| Knight Newman Ltd | Construction | 2026 |
| Knights Mobile Bars Ltd | Hospitality | 2024 |
| Knoa.Store Limited | Manufacturing | 2021 |
| Knockhatch Adventure Park Limited | Arts & recreation | 2002 |
| Knockhatch Forest School Limited | Arts & recreation | 2023 |
| Knockhatch Leisure Limited | Arts & recreation | 1989 |
| Knockhatch SKI School Limited | Arts & recreation | 2023 |
| Knowledge Strategy Infra Limited | Professional & scientific | 2003 |
| Kocare Ltd | Public administration | 2025 |
| Kolab Social Ltd | Information & communication | 2023 |
| Koldfast Limited | Extraterritorial | 2012 |
| Kombuki Ltd | Manufacturing | 2019 |
| Kompass (UK) Limited | Information & communication | 2011 |
| Ksec Group Holdings Ltd | Financial services | 2025 |
| Ksec Worldwide Ltd | Wholesale & retail | 2021 |
| KSR Talent Ltd | Information & communication | 2020 |
| KTW Translations Ltd | Professional & scientific | 2012 |
| KW Building Services. Ltd | Construction | 2025 |
| Kwikfield Construction Limited | Construction | 2020 |
| Kyle Contracting Limited | Agriculture & fishing | 2015 |
| L & L Optical Limited | Wholesale & retail | 1992 |
| L T Property Improvements Limited | Construction | 2016 |
| L.F. Architecture Limited | Professional & scientific | 2004 |
| LA Sante Medical Limited | Health & social care | 2019 |
| Laburnum House (9 Darley Road) Limited | Households | 2008 |
| Lace & Favour Ltd | Wholesale & retail | 2011 |
| Lace DMS Limited | Wholesale & retail | 2004 |
| Lackford Engineering Limited | Wholesale & retail | 2018 |
| Lackford Racing Limited | Wholesale & retail | 2018 |
| Lake Electrical Limited | Energy | 2008 |
| Lake Home AV & Automation Ltd | Administrative & support | 2018 |
| Laleham Inns Ltd | Hospitality | 2018 |
| Lanfen Limited | Construction | 2016 |
| Langford Plumbing and Heating Limited | Construction | 2010 |
| Langham Travel Ltd | Hospitality | 2022 |
| Language Experience Abroad Ltd | Education | 2018 |
| LAR 4 X 4 Limited | Wholesale & retail | 2023 |
| Laramax Ltd | Health & social care | 2019 |
| Lark Property Investors Ltd | Real estate | 2022 |
| Larkin Ceilings and Partitions Limited | Construction | 2019 |
| Laser Developments Ltd | Real estate | 2018 |
| Laughton Hotels Limited | Hospitality | 1999 |
| Laughton Self Store Limited | Other services | 2021 |
| Launchd Ltd | Information & communication | 2026 |
| Laurel Consultancy Limited | Professional & scientific | 2026 |
| Laurence Main Building Services Limited | Construction | 2022 |
| Laurie's Foods Ltd | Manufacturing | 2012 |
| Lavender Care (Sussex) Limited | Health & social care | 2025 |
| Lavender Leaf Limited | Professional & scientific | 2025 |
| Lawes Property Investments Limited | Real estate | 2026 |
| LBP Locksmiths Brighton Ltd | Administrative & support | 2022 |
| LDR Roofing Solutions Limited | Construction | 2019 |
| Leach Bousba Investments Limited | Real estate | 2025 |
| Leach Hardwicke Limited | Real estate | 2013 |
| Lebou Limited | Financial services | 2026 |
| LEE Baldock Public Relations Ltd | Professional & scientific | 2022 |
| LEE Gorringe Ltd | Professional & scientific | 2024 |
| Leeds Surgical Services LLP | | 2024 |
| Legacy X Construction Ltd | Construction | 2024 |
| Lennox Lodge Limited | Health & social care | 2014 |
| Leritage Ltd | Real estate | 2025 |
| Letchfield Properties Limited | Construction | 1991 |
| Lewis Interiors Limited | Construction | 2003 |
| LGD Wealth Management Ltd | Professional & scientific | 2025 |
| Liams DRY Lining Limited | Construction | 2024 |
| Light & SEG Limited | Professional & scientific | 2002 |
| Lighthouse Property Services Ltd | Hospitality | 2026 |
| Lightworkers in Business Limited | Administrative & support | 2018 |
| Like a Fish in Water Ltd | Professional & scientific | 2019 |
| Lildin Limited | Administrative & support | 1985 |
| Lili Stoycheva Limited | Health & social care | 2016 |
| Lillie Property Investments Ltd | Real estate | 2020 |
| Lily of Life Family Services Ltd | Health & social care | 2024 |
| Lime Park Estate Limited | Households | 1985 |
| Lined OUT Limited | Manufacturing | 2015 |
| Linlifetravel Ltd | Administrative & support | 2024 |
| Lisa Hallewell Design Ltd | Administrative & support | 2008 |
| Little Castle Nursery Pevensey Ltd | Health & social care | 2022 |
| Little People Care and Development Ltd | Health & social care | 2019 |
| Little Saffrons Nursery Limited | Public administration | 2011 |
| Live Production Management Limited | Arts & recreation | 2014 |
| Livepilates Limited | Other services | 2026 |
| Livesley Projects Limited | Construction | 2009 |
| Lizbek Limited | Financial services | 2019 |
| LJH Developments Ltd | Construction | 2018 |
| LJT Property Investment Limited | Real estate | 2020 |
| LMT Consulting Services Limited | Professional & scientific | 2014 |
| Lnctw Limited | Other services | 2012 |
| Loetz Property Services LLP | | 2017 |
| LOG6 Engineering Ltd | Professional & scientific | 2019 |
| Logical Business Solutions Ltd | Extraterritorial | 2022 |
| Logijessax Limited | Real estate | 2019 |
| Logos Design Solutions Limited | Administrative & support | 2012 |
| Logpoint Limited | Professional & scientific | 2000 |
| London Analogue Festival Ltd | Arts & recreation | 2013 |
| London Realty Limited | Real estate | 2002 |
| London Scrap Terminal Limited | Wholesale & retail | 2003 |
| Long Nose Puppets Ltd | Arts & recreation | 2015 |
| Look Designs Limited | Manufacturing | 1965 |
| Lothbury Surveyors Limited | Professional & scientific | 2020 |