| JWE Promotions Limited | Arts & recreation | 2023 |
| JWE Property Limited | Real estate | 2025 |
| JWJ Associates Ltd | Professional & scientific | 2008 |
| K.G. Beard Limited | Real estate | 1997 |
| KA Management Limited | Real estate | 1998 |
| Kakadu Systems Limited | Professional & scientific | 1998 |
| Kaladin Limited | Professional & scientific | 2022 |
| Karma One Limited | Information & communication | 2013 |
| Katie Townsend Ltd | Other services | 2013 |
| KB Nails Ltd | Other services | 2026 |
| Keene Properties Limited | Real estate | 2003 |
| Kefford Crosby Facilities Management Limited | Construction | 2011 |
| Kelcath Limited | Professional & scientific | 2004 |
| Kenneth Brian Associates Limited | Administrative & support | 2016 |
| Kenniston & Associates Limited | Real estate | 1990 |
| Kensington Westside NO. 2 Limited | Extraterritorial | 2000 |
| Kent Branding Solutions Ltd | Professional & scientific | 2026 |
| Kentdean Limited | Extraterritorial | 1992 |
| Keras Resources PLC | Administrative & support | 2010 |
| Kertoa Limited | Professional & scientific | 2020 |
| KF Property Limited | Construction | 2026 |
| Kickoff Gaming Ltd | Arts & recreation | 2026 |
| Kidscoach Limited | Education | 2011 |
| Kidson Consulting Limited | Professional & scientific | 2025 |
| Kili Advisors Ltd | Professional & scientific | 2024 |
| Kinda Living Ltd | Real estate | 2025 |
| Kingfisher Property Finance Limited | Professional & scientific | 2020 |
| Kingshill Homes Ltd | Real estate | 2016 |
| Kingswear Homes Limited | Construction | 2006 |
| Kingswear Limited | Real estate | 2017 |
| Kingswear Properties Limited | Construction | 2010 |
| Kinocrat Estates Limited | Extraterritorial | 2012 |
| Kirkrealm Limited | Real estate | 1983 |
| Kits Flat Limited | Real estate | 2014 |
| Kjsl LLP | | 2024 |
| KLG Management Group Ltd | Real estate | 2024 |
| KLG Property Group Ltd | Professional & scientific | 2020 |
| KLV Corporate Finance LLP | | 2025 |
| KMN Media Ltd | Information & communication | 2019 |
| KN & KD Auto Ltd | Administrative & support | 2021 |
| Knightsbury Financial Planning Limited | Financial services | 2026 |
| Knoll House Management Company Limited | Real estate | 2005 |
| Knowle Hill Park Limited | Households | 2016 |
| Konagold Limited | Administrative & support | 2006 |
| KPF Developments Limited | Administrative & support | 2018 |
| KRD Homes Limited | Real estate | 2025 |
| L Livingstone Promotions Limited | Arts & recreation | 2021 |
| L Nails & Beauty Ltd | Other services | 2025 |
| L Stevens Ltd | Administrative & support | 2022 |
| L&P Investments Ltd | Real estate | 2021 |
| L'Oliveto Limited | Real estate | 2023 |
| LA Collina Italy Ltd | Real estate | 2026 |
| Lacroix Estates Limited | Real estate | 2008 |
| Lalys Portfolio Ltd | Real estate | 2012 |
| Lamal Partners Limited | Administrative & support | 2025 |
| Lamarck Limited | Professional & scientific | 2007 |
| Lambourne Drive Management Company Limited | Households | 1993 |
| Landscape Homes Limited | Construction | 2025 |
| Latham Industries Ltd | Professional & scientific | 2024 |
| Law Group Holdings Limited | Financial services | 2026 |
| Law Locations Ltd | Education | 2014 |
| Lawmans (UK) Limited | Construction | 2014 |
| Lawmens Limited | Administrative & support | 1999 |
| Lawmens Property Limited | Professional & scientific | 2000 |
| Lawrence Capital Hermann Limited | Professional & scientific | 2009 |
| LBR8 Limited | Professional & scientific | 2006 |
| LC6 Homes Limited | Real estate | 2026 |
| LE Petit Nantais Limited | Hospitality | 1997 |
| LEA W Ltd | Health & social care | 2023 |
| Leasle Limited | Information & communication | 2018 |
| LEE Yuen Company Limited | Construction | 2025 |
| Legio Augusta Limited | Real estate | 2020 |
| Leigh Place Cobham,Residents Association Limited(The) | Households | 1955 |
| Leighhill Developments Ltd | Real estate | 2025 |
| Leisure People Ltd | Administrative & support | 2002 |
| Leisurejobs.Com Ltd | Administrative & support | 1997 |
| Letap Properties Ltd | Real estate | 2011 |
| Life Skills Ministries Intl Limited | Information & communication | 2023 |
| Lifethyme Ltd | Health & social care | 2025 |
| Lifethyme Nutrition Ltd | Health & social care | 2025 |
| Lilyskye Support Services Limited | Professional & scientific | 2019 |
| Lime Farm Limited | Wholesale & retail | 2023 |
| Lime Property Investments Limited | Real estate | 2011 |
| Lime Tree Thames Ditton Limited | Wholesale & retail | 2005 |
| Limitless Services Group Ltd | Professional & scientific | 2023 |
| Linda Barrow Consulting Ltd | Professional & scientific | 2025 |
| Lindon-Travers Associates Limited | Administrative & support | 2014 |
| Line + Line Ltd | Professional & scientific | 2021 |
| Linked Provisions Limited | Education | 2025 |
| Lisa Estates (ST Albans) Limited | Extraterritorial | 2003 |
| Little Chicks Childminding Limited | Health & social care | 2026 |
| Little Emperor Studios Ltd | Information & communication | 2019 |
| Littleheath Financial Services Limited | Professional & scientific | 2017 |
| Live Less Lonely Ltd | Administrative & support | 2025 |
| Liverpool One Limited | Real estate | 2010 |
| LIZ Cole Limited | Administrative & support | 2017 |
| Lj's Brew & Bites Ltd | Hospitality | 2025 |
| LJK Consultants Limited | Professional & scientific | 2014 |
| LJS Representation Limited | Other services | 2025 |
| LKS Agency Limited | Arts & recreation | 2024 |