| LK Droitwich Limited | Other services | 2019 |
| LLM Developments Limited | Real estate | 2011 |
| LLM Holdings Limited | Real estate | 2022 |
| LLM Properties Limited | Construction | 2019 |
| LMC Utilities Limited | Construction | 2023 |
| LMS Precision (Droitwich) Limited | Administrative & support | 2013 |
| LMS Precision (Holdings) Limited | Administrative & support | 2013 |
| Loch Coull Limited | Financial services | 2016 |
| Lockley Bro's Ltd | Financial services | 2022 |
| Lockley Consultancy Group Limited | Information & communication | 2025 |
| Locus Investments Limited | Real estate | 2020 |
| Lodge House 20 Limited | Administrative & support | 2020 |
| Lodi UK Ltd | Wholesale & retail | 2004 |
| Loewenhert Ltd | Wholesale & retail | 2017 |
| Logica Security Limited | Information & communication | 2019 |
| Logitravel Limited | Administrative & support | 2013 |
| Logos Medical Ltd | Health & social care | 2024 |
| Lok'N Leave Limited | Construction | 2016 |
| Lombardy (Midlands) Group Limited | Financial services | 2011 |
| Lombardy (Midlands) Limited | Wholesale & retail | 2002 |
| Lombardy Management LLP | | 2012 |
| London & Europe Limited | Extraterritorial | 2013 |
| London & Global Limited | Extraterritorial | 2013 |
| London & Midland Limited | Extraterritorial | 2013 |
| London & Midland Securities Limited | Professional & scientific | 2005 |
| London Filmworks Limited | Information & communication | 2010 |
| Long Held Edge Limited | Professional & scientific | 2016 |
| Lorcadia Care Services Limited | Health & social care | 2016 |
| Lotol Limited | Professional & scientific | 2026 |
| Lotus Angel Investments Limited | Real estate | 2019 |
| Lotus House Midlands Ltd | Hospitality | 2022 |
| Louise Young Vocal Coaching Limited | Arts & recreation | 2025 |
| Love Equine Limited | Agriculture & fishing | 2016 |
| Love Logs Limited | Wholesale & retail | 2020 |
| Lovelife Music Limited | Wholesale & retail | 2022 |
| Loveplaza Ltd | Transport & logistics | 2019 |
| LOW 6 Limited | Information & communication | 2017 |
| Lower Froyle Ltd | Administrative & support | 2022 |
| Lowy Hamilton Artists Limited | Arts & recreation | 2008 |
| LP Carpentry and Installations Ltd | Construction | 2025 |
| LP Productions Ltd | Arts & recreation | 2023 |
| LPE Designs Ltd | Professional & scientific | 2020 |
| Lpex International Limited | Professional & scientific | 2009 |
| LSE Operations Ltd | Arts & recreation | 2026 |
| LSS Asset Management Ltd | Financial services | 2009 |
| Lucas Hydraulics Limited | Real estate | 2000 |
| Lucerne Amersham Limited | Administrative & support | 2022 |
| Lucerne Holdings Limited | Administrative & support | 2017 |
| Lumacett Holdings Limited | Administrative & support | 2020 |
| Luminare Property Limited | Administrative & support | 2022 |
| Lunch Box Limited | Real estate | 1951 |
| Luxury Latchi Villas Limited | Hospitality | 2014 |
| Luxus Projects Ltd | Wholesale & retail | 2021 |
| LVF Ltd | Hospitality | 2024 |
| LYM Holdings Limited | Financial services | 2021 |
| Lyons Group Ltd | Real estate | 2018 |
| Lyons Investments Limited | Administrative & support | 2018 |
| Lyons Worx Ltd | Construction | 2025 |
| Lyras Medical Ltd | Health & social care | 2016 |
| LZM Properties Ltd | Real estate | 2025 |
| M & H Electrical Services Ltd | Construction | 2022 |
| M & M Holdings Limited | Real estate | 2004 |
| M & O Cole Ltd | Financial services | 2024 |
| M & R Medical Record Collation Ltd | Professional & scientific | 2023 |
| M & S Emery Property Limited | Real estate | 2024 |
| M & S Motor Vehicle Services Limited | Wholesale & retail | 2009 |
| M J Fitter Services Ltd | Construction | 2026 |
| M Lock Investments Limited | Financial services | 2021 |
| M R Allen Limited | Construction | 1997 |
| M W Electrical Services (UK) Limited | Construction | 2006 |
| M&B Duct Solutions Ltd | Administrative & support | 2023 |
| M&Dk Property Ltd | Real estate | 2023 |
| M.A.R Roofing Ltd | Construction | 2025 |
| M.C.D. Company. Ltd | Wholesale & retail | 2018 |
| M.E.R. Services Limited | Manufacturing | 2004 |
| M3 Floodtec Holdings Limited | Financial services | 2022 |
| M3 Global Flood Technologies Limited | Manufacturing | 2018 |
| M3K Buildings Limited | Real estate | 2026 |
| M3K Medical Limited | Health & social care | 2016 |
| Macarthur Barstow & Gibbs Limited | Professional & scientific | 2011 |
| Mach Accounting Ltd | Professional & scientific | 2013 |
| Macheron Limited | Financial services | 2025 |
| Machine Tech Solutions Limited | Manufacturing | 2005 |
| Macneil's Smoke House Ltd. | Hospitality | 2014 |
| MAD Haulage Ltd | Transport & logistics | 2022 |
| MAD4 Holdings Limited | Financial services | 2024 |
| Madden Industrial Ltd | Manufacturing | 2020 |
| Magic Rooms Accommodation Ltd | Administrative & support | 2014 |
| Magnus & Jensen Design Limited | Administrative & support | 2023 |
| Maiden Family Limited Liability Partnership | | 2011 |
| Make I.T. Simple (2011) Limited | Information & communication | 2010 |
| Make IT Possible Ltd | Transport & logistics | 2019 |
| Making Menopause Work Ltd | Education | 2024 |
| Making Tax Digital Limited | Extraterritorial | 2016 |
| Makinsons Ltd | Information & communication | 2009 |
| Management and Maintenance Solutions Limited | Real estate | 2015 |
| Maple Investments and Professional Services Limited | Real estate | 2022 |
| Mapped Solutions Limited | Information & communication | 2016 |
| Maquarie Projects Ltd. | Administrative & support | 2020 |
| March Trauma Systems Limited | Manufacturing | 2014 |