| IL Pecoro Ltd | Hospitality | 2016 |
| Imagination Dance C.I.C. | Health & social care | 2020 |
| Immunitor Ltd | Manufacturing | 2020 |
| Impact Furniture Limited | Wholesale & retail | 2007 |
| Improve.It Design Limited | Professional & scientific | 2004 |
| Impulse Point of Purchase Limited | Manufacturing | 2005 |
| Incredible Group Holdings Ltd | Financial services | 2025 |
| Incredible PUB Management Ltd | Hospitality | 2025 |
| Indiana New York Limited | Extraterritorial | 2018 |
| Inqi B Limited | Information & communication | 2019 |
| Inqi Limited | Real estate | 2016 |
| Inqi Properties Limited | Real estate | 2019 |
| Insight Unbound Ltd | Professional & scientific | 2022 |
| Inteliflow Limited | Professional & scientific | 2013 |
| Intelligent Catering Design Limited | Extraterritorial | 2013 |
| Intelligent Design Solutions Ltd | Professional & scientific | 2024 |
| Intensive Sports Limited | Arts & recreation | 2015 |
| International Eco Fund | Other services | 2022 |
| Ionic Engineering Limited | Manufacturing | 1988 |
| Ionic Manufacturing Limited | Manufacturing | 1995 |
| Iota Training Ltd | Other services | 2019 |
| Irthling Corporate Services Limited | Professional & scientific | 2019 |
| Irthling Limited | Professional & scientific | 2017 |
| Isambard Limited | Agriculture & fishing | 2014 |
| Ishal Healthcare Ltd | Health & social care | 2025 |
| IT Doctor (West Anglia) Limited | Information & communication | 2003 |
| IT Probity Limited | Information & communication | 2018 |
| Ivel Holdings Limited | Real estate | 1954 |
| Ivel Holdings Newco Limited | Financial services | 2017 |
| Ivory Lounge Sandy Ltd | Hospitality | 2020 |
| J & C Carpets Ltd | Wholesale & retail | 2003 |
| J & P Farming Limited | Agriculture & fishing | 2018 |
| J & P Plant Holdings Ltd | Financial services | 2020 |
| J & P Plant Limited | Construction | 2005 |
| J & S Dickinson Builders Limited | Construction | 2005 |
| J C & Associates Ltd | Professional & scientific | 2015 |
| J Ffrench Group Limited | Financial services | 2019 |
| J Ffrench Plant Hire Ltd | Construction | 2012 |
| J Kiely Building Services Ltd | Construction | 2016 |
| J&P Building Solutions Ltd | Construction | 2021 |
| J&P Management (Gamlingay) Limited | Professional & scientific | 2021 |
| J. S. Alsford Butchers Ltd | Wholesale & retail | 2020 |
| J17 Painters Limited | Construction | 2025 |
| JAC Settlement Trust Corporation Limited | Professional & scientific | 2003 |
| Jacob's Flock Ltd. | Agriculture & fishing | 2013 |
| Jade HR Consulting Ltd | Administrative & support | 2026 |
| JB Moto Limited | Arts & recreation | 2015 |
| Jbbh Limited | Professional & scientific | 2025 |
| JC Marketingfba Ltd | Wholesale & retail | 2026 |
| JCM Photos Limited | Professional & scientific | 2025 |
| JDL Carpentry Limited | Financial services | 2024 |
| Jeanie Junkyard Ltd | Information & communication | 2023 |
| Jebs Enterprises Limited | Real estate | 2013 |
| Jems Media Limited | Information & communication | 2015 |
| JG Contract Flooring Limited | Construction | 2015 |
| Jgaudits Ltd | Construction | 2025 |
| JJ Nails Limited | Other services | 2014 |
| JMK Land Investments Limited | Real estate | 2009 |
| John Howells Golf Limited | Education | 2026 |
| John O'Gaunt Golf and Country Club (1962) Limited | Arts & recreation | 1962 |
| John O'Gaunt Golf Club Limited | Hospitality | 2022 |
| John Street Productions Limited | Information & communication | 2014 |
| Johny Drive Limited | Transport & logistics | 2024 |
| Joinery 47 Ltd | Manufacturing | 2019 |
| JON Hutton & Associates Ltd | Professional & scientific | 2025 |
| Jonathan Bonnett Limited | Information & communication | 2003 |
| Jonathan Paul Langley Ltd | Extraterritorial | 2024 |
| Josephine Design Studio Ltd | Professional & scientific | 2026 |
| JPB Carpentry Limited | Construction | 2025 |
| JPR Fire Protection Limited | Professional & scientific | 2006 |
| Jungle Jim's Playland Ltd | Health & social care | 2012 |
| K. Patel Advisory Ltd | Information & communication | 2026 |
| K.M. Software Systems Limited | Information & communication | 1994 |
| K2 Partners (Executives) Ltd | Extraterritorial | 2011 |
| K2 Partners Ltd | Professional & scientific | 2001 |
| K2 Sheetmetal and Painting Ltd | Manufacturing | 2024 |
| K4 Solutions Ltd | Professional & scientific | 2013 |
| Karla Transport Ltd | Transport & logistics | 2017 |
| Katherine Daniels Cosmetics Limited | Wholesale & retail | 1993 |
| Kaufman Limited | Information & communication | 2009 |
| KC Clinical Ltd. | Administrative & support | 2017 |
| KC Rockers Limited | Hospitality | 2012 |
| Kchis Investment Ltd | Health & social care | 2020 |
| Keens Shay Keens Limited | Professional & scientific | 2002 |
| Keep ME Running Limited | Wholesale & retail | 2016 |
| Kelfin Autos Limited | Extraterritorial | 2024 |
| Kennedy & Allen Limited | Real estate | 2020 |
| Kenwright Electrical Testing Limited | Manufacturing | 2013 |
| Key Tones Media Ltd | Arts & recreation | 2018 |
| Keyturn Properties Ltd | Real estate | 2017 |
| KH Consultancy Limited | Arts & recreation | 2010 |
| KH First AID Training Limited | Other services | 2019 |
| Kingspan Timber Solutions Limited | Manufacturing | 2003 |
| Kishen-Tech Limited | Wholesale & retail | 2004 |
| KMG Systems Limited | Manufacturing | 1978 |
| Krause Autos Ltd | Wholesale & retail | 2020 |
| Kubi-Kid Productions Limited | Information & communication | 2012 |
| Kypol Limited | Real estate | 1970 |
| Kyps Fitness Limited | Arts & recreation | 2026 |
| L & a Westrop Limited | Construction | 2011 |