| Little Star Education Limited | Education | 2022 |
| Live Global Sport Management Ltd | Other services | 2024 |
| Living and Mobility Care Ltd | Wholesale & retail | 2013 |
| LMR Construction Ltd | Construction | 2024 |
| LN & Co South Limited | Construction | 2023 |
| Local BOY Holdings Limited | Water & waste | 2023 |
| Local Financial Advisor Ltd | Administrative & support | 2011 |
| Local I.G Landscapes Limited | Administrative & support | 2011 |
| Local Places Consultancy Limited | Professional & scientific | 2025 |
| Lochside Consultancy Ltd | Professional & scientific | 2024 |
| Lockton Family Office Ltd | Financial services | 2025 |
| Lola’S Lounge Limited | Other services | 2025 |
| London & Bohemia Properties Limited | Real estate | 2014 |
| Long Play Holdings Ltd | Financial services | 2020 |
| Long Wealth UK Limited | Wholesale & retail | 2020 |
| Long White Cloud Ltd | Professional & scientific | 2024 |
| Longevity Biotech Ltd | Professional & scientific | 2020 |
| Longthorpe Growth Limited | Real estate | 2019 |
| Loughran Bros Limited | Wholesale & retail | 1999 |
| Louis' Kitchen Limited | Hospitality | 2011 |
| Lower Bray Limited | Financial services | 2025 |
| LP Real Estate Holdings Limited | Real estate | 2025 |
| LPJ Ltd | Health & social care | 2022 |
| LS Racing Limited | Administrative & support | 2023 |
| LTF Ventures Ltd | Real estate | 2022 |
| LU & Co. Accountants Limited | Professional & scientific | 2008 |
| Lucas Bridge Business Park Management Company Limited | Households | 2008 |
| Lucidity Change Consultancy Ltd | Professional & scientific | 2026 |
| Ludgate Design Solutions Limited | Professional & scientific | 2017 |
| Lumber Lane Limited | Households | 2021 |
| Luna Waste Services Ltd | Water & waste | 2019 |
| LUNA8 Limited | Administrative & support | 2019 |
| Lundazi Automotive Consultants Limited | Professional & scientific | 2020 |
| Luxury Nails Towcester Ltd | Other services | 2025 |
| Lvrecruitment Ltd | Administrative & support | 2020 |
| Lydon Contracting Ltd | Construction | 1999 |
| Lyra Lettings Limited | Real estate | 2017 |
| M & J Stilp Limited | Construction | 2001 |
| M Leonard Consulting Limited | Professional & scientific | 2025 |
| M N E Cranage Ltd | Construction | 2013 |
| M&M The-Kitchen Ltd | Hospitality | 2025 |
| M.A.S.S. Health Ltd | Wholesale & retail | 2015 |
| Mabec (Lincoln) Ltd | Real estate | 2026 |
| Mabec (Nottingham) Limited | Real estate | 2010 |
| Machinery Plant Services Limited | Manufacturing | 1972 |
| Mackellar Racing Ltd | Transport & logistics | 2016 |
| MAD Croc Karting UK Ltd | Arts & recreation | 2015 |
| Made Wise Ltd | Arts & recreation | 2011 |
| Magna Rose Ltd | Professional & scientific | 2025 |
| Maid UP Ltd | Information & communication | 2016 |
| Maidford Service Station Limited | Wholesale & retail | 2022 |
| Mailcrafters UK Ltd | Manufacturing | 2016 |
| Mainline Management Limited | Administrative & support | 1985 |
| Make Waves Group Limited | Other services | 2023 |
| Makkipak Ltd | Manufacturing | 1999 |
| Malone and Neptune Limited | Professional & scientific | 2017 |
| Malpertuis Designs Ltd | Administrative & support | 2009 |
| Malt House, the Stocks Management Company Ltd | Households | 2020 |
| Mandala KIN Ltd | Professional & scientific | 2020 |
| Mander Business Services Ltd | Administrative & support | 2019 |
| Mander Holdings Group Ltd | Financial services | 2026 |
| Manea Logistics Ltd | Transport & logistics | 2026 |
| Maneater Entertainment Ltd | Arts & recreation | 2021 |
| Mango Photography Limited | Professional & scientific | 2022 |
| Manoranjan Properties Limited | Real estate | 2020 |
| Manufacturing & Services Ltd | Administrative & support | 2024 |
| Maple (Sheq) Management Services Limited | Professional & scientific | 2016 |
| Maple Hairdressing Ltd | Other services | 2025 |
| Marame Clothing Ltd | Wholesale & retail | 2022 |
| Marcus R Blake Limited | Financial services | 2019 |
| Marina Racing Ltd | Arts & recreation | 2022 |
| Mark Cockerill Ltd | Administrative & support | 2024 |
| Mark Lovegrove Ltd | Information & communication | 2010 |
| Mark the Mountain Guide Ltd | Information & communication | 2019 |
| Market Explorers Limited | Professional & scientific | 2007 |
| MARKET2GETHER Limited | Professional & scientific | 2012 |
| Marketing Distribution Services Limited | Professional & scientific | 2005 |
| Marquis Financial Planning Ltd. | Financial services | 1998 |
| Marshside Health & Safety Ltd | Administrative & support | 2010 |
| Martin's Minibus Hire Ltd | Transport & logistics | 2025 |
| Martins Motorsports Logistics Limited | Transport & logistics | 2020 |
| Masskapital Limited | Administrative & support | 2018 |
| Maths & Physics Tutor Limited | Education | 2018 |
| Matt Clark Project Management Limited | Arts & recreation | 2022 |
| Matterhorn Languages Limited | Professional & scientific | 2005 |
| Mauve Group Topco Limited | Arts & recreation | 2017 |
| Maxdeliver UK Ltd | Transport & logistics | 2017 |
| Mayfair Bloodstock Limited | Agriculture & fishing | 2017 |
| MB & LB Associates Limited | Professional & scientific | 2015 |
| MB Project Services Limited | Information & communication | 2018 |
| Mbep Enterprises Limited | Real estate | 2018 |
| Mbep Trading and Services LLP | | 2020 |
| Mcgowan Group (Midlands) Ltd | Financial services | 2025 |
| Mcgrady Developments Ltd | Construction | 2025 |
| Mckenzie Asset Management Ltd | Real estate | 2015 |
| Mclay James Financial Ltd | Financial services | 2021 |
| Mcscentz Ltd | Information & communication | 2026 |
| Mcwilliam Electrical Services Limited | Construction | 2023 |
| MD Cars Holdings Limited | Financial services | 2023 |
| MDB Investments Limited | Real estate | 2020 |