| JDB Property Investments Ltd | Real estate | 2017 |
| JDS Self Storage Limited | Transport & logistics | 2015 |
| JDS Trade Limited | Wholesale & retail | 2012 |
| JE Wellbeing Limited | Wholesale & retail | 2025 |
| Jemm CD Holdings Limited | Other services | 2011 |
| Jemm Corporate Development Limited | Other services | 2011 |
| Jezamagi Group Limited | Financial services | 2024 |
| Jhct Food Ltd | Hospitality | 2025 |
| Jhf-Sport-Venture Ltd | Professional & scientific | 2018 |
| JHJ Developments Limited | Construction | 2003 |
| JJG Consultancy & Executive Coaching Services Ltd | Administrative & support | 2018 |
| JKA Properties Limited | Real estate | 1999 |
| JLS Building & Developments Limited | Construction | 2003 |
| JLT Living Ltd | Real estate | 2025 |
| JMK Cosmetics Ltd | Other services | 2018 |
| JMW Carpentry & Builders Ltd | Construction | 2016 |
| John Bodman Limited | Construction | 2000 |
| JPM Builders Ltd | Construction | 2017 |
| JPO Construction Ltd | Construction | 2006 |
| JPO Labour Solutions Limited | Administrative & support | 2014 |
| JRM Drylining Ltd | Construction | 2025 |
| JSA Carpentry and Construction Ltd | Construction | 2023 |
| Juno Funding Ltd | Information & communication | 2026 |
| Just James Games Ltd | Information & communication | 2025 |
| Jwblackbourn Ltd | Administrative & support | 2020 |
| Jzmg Property Deals Ltd | Real estate | 2025 |
| K Thornton Construction Ltd | Construction | 2014 |
| K&K 09 Limited | Real estate | 2009 |
| K&K 22 Limited | Real estate | 2022 |
| K&K Holdco Limited | Financial services | 2022 |
| K&K RAD Ltd | Health & social care | 2021 |
| Kalra Consulting Services Ltd | Professional & scientific | 2018 |
| Kalra Property Services Ltd | Real estate | 2016 |
| Kambei Solutions Ltd | Professional & scientific | 2014 |
| Kanwal & Daughters Ltd | Hospitality | 2025 |
| Karl Lawson Consulting Ltd | Information & communication | 2020 |
| Kate Cadbury Designs Ltd | Wholesale & retail | 2022 |
| Katie Brooks RDH Limited | Health & social care | 2023 |
| Kauto Properties Limited | Real estate | 2020 |
| KD Construction and Property Ltd | Construction | 2026 |
| Kdsb Property Group Ltd | Real estate | 2022 |
| Kennedy Prime Properties Limited | Real estate | 2024 |
| Kenneth Lettings Ltd | Administrative & support | 2022 |
| Kens Cars Limited | Wholesale & retail | 2002 |
| KEW Solutions Ltd | Information & communication | 2014 |
| Keyhouse Property Group Ltd | Financial services | 2025 |
| Keyhouse Property Ltd | Real estate | 2020 |
| Keypad Homes Ltd | Real estate | 2019 |
| KGH Electrical Ltd | Construction | 2022 |
| Kindheart Search Angels CIC | Other services | 2021 |
| Kinetic Portfolio Ltd | Financial services | 2017 |
| Kingfisher Wetlands Ltd | Other services | 2021 |
| Kirosh Ltd | Professional & scientific | 2021 |
| KK Consortium Ltd | Financial services | 2025 |
| KK Imaging Ltd | Health & social care | 2025 |
| Knight Heating & Plumbing Ltd | Construction | 2016 |
| Knott & Shepherd Developments Ltd | Construction | 2026 |
| Knott & Shepherd Group Ltd | Financial services | 2026 |
| Koha Properties Ltd | Real estate | 2020 |
| Koha Services Ltd | Professional & scientific | 2022 |
| Konnect International Ltd | Wholesale & retail | 2008 |
| Koolfog Limited | Arts & recreation | 1999 |
| KQ Group Ltd | Financial services | 2023 |
| KS Lawson Consulting Ltd | Information & communication | 2026 |
| Kubrat Estate Limited | Real estate | 2019 |
| Kudos Recruitment Services Limited | Administrative & support | 2003 |
| Kuscinska Limited | Professional & scientific | 2019 |
| L P B Fitness Ltd | Arts & recreation | 2015 |
| L.M.L. Products Limited | Manufacturing | 1968 |
| LA Building Property Maintenance Services Ltd | Construction | 2016 |
| Laminaheat UK Ltd | Manufacturing | 2023 |
| Lappin Properties Ltd | Real estate | 2016 |
| Larsen Oliver Ltd | Manufacturing | 2012 |
| Latency & Co Ltd | Information & communication | 2026 |
| Laurence S Eastham Limited | Information & communication | 2003 |
| Law Builders Ltd | Construction | 2022 |
| LCM Hairdressing Ltd | Other services | 2015 |
| LD Heating & Plumbing Ltd | Construction | 2022 |
| LE Mela Limited | Manufacturing | 2021 |
| Leafy Ltd | Real estate | 2017 |
| LEE Jackson Roofing Ltd | Construction | 2016 |
| Leisure 42 Limited | Real estate | 2022 |
| Lenus Services Ltd | Information & communication | 2017 |
| Leto Investment Management Ltd | Professional & scientific | 2020 |
| Lewis Building Limited | Construction | 2013 |
| Leyline Roofing & Leadwork Specialists Ltd | Construction | 2024 |
| Lightning Learners Ltd | Education | 2025 |
| Lilygrace Solutions Ltd | Administrative & support | 2015 |
| Little Foxes (OUT of School) Limited | Professional & scientific | 1999 |
| Littlecott Traders Limited | Financial services | 2007 |
| Live Strong Limited | Other services | 2023 |
| Living HER Dreams Ltd | Information & communication | 2025 |
| LJK Property Investments Limited | Real estate | 2017 |
| LML Limited | Manufacturing | 2008 |
| Logged-On Ltd | Information & communication | 2013 |
| Lorncliffe Arts Ltd | Wholesale & retail | 2024 |
| Lorraine Solway Limited | Professional & scientific | 2013 |
| Loxdale-Meade Ltd | Real estate | 2015 |
| LP Construction Ltd | Construction | 2026 |
| LRH Retail Ltd | Wholesale & retail | 2025 |