| Ker-Im-Uk Ltd | Financial services | 2022 |
| Kevixfelin Limited | Real estate | 2019 |
| KH Plumbing & Heating Limited | Construction | 2017 |
| Kidnap and Ransom Expert Limited | Financial services | 2011 |
| Kilato Consulting Ltd | Professional & scientific | 2020 |
| Kind Collection Ltd | Manufacturing | 2020 |
| Kind Jewellery Limited | Manufacturing | 2019 |
| King's Church Uckfield Limited | Other services | 2008 |
| Kitchen Creations Ltd | Manufacturing | 2025 |
| Kitchen Door Workshop Limited | Wholesale & retail | 1995 |
| Kitoff Limited | Wholesale & retail | 2004 |
| Kittiwake Maharaja Limited | Wholesale & retail | 2017 |
| Kixfix Ltd | Construction | 2014 |
| KK Real Estate Investments Ltd | Real estate | 2020 |
| Kkgd Ltd | Professional & scientific | 2018 |
| KMR Incorporations Limited | Real estate | 2024 |
| Knox Growth Ltd | Professional & scientific | 2026 |
| Koflach Engine Developments Ltd | Administrative & support | 2016 |
| KR Expert Limited | Financial services | 2011 |
| KSB Property Solutions Limited | Real estate | 2025 |
| KSV Limited | Extraterritorial | 2003 |
| Kuul Group Limited | Information & communication | 2018 |
| Kuuleats Limited | Hospitality | 2018 |
| LAB 365 Ltd | Manufacturing | 2025 |
| Labtek Limited | Professional & scientific | 2026 |
| Ladbroke Management Services Limited | Professional & scientific | 2002 |
| Lampon & Co Limited | Administrative & support | 1984 |
| Lampon Lets Limited | Real estate | 2018 |
| Lance Warren Associates Limited | Professional & scientific | 2019 |
| Lancelot MOT Ltd | Wholesale & retail | 2017 |
| Lancelot Property Ltd | Real estate | 2021 |
| Lansdowne Risk Limited | Professional & scientific | 2008 |
| Larssen Invest Limited | Financial services | 2019 |
| Latchetts Farm Limited | Manufacturing | 2014 |
| Laughing Fish Isfield Ltd | Hospitality | 2026 |
| Lavender Line Limited | Transport & logistics | 1991 |
| Lavylites World Ltd | Administrative & support | 2019 |
| Lawrence & Lovatt Ltd | Wholesale & retail | 2026 |
| Lawrence House Residents Association Limited | Real estate | 1991 |
| LBM Energy Limited | Information & communication | 2025 |
| LBM Holdco Limited | Financial services | 2025 |
| LBM Property Media Limited | Information & communication | 2023 |
| LE Blount Construction Ltd | Construction | 2026 |
| LE Flamant Ltd | Hospitality | 2024 |
| Lead Sheet Training Academy Limited | Other services | 1926 |
| Lendaly Ltd | Financial services | 2024 |
| Leonards Ingredients LLP | | 2022 |
| Leslie Motors Limited | Wholesale & retail | 2015 |
| Lewes & District Taxis Limited | Transport & logistics | 2005 |
| Lewis Business Media (Arts) Limited | Information & communication | 2015 |
| Liability Expert Limited | Financial services | 2011 |
| Libbu Ltd | Hospitality | 2025 |
| Liberty Resolve Limited | Administrative & support | 2014 |
| License Marketing Ltd | Financial services | 2018 |
| Lignin Enterprises Ltd | Financial services | 2020 |
| Linea-X Ltd | Professional & scientific | 2023 |
| Lion Mews Properties Limited | Real estate | 2001 |
| Liora Security Ltd | Information & communication | 2025 |
| Liquidcanvass Limited | Information & communication | 2012 |
| Little Bees Larder Ltd | Manufacturing | 2025 |
| Little Brook Farm Ltd | Agriculture & fishing | 2005 |
| Littlemeads (Residents' Association) Limited | Households | 1986 |
| Live Global Management UK LLP | | 2017 |
| Live the Adventure BUS Ltd | Hospitality | 2024 |
| Livestreet Ltd | Wholesale & retail | 2018 |
| LJ Business Media Limited | Financial services | 2025 |
| LJ News Limited | Wholesale & retail | 2018 |
| LOB Property Ltd | Construction | 2021 |
| Local GAS Limited | Construction | 2010 |
| Logan Road Ltd | Wholesale & retail | 2026 |
| Lokalista Ltd | Information & communication | 2016 |
| Lollygag Ltd | Real estate | 2019 |
| London Law Group Limited | Professional & scientific | 2008 |
| London Tours Team Ltd | Administrative & support | 2011 |
| Lossea Fell Risk Consultants Limited | Professional & scientific | 2022 |
| Lotus Chemist Limited | Wholesale & retail | 1999 |
| Love and Blessings Ltd | Wholesale & retail | 2015 |
| Love Coco Ltd | Wholesale & retail | 2021 |
| Loxfield Lodge Management Company Limited | Other services | 2014 |
| Loxfield Lodge Trustee Company Limited | Other services | 2012 |
| LT Corp. Ltd. | Information & communication | 2019 |
| Luke Harris Residential Limited | Real estate | 2016 |
| Lumo Advisors Ltd | Professional & scientific | 2025 |
| Lumoscript Ltd | Information & communication | 2018 |
| Luna Store HS Ltd | Wholesale & retail | 2026 |
| Lupa Building and Construction Ltd | Manufacturing | 2023 |
| Lyndendown Limited | Real estate | 1954 |
| Lyon Williams Heating and Plumbing Ltd | Construction | 2025 |
| M & W (Brighton) Limited | Wholesale & retail | 2004 |
| M E Cassam Associates Ltd | Professional & scientific | 1999 |
| M E H Physiotherapy Ltd | Health & social care | 2012 |
| M Music Ltd | Information & communication | 2024 |
| M. P. E. Electronics Limited | Manufacturing | 1986 |
| M2X Ltd | Professional & scientific | 2002 |
| Mackenzie Fine Wines Limited | Professional & scientific | 2024 |
| Madlah MEP Limited | Professional & scientific | 2022 |
| Madway Ltd | Real estate | 2022 |
| Mag-Tronics Ltd | Manufacturing | 2013 |
| Magnetic Attractions Limited | Extraterritorial | 2009 |
| Maia Wolf Ltd | Wholesale & retail | 2022 |