| Mornington Oak Limited | Information & communication | 2019 |
| Mountbarrow Limited | Wholesale & retail | 2021 |
| MR B J R Moate Limited | Health & social care | 2010 |
| MRN Property Ltd | Real estate | 2020 |
| MSR Engineering Management Consultancy Limited | Professional & scientific | 2024 |
| MT Wood Property & Maintenance Limited | Construction | 2010 |
| MTM Scalable Solutions Limited | Education | 2022 |
| MTM Solutions Ltd | Wholesale & retail | 2009 |
| Multipass 3D Laser Scans Ltd. | Administrative & support | 2006 |
| Multipass Limited | Extraterritorial | 2019 |
| Mustard Hill Limited | Real estate | 2023 |
| MVC Design Limited | Professional & scientific | 2017 |
| MW Energy & Engineering Ltd | Professional & scientific | 2022 |
| My Kind of Clean - Care Ltd | Administrative & support | 2019 |
| My Kind of Clean - Commercial Ltd | Administrative & support | 2019 |
| My Kind of Clean Ltd | Other services | 2018 |
| Mycelium Thinking CIC | Information & communication | 2021 |
| N Design Limited | Professional & scientific | 2018 |
| N. P. Properties Ltd | Real estate | 2002 |
| Natalie Wilson Wellbeing Limited | Health & social care | 2024 |
| Natasha's (Cumbria) Limited | Administrative & support | 2008 |
| Nathaniel Hardie Consult Limited | Professional & scientific | 2024 |
| Neil Porter Building & Stonework Limited | Administrative & support | 2017 |
| Neil Price Holdings Limited | Financial services | 2023 |
| Neil Price Limited | Construction | 1996 |
| Nesscare Ltd | Health & social care | 2022 |
| New Kadampa Tradition - International Kadampa Buddhist Union | Other services | 1992 |
| Newbiggin Shellfish Limited | Agriculture & fishing | 2002 |
| Newby Bridge Management Company Limited | Real estate | 2011 |
| Newfield Residents Management Company Limited | Households | 2021 |
| Newland Furnace Trust | Arts & recreation | 1998 |
| Nexthouse Agencies Limited | Health & social care | 2022 |
| NH Ec&I Engineering Services Ltd | Manufacturing | 2014 |
| Nick Watson Building Contractor Limited | Construction | 2014 |
| Nicky Lynn Limited | Administrative & support | 2025 |
| Nina Pitcairn Aviation Limited | Transport & logistics | 2020 |
| Nisha Halo Ltd | Manufacturing | 2020 |
| Nixor Solutions Limited | Information & communication | 2016 |
| NKM Architecture Ltd | Professional & scientific | 2017 |
| NMP Property Ltd | Real estate | 2025 |
| Nomad Trailer Made Events Ltd | Hospitality | 2024 |
| Nomad Trailer Made Pizzas Ltd | Hospitality | 2023 |
| Nordic Suites Limited | Hospitality | 2015 |
| North Lonsdale Properties Limited | Financial services | 2024 |
| North Projects Limited | Construction | 2023 |
| North West Renewable Energy Installations Limited | Construction | 2024 |
| Northern Centre (A.C.U.) Limited | Arts & recreation | 2007 |
| Northern Roadstone Company Limited | Manufacturing | 2025 |
| Nouman Hanif Ltd | Wholesale & retail | 2025 |
| NP Leisure Limited | Real estate | 2019 |
| NSE Solutions Limited | Construction | 2023 |
| Nuttall & Waters Limited | Real estate | 2023 |
| Oakbank Surgery Ltd | Real estate | 2023 |
| Oakwood Property Renovations Ltd | Construction | 2024 |
| Obrana Ltd | Administrative & support | 2022 |
| Officelife Developments Limited | Construction | 1994 |
| Official Registrations Limited | Wholesale & retail | 2025 |
| OHS Commissioning Limited | Administrative & support | 2024 |
| Oktem Brothers Ulverston Limited | Hospitality | 2023 |
| Old Farmhouse Ulverston Limited | Hospitality | 2016 |
| Old Mart Group Community Interest Company | Construction | 2024 |
| Old Newbarns Limited | Construction | 2019 |
| Olivia Benjamin Ltd | Wholesale & retail | 2018 |
| Omnom Limited | Information & communication | 2021 |
| OMS Technical Services (OTS) LLP | | 2015 |
| OMS Technical Services Limited | Professional & scientific | 2004 |
| ON the TIN Limited | Professional & scientific | 2009 |
| Only Wind and Water Limited | Transport & logistics | 2010 |
| Onside Sports Arena Limited | Construction | 2017 |
| Onside Sports Coaching South Lakes Limited | Arts & recreation | 2002 |
| Open Business Group Limited | Financial services | 2024 |
| Open Tracking Limited | Manufacturing | 2015 |
| Operational Construction Management Ltd | Construction | 2012 |
| Opteama (UK) Limited | Professional & scientific | 1999 |
| Orange Box Self Store Limited | Transport & logistics | 2020 |
| Orcina Holdings Limited | Financial services | 2007 |
| Orotau Ltd | Information & communication | 2018 |
| ORS Overseas Resource Services (2015) LLP | | 2015 |
| ORS Overseas Resource Services Limited | Administrative & support | 2014 |
| Orwin & Orwin Limited | Administrative & support | 2017 |
| Otaq Connectors Limited | Manufacturing | 1997 |
| Otaq Offshore Limited | Extraterritorial | 2026 |
| Otter Tarn Limited | Real estate | 2025 |
| Outstanding Property Ltd | Real estate | 2018 |
| Owen Bayliss Digital Ltd | Information & communication | 2006 |
| Oxford Housing Developments Limited | Construction | 2004 |
| P & D Wilkin Limited | Hospitality | 2001 |
| P & H Construction Limited | Construction | 2002 |
| P J Contracting Services Limited | Construction | 2001 |
| P J Smith (Garafix) Limited | Construction | 2002 |
| P M Engineering Consultants Limited | Professional & scientific | 2012 |
| Pace Hire Ltd | Administrative & support | 2025 |
| Paper Bunny Limited | Wholesale & retail | 2018 |
| Park Ground Farm Estates Limited | Agriculture & fishing | 2018 |
| Park Road Garage (Swarthmoor) Limited | Wholesale & retail | 2015 |
| Parkamoor Limited | Administrative & support | 2020 |
| Parkside Facility Services Ltd | Administrative & support | 2011 |
| Paul Irving Consulting Limited | Information & communication | 2015 |
| Paul Lancaster Limited | Professional & scientific | 2007 |
| Paxos Property Ltd | Real estate | 2025 |