| Muntons plc | Stowmarket | A rating |
| Munyasha LTD | Boston | A rating |
| Mura Technology Limited | Cleveland | A rating |
| Muraai Information Technologies Limited | Coventry | A rating |
| MURAD'S GROUP LTD | Salford | A rating |
| Muragen Limited | Harrow | A rating |
| Murano Systems Ltd | London | A rating |
| Murasaki London Ltd | London | A rating |
| MURASPEC DECORATIVE SOLUTIONS LIMITED | HEMEL HEMPSTEAD | A rating |
| MURAT FOOD CENTRE LTD | Nottingham | A rating |
| Murata Power Solutions | Milton Keynes | A rating |
| Murata Power Solutions Celab Limited | Bordon | A rating |
| MURATSUPERMARKET LTD | LONDON | A rating |
| Murcott Energy Ltd | Worcester | A rating |
| Murdoch Allan | Peterhead | A rating |
| Murex UK Limited | London | A rating |
| Murge Take away Limited | Newry | A rating |
| Murieston Convenience Store Ltd | Livingston | A rating |
| MURKZ CONCRETE PRODUCTS LIMITED | Birmingham | A rating |
| Murley Auto Limited | Warwick | A rating |
| Murlough House | Newcastle | A rating |
| Murphy and Son Limited | Nottingham | A rating |
| Murphy Geospatial UK Ltd | Watford | A rating |
| Murphy Philipps Associates LLP | London | A rating |
| Murphy's Hair and Beauty Ltd | London | A rating |
| MurphyGroup | London | A rating |
| Murray Chalmers Limited | London | A rating |
| Murray Home Care Ltd | Preston | A rating |
| Murray McGregor Ltd t/a Denrosa Apiaries | BLAIRGOWRIE | A rating |
| Murrelektronik Ltd | Manchester | A rating |
| Murrey Traders Limited | London | A rating |
| Mursla | Cambridge | A rating |
| Murugesu Associates | London | A rating |
| Murus Sanctus Polo Team | Liphook | A rating |
| Murzuq Oil Services Limited | London | A rating |
| MUS ACCOUNTANTS LIMITED | Slough | A rating |
| MUS4BANJ LTD | Manchester | A rating |
| Musa Fast Food Ltd | Darlington | A rating |
| MUSA HALAL SUPERMARKET LTD | Luton | A rating |
| Musa Takeaway Ltd T/A Baba's Indian Takeaway | Plymouth | A rating |
| MUSAABUILDERS LIMITED | London | A rating |
| Musafari Ltd | Sunderland | A rating |
| MUSAIP LTD | London | A rating |
| MUSARUBRA UK SUBSIDIARY 3 LTD | Slough | A rating |
| MUSAS COLLECTION LIMITED | TIPTON | A rating |
| Muscatt Black Graf LLP | London | A rating |
| Muscleworks Ltd | LONDON | A rating |
| Musco Lighting Europe LTD | Bolton | A rating |
| Muscular Dystrophy Group | London | A rating |
| Muse Coffee Company Limited | Southampton | A rating |
| MUSE NUSUN LTD | London | A rating |
| Muse Soton Limited t/a Muse Coffee Co (London Road) | Southampton | A rating |
| MUSE THE AGENCY LTD | MANCHESTER | A rating |
| MUSELAB SOCIAL LTD | Coventry | A rating |
| Museum of East Anglian Life | Stowmarket | A rating |
| Museum of East Asian Art | Bath | A rating |
| MUSF Ltd t/a T.J Mini Market | Edinburgh | A rating |
| Mushambi and Associates Limited | London | A rating |
| MUSHAVI PRIVATE LIMITED | PORTSMOUTH | A rating |
| MUSHKIL AASAAN | London | A rating |
| MUSHROOM GROUP OF COMPANIES UK LIMITED | London | A rating |
| Mushroom Technologies Ltd | Rainham | A rating |
| MUSHTAQ AND SONS HEALTHCARE LIMITED T/A Beeston Manor Pharmacy | Dudley | A rating |
| MUSHTAQ SWEETS CARDIFF LTD | Cardiff | A rating |
| MUSHTAQ'S SAMOSAS LIMITED | Bradford | A rating |
| Mushtaqs Investments Ltd | Hamilton | A rating |
