| Motion Control Products Limited | Wholesale & retail | 1994 |
| Motivebrook Limited | | 1982 |
| Motocorsa Limited | Wholesale & retail | 2004 |
| Motorcycle Addicts Ltd | Wholesale & retail | 2026 |
| Motorpoint (Poole) Limited | Wholesale & retail | 2014 |
| Motorvation Garage Limited | Wholesale & retail | 2024 |
| Motrr Ltd | Administrative & support | 2026 |
| Mount Flagon Management Company Limited | Households | 2006 |
| Mount Grace Properties Limited | Real estate | 2009 |
| Mountain ASH Services Limited | Information & communication | 2000 |
| Mountain Bear Limited | Wholesale & retail | 2022 |
| Mountbatten Lodge Freehold Limited | Households | 2004 |
| Mountclere Management Company Limited | Households | 2009 |
| Mountpride Agencies Ltd | Hospitality | 1998 |
| Moushill Developments Limited | Construction | 2004 |
| Move Your Feet UK Limited | Arts & recreation | 2019 |
| Movecliff Limited | Hospitality | 1978 |
| Movement Culture Gym Ltd | Arts & recreation | 2022 |
| Moversmarket Ltd | Information & communication | 2024 |
| Movetti Limited | Extraterritorial | 2008 |
| Movie BH2 Ltd | Information & communication | 2021 |
| Moving Professionals Ltd | Transport & logistics | 2023 |
| Mower & HOE Gardening Service Ltd | Other services | 2008 |
| Mowlem Beaumont Investments Limited | Professional & scientific | 2019 |
| Moyra Race Strategic Buying Consulting Services Ltd | Professional & scientific | 2018 |
| MP Admin Services Ltd | Public administration | 2025 |
| MP Ceramics Limited | Construction | 2015 |
| MP Clay Limited | Other services | 2015 |
| MP Dream Properties Ltd | Real estate | 2026 |
| MP Hospitality Limited | Professional & scientific | 2014 |
| MP Joscelyne Financial Services Ltd | Financial services | 2025 |
| MP Logistic Services Ltd | Transport & logistics | 2024 |
| MP Precision Engineering Limited | Manufacturing | 2011 |
| MP1 (Poole) Freehold Limited | Households | 2011 |
| MPA Financial Solutions Ltd | Professional & scientific | 2017 |
| MPC 25 Limited | Real estate | 2024 |
| Mpcf Ltd | Financial services | 2019 |
| MPE Digital Media Ltd | Arts & recreation | 2026 |
| MPJ Construction Limited | Construction | 2005 |
| Mpjb Limited | Transport & logistics | 2019 |
| Mpln Ltd | Hospitality | 2024 |
| MPM Warwick Homes Limited | Construction | 2025 |
| MPP (Bournemouth) Ltd | Administrative & support | 2025 |
| MPS Developments Ltd | Construction | 2020 |
| MQIC01 Ltd | Real estate | 2025 |
| MR & MRS Clarke Ltd | Real estate | 2014 |
| MR Falafel Sandwich Express Ltd | Hospitality | 2023 |
| MR Green Estate Agents Ltd | Real estate | 2015 |
| MR Green Lettings Ltd | Real estate | 2017 |
| MR Paper Trustees Limited | Professional & scientific | 2024 |
| MR Property & Development Ltd | Real estate | 2025 |
| MR Roofing Ltd | Construction | 2025 |
| MR Simms Bournemouth Ltd | Wholesale & retail | 2021 |
| MR Strongmans Ltd | Manufacturing | 2024 |
| MR Till Roll Limited | Extraterritorial | 2013 |
| MR. Corrosion Ltd | Wholesale & retail | 2025 |
| MR. Martin Edwards Ltd | Extraterritorial | 2024 |
| Mr.White Capital Ltd | Wholesale & retail | 2016 |
| MRH Resources Limited | Manufacturing | 2021 |
| MRK Health Sciences Limited | Health & social care | 2018 |
| Mrozik Interiors Ltd | Manufacturing | 2021 |
| MRP Brickwork Limited | Construction | 2002 |
| MS & MB Ltd | Real estate | 2018 |
| MS Arts Ltd | Arts & recreation | 2026 |
| MS Lines Limited | Administrative & support | 2015 |
| MS Marine Servis Ltd | Manufacturing | 2025 |
| MS Marketing Consultancy Ltd | Information & communication | 2018 |
| Msafe Fire Ltd | Professional & scientific | 2024 |
| Msafe Risk Management Limited | Professional & scientific | 2006 |
| MSB Plumbing & Heating Ltd | Construction | 2012 |
| MSH Medical Limited | Health & social care | 2014 |
| Msh&Co Investments Ltd | Real estate | 2023 |
| Msib Group Services Ltd | Construction | 2024 |
| MSM Consult Ltd | Administrative & support | 2025 |
| MSM Training South Limited | Education | 2023 |
| Msmk Prime Ltd | Hospitality | 2018 |
| MSO Cleaning Services Limited | Administrative & support | 2024 |
| MSP Business Services Limited | Professional & scientific | 2016 |
| MSP Media Ltd | Manufacturing | 2019 |
| MSR South Limited | Hospitality | 2023 |
| Mssco Ltd | Information & communication | 2012 |
| MST Gallery Ltd | Arts & recreation | 2013 |
| MT Leisure Limited | Hospitality | 2019 |
| MT Representations Ltd | Wholesale & retail | 2022 |
| MT Telecoms Ltd | Information & communication | 2018 |
| MTC South Limited | Financial services | 2018 |
| MTM Scaffolding Ltd | Construction | 2022 |
| MTS Craft Studio Ltd | Wholesale & retail | 2023 |
| Muang Thai Market Ltd | Wholesale & retail | 2014 |
| Mudeford Green (Management) Limited | Households | 1982 |
| Mudeford Lettings Ltd | Real estate | 2016 |
| Mudi's Hub Ltd | Transport & logistics | 2023 |
| Mufg Retirement Solutions Pension Administration (HS) Limited | Administrative & support | 1985 |
| Mufg Retirement Solutions Pension Administration Limited | Financial services | 2017 |
| Muhammad Sulaiman Ltd | Wholesale & retail | 2025 |
| Mullett Madness Ltd | Other services | 2018 |
| Mullucks Franchising Limited | Real estate | 1999 |
| Multi Landlords Build Ltd | Construction | 2019 |
| Multi-Champs Holiday Camp Limited | Health & social care | 2022 |
| Multiplex Cabins Limited | Manufacturing | 2023 |