| Knight Property Partnership Limited | Real estate | 2020 |
| Knightcroft Limited | Hospitality | 1990 |
| Knoll Financial Limited | Administrative & support | 2013 |
| KNP Trust Limited | Other services | 2017 |
| Kodebot Limited | Information & communication | 2021 |
| KOP Holdings Cotleigh Road Ltd | Real estate | 2022 |
| Kosar Wholesale Ltd | Wholesale & retail | 2025 |
| KPA Repairs Ltd | Other services | 2025 |
| KR Law Limited | Professional & scientific | 2016 |
| Kreative Global Ltd | Information & communication | 2020 |
| Kripa Shah Optometry Services Ltd | Health & social care | 2021 |
| Krisham Investment Limited | Real estate | 2021 |
| Krishna Property Limited | Real estate | 2020 |
| Krispar Holdings Limited | Financial services | 2021 |
| Krispar Investments & Properties Ltd | Real estate | 1996 |
| Krsh Limited | Administrative & support | 2017 |
| Krsna 108 Limited | Health & social care | 2022 |
| KRV Consultancy Limited | Professional & scientific | 2026 |
| Ks&Ja Properties Ltd | Real estate | 2021 |
| KSC Legal Ltd | Professional & scientific | 2023 |
| Ksgteeth Ltd | Health & social care | 2024 |
| KSM Optical Investments Ltd | Real estate | 2020 |
| KSM Professional Services Ltd | Professional & scientific | 2010 |
| KST Consultants Ltd | Professional & scientific | 2019 |
| Kudos 2024 Ltd | Financial services | 2024 |
| Kumar Property Management LLP | | 2020 |
| Kuradocs Limited | Administrative & support | 2014 |
| Kurumidza Limited | Arts & recreation | 2017 |
| Kustepe Ltd | Hospitality | 2021 |
| Kuyo Foods Limited | Wholesale & retail | 2024 |
| Kwik Film Limited | Professional & scientific | 1994 |
| Kwikside Limited | Real estate | 2014 |
| KYA Developments Ltd | Construction | 2018 |
| Kyra Consultancy Services Limited | Professional & scientific | 2014 |
| Kyrann Holdings Ltd | Financial services | 2025 |
| Kyrann Ltd | Real estate | 2017 |
| Kyrann Real Estate Ltd | Real estate | 2024 |
| L & I Goldea Limited | Wholesale & retail | 2022 |
| L K Development Consultants Limited | Construction | 2024 |
| L T C Film Services Limited | Construction | 2012 |
| L&P Construct Scenery Ltd | Construction | 2022 |
| L&S Services Ltd | Real estate | 2006 |
| L&Y Dental City Limited | Administrative & support | 2022 |
| L&Y Dental Ltd | Health & social care | 2020 |
| L. Philbin Properties Limited | Real estate | 2023 |
| LA Finca Bar and Restaurant Limited | Financial services | 2021 |
| Labyrinth Technology Limited | Wholesale & retail | 2001 |
| LAM Investment Properties Limited | Real estate | 2023 |
| Lamb Flooring Limited | Construction | 2003 |
| Lams Holdings Limited | Real estate | 2020 |
| Landak Ltd | Households | 2023 |
| Landbased Limited | Wholesale & retail | 2001 |
| Landmark Homes (Birmingham) Limited | Health & social care | 2007 |
| Lanika Limited | Wholesale & retail | 2012 |
| Lansdowne Properties Limited | Real estate | 2009 |
| Lapiny Limited | Wholesale & retail | 2022 |
| LAR Education Northwood LLP | | 2012 |
| LAR Education Stanmore LLP | | 2015 |
| LAR Northwood Limited | Education | 2012 |
| Latimer Place (Northwood) Residents Association Limited | Households | 2001 |
| Latimer West Ltd | Professional & scientific | 2021 |
| Latin Tails Ltd | Other services | 2021 |
| Law Cost Consultancy Ltd | Real estate | 2009 |
| Lawlor's the Bakers Ltd | Manufacturing | 2020 |
| Layer IX Ltd | Wholesale & retail | 2026 |
| LBL Estates & Services Limited | Real estate | 2019 |
| LBL UK Services Ltd | Administrative & support | 2022 |
| LDB Creative Ltd | Professional & scientific | 2015 |
| Leapfrog Agency Ltd | Information & communication | 2019 |
| Learningways Ltd | Education | 2026 |
| Lees Holm Limited | Real estate | 2018 |
| Leisure Opportunities Limited | Real estate | 2011 |
| LEO Alliance Ltd | Wholesale & retail | 2016 |
| LEO Fresh Bins Ltd | Administrative & support | 2026 |
| LEO Scorpio Limited | Professional & scientific | 2015 |
| Level Inn Ltd | Administrative & support | 2017 |
| Lewis Payne Consultants Limited | Professional & scientific | 2026 |
| Leyland (MK) Holdings Ltd | Real estate | 2014 |
| Leyland (MK1) Ltd | Real estate | 2014 |
| LFS Safety Limited | Administrative & support | 2018 |
| Lfsl Ltd | Hospitality | 2023 |
| LG Financial Planning Ltd | Financial services | 2025 |
| Lgeg Company Ltd | Transport & logistics | 2018 |
| LGM Holdings (London) Limited | Health & social care | 2025 |
| LHM Consultancy Limited | Information & communication | 2017 |
| Liberty Assets Ltd. | Extraterritorial | 2000 |
| Licentia Live-In Support Ltd | Health & social care | 2023 |
| Lighthouse Property Management Limited | Real estate | 2025 |
| Ligna Trading Limited | Wholesale & retail | 2020 |
| Lily UN Limited | Financial services | 2026 |
| Lina Consultant Services Limited | Administrative & support | 2006 |
| Lina Creative Production Ltd | Information & communication | 2024 |
| Linden Mews Islington Limited | Households | 2003 |
| Linear Building Contractors Limited | Construction | 2011 |
| Lingua Franca Languages Ltd | Professional & scientific | 2025 |
| Lingyue Beauty Industry Ltd | Wholesale & retail | 2023 |
| Linwoods Developments Limited | Real estate | 2003 |
| LIT Legal Limited | Professional & scientific | 2018 |
| Little Bear Investments Limited | Financial services | 2020 |
| Little Nugget Pictures Limited | Information & communication | 2022 |