| MUSIC & BEANS LIMITED | London | A rating |
| Music & Fashion Exchange Limited | London | A rating |
| Music Action International | Salford | A rating |
| Music Beyond Mainstream Ltd | Basingstoke | A rating |
| Music Broth | Glasgow | A rating |
| MUSIC EDUCATION TECHNOLOGIES LIMITED | London | A rating |
| MUSIC FOR FILM LIMITED | Southport | A rating |
| Music for Life Academy | Lisburn | A rating |
| MUSIC I LIMITED | BIRMINGHAM | A rating |
| Music Managers Forum Ltd. | London | A rating |
| Music Minds Limited | Birmingham | A rating |
| Music Plus Sport Ltd | London | A rating |
| MUSICALLY LIMITED | LONDON | A rating |
| musicMagpie plc | Stockport | A rating |
| MUSKAAN NO.4 LIMITED | London | A rating |
| Muslim Aid | London | A rating |
| Muslim Association of Nigeria (UK) | London | A rating |
| MUSLIM ASSOCIATION OF SALISBURY | SALISBURY | A rating |
| MUSLIM BUTCHERS LTD | Peterborough | A rating |
| Muslim Charity Helping the Needy | Retford | A rating |
| Muslim Hands | Nottingham | A rating |
| Muslim Khoja Shia Ithna-Asheri Of Leicester | Leicester | A rating |
| Muslim Project Foundation | London | A rating |
| Muslim World League London Office Trust | London | A rating |
| MUSO TNT LTD | London | A rating |
| Musrat Bi t/a Bury Park Post Office | Luton | A rating |
| MUSSA & MARY LTD | Bishops Stortford | A rating |
| Musselburgh Baptist Church | Musselburgh | A rating |
| Musslelburgh Wagon Coachworks | Musselburgh | A rating |
| Must Investment UK | New Malden | A rating |
| Mustafa 247 Shop | West Midlands | A rating |
| Mustafa Alukaidey T/A Elliot Carter Estate Agents and Maintenance | Hillingdon | A rating |
| Mustafa Homes & Development Ltd | Woking | A rating |
| MUSTAFA JEWELLERS LIMITED | Luton | A rating |
| MUSTAFA WELFARE SOCIETY BOLTON | Bolton | A rating |
| MUSTAFIA SHARIF | Stockport | A rating |
| MUSTAK DAUDMIA T/A MARBLE NEWS | SOUTHPORT | A rating |
| Mustang Engineering Limited | Woking | A rating |
| Mustang Hospitality Ltd T/A Kathmandu Restaurant and Bar | Solihull | A rating |
| Mustard Rainham Ltd | Hornchurch | A rating |
| Mustard Seed Gardens Limited | Liverpool | A rating |
| Mustard Seeds Educational Ltd | Merton District | A rating |
| Mustard Systems Limited | London | A rating |
| Musters Medical Practice | Nottingham | A rating |
| MUSTI R MUSTI LTD | London, England | A rating |
| MUSU | Manchester | A rating |
| Mutalib & Sons Limited TA Shell Tottenham Service Station | London | A rating |
| MUTARES UK LTD | Birmingham | A rating |
| MUTEURO LIMITED T/A MORIAH HEALTHCARE SERVICES | Norwich | A rating |
| Mutfak Limited | London | A rating |
| Muthu & Co Ltd | Plymouth | A rating |
| Muthu Clumber Park Hotel & Spa | Worksop | A rating |
| Mutimer Partnership Ltd | Norwich | A rating |
| Mutley Barbers 1 Limited | Plymouth | A rating |
| MUTMAEN LTD | London | A rating |
| Mutta constructions limited | Nuneaton | A rating |
| Mutti Building Contractors Ltd | Dagenham | A rating |
| Mutti UK Limited | London | A rating |
| Mutual Energy Limited | belfast | A rating |
| MUTUS TECH LTD | Liverpool | A rating |
| Muuto Consulting Limited | London | A rating |
| Muutto LTd | Manchester | A rating |
| MUX SERVICES LIMITED T/A DUNSTABLE PHONE REPAIRS | DUNSTABLE | A rating |
