| Kasozi Wellbeing Ltd | Arts & recreation | 2020 |
| Kasteel Construction Ltd | Construction | 2016 |
| Kate Hempsall PR & Communications Limited | Professional & scientific | 2016 |
| Kayfyhome Improvements Limited | Other services | 2026 |
| KDM Communications Limited | Professional & scientific | 1987 |
| KE Sales Limited | Administrative & support | 2003 |
| Keeley's Holiday Lettings Limited | Real estate | 2020 |
| Keeley's Property Sales Limited | Administrative & support | 2018 |
| Keeleys Lettings Limited | Real estate | 2011 |
| Keep ME Informed Ltd | Information & communication | 2015 |
| Kember Developments Ltd | Real estate | 2025 |
| Key Motor Services Ltd | Wholesale & retail | 2017 |
| KFD Construction Ltd | Construction | 2020 |
| Kickin Kilos Ltd | Health & social care | 2025 |
| Kimba Art Ltd | Administrative & support | 2008 |
| Kimbolton Properties Limited | Real estate | 2005 |
| Kingdom Martial Arts Ltd | Education | 2026 |
| Kingfisher Independent Funeral Services Ltd | Other services | 2010 |
| Kingfisher Timber Products Limited | Wholesale & retail | 1993 |
| Kippenvet Ltd | Professional & scientific | 2018 |
| Kirsty-The-Virtual-Pa Ltd | Professional & scientific | 2024 |
| Kitchen Culture (Cambridgeshire) Ltd. | Construction | 2016 |
| Kite Utility Services Limited | Construction | 2013 |
| KK Service Station Ltd | Wholesale & retail | 2025 |
| Kmec Property Ltd | Real estate | 2026 |
| KN Consultancy Services Limited | Professional & scientific | 2022 |
| Knappers Ltd | Arts & recreation | 2023 |
| Knight Holden Limited | Wholesale & retail | 1991 |
| Knight Holden Properties Ltd | Financial services | 2019 |
| Knives & Faulks Ltd | Hospitality | 2025 |
| Knowles Properties Limited | Real estate | 2016 |
| Kollidan Ltd | Other services | 2021 |
| Konstruktiv International Ltd | Administrative & support | 2021 |
| Kordia IT Ltd | Information & communication | 2026 |
| KP Landscaping & Carpentry Ltd | Construction | 2021 |
| KPS Building and Renovation Ltd | Construction | 2017 |
| KPS Building Ltd | Construction | 2024 |
| Krasnicki Motors Limited | Wholesale & retail | 2026 |
| KRM Carpentry Limited | Construction | 2013 |
| KS Fish & Chips Ltd | Hospitality | 2025 |
| Kssa Limited | Hospitality | 2018 |
| Kudos Equilibria Ltd | Manufacturing | 2018 |
| KVM Consultancy Ltd | Construction | 2012 |
| L & P Chess Limited | Real estate | 1993 |
| L Beauty Studio Ltd | Other services | 2019 |
| L Rose Limited | Hospitality | 2025 |
| L&L Dale Properties Limited | Real estate | 2025 |
| L. Sykes (Abbotsley) Limited | Wholesale & retail | 1965 |
| L.Sykes Farmers Limited | Agriculture & fishing | 1965 |
| L2S GEN Ltd | Energy | 2024 |
| LA Brutine Limited | Information & communication | 2016 |
| LA Maison DE Grand-Mere Limited | Wholesale & retail | 2010 |
| Lacud Ltd | Other services | 2024 |
| Ladaras Ltd | Other services | 2024 |
| Lakeside Kitchen Ltd | Hospitality | 2017 |
| Lalac Ltd | Professional & scientific | 2024 |
| Lanbrook Estates Ltd | Construction | 2003 |
| Lanbrook Property Services Ltd | Real estate | 2018 |
| Land Promotions and Development Ltd | Professional & scientific | 2017 |
| Landsgate B2L Property 1 Limited | Real estate | 2023 |
| Landsgate B2S Property 1 Limited | Real estate | 2023 |
| Landsgate Capital Holdings Limited | Financial services | 2023 |
| Landsgate Property Brokers 1 Limited | Real estate | 2023 |
| Landsgate Property Management 1 Limited | Real estate | 2023 |
| Landsgate R2R Property 1 Limited | Real estate | 2023 |
| Lane Contracts and Trading Ltd | Agriculture & fishing | 2022 |
| Langan London Ltd | Professional & scientific | 2014 |
| Lapis Horizons Limited | Professional & scientific | 2026 |
| Lapme Limited | Information & communication | 2008 |
| Lateral Cognition Ltd | Information & communication | 2010 |
| Laughter Craft Comedy Limited | Administrative & support | 2024 |
| Laura Cook Creative Ltd | Professional & scientific | 2021 |
| Laysmart Utilities Ltd | Real estate | 2026 |
| Lazzik Ltd | Other services | 2024 |
| LC Bar Ltd | Hospitality | 2025 |
| LE French Bean Limited | Professional & scientific | 2012 |
| Lebon Consulting Ltd | Information & communication | 2022 |
| Ledsupplies Limited | Wholesale & retail | 2012 |
| Leech Performance Partners Limited | Professional & scientific | 2018 |
| Legal Talent Solutions Limited | Administrative & support | 2025 |
| Lekky Lytes Ltd | Manufacturing | 2026 |
| Leksing Limited | Professional & scientific | 2007 |
| Lenbeth Consulting Ltd | Professional & scientific | 2014 |
| LET Them Ltd | Professional & scientific | 2025 |
| Lewis Masonic Limited | Information & communication | 2021 |
| LEX Engineering UK Ltd | Administrative & support | 2011 |
| LEX Proprius Ltd | Professional & scientific | 2023 |
| LFS Automotive Ltd | Administrative & support | 2023 |
| Liba Energy Limited | Manufacturing | 2020 |
| Liberty Windows Limited | Construction | 2025 |
| Life Energetics Ltd | Administrative & support | 2021 |
| Lifelong Kitchens Limited | Construction | 2013 |
| Lifeplus Europe Limited | Wholesale & retail | 1996 |
| Lifeplus Limited | Wholesale & retail | 2018 |
| Lightspeed Solar Ltd | Wholesale & retail | 2024 |
| Lightworks Electrical Limited | Construction | 2016 |
| Lightworks Lettings Ltd | Real estate | 2025 |
| Like Your Smile Limited | Health & social care | 2025 |
| Lilac James Co. Ltd | Professional & scientific | 2008 |
| Lillyvale 2 Ltd | Wholesale & retail | 2011 |