| Lincoln Court Residents Limited | Households | 1993 |
| Lincoln Park LLP | | 2008 |
| Linguabite Ltd | Information & communication | 2008 |
| Lister Inhealth Limited | Professional & scientific | 2000 |
| Little Explorers Limited | Education | 1998 |
| Little House Pilates Limited | Arts & recreation | 2024 |
| Littlegood Limited Partnership | | 2022 |
| Littlegood Ventures Limited | Wholesale & retail | 2023 |
| LIV Lindley Ltd | Manufacturing | 2017 |
| Livbetter Ltd | Health & social care | 2024 |
| Live Living Ltd | Real estate | 2020 |
| Livingstone Aviation Ltd | Administrative & support | 2021 |
| LOA Properties Limited | Real estate | 2018 |
| Load Reformer Limited | Arts & recreation | 2025 |
| Lobera Consulting Ltd | Professional & scientific | 2021 |
| Locke Holdings Limited | Real estate | 2025 |
| Locker Days Limited | Wholesale & retail | 2018 |
| Lockett Design and Engineering Ltd | Professional & scientific | 2023 |
| Loco Loco Ltd | Real estate | 2012 |
| Locus London Ltd | Hospitality | 2017 |
| Logi Homes Ltd | Construction | 2015 |
| London Cladding Ltd | Construction | 2023 |
| London Street Brasserie Holdings Limited | Financial services | 2018 |
| Long Rock Property Limited | Real estate | 2000 |
| Long Wood Drive Management Limited | Households | 1967 |
| Longacre Turkey Farm Limited | Real estate | 1961 |
| Looe Glamping Limited | Hospitality | 2021 |
| Love Katie Ltd | Wholesale & retail | 2023 |
| Love Lane Holdings Ltd | Professional & scientific | 2019 |
| Love London Living Limited | Real estate | 2017 |
| Love Underdogs | Professional & scientific | 2012 |
| Lower Sauncey Wood Management Company Limited | Households | 2021 |
| LOX Security Limited | Other services | 2010 |
| Loyal Oak Partners Limited | Professional & scientific | 2025 |
| LPA Process Limited | Professional & scientific | 2007 |
| LPS Facilities Limited | Other services | 2013 |
| LQX Ltd | Arts & recreation | 2025 |
| Lucas Garcia Studio Ltd | Professional & scientific | 2026 |
| Lucas Place Limited | Real estate | 2020 |
| Lucky Panda Investments Limited | Real estate | 2022 |
| Lucroband Limited | Information & communication | 2017 |
| Lunanueva Ltd | Hospitality | 2024 |
| Lunar Fitness Ltd | Information & communication | 2025 |
| Lunnon & Tilbury Limited | Construction | 2006 |
| Luscinia Developments Ltd | Construction | 2018 |
| Luscinia Homes Ltd | Construction | 2018 |
| Luxe Asset Finance Limited | Financial services | 2019 |
| Luxe Escapes Ltd | Administrative & support | 2024 |
| Luxiniti Ltd | Administrative & support | 2021 |
| LW Surveying & Design Ltd | Professional & scientific | 2025 |
| Lydford Advisory Limited | Administrative & support | 2013 |
| Lynne Chapman Reproductive Health (Lcrh) Ltd | Health & social care | 2019 |
| M F Jarrett & Sons Limited | Administrative & support | 2002 |
| M Hughes Consulting Limited | Education | 2020 |
| M P Works Ltd | Administrative & support | 2023 |
| M&J Dwellings Ltd | Real estate | 2025 |
| M.A.Rance & Company Limited | Real estate | 1944 |
| M.F. Penfold Limited | Hospitality | 1964 |
| M.J. Owen Limited | Professional & scientific | 1994 |
| M.Markiewicz Ltd | Construction | 2016 |
| M40 4X4 Ltd | Wholesale & retail | 2025 |
| M4HEALTH Ltd | Health & social care | 2018 |
| Mabrouka Events Limited | Administrative & support | 2001 |
| Macdev Ltd | Professional & scientific | 2014 |
| Machekanyanga Home Limited | Real estate | 2024 |
| Macleeds & Co. Ltd | Construction | 2020 |
| Macleeds (ST Martins) LLP | | 2021 |
| Macone Consulting Limited | Professional & scientific | 2026 |
| Macrotech (London) Limited | Information & communication | 2023 |
| MAD Cat Props Ltd. | Manufacturing | 2014 |
| Made UP Systems Limited | Professional & scientific | 2022 |
| Maegter Limited | Construction | 2012 |
| Magenta Gym Limited | Arts & recreation | 2022 |
| Maggiore Restaurants Limited | Hospitality | 1999 |
| Magna Gardens Management Company Limited | Households | 2023 |
| Maheto Limited | Professional & scientific | 2015 |
| Maiden Lane Vaults Limited | Administrative & support | 2017 |
| Maiden London Limited | Hospitality | 2007 |
| Maidenhead Sailing Club Limited | Arts & recreation | 2026 |
| Majestic VIP Chauffeurs Ltd | Transport & logistics | 2026 |
| Major Point Limited | Professional & scientific | 2020 |
| Maker London Limited | Professional & scientific | 2014 |
| Makeup-Effects Limited | Hospitality | 2012 |
| Makeuptagg Ltd | Other services | 2025 |
| Making Smiles 2 Limited | Real estate | 2019 |
| Makingsmiles Ltd | Health & social care | 2014 |
| Malthouse Properties Ltd | Real estate | 2020 |
| Mamamoosh Ltd | Wholesale & retail | 2013 |
| Manawatu Management Company (Beaconsfield) Limited | Households | 1991 |
| Manitos Limited | Other services | 2024 |
| Manlet Group Holdings Limited | Construction | 1982 |
| Manor Chiltern Limited | Real estate | 1999 |
| Manor Farm (Seer Green) Management Company Limited | Households | 1976 |
| Manor House Kynance Ltd | Construction | 2025 |
| Manor House Ledborough Lane Management Company Ltd | Households | 2023 |
| Manor Place (Monicas Lodge) Management Company Limited | Households | 2013 |
| Manor Student Villages Ltd | Extraterritorial | 2015 |
| Manor Villages Limited | Real estate | 2005 |
| Manrin Limited | Real estate | 2021 |
| MAP Solar Limited | Administrative & support | 2013 |