| JCF (2020) Ltd | Financial services | 2020 |
| JD Golf Shop Ltd | Wholesale & retail | 2024 |
| JD Property Holdings Ltd | Real estate | 2018 |
| JDC Chem Ltd | Extraterritorial | 2023 |
| Jennifer Neill Aesthetics Ltd | Other services | 2024 |
| Jenttleman Limited | Wholesale & retail | 2012 |
| JGB Leisure Limited | Arts & recreation | 2021 |
| JGB Property Management Limited | Real estate | 2025 |
| JGB Sporting Limited | Arts & recreation | 2019 |
| JGD Projects Limited | Professional & scientific | 2010 |
| JK Evans Holdings Limited | Financial services | 2022 |
| JKJ Racing Ltd | Wholesale & retail | 2026 |
| JNH Wealth Management Limited | Financial services | 2016 |
| John a. Hulme Ltd | Professional & scientific | 2012 |
| John Davies Investment and Mortgage Services LLP | | 2013 |
| John Osman Groundcare Ltd | Professional & scientific | 1994 |
| Johnson & Edwards Plumbing and Heating Limited | Construction | 2013 |
| Jolyons Ltd | Hospitality | 2024 |
| Joma Homes Ltd | Real estate | 2025 |
| JON Shield Ltd | Administrative & support | 2014 |
| Jonby Limited | Agriculture & fishing | 2018 |
| Jondell Limited | Construction | 2006 |
| Jones & Hughes Limited | Wholesale & retail | 2003 |
| Jones Brothers Properties Limited | Extraterritorial | 2009 |
| Jones Brothers Weston Rhyn Limited | Construction | 1986 |
| Jones Transport Consultancy Ltd | Professional & scientific | 2024 |
| Jonty Turnbull Limited | Construction | 2009 |
| Jr&R Properties Limited | Real estate | 2024 |
| Jrjc Holdings Limited | Financial services | 2024 |
| Jrny Fleet Ltd | Information & communication | 2025 |
| Jrny Holdings Ltd | Financial services | 2025 |
| Jrny Services Ltd | Information & communication | 2025 |
| JTH (Oswestry) Holdings Limited | Financial services | 2014 |
| JUA Solutions Ltd | Professional & scientific | 2008 |
| JUS 4 Paws Pet Supplies Ltd | Wholesale & retail | 2017 |
| Just Black Coffee Ltd | Wholesale & retail | 2026 |
| Just Impact Research Ltd | Professional & scientific | 2024 |
| Just Like That Limited | Administrative & support | 2009 |
| K & E Holloway Road (Commercial Units) Limited | Real estate | 2013 |
| K C Jones Car Sales Ltd | Wholesale & retail | 2010 |
| K C Jones Holdings Limited | Financial services | 2018 |
| K C Jones Motor Repairs Limited | Wholesale & retail | 2003 |
| K C Jones Properties Ltd | Real estate | 2022 |
| K&D Auto Repairs Ltd | Manufacturing | 2024 |
| KAL Transport 1979 Ltd | Transport & logistics | 2020 |
| Kamz Telecom Ltd | Construction | 2015 |
| Kana Foods Limited | Hospitality | 2025 |
| Katana Technical Solutions Limited | Administrative & support | 2008 |
| Katie L Jones Limited | Professional & scientific | 2022 |
| KCJ Estates Ltd | Real estate | 2022 |
| KDI Heatseeker Stoves Ltd | Construction | 2011 |
| Keepers Cards and Gifts Limited | Wholesale & retail | 2019 |
| Keith Mayer Limited | Construction | 2021 |
| Kelvington Development Limited | Wholesale & retail | 2011 |
| Kemid Holdings Limited | Real estate | 2008 |
| Kensington & Edinburgh Estates (Dunford Road) Limited | Real estate | 2015 |
| Kensington & Edinburgh Estates (Holloway Road - BLOCKS1/2) Limited | Real estate | 2016 |
| Kensington & Edinburgh Estates (Holloway Road - Retail Unit 1) Limited | Real estate | 2016 |
| Kensington & Edinburgh Estates (Holloway Road - Retail Unit 2) Limited | Real estate | 2016 |
| Kensington & Edinburgh Estates (Holloway Road - Retail Unit 3) Limited | Real estate | 2016 |
| Kensington & Edinburgh Estates (Holloway Road - Retail Unit 4) Limited | Real estate | 2016 |
| Kensington & Edinburgh Estates (Holloway Road) Limited | Real estate | 2012 |
| Kensington & Edinburgh Estates Limited | Real estate | 2002 |
| Kensington Royle Limited | Wholesale & retail | 2024 |
| Key Quality Solutions Limited | Financial services | 2012 |
| Kian MED Ltd | Wholesale & retail | 2025 |
| Kidszone Nursery Ltd | Education | 2021 |
| Kiing Hair CUT Ltd | Other services | 2025 |
| Kinetic IOT Solutions Limited | Information & communication | 2022 |
| Kingdom Dressage Ltd | Arts & recreation | 2021 |
| Kingdom Property Rentals Limited | Real estate | 2022 |
| Kingsland Group Limited | Real estate | 2002 |
| Kingston Farm Management Company Limited | Real estate | 2017 |
| Kinsman Leisure Limited | Hospitality | 2022 |
| KIP Securities Limited | Professional & scientific | 2020 |
| Kirkham and Ellis Limited | Hospitality | 2023 |
| Kirkham Hospitality Limited | Hospitality | 2018 |
| Kitchen @ the Castle Ltd | Hospitality | 2025 |
| KLM Entertainment Limited | Hospitality | 2026 |
| Knockin & Kinnerley Cricket Club Limited | Arts & recreation | 2017 |
| Knockin Flying Club Limited | Arts & recreation | 1997 |
| Kore I.T. Solutions Limited | Information & communication | 2021 |
| Kotaproductsun Limited | Wholesale & retail | 2024 |
| Kros Bros Ltd | Arts & recreation | 2016 |
| Ktrg Ltd | Real estate | 2024 |
| Kunene Holdings Limited | Financial services | 2015 |
| KWK Investments Ltd | Real estate | 2023 |
| L & J Health Ltd | Wholesale & retail | 2009 |
| L & R Holiday Homes and Letting Limited | Hospitality | 2025 |
| L.A Boxing & Fitness Ltd | Arts & recreation | 2025 |
| Lace Carpentry and Joinery Limited | Construction | 2016 |
| Lace Crane Hire Ltd | Administrative & support | 2025 |
| LAF Lending Limited | Extraterritorial | 2018 |
| Lake Utility Consultants Ltd | Professional & scientific | 2022 |
| Land Right Holdings Limited | Administrative & support | 2022 |
| Land Right Services Limited | Administrative & support | 2015 |
| Lane Investment Property Ltd | Real estate | 2020 |
| Langstone Quays Hotel Limited | Hospitality | 2018 |
| Langton Park (Eccleshall) Management Company Limited | Households | 2018 |
| Lantern IT Services Limited | Information & communication | 2007 |