| Little Swimology Ltd | Education | 2025 |
| LMS Estates Ltd | Construction | 2005 |
| Longhouse HQ Limited | Administrative & support | 2025 |
| Lotus Carlton Estate Agents Limited | Real estate | 2024 |
| Lotus Carlton Lettings Limited | Real estate | 2024 |
| LPT Legal Limited | Professional & scientific | 2011 |
| Lucid Fitness Limited | Other services | 2015 |
| Lytton Enterprises Limited | Arts & recreation | 1970 |
| Lytton Land Limited | Real estate | 2017 |
| M & O Candy Beans Consulting Ltd | Information & communication | 2014 |
| M&B Aurora Ltd | Administrative & support | 2025 |
| M&M Online UK Ltd | Wholesale & retail | 2020 |
| M&S Herts Cars Ltd | Wholesale & retail | 2022 |
| M.S Letters UK Limited | Transport & logistics | 2014 |
| MAD K Beer Company Ltd | Hospitality | 2001 |
| Magic Mops Hertfordshire Ltd | Administrative & support | 2022 |
| Magic Mops Ltd | Administrative & support | 2022 |
| Magnolia Consulting Ltd | Professional & scientific | 2026 |
| Mamman Limited | Wholesale & retail | 2018 |
| Manor Engineering Limited | Construction | 2012 |
| Mardleybury Cars Limited | Wholesale & retail | 2018 |
| Maresh Ltd | Health & social care | 2012 |
| Marksimon Estates Limited | Real estate | 2002 |
| Marshmallow (UK) Limited | Wholesale & retail | 2006 |
| Marwyn Equestrian RUG Washing Limited | Other services | 2025 |
| Mass Spectrometry Imaging Solutions Ltd | Professional & scientific | 2024 |
| Maxfx Solutions Ltd | Construction | 2013 |
| Maxx Wattage Electricals Ltd | Manufacturing | 2024 |
| Maylee Therapy Ltd | Health & social care | 2023 |
| MB GB Consultancy Ltd | Professional & scientific | 2022 |
| MBG Mortgages Ltd | Financial services | 2012 |
| MDM Blinds Limited | Wholesale & retail | 2005 |
| ME Drive Ltd | Administrative & support | 2025 |
| Meadow View Glamping Ltd | Hospitality | 2025 |
| Menus Care Services Ltd | Other services | 2015 |
| Meta Consulting Limited | Professional & scientific | 1995 |
| Meta Counselling Limited | Health & social care | 2024 |
| Metcalfe Associates Limited | Professional & scientific | 2024 |
| Mine of Innovation Limited | Information & communication | 2011 |
| Ming WEI Limited | Extraterritorial | 2001 |
| Minhas Consultancy Ltd | Health & social care | 2020 |
| MK Project Management Limited | Professional & scientific | 2017 |
| Mortgage Advice Network UK Ltd | Financial services | 2019 |
| MRS Mummypenny Ltd | Professional & scientific | 2015 |
| My Blowdry Bar Ltd | Other services | 2026 |
| Myskeld Ltd | Real estate | 2019 |
| Nancy Research Limited | Professional & scientific | 2021 |
| NCV Group Limited | Administrative & support | 2021 |
| Neighbay Ltd | Extraterritorial | 2023 |
| Neuro Kind Mentors Ltd | Education | 2026 |
| Nimbus Dynamics Ltd | Real estate | 2024 |
| NO.83 Ltd | Other services | 2024 |
| Noka Hospitality Ltd | Hospitality | 2025 |
| Nordkapp Media Ltd | Information & communication | 2015 |
| NYX Global Ltd | Professional & scientific | 2020 |
| Nziraxa Ltd | Financial services | 2025 |
| Oakfields Wealth Management Ltd | Financial services | 2018 |
| Ognatura Ltd | Wholesale & retail | 2019 |
| OH Dear Ltd | Arts & recreation | 2024 |
| Omega Services Group Ltd | Administrative & support | 2022 |
| One Further Limited | Information & communication | 2014 |
| One Stop N Shop Limited | Wholesale & retail | 2024 |
| Orchardton Management Services Limited | Professional & scientific | 2012 |
| Ovrsite Ltd | Professional & scientific | 2025 |
| Oxbo Ltd | Administrative & support | 2021 |
| P W Piper Limited | Administrative & support | 2004 |
| P.P.Shah Services Ltd | Real estate | 2020 |
| Paul Woodley Photography Ltd | Professional & scientific | 2022 |
| Pcarter Physio Ltd | Health & social care | 2024 |
| Pelman & Co Ltd | Construction | 2020 |
| Pennington Perkins LLP | | 2015 |
| People Pathfinder Limited | Professional & scientific | 2024 |
| People Process Profits Ltd | Professional & scientific | 2025 |
| PH Build Ltd | Construction | 2017 |
| Physio Vineyards Limited | Health & social care | 2000 |
| Physiofoam Ltd | Wholesale & retail | 2016 |
| PJC Smith Limited | Construction | 2013 |
| PL84U Ltd | Manufacturing | 2023 |
| Polbridge Health Ltd | Administrative & support | 2017 |
| Portrait Landscape Supplies Limited | Wholesale & retail | 2004 |
| Potstop Limited | Wholesale & retail | 2008 |
| Pound Plus World Limited | Wholesale & retail | 2003 |
| Power Response Limited | Administrative & support | 2015 |
| PRE- CEC International Ltd | Wholesale & retail | 2016 |
| Presland Medical Limited | Health & social care | 2012 |
| Prime Grass Limited | Administrative & support | 2004 |
| PWS Films Limited | Information & communication | 2013 |
| Quantik Ltd | Information & communication | 2019 |
| Raceedge Ltd | Wholesale & retail | 2025 |
| Rachel Hill Design Limited | Information & communication | 2007 |
| Rainberg Home Limited | Real estate | 2024 |
| Ramsey Stone Consultants Ltd | Construction | 2017 |
| Reach Online Tutoring & Learning Limited | Education | 2024 |
| Recbos Funding Solutions Ltd | Administrative & support | 2026 |
| Recbos Ltd | Administrative & support | 2026 |
| Recruitment Back Office Solutions Ltd | Administrative & support | 2026 |
| Reilly Commerce Ltd | Wholesale & retail | 2026 |
| Retail Engineering Solutions Ltd | Professional & scientific | 2015 |
| Rhindon Limited | Information & communication | 2010 |
| RJS Hydraulics Ltd | Manufacturing | 2019 |