| Lorraine Kidd Ltd | Administrative & support | 2020 |
| Lots Road Trustees Limited | Professional & scientific | 2023 |
| Lottbridge Motoring Centre Limited | Wholesale & retail | 1999 |
| Lotus Brighton Ltd | Wholesale & retail | 2026 |
| Lou's Sparkle Cleaning Ltd | Administrative & support | 2023 |
| Loud and Clear Audio Visual Installations Limited | Wholesale & retail | 2014 |
| Louiscomm Networks Limited | Information & communication | 2013 |
| Louise Bradbury Mortgages Limited | Financial services | 2007 |
| Love Clean Streets C.I.C | Administrative & support | 2009 |
| Love Welcomes Community Interest Company | Other services | 2018 |
| Love Your Smile by Shiv Limited | Health & social care | 2021 |
| Lovedub Ltd | Wholesale & retail | 2022 |
| Lovell Court (Eastbourne) Management Company Limited | Households | 1985 |
| Loverboy Studio Limited | Other services | 2023 |
| Lovincare Medical Ltd | Health & social care | 2018 |
| LOW Impact Development Limited | Real estate | 2021 |
| Lowcroft Dental Surgery Ltd | Health & social care | 2010 |
| Lowe Medical Services Limited | Health & social care | 2025 |
| Lower and Saxbee Ltd | Wholesale & retail | 2026 |
| Lown Building Contractors Ltd | Administrative & support | 2017 |
| Lowri Hanna Ltd | Health & social care | 2022 |
| LQ4S Ltd | Wholesale & retail | 2023 |
| LQD LDN Ltd | Information & communication | 2021 |
| LRM Investments Limited | Real estate | 2018 |
| LRP Management Services Limited | Construction | 2011 |
| LRR Holdings Limited | Financial services | 2020 |
| LS Collaborations Limited | Professional & scientific | 2021 |
| LS Management South East 2 Limited | Real estate | 2025 |
| LS Management South East Limited | Real estate | 2021 |
| LSA Estates Ltd | Real estate | 2015 |
| LSL Family Law Limited | Professional & scientific | 2017 |
| LSW Secure Limited | Wholesale & retail | 2010 |
| LTF Investments Limited | Real estate | 2015 |
| Lucent Homes Contracts Ltd | Construction | 2019 |
| Lucid 108 Limited | Health & social care | 2022 |
| Lucinda Rogers Limited | Arts & recreation | 2000 |
| Lucky Lane Competitions Limited | Arts & recreation | 2025 |
| Luckys Convenient Store Limited | Wholesale & retail | 2025 |
| Lucmil Ltd | Information & communication | 2021 |
| Lucy Haggis HR Limited | Administrative & support | 2015 |
| Luke Thorley Limited | Health & social care | 2013 |
| Lumens Electrical Ltd | Construction | 2021 |
| Lumi G Designs Ltd | Construction | 2024 |
| Lumielle Group Ltd | Health & social care | 2026 |
| Lumigreen Ltd | Health & social care | 2025 |
| Luminous Cosmetics Ltd | Wholesale & retail | 2026 |
| Luminous Nutrition Limited | Wholesale & retail | 2025 |
| Lumira Group (Bootle Golf) Ltd | Arts & recreation | 2025 |
| Lumira Group Holdings Ltd | Financial services | 2025 |
| Luna Dental Limited | Health & social care | 2020 |
| Lunar G Ltd | Real estate | 2020 |
| Lunar Maria Limited | Information & communication | 2022 |
| Lunar Productions Ltd | Information & communication | 2022 |
| Lunsford Cross Nursery Limited | Wholesale & retail | 2014 |
| Luscious Aesthetics Academy Ltd | Education | 2019 |
| Luscious Aesthetics Limited | Education | 2018 |
| Lushington Chiropractic Limited | Health & social care | 2010 |
| Luxferus Veritas Ltd | Education | 2025 |
| Luxor Wellbeing LLP | | 2023 |
| LVT Installation Specialists Limited | Construction | 2025 |
| LW Ceramics Limited | Construction | 2013 |
| LW Hair Salon Limited | Other services | 2009 |
| Lycoris Limited | Information & communication | 2012 |
| Lydia Mouratidou Ltd | Administrative & support | 2015 |
| Lynfield Court Freehold Limited | Households | 2005 |
| Lynfield Court Management Limited | Households | 1970 |
| Lynfield Investments Ltd | Real estate | 2017 |
| Lynholm Ltd | Real estate | 2024 |
| Lynn's Travel Ltd | Administrative & support | 2002 |
| Lynne Boon Ltd | Professional & scientific | 2014 |
| Lynn’S Cars Ltd | Transport & logistics | 2026 |
| Lénorr Ltd | Wholesale & retail | 2024 |
| M & a Property Rentals Limited | Real estate | 1995 |
| M & D Motor Care Limited | Wholesale & retail | 2015 |
| M & J Catering Sussex Limited | Hospitality | 2015 |
| M & L Construction (Sussex) Limited | Construction | 2014 |
| M & M Singh Ltd | Real estate | 2022 |
| M & SJ Properties Ltd | Real estate | 2020 |
| M and a Property and Build Ltd | Real estate | 2025 |
| M and H Consulting Ltd | Professional & scientific | 2026 |
| M and M Electrical Services Ltd | Energy | 2021 |
| M Ashir Limited | Health & social care | 2017 |
| M C Gallagher Limited | Health & social care | 2019 |
| M D Medical Ltd | Health & social care | 2023 |
| M Fisher UV Consultancy Limited | Information & communication | 2024 |
| M Franks Dental Ltd | Health & social care | 2022 |
| M I B Properties Limited | Real estate | 2002 |
| M Ibrahim Dental Ltd | Health & social care | 2022 |
| M J Cull Electrical Services Ltd | Construction | 2022 |
| M J Kennett Construction Limited | Construction | 2003 |
| M Jaques Groundworks Limited | Construction | 2015 |
| M Lamb Consultancy Ltd | Education | 2024 |
| M Ridgway & SON Ltd | Real estate | 2020 |
| M S Steelwork Limited | Manufacturing | 2012 |
| M Star Quality Ltd | Administrative & support | 2017 |
| M T E M Holdings Limited | Real estate | 2017 |
| M Vosloo Construction Ltd | Administrative & support | 2017 |
| M Y a Consulting Limited | Professional & scientific | 2002 |
| M&H Consulting Ltd | Professional & scientific | 2026 |
| M&J Property Rentals Limited | Real estate | 2025 |