| Marylebone Health Group lTD | London | A rating |
| Marylebone Lab Limited | London | A rating |
| Marymo Ltd | Middlesbrough | A rating |
| Marymount International School | Kingston upon Thames | A rating |
| MARYON ROAD MINI MARKET | Charlton | A rating |
| Maryport Group Practice | Maryport | A rating |
| MARYPORT SMILE CENTRE LTD | Maryport | A rating |
| MaryRuth Care Services Ltd | Sheffield | A rating |
| Marys Meals International | Glasgow | A rating |
| MARYSVILLE MEDICAL PRACTICE | SHREWSBURY | A rating |
| Maryvale & News & Wine Limited | Birmingham | A rating |
| Marzano Limited | York | A rating |
| MAS & PAS LIMITED | London | A rating |
| MAS Associates (Scot) Limited | Glasgow | A rating |
| Mas Bazaar Ltd T/A Ujan Bhati | Bedfordshire | A rating |
| Mas Bazaar Retail and Wholesale Limited | Newport | A rating |
| Mas Bazar Birmingham Ltd | Birmingham | A rating |
| MAS BAZAR LTD T/A Quality Seafoods | Barking | A rating |
| MAS BAZAR LUTON LTD | Luton | A rating |
| MAS BAZAR WHITECHAPEL LIMITED | LONDON | A rating |
| MAS BUILDERS WAREHOUSE LTD | Bradford | A rating |
| MAS CB LTD | Middlesex | A rating |
| MAS INTIMATES UK LIMITED | Herts | A rating |
| MAS Logistics UK Ltd | Southall | A rating |
| Mas United for electromechanical solutions | Garforth | A rating |
| MASA Express Ltd | Heckmondwike | A rating |
| Masabi Limited | London | A rating |
| Masafina Limited | Kings Langley | A rating |
| Masala 910 Limtied | Ilford | A rating |
| Masala Art Limited | Darlington | A rating |
| Masala Bay Limited | Ventnor | A rating |
| Masala Bazaar Bristol LTD | Cwmbran | A rating |
| Masala Bazaar Cardiff LTD | Cwmbran | A rating |
| MASALA BAZAAR CHADWELL LTD | Cwmbran | A rating |
| MASALA BAZAAR HOLDINGS LTD | Cwmbran | A rating |
| MASALA BAZAAR NEWPORT LTD | Cwmbran | A rating |
| Masala Bazaar Perry Barr Ltd | Birmingham | A rating |
| MASALA BAZAAR SMALL HEATH LTD | Birmingