 |
| IPH Bulk Haulage Limited | Transport & logistics | 2008 |
| Ipsissima Limited | Administrative & support | 2002 |
| IQ Capital Limited | Information & communication | 2022 |
| Iron Horse Landscaping and Building Services Ltd | Construction | 2024 |
| Ironstride Farriery Solutions Ltd | Agriculture & fishing | 2025 |
| Irooni Boutique Ltd | Wholesale & retail | 2024 |
| Irriplan Limited | Professional & scientific | 1997 |
| ISG Sales and Marketing Limited | Construction | 2023 |
| Isla Real Estates Ltd | Real estate | 2022 |
| Islas Naturals Ltd | Wholesale & retail | 2020 |
| Istanbol Barbers Ltd | Other services | 2024 |
| Istanbul Berber Leicester Ltd | Other services | 2025 |
| Istanbul Express Limited | Hospitality | 2019 |
| Istudio Software Limited | Information & communication | 2012 |
| IT Business Enablers Ltd | Information & communication | 2017 |
| IT Experts VIP Ltd | Other services | 2024 |
| IT IS OUR Birthday Limited | Arts & recreation | 2024 |
| Itec Properties Ltd | Real estate | 2023 |
| ITS Software Systems Limited | Information & communication | 2002 |
| Ivanhoe Feeds Limited | Wholesale & retail | 1990 |
| Iveshead Properties Limited | Real estate | 2021 |
| Ivyhouse Investments Limited | Financial services | 2011 |
| Ixon Innovation Limited | Extraterritorial | 2007 |
| IYC Lifestyle Limited | Wholesale & retail | 2025 |
| Izzet Limited | Hospitality | 2026 |
| J & J Heritage Limited | Professional & scientific | 2016 |
| J a Hargreaves Surveying Ltd | Professional & scientific | 2022 |
| J C Independent Estates Limited | Real estate | 2017 |
| J D International Consulting Limited | Professional & scientific | 2008 |
| J D S Associates Limited | Professional & scientific | 1998 |
| J Finnigan Electrical Ltd | Construction | 2016 |
| J G Interiors Ltd | Manufacturing | 2025 |
| J G Rewinds Ltd | Manufacturing | 2024 |
| J H Electrical Services (Leics) Ltd | Manufacturing | 2015 |
| J J Daughters Limited | Wholesale & retail | 2015 |
| J Jones Ltd | Hospitality | 2015 |
| J K Motorsport Consultancy Limited | Arts & recreation | 2001 |
| J K Optical Limited | Health & social care | 2012 |
| J L Tarr Limited | Professional & scientific | 2010 |
| J M (UK) Limited | Wholesale & retail | 2007 |
| J Mcleod Engineering Limited | Manufacturing | 2015 |
| J P a Freight Limited | Transport & logistics | 2016 |
| J Parker Properties Ltd | Real estate | 2021 |
| J R Ahmed Ltd | Administrative & support | 2017 |
| J R Maintenance & Civil Engineers Ltd | Construction | 2003 |
| J R Personnel Limited | Extraterritorial | 2006 |
| J Woolley Construction Limited | Construction | 2022 |
| J Wright Roofing Limited | Construction | 2000 |
| J&A Property Services Limited | Real estate | 2016 |
| J&K Ford Holdings Ltd | Financial services | 2026 |
| J&K Harris Properties Ltd | Real estate | 2025 |
| J&S Moss Holdings Ltd | Real estate | 2019 |
| J&S Oriental Limited | Wholesale & retail | 2023 |
| J.Alex Swift Limited | Manufacturing | 1957 |
| J.B Electrical Services Ltd | Construction | 2021 |
| J.C. Holdings Investments Limited | Financial services | 2022 |
| J.F. Hewitt & SON Limited | Construction | 1992 |
| J.L.Putt & Sons Limited | Wholesale & retail | 1961 |
| J.R.W Gibson Plumbing and Heating Ltd | Construction | 2026 |
| J.V.F. (Communications) Limited | Information & communication | 1987 |
| J.V.F. Systems Limited | Real estate | 1992 |
| J23 Pallets Ltd | Wholesale & retail | 2018 |
| JA Hospitality Ltd | Hospitality | 2026 |
| JAB Financial Solutions Ltd | Professional & scientific | 2021 |
| Jacey and Maxwell Ltd | Households | 2023 |
| Jack Barrington Limited | Professional & scientific | 2019 |
| Jack Bott Construction Ltd | Construction | 2023 |
| Jack Harvey Ltd | Agriculture & fishing | 2025 |
| Jack Sherwood Racing Promotions Limited | Education | 2023 |
| Jackpot Properties Ltd | Real estate | 2026 |
| Jackson & Forsythe Ltd | Real estate | 2018 |
| Jackson and Ferguson Lettings Limited | Real estate | 2024 |
| Jackson-Miles Property Development Ltd | Real estate | 2022 |
| Jacksons Mechanical Pipework Limited | Construction | 2016 |
| Jackson’S Property and Developments Ltd | Construction | 2024 |
| Jacm Holdings Ltd | Financial services | 2025 |
| Jacob Street Developments Limited | Construction | 2012 |
| Jacoby 319 Ltd | Professional & scientific | 2015 |
| Jacqueline Green Ltd | Health & social care | 2016 |
| Jadeyo Limited | Information & communication | 2018 |
| Jadeyo Property Limited | Real estate | 2023 |
| Jadie James Ltd | Real estate | 2019 |
| Jags Real Estate Ltd | Real estate | 2025 |
| JAI Jagannath (Kalinga Patliputra) Ltd | Hospitality | 2020 |
| JAM Today AI Ltd | Information & communication | 2026 |
| James Alvey Limited | Other services | 2002 |
| James Crane Limited | Manufacturing | 2004 |
| James Etty Limited | Real estate | 2009 |
| James Gibson Performance Consultancy Ltd | Other services | 2016 |
| James Glover Limited | Professional & scientific | 2013 |
| James Hannah Property Ltd | Real estate | 2021 |
| Jammeh Kinteh Ltd | Other services | 2020 |
| Jangro (Leicester) Limited | Wholesale & retail | 1981 |