| Looking Good Forever Ltd | Other services | 2021 |
| Loony Garage Limited | Information & communication | 2010 |
| Loop Productions Ltd | Information & communication | 2009 |
| Loralex Haulage Ltd | Transport & logistics | 2021 |
| Lossless AI Limited | Information & communication | 2026 |
| Louie Entertainment Ltd | Information & communication | 2025 |
| Louisa Earley Developing Potential Limited | Administrative & support | 2012 |
| Lounges Supplier Limited | Hospitality | 2025 |
| Love & Marriage Wedding Planner Ltd | Arts & recreation | 2018 |
| Love Productions Limited | Information & communication | 2004 |
| LOW Voices Limited | Information & communication | 2021 |
| LP Discount Auto Limited | Wholesale & retail | 2007 |
| LPD Decorating Ltd | Construction | 2024 |
| LQA Holdings Ltd | Real estate | 2026 |
| Lsrp Limited | Real estate | 2023 |
| Luis & Clarke Building Maintenance Ltd | Construction | 2016 |
| Lumi Clinic Ltd | Health & social care | 2025 |
| Luminara Productions and Events Ltd | Hospitality | 2026 |
| Luqmakesbeats Ltd | Arts & recreation | 2025 |
| Luthra DR Limited | Health & social care | 2021 |
| Luwxwa Ltd | Information & communication | 2022 |
| Luxeline Group Limited | Transport & logistics | 2026 |
| Luxovia Living Ltd | Real estate | 2025 |
| LWDS2015 Ltd | Administrative & support | 2023 |
| LXP Properties Ltd | Real estate | 2024 |
| Lyricraft Media Limited | Information & communication | 2025 |
| Lysander Solutions Limited | Information & communication | 2024 |
| M & a Drive Ltd | Transport & logistics | 2025 |
| M & M Edyta Services Ltd | Information & communication | 2024 |
| M & M Hair Academy Limited | Other services | 2003 |
| M B Curtains Ltd | Manufacturing | 2023 |
| M Brar Properties Ltd | Real estate | 2024 |
| M Construction & Decor Ltd | Construction | 2026 |
| M K Plumbing & Heating Engineers Limited | Construction | 2010 |
| M Support Crew Ltd | Administrative & support | 2024 |
| M Support Ltd | Professional & scientific | 2019 |
| M T C London Limited | Manufacturing | 1996 |
| M&Aa Ltd | Real estate | 2024 |
| M&B Recruitment Ltd | Administrative & support | 2025 |
| M&M Tansport Ltd | Transport & logistics | 2025 |
| M&P Stays Ltd | Administrative & support | 2025 |
| M. Winward Brickwork Services Ltd | Construction | 2008 |
| M.A.M Brothers Ltd | Hospitality | 2018 |
| M.O.K Construction Services Limited | Construction | 2024 |
| M.Sparkles Ltd | Wholesale & retail | 2025 |
| M46 Properties Ltd | Real estate | 2019 |
| M5RAMA Limited | Construction | 2026 |
| MA Hotel Management Limited | Professional & scientific | 2008 |
| MA Investments Holdings Ltd | Financial services | 2021 |
| Maars Innovation Ltd | Real estate | 2025 |
| Maaz Kettering Limited | Hospitality | 2025 |
| MAB Construction Limited | Professional & scientific | 2024 |
| MAB Consult Ltd | Professional & scientific | 2026 |
| MAC Valeting Ltd | Wholesale & retail | 2023 |
| Macrights Limited | Construction | 2015 |
| Macury Ltd | Construction | 2020 |
| Madhan Solutions Ltd | Real estate | 2025 |
| Madhan Superstore Limited | Wholesale & retail | 2025 |
| Madibor Ltd | Transport & logistics | 2023 |
| Maeve Clinic Ltd | Other services | 2026 |
| MAG Housing Limited | Hospitality | 2025 |
| Magic Lamps International Limited | Wholesale & retail | 2021 |
| Mahadev Roofing & Construction Ltd | Construction | 2025 |
| Mahanaim Trading Ltd | Administrative & support | 2021 |
| Mahi Consultants Limited | Information & communication | 2010 |
| Mahit Limited | Professional & scientific | 2019 |
| Maisonettes (Sutton Hall) Residents Association Limited | Households | 1969 |
| MAK Group LDN Limited | Construction | 2022 |
| MAK Investments LDN Limited | Construction | 2022 |
| MAK London Construction Ltd | Construction | 2024 |
| Mak's MOT Centre Ltd | Wholesale & retail | 2010 |
| Make UK Healthy Again Ltd | Wholesale & retail | 2025 |
| Makeup by Meera Ltd | Other services | 2024 |
| Makh Builder Ltd | Construction | 2020 |
| Malabar Salkara Limited | Hospitality | 2025 |
| Malak Land Ltd | Hospitality | 2021 |
| Malhi Hair & Beauty Limited | Wholesale & retail | 2024 |
| Malhotra Property Services Ltd | Real estate | 2020 |
| Maligee Limited | Administrative & support | 2018 |
| Malik Instruments Ltd | Wholesale & retail | 2018 |
| Malik UK Traders Ltd | Wholesale & retail | 2019 |
| Malikz Supplies Limited | Wholesale & retail | 2026 |
| Malin Properties Limited | Real estate | 2015 |
| Malt Room Bars Limited | Hospitality | 2016 |
| Maltmas Investments Ltd | Real estate | 2018 |
| Maltzone Limited | Extraterritorial | 2012 |
| Malyas Limited | Real estate | 2021 |
| Manage Services Ltd | Extraterritorial | 2018 |
| Mangala Limited | Real estate | 2019 |
| Mani Fittings Wardrobe Ltd | Construction | 2025 |
| Manith Property Ltd | Households | 2025 |
| Mann Solutions Ltd | Information & communication | 2022 |
| Manor Gatehouse Development LLP | | 2020 |
| Manor House Court Management Limited | Households | 1986 |
| Manor Main House Development LLP | | 2023 |
| Manor Stables Development LLP | | 2020 |
| Manzoni Uomo Ltd | Manufacturing | 2019 |
| Maradan Limited | Other services | 2020 |
| Marble Bros Ltd. | Manufacturing | 2012 |
| Marcel Leisure Ltd | Hospitality | 2023 |