| Jonsoft Ltd | Information & communication | 2022 |
| Jordan Car Sales Limited | Wholesale & retail | 2002 |
| Joshua Jones Limited | Wholesale & retail | 1992 |
| JP Endeavour Ltd | Administrative & support | 2023 |
| JPS Communications (Bournemouth) Limited | Information & communication | 2017 |
| JR Bearings UK Ltd | Financial services | 2013 |
| JR Lead Solutions Ltd | Professional & scientific | 2025 |
| JR Maritime Limited | Professional & scientific | 2022 |
| JR2N Properties Limited | Households | 2012 |
| JRA Consulting Services Limited | Professional & scientific | 1999 |
| JRF Consulting Services Ltd | Information & communication | 2024 |
| Jrhw Trading Limited | Wholesale & retail | 2021 |
| JRL Consulting Group Limited | Professional & scientific | 2026 |
| JRS Financial Services Limited | Financial services | 2015 |
| JS Healthcare Experts Limited | Health & social care | 2016 |
| JT Sports Consulting Limited | Professional & scientific | 2023 |
| JTH Design Ltd | Professional & scientific | 2019 |
| Jubilee Optical Ltd | Health & social care | 2023 |
| Judy's House Limited | Education | 2007 |
| Jukes Farms Limited | Professional & scientific | 1959 |
| Julia Millard Interior Design Ltd | Professional & scientific | 2024 |
| Julia's House Limited | Health & social care | 1997 |
| Julia's House Trading Ltd | Wholesale & retail | 2007 |
| Juliet Blackburn Consulting Limited | Professional & scientific | 2018 |
| Juliet Street Ltd | Professional & scientific | 2022 |
| Julius Meinl UK Limited | Wholesale & retail | 2013 |
| Junction Theatre Academy LLP | | 2022 |
| Jupiter Sterling Management Limited | Information & communication | 2026 |
| Jurassic Care Limited | Health & social care | 2022 |
| Jurassic Lyme Property Ltd | Real estate | 2024 |
| Jurrasic Charters Ltd | Agriculture & fishing | 2007 |
| Jury Consulting Ltd | Information & communication | 2023 |
| Jusko Ltd. | Construction | 2003 |
| Just AJD Ltd | Manufacturing | 2023 |
| Just Different Groundworks & Construction Ltd | Construction | 2025 |
| Just GB Assetts Ltd | Manufacturing | 2017 |
| Just People Consultancy Solutions Limited | Public administration | 2025 |
| Just the JOB (Wessex) Ltd. | Construction | 2007 |
| JV IT Services Limited | Information & communication | 2022 |
| JV Studios Limited | Professional & scientific | 2024 |
| JV Upholstery Limited | Manufacturing | 2006 |
| JW Finance Solutions Limited | Professional & scientific | 2024 |
| JW Systems Consulting Ltd | Information & communication | 2024 |
| JWA Catering Ltd | Hospitality | 2022 |
| Jwconsulting Ltd | Professional & scientific | 2026 |
| Jwsc Limited | Information & communication | 2017 |
| K & L Bailey Ltd | Construction | 2016 |
| K Andrews Partnership Ltd | Administrative & support | 2015 |
| K D Wilkinson Builders Limited | Construction | 2019 |
| K&E Subsea Consultants Ltd | Professional & scientific | 2025 |
| K.C. Horwood Limited | Construction | 2014 |
| K.P.M. Venture Limited | Information & communication | 2018 |
| K.Russell Limited | Information & communication | 2024 |
| K9 Unit Manchester Ltd | Administrative & support | 2024 |
| KA Project Management Services Limited | Real estate | 2013 |
| KA Wealth and Property Ltd | Real estate | 2025 |
| Kabenla Ltd | Information & communication | 2022 |
| KAI Communications Limited | Information & communication | 2009 |
| Kairos Connect Ltd | Information & communication | 2026 |
| Kaizen Financial Planning Limited | Financial services | 2020 |
| Kalkay Limited | Real estate | 2017 |
| Kallioppe Ltd | Information & communication | 2018 |
| Kalyana Health and Beauty Ltd | Health & social care | 2023 |
| Kamam Properties Limited | Real estate | 2017 |
| Kane Digital Consultancy Ltd | Information & communication | 2026 |
| Kangaw Place Residents Company Limited | Households | 2001 |
| Kanto Pro Limited | Information & communication | 2019 |
| Karmalife Chiropractic Ltd | Health & social care | 2021 |
| Kate Elkin OT Limited | Health & social care | 2013 |
| Kate Pottinger Consulting Limited | Professional & scientific | 2025 |
| Katec Limited | Professional & scientific | 2021 |
| Kathiron Ltd | Wholesale & retail | 2023 |
| Kathryn Hellewell Therapy Limited | Information & communication | 2008 |
| KAY Steel Design Limited | Professional & scientific | 2008 |
| Kayayay Management Limited | Professional & scientific | 2023 |
| Kazale IT Limited | Information & communication | 2021 |
| Kazang Ltd | Wholesale & retail | 2022 |
| KBD Group Services Ltd | Administrative & support | 2022 |
| KBN Architecture Limited | Professional & scientific | 2022 |
| KC Commercial Services & Supplies Limited | Construction | 2023 |
| KD Property Investment Ltd | Real estate | 2023 |
| Kdit Consulting Limited | Information & communication | 2011 |
| Keen Holdings Ltd | Financial services | 2021 |
| Keenan Cable Services Ltd | Professional & scientific | 2016 |
| Keene Development Limited | Information & communication | 2016 |
| Keep OFF the Grass Ltd | Arts & recreation | 2021 |
| Keeper Huts Ltd | Manufacturing | 2018 |
| Keeprs Consulting Ltd | Information & communication | 2026 |
| Keith Spicer Limited | Manufacturing | 1939 |
| Kelana Jaya Ltd | Information & communication | 2015 |
| Kelar Consulting Limited | Information & communication | 2026 |
| Kemp Sails Limited | Wholesale & retail | 1985 |
| Kempshall Engineering Ltd | Manufacturing | 2024 |
| Kend Holdings Ltd | Professional & scientific | 2023 |
| Kendrick Fencing Limited | Construction | 2000 |
| Kenga Engineering Ltd | Professional & scientific | 2019 |
| Kenilworth Freehold Limited | Real estate | 2013 |
| Kenrock Properties Limited | Real estate | 2016 |
| Kensey Valley Ltd | Construction | 2023 |
| Kerntiff Publishing Systems Limited | Information & communication | 2010 |