| Melodious Technology Limited | Information & communication | 1996 |
| Memphis Empire Limited | Wholesale & retail | 2013 |
| MEO Consulting Limited | Administrative & support | 2018 |
| Merlin Engineers Limited | Manufacturing | 2003 |
| Merton Grange Barns Management Company Limited | Real estate | 2015 |
| Metapraxis Holdings Limited | Information & communication | 2023 |
| Metapraxis International Limited | Information & communication | 1987 |
| Metapraxis Limited | Information & communication | 1979 |
| MHA Global Ltd | Wholesale & retail | 2021 |
| Michael Kirsop Limited | Construction | 2014 |
| Migal Ltd | Manufacturing | 2022 |
| Mimpipj Ltd | Administrative & support | 2024 |
| Mindfit for ALL CIC | Education | 2019 |
| Minds for Minds Ltd | Education | 2016 |
| Mingle Films Limited | Information & communication | 2018 |
| Miniature Mayhem Ltd | Wholesale & retail | 2025 |
| Minibeast Limited | Wholesale & retail | 2014 |
| Mirakin Limited | Extraterritorial | 2007 |
| MIZ IT Support Ltd | Information & communication | 2014 |
| Mjjr Construction Services Limited | Professional & scientific | 2014 |
| MNS Nails&Beauty Supply Ltd | Wholesale & retail | 2026 |
| Moatside Properties Limited | Construction | 1997 |
| Mobile Food Hub Ltd | Hospitality | 2026 |
| Modbench Ltd | Manufacturing | 2026 |
| Molehill Barns Management Co Ltd | Real estate | 2015 |
| Mollymay Clothing & Gifts Ltd | Wholesale & retail | 2021 |
| Moneybudgie Limited | Information & communication | 2004 |
| Monsoon Film 2018 Limited | Information & communication | 2018 |
| Montila Engineering Limited | Construction | 2007 |
| Mooch & Mooch Ltd | Information & communication | 2025 |
| Moonspun Films Limited | Information & communication | 2010 |
| More Simple Solutions (Cambs) Ltd | Professional & scientific | 2016 |
| Mouldguard Services Ltd | Construction | 2025 |
| Mouse Manoeuvres Limited | Information & communication | 1994 |
| Moviola Films Limited | Information & communication | 2013 |
| Muhammad Wasif Ltd | Wholesale & retail | 2025 |
| Murati Aldridge Ionian Property Limited | Real estate | 2025 |
| Music Room Direct Limited | Extraterritorial | 2003 |
| Muybridge Ltd | Construction | 2019 |
| Mvngeeks Limited | Information & communication | 2015 |
| My Healthy Mind Coaching Ltd | Health & social care | 2025 |
| My Money Mindset Ltd | Education | 2026 |
| Myislandservice Ltd | Wholesale & retail | 2016 |
| MZM Properties Limited | Real estate | 2023 |
| N Trye Building Ltd | Construction | 2019 |
| N Y Parry Ltd | Information & communication | 2019 |
| Nabbsa Consulting Ltd | Administrative & support | 2017 |
| Naked EYE Productions Limited | Information & communication | 2006 |
| Natural Talents (Cambridge) Limited | Administrative & support | 2005 |
| Neil Stevens Window Cleaning Limited | Administrative & support | 2007 |
| Newdale Cambridge Ltd | Real estate | 2024 |
| Newvel Distribution Limited | Other services | 2011 |
| Nexus Property Holdings Ltd | Real estate | 2025 |
| NIC & Associates Limited | Wholesale & retail | 2007 |
| Ninja Props Limited | Information & communication | 2015 |
| Nistorhaula-Ge Ltd | Transport & logistics | 2024 |
| NO. 7 Films Ltd | Information & communication | 2012 |
| Noble Consortium Ltd | Financial services | 2026 |
| Noble Healthcare Limited | Manufacturing | 2021 |
| Noel Accounting Solutions Ltd | Real estate | 2007 |
| Nonyem Consultancy Ltd | Arts & recreation | 2020 |
| Norfolk Blue Limited | Professional & scientific | 2010 |
| North Bedfordshire PUB Management Ltd | Administrative & support | 2024 |
| Notify Ltd. | Information & communication | 1991 |
| NPT Consulting Limited | Professional & scientific | 2013 |
| NRH Heating & Plumbing Ltd | Construction | 2023 |
| NRT Properties Ltd | Real estate | 2022 |
| Nslc Ltd | Transport & logistics | 2024 |
| Nslc Online Ltd | Wholesale & retail | 2024 |
| Number 20 Films Limited | Information & communication | 2018 |
| Nutri-Rich Ltd | Agriculture & fishing | 2024 |
| Oak and Acre Ltd | Hospitality | 2025 |
| Oakley Hough Limited | Professional & scientific | 2012 |
| Oasys Technologies Limited | Manufacturing | 1998 |
| Obilogic Limited | Information & communication | 2004 |
| Octanebytes Ltd | Wholesale & retail | 2019 |
| Odea Installations Ltd | Construction | 2019 |
| OJP Lloyd-Fox Ltd | Information & communication | 2014 |
| ON Plan Properties Ltd | Real estate | 2019 |
| Once I WAS Ltd | Manufacturing | 2017 |
| One Habitat Ltd | Construction | 2025 |
| OP Base Camp Ltd | Arts & recreation | 2024 |
| Open Space Property Limited | Real estate | 2020 |
| Opendale Ltd | Hospitality | 2025 |
| Optimum Care Solutions Limited | Hospitality | 2017 |
| Orbital Service UK Ltd | Wholesale & retail | 2022 |
| Oriain Engineering Services Ltd | Professional & scientific | 2016 |
| Osnpadler Ltd | Transport & logistics | 2017 |
| Ouse Valley Bait Company Limited | Agriculture & fishing | 1977 |
| Outside the Box Concepts Limited | Manufacturing | 2017 |
| OV Mateo Limited | Other services | 2023 |
| Owen Media Systems Ltd | Professional & scientific | 2025 |
| Oxford Road Property Holdings Ltd | Professional & scientific | 2019 |
| Oystergem Limited | Mining & quarrying | 2025 |
| Ozoattic Ltd | Financial services | 2025 |
| Ozzys Garage Ltd | Wholesale & retail | 2021 |
| P Temple Building Services Ltd | Construction | 2024 |
| P. S. Engineers Ltd | Construction | 2008 |
| Packinglist Limited | Wholesale & retail | 2025 |
| Pagico Limited | Real estate | 2024 |