| Mux UK Limited | London | A rating |
| MUXAKAY LIMITED | Redish | A rating |
| MUXI UK LIMITED | LONDON | A rating |
| Muz's Enterprise Limited | Swansea | A rating |
| Muza Lab Ltd | London | A rating |
| Muzaana Care Services | Feltham | A rating |
| Muzac Ltd | Essex | A rating |
| Muzda Stratford Ltd | London | A rating |
| Muze Capital Advisors Limited | London | A rating |
| MUZE CONSTRUCTION & CONSULTANCY LTD | Milton Keynes | A rating |
| Muzika Limited | London | A rating |
| Muzinich & Co. Limited | London | A rating |
| MUZIRIS LTD T/A MUZIRIS | ILFORD | A rating |
| Muzulu Limited | Oxford | A rating |
| Muzz Ltd | Ilford | A rating |
| MV & VS Limited | Brentwood | A rating |
| MV Advisers LLP | London | A rating |
| MV FOOD&WINE LTD | Bury St. Edmunds | A rating |
| MV Fruehauf Limited | Airdrie | A rating |
| MV PUBLIC RELATIONS LIMITED | London | A rating |
| MV RETAIL LEICESTER LTD T/A VAMA COLLECTIONS | LEICESTER | A rating |
| MV Shop Limited | Manchester | A rating |
| MV SPORTS & LEISURE LIMITED | BIRMINGHAM | A rating |
| MV Stella Maris Ltd | Gairloch | A rating |
| MVC TOURISM LIMITED | LONDON | A rating |
| MVCI Europe Limited | London | A rating |
| MVE MANAGEMENT LIMITED | LONDON | A rating |
| Mvecare Health Solutions | Sheffield | A rating |
| MVEER CONSTRUCTION LTD | SLOUGH | B rating |
| MVF Creations Ltd T/A Sugaholics | London | A rating |
| MVI RNTERPRISE LTD | WEMBLEY | A rating |
| MVK GROUP HOLDINGS LTD | London | A rating |
| MVM ADVISORY GROUP LTD | London | A rating |
| MVM2 Limited | East Sussex | A rating |
| MVP PRO UK Limited | Milton Keynes | A rating |
| MVPQ Capital Limited | London | A rating |
| MVR IT Limited | Crownhill | A rating |
| MVSN LTD | Bodicote | A rating |
| MVV Environment Ltd | Plymouth | A rating |
| MW CARE UK LTD | Uxbridge | A rating |
| MW EAT LTD | London | A rating |
| MW ENCAP LTD | LIVINGSTON | A rating |
| MW IT Services Limited | Hove | A rating |
| MW Nutrition ltd | London | A rating |
| MW&L Capital Partners Limited | London | A rating |
| MWA AUTOS LTD | Nottingham | A rating |
| MWA Financial Limited | Fareham | A rating |
| MWA Global Ltd | Southall | A rating |
| MWAI Limited | London | A rating |
| Mwaves Ltd | London | A rating |
| MWC Group UK | Newark | A rating |
| MWCLUBB LIMITED | Aberdeen | A rating |
| MWH Treatment Limited | Hattersley | A rating |
| MWM LURMS LTD | HAYES | A rating |
| MWN INNOVATION LTD | London | A rating |
| MWS Limited | Leicester | A rating |
| MX FOOD PRODUCTS LTD | Brierley Hill | A rating |
| MX PHARMACY LIMITED | Preston | A rating |
| MX Reality Ltd | Milton Keynes | A rating |
| MXB Devon Operations Limited | bideford | A rating |
| MXM Contractors Ltd | London | A rating |
| MXP Prime Platform Ltd T/A SellerX | London | A rating |
| MY 3 CHICKENS LIMITED | WATFORD | A rating |
| MY ABASEEN ACCRINGTON LTD | Accrington | A rating |
| MY ADVISORY SERVICE LIMITED | Challock | A rating |
| My AdWorld Limited | Beccles | A rating |
| My Aesthetics Limited | London | A rating |
| MY BASSINGHAM LIMITED trading as Bassingham Care Centre | Lincoln | A rating |
| My Beautiful City Limited | London | A rating |
| My Beauty and Care Ltd | Watford | A rating |
| MY BEAUTY BASICS LTD | Hayes | A rating |