| KPJ2 Investments Limited | Real estate | 2025 |
| KR & JEJ Limited | Real estate | 2024 |
| Kris Hospitality Co. Limited | Hospitality | 2012 |
| Kromp Transport Ltd. | Transport & logistics | 2017 |
| Kuduriver Gundogs Ltd | Wholesale & retail | 2024 |
| Kurty Interbiz Ltd | Wholesale & retail | 2006 |
| KZ Limited | Extraterritorial | 2007 |
| L a - Clinic Limited | Other services | 2018 |
| L Best Homes Ltd | Extraterritorial | 2025 |
| L H Equites LLP | | 2025 |
| L Hastie Engineering Ltd | Professional & scientific | 2013 |
| L Squared Partnership Ltd | Professional & scientific | 2017 |
| L&J Collectables Limited | Wholesale & retail | 2024 |
| L-J Alpha Ltd | Professional & scientific | 2017 |
| L.I.F.ECOACH121.COM Limited | Education | 2024 |
| LA Pubs (Cambs) Limited | Hospitality | 2026 |
| Lafabricadelosrecuerdos Ltd | Administrative & support | 2023 |
| Lambourn Equine Clinic Limited | Professional & scientific | 2011 |
| Lambourn Equine Hospital Limited | Professional & scientific | 2011 |
| Landlord Check Limited | Other services | 2025 |
| Landmark London Scaffolding Limited | Construction | 2024 |
| Landmark Scaffolding Limited | Administrative & support | 1998 |
| Lantern & Larks Limited | Hospitality | 2008 |
| Lantern Property Development Ltd | Construction | 2023 |
| Lanwades Garden Ltd | Hospitality | 2014 |
| Lanwades Hall LLP | | 2016 |
| Larke Aeronautics Limited | Other services | 2023 |
| Larpent Bloodstock Limited | Agriculture & fishing | 2023 |
| Last Word Apparel Ltd | Wholesale & retail | 2014 |
| Latham Ventures Limited | Information & communication | 2026 |
| Laureate Estates LLP | | 2008 |
| Lauren RAE Coaching Ltd | Other services | 2022 |
| Lavender Blue Events Ltd | Construction | 2026 |
| Lawdene Limited | Financial services | 1999 |
| Lawlock Limited | Real estate | 1999 |
| LB Medical Aesthetics Ltd | Health & social care | 2018 |
| LBM Plumbing and Heating Limited | Construction | 2019 |
| LCM Holiday Lets Ltd | Real estate | 2022 |
| Lcpc Developments Limited | Construction | 2017 |
| LD Limited | Extraterritorial | 2014 |
| LDM Industries Ltd | Construction | 2022 |
| LDS Bloodstock Limited | Agriculture & fishing | 2022 |
| Learnly Ltd | Education | 2020 |
| Legalsway Ltd | Wholesale & retail | 2023 |
| Leisure & Commercial Direct Ltd | Wholesale & retail | 2025 |
| Leisure Lists Limited | Information & communication | 2018 |
| Lemontree Lettings & Management Ltd | Real estate | 2009 |
| LEO S Financial Services Limited | Professional & scientific | 2022 |
| Level UP Print Limited | Manufacturing | 2020 |
| Levels Pizza Ltd | Hospitality | 2026 |
| Lewa Hair Ltd | Other services | 2018 |
| Lewa Limited | Other services | 2023 |
| LF Ltd | Extraterritorial | 2009 |
| LGA Growth Ltd | Professional & scientific | 2025 |
| LGS Homes (Suffolk) Limited | Construction | 2022 |
| LH Leisure Caravans Ltd | Wholesale & retail | 2020 |
| LI Ltd | Extraterritorial | 2008 |
| Libate Fine Wines Ltd | Wholesale & retail | 2021 |
| Libra Scale Company Limited | Wholesale & retail | 1982 |
| Lidgate Star (2015) Limited | Hospitality | 2015 |
| Lifestuff Ltd | Health & social care | 2014 |
| Lifestyle Media Group Limited | Wholesale & retail | 1999 |
| Lightcure Limited | Health & social care | 2023 |
| Lightmanor Limited | Real estate | 2002 |
| Ligna Consultancy Ltd | Professional & scientific | 2016 |
| Lily Event Ltd | Hospitality | 2025 |
| Lioraink Ltd | Other services | 2025 |
| Lisaleen Ltd | Real estate | 2018 |
| Little Buck Limited | Professional & scientific | 2000 |
| Little Buds Pre-School Limited | Education | 2008 |
| Little Life Learning Ltd | Wholesale & retail | 2024 |
| LL Advisory Limited | Professional & scientific | 2024 |
| LL Ltd | Extraterritorial | 2021 |
| LM Ltd | Extraterritorial | 2009 |
| LM Print Services Ltd | Manufacturing | 2023 |
| LMS (BSE) Limited | Construction | 2025 |
| LO Limited | Extraterritorial | 2008 |
| Locally Grown Plants Limited | Information & communication | 2010 |
| Lodgeday Commercial Limited | Construction | 1988 |
| Lodgeday Properties Limited | Construction | 1984 |
| Loft Solutions Building Contractors Ltd | Construction | 2025 |
| London Tech Ltd | Wholesale & retail | 2025 |
| Longholes Farm Ltd | Agriculture & fishing | 2021 |
| Longlands Close Management Company Limited | Real estate | 2006 |
| Lords Healthcare Ltd | Administrative & support | 2012 |
| Lordship Stud Limited | Agriculture & fishing | 1997 |
| Loud FOX Ltd | Professional & scientific | 2026 |
| Lounalao 110 Limited | Financial services | 2024 |
| Love Food Packaging Limited | Administrative & support | 2026 |
| Loveridge Estates Ltd | Real estate | 2022 |
| Loxwood Consulting Limited | Professional & scientific | 2018 |
| LP Ltd | Extraterritorial | 2008 |
| LR Design Limited | Professional & scientific | 2021 |
| LS Lean Consulting Ltd | Professional & scientific | 2020 |
| LSZ Engineering Ltd | Manufacturing | 2016 |
| Lucas Close (Burwell NO.2) Management Company Limited | Households | 2026 |
| Ludo Ltd | Information & communication | 2024 |
| Ludutrades Ltd | Wholesale & retail | 2026 |
| Lundy Jones Ltd | Administrative & support | 2025 |
| Lunesdale Consulting Limited | Professional & scientific | 2016 |