| LSJ Scaffolding Limited | Construction | 2020 |
| LST Portfolio Ltd | Real estate | 2026 |
| LT-23 Ltd | Financial services | 2025 |
| LTR Electrical Services Limited | Other services | 2014 |
| Luca's Gardening Services Ltd | Administrative & support | 2022 |
| Luchi Enterprises Limited | Professional & scientific | 2024 |
| Lucky Star Investors Ltd | Real estate | 2016 |
| Ludoshe Limited | Wholesale & retail | 2023 |
| LUK Building Services Ltd | Construction | 2014 |
| Luke Mills Garden Design Ltd | Professional & scientific | 2024 |
| Lula Loves Pearl Ltd | Wholesale & retail | 2024 |
| Luliu Limited | Manufacturing | 2022 |
| Lulu's Pre-School Ltd | Education | 2018 |
| Luna Build Ltd | Construction | 2025 |
| Lupu Logistics Ltd | Professional & scientific | 2018 |
| Lushres Global Relocation Ltd | Hospitality | 2022 |
| Lushweddingcollection Ltd | Wholesale & retail | 2026 |
| Luxe Edition Ltd | Construction | 2025 |
| Luxific PPM Ltd | Professional & scientific | 2024 |
| Luximez Ltd | Wholesale & retail | 2021 |
| Luxterra Consulting Ltd | Construction | 2024 |
| LW Auto Deals Limited | Wholesale & retail | 2018 |
| LWH Consulting LLP | | 2021 |
| Lxlyf Ltd | Hospitality | 2025 |
| LY Maxx Retail Limited | Wholesale & retail | 2025 |
| Lyin&Syang Ltd | Wholesale & retail | 2021 |
| Lyonette LLP | | 2026 |
| Lyons Morrison Estates Ltd | Real estate | 2021 |
| Lyons Video Limited | Information & communication | 2007 |
| LZ Enterprises Ltd | Health & social care | 2023 |
| M & M B Limited | Professional & scientific | 2013 |
| M & M Solutions Global Ltd | Real estate | 2021 |
| M & M4 Limited | Health & social care | 2016 |
| M & O Plumbing and Heating Ltd | Construction | 2018 |
| M a Everett Consulting Ltd | Professional & scientific | 2019 |
| M Benedikt Ltd | Administrative & support | 2020 |
| M G Electrical Supplies Limited | Extraterritorial | 2008 |
| M J Parker Contractors Limited | Construction | 2009 |
| M L Inspection Limited | Construction | 2014 |
| M Petkova Limited | Professional & scientific | 2021 |
| M Squared Construction Ltd | Professional & scientific | 2024 |
| M Thomas Building Services Ltd | Construction | 2015 |
| M&3 Ltd | Construction | 2018 |
| M&A DAL Ltd | Extraterritorial | 2025 |
| M&G Staffing Limited | Administrative & support | 2019 |
| M&M&S Property UK Ltd | Real estate | 2023 |
| M&Neta Ltd | Transport & logistics | 2025 |
| M.A Zamani Holding Ltd | Financial services | 2025 |
| M.A. Taplin Limited | Construction | 2001 |
| M.B Williams & Co Ltd | Hospitality | 2025 |
| M.S.N.I Consultancy Ltd | Professional & scientific | 2015 |
| M.Zee Limited | Health & social care | 2023 |
| M3S Property Services Ltd | Construction | 2019 |
| M5 Maintenance Limited | Construction | 2024 |
| MA Digital Limited | Professional & scientific | 2023 |
| MA Larson Limited | Professional & scientific | 2015 |
| MAB Design & Development Limited | Professional & scientific | 2017 |
| Macan Jewellers Ltd | Wholesale & retail | 2017 |
| Mad.Greek Fish Limited | Hospitality | 2017 |
| Madden Gardens Residents Management Company Limited | Households | 2014 |
| Made IT Clothing Ltd | Manufacturing | 2024 |
| Mady Aesthetic Limited | Health & social care | 2025 |
| MAE Visuals Ltd | Information & communication | 2025 |
| Magic Smoke Limited | Information & communication | 2003 |
| Magnacures Limited | Wholesale & retail | 2017 |
| MAH Letting and Management Limited | Real estate | 2017 |
| Maho 1907 Ltd | Administrative & support | 2024 |
| Mahoney Communications Limited | Information & communication | 2002 |
| MAI Serv Ltd | Construction | 2017 |
| MAI Thai Kitchen Ltd | Hospitality | 2019 |
| Maidenhead Gunes Limited | Hospitality | 2025 |
| Main Extract Limited | Professional & scientific | 2021 |
| Maintenance Hive Ltd | Professional & scientific | 2018 |
| Maisa Holdings Ltd | Financial services | 2022 |
| Maison Aubrie Limited | Wholesale & retail | 2025 |
| Maitena Group Limited | Wholesale & retail | 2025 |
| Maivand Lemar Ltd | Health & social care | 2014 |
| MAJ Accountants Ltd | Professional & scientific | 2019 |
| Majestic Builders Ltd | Construction | 2025 |
| Majestic Dawn Properties Limited | Real estate | 2026 |
| Majime Engineering Limited | Construction | 2024 |
| Major Holdings Ltd | Financial services | 2025 |
| Majortech Ltd | Professional & scientific | 2025 |
| Maltings Court Management Limited | Households | 1976 |
| Managed Information Technologies Limited | Information & communication | 1998 |
| Mancave Grooming Salon Ltd | Other services | 2025 |
| Manestream Laboratories Limited | Professional & scientific | 2013 |
| Manestream Limited | Professional & scientific | 2017 |
| Manhattan Plaza Management Limited | Construction | 2015 |
| Mania Drinks Ltd | Wholesale & retail | 2025 |
| Manifest Homes Limited | Construction | 2019 |
| Manista Ltd. | Health & social care | 2022 |
| Manor Rigging Ltd | Arts & recreation | 2024 |
| Manpower Builders Team Ltd | Construction | 2025 |
| Manpower Cleaners Ltd | Administrative & support | 2025 |
| Mansion House Construction Limited | Real estate | 2002 |
| Mansoon Limited | Hospitality | 2016 |
| Manyideas Limited | Real estate | 2003 |
| Manyumbu & Co Holdings Ltd | Financial services | 2023 |
| Manyumbu & Co Ltd | Administrative & support | 2022 |