| Momentum Consult Limited | Wholesale & retail | 2013 |
| Monkey Palace Limited | Hospitality | 2018 |
| Monsterworx Ltd | Manufacturing | 2022 |
| Monte Carlo Media Limited | Other services | 2012 |
| Moore Energy (Wells) Limited | Extraterritorial | 2003 |
| Moore Solutions (South West) Ltd | Administrative & support | 2025 |
| Morgan Grenville Watler Ltd | Manufacturing | 2024 |
| Motoring Solutions Limited | Wholesale & retail | 2019 |
| MR COD (GB) Ltd | Professional & scientific | 2009 |
| MR Uncle Ltd | Transport & logistics | 2019 |
| Mrdonerkebab Ltd | Hospitality | 2025 |
| MRM Property Services Ltd | Professional & scientific | 2008 |
| Msafe Consulting Ltd | Professional & scientific | 2021 |
| MUD HUT Montessori Ltd | Education | 2018 |
| MUL2PLY Limited | Information & communication | 2010 |
| Multiple Sclerosis Therapy Centre (Wessex) Limited | Health & social care | 1988 |
| Multivarious Enterprises Limited | Construction | 1997 |
| Munro People Performance Ltd | Professional & scientific | 2017 |
| Munro Property Ltd | Households | 2018 |
| Myall Property Management Limited | Real estate | 2020 |
| Mystery Meets History CIC | Health & social care | 2019 |
| N & K Tours Limited | Transport & logistics | 2014 |
| Nagaachillis Limited | Hospitality | 2025 |
| Naomi Jayne Ltd | Health & social care | 2022 |
| Naomi Mckeever Ltd | Wholesale & retail | 2012 |
| Ncomp@Ss Ltd. | Wholesale & retail | 1998 |
| Ncsg Limited | Other services | 2023 |
| NDC Certification Bureau Limited | Information & communication | 2024 |
| NDC Certification Services Limited | Professional & scientific | 2019 |
| Neighbourhood Warminster Ltd | Wholesale & retail | 2025 |
| Neil Shad Ltd | Health & social care | 2025 |
| Neon Digital Clicks Ltd | Administrative & support | 2022 |
| Neon Fields Ltd | Arts & recreation | 2021 |
| Neutral Bay Freight Management Ltd | Transport & logistics | 2024 |
| Nevadiss Ltd | Real estate | 2026 |
| New Hill Management Limited | Financial services | 2010 |
| New Realities Gaming Ltd | Wholesale & retail | 2022 |
| New Road Service Station Limited | Wholesale & retail | 1995 |
| Newco (Stockbridge) Limited | Real estate | 2012 |
| Newco B (Stockbridge) Limited | Hospitality | 2012 |
| Newcoinvest Limited | Professional & scientific | 2018 |
| Newlooks Wiltshire Ltd | Other services | 2024 |
| Newton Nottingham LLP | | 2004 |
| Newton Nottingham NO.2 LLP | | 2024 |
| Newville Associates Limited | Hospitality | 2015 |
| Nexacast AI Ltd | Information & communication | 2023 |
| Nexacast Group Limited | Financial services | 2025 |
| Nexacast Ltd | Information & communication | 2025 |
| Nick Jenkins Foundation | Health & social care | 2010 |
| Nimbus Services Limited | Professional & scientific | 2016 |
| NJM Holdings Limited | Professional & scientific | 2016 |
| NMC2 Limited | Professional & scientific | 2006 |
| Nnoblegreen Properties Limited | Real estate | 2025 |
| NNT Services Europe Ltd | Transport & logistics | 2021 |
| Noble Electrical (Warminster) Limited | Construction | 2025 |
| Noble Tree Services Limited | Agriculture & fishing | 2019 |
| Norbeck Holdings Limited | Real estate | 2021 |
| Norbeck Limited | Information & communication | 1990 |
| North Street Nurseries Limited | Wholesale & retail | 1998 |
| Northwood (West Wiltshire) Limited | Real estate | 2004 |
| NOS 4 Limited | Real estate | 2006 |
| NOS 5 Limited | Real estate | 2006 |
| NOS 6 Limited | Real estate | 2007 |
| NOS Holdings Limited | Real estate | 2020 |
| NP Nails & Spa Limited | Other services | 2022 |
| Nspencatering Ltd | Hospitality | 2025 |
| NT Utilities Ltd | Construction | 2022 |
| Number TEN Interiors Ltd | Wholesale & retail | 2017 |
| Nurture Company Health Ltd | Professional & scientific | 2009 |
| Nurture Robotics Ltd | Professional & scientific | 2024 |
| Nutwell Logistics Limited | Manufacturing | 2006 |
| NV1 Management Limited | Real estate | 2024 |
| Nóinín Consulting Ltd | Professional & scientific | 2024 |
| Obelisk Court Residents Management Company Limited | Households | 1989 |
| Objective Ingenuity Limited | Professional & scientific | 2004 |
| Octopus Productions Limited | Information & communication | 2021 |
| Oddity Theatre Ltd | Arts & recreation | 2024 |
| OFE Catering Ltd | Hospitality | 2026 |
| Office Interiors (Milton Keynes) Limited | Professional & scientific | 2002 |
| Ohdc Associates Limited | Administrative & support | 2023 |
| Old Baker RTM Company Limited | Real estate | 2014 |
| Old Bury Farmyard Management Company Limited | Households | 2019 |
| Old Forge Close Management Limited | Real estate | 2009 |
| Old Garden House Management Limited | Real estate | 2013 |
| Old School Roots Limited | Hospitality | 2025 |
| Oliris Estates Limited | Real estate | 2025 |
| Olive Training Limited | Education | 2021 |
| Olivia Pope Studio Ltd | Other services | 2025 |
| Ollie and Lucy's Limited | Wholesale & retail | 2021 |
| Oluwa's Touch Limited | Wholesale & retail | 2021 |
| Ombra Real Estate Ltd | Real estate | 2023 |
| Opus Tool Hire Limited | Administrative & support | 2025 |
| OR Vend Limited | Wholesale & retail | 2026 |
| Orchardleigh Events Ltd | Hospitality | 2024 |
| Ordinary Life Project Association(The) | Health & social care | 1986 |
| Orhan Golden Scissors Ltd | Transport & logistics | 2020 |
| Orla's Hair and Beauty Limited | Other services | 2022 |
| Otronics Media Services Limited | Arts & recreation | 2009 |
| Outdoor Play South West Ltd | Manufacturing | 2018 |
| Outside in Limited | Financial services | 2004 |