| Keep IT Moving Auto Repairs Ltd | Wholesale & retail | 2026 |
| Kefco Group Limited | Financial services | 2021 |
| Kefco Sales Limited | Hospitality | 1972 |
| Keith Vowles Agencies Limited | Wholesale & retail | 2019 |
| Kelly Castle Cricket Academy Ltd | Education | 2025 |
| Kemnor Limited | Professional & scientific | 2010 |
| Kendricks of Rochford Limited | Other services | 2022 |
| Kenect (South Essex) Limited | Administrative & support | 2023 |
| Kestrel Lodge Property Ltd | Financial services | 2024 |
| Khafabi Ltd | Wholesale & retail | 2024 |
| Kibble Close Residents Association Limited | Households | 2012 |
| Kidd Art Consultancy Limited | Wholesale & retail | 2021 |
| Kiga Limited | Wholesale & retail | 1997 |
| Kildun Carpentry & Joinery Ltd | Construction | 2015 |
| Kildun Developments Ltd | Real estate | 2022 |
| Kilnwood Advisors Limited | Professional & scientific | 2017 |
| Kind Cups Ltd | Administrative & support | 2019 |
| King Group Essex Limited | Transport & logistics | 2026 |
| Kings and Conquerors Limited | Construction | 2014 |
| Kinlab Ltd | Health & social care | 2024 |
| Kiruto Ltd | Wholesale & retail | 2024 |
| Kite Smart Living Ltd | Information & communication | 2019 |
| Kits Consultancy Ltd | Professional & scientific | 2022 |
| Kkbt Ltd | Wholesale & retail | 2021 |
| Klas Tech Ltd | Wholesale & retail | 2015 |
| KM2 Ethical Finance Ltd | Professional & scientific | 2019 |
| KMH Property Ltd | Real estate | 2020 |
| KMS Building Maintenance Ltd | Construction | 2021 |
| Knight Construction & Building Refurbishments Ltd | Construction | 2025 |
| KNIGHT360 Limited | Professional & scientific | 2010 |
| Knightly Construction Ltd. | Construction | 2021 |
| KNM Homes Ltd | Real estate | 2020 |
| KNM Technologies Ltd | Information & communication | 2017 |
| Knutsford Software Limited | Information & communication | 1996 |
| Kobyte Limited | Information & communication | 2011 |
| KRG Data Analytics Limited | Professional & scientific | 2020 |
| KRG Enterprise Solutions Ltd | Construction | 2022 |
| KRG Maintenance Ltd | Construction | 2025 |
| KSC SE Construction Ltd | Construction | 2017 |
| Ksss Investments Ltd | Real estate | 2022 |
| KUA Limited | Hospitality | 2026 |
| Kudos Carpentry Limited | Construction | 2010 |
| Kudos Films Ltd | Arts & recreation | 2021 |
| KW Property Sourcing Ltd | Real estate | 2020 |
| Kyanite Services Ltd | Construction | 2023 |
| L & K Interiors Ltd | Construction | 2018 |
| L & L Cleaning Services Limited | Administrative & support | 1991 |
| L & M Y Rogerson Limited | Other services | 2002 |
| L G Software Solutions Limited | Information & communication | 2013 |
| L J Management Services Limited | Professional & scientific | 2006 |
| L.A.T. Construction Ltd | Construction | 2014 |
| LAA Creative Limited | Professional & scientific | 2024 |
| Lacey Group Holdings Limited | Financial services | 2022 |
| Lacey Investments (London) Limited | Real estate | 2022 |
| Ladebak Limited | Wholesale & retail | 2009 |
| Lady Barber Luxury Male Grooming Ltd | Extraterritorial | 2019 |
| Laffar & Sons Ltd | Real estate | 2023 |
| LAG Investments Limited | Financial services | 2023 |
| Lance Neville Limited | Construction | 2014 |
| Land Pirates Gardens & Tree Care Limited | Administrative & support | 2023 |
| Lansman Consulting Ltd | Manufacturing | 2025 |
| Latchingdon Park Management Company Limited | Households | 2017 |
| Launchcharts Ltd | Manufacturing | 2025 |
| Launchpad Solutions Ltd | Manufacturing | 2026 |
| Laurel Court Residents Association Limited | Households | 2011 |
| Lawesy Ltd | Financial services | 2026 |
| Lawrie Park Limited | Real estate | 1979 |
| Lawsons Surveying Ltd | Professional & scientific | 2024 |
| Laygrix Associates Limited | Construction | 2019 |
| Laygrix Properties Limited | Real estate | 2023 |
| LDG Services Ltd | Construction | 2012 |
| Ldlsales Ltd | Wholesale & retail | 2025 |
| Leaseholders United.Com Limited | Information & communication | 2001 |
| Legacy CRE8TIVE Ltd | Wholesale & retail | 2024 |
| Legacy Strategies Limited | Professional & scientific | 2016 |
| Legacy Timekeepers Ltd | Other services | 2024 |
| Legio XX Limited | Administrative & support | 2019 |
| Leigh Glow Laser Hair Removal Ltd | Wholesale & retail | 2021 |
| Leighden Haulage Limited | Transport & logistics | 2015 |
| Lemon Witch Events Limited | Hospitality | 2019 |
| Lemon Witch Limited | Hospitality | 2019 |
| Lersta Properties Ltd | Real estate | 2024 |
| Lewis Durham Capital Ltd | Professional & scientific | 2024 |
| Li'Ajdaadi Ltd. | Hospitality | 2025 |
| Liahona Ltd | Professional & scientific | 2024 |
| Lime Grove Bardney Management Company Ltd | Households | 2024 |
| Lina Construction Design & Build Ltd | Construction | 2016 |
| Lina Construction Ltd | Construction | 2014 |
| Lincoln Court Manco Limited | Administrative & support | 2024 |
| Lindberg Block Management Ltd | Real estate | 2018 |
| Lindberg Portfolio Limited | Real estate | 2025 |
| Linden Lodge Leisure Limited | Education | 2025 |
| Lindsey Booth Consulting Limited | Professional & scientific | 2010 |
| Lings Electrical Services Limited | Construction | 2025 |
| Links Court Freehold (Southend) Limited | Households | 1973 |
| Linxit Limited | Information & communication | 2001 |
| Lion Carpentry & Joinery Ltd | Construction | 2022 |
| Lion Creek Imports Ltd | Wholesale & retail | 2021 |
| Lionheart Ventures Limited | Households | 2025 |
| Lite 'N' UP Ltd | Construction | 2016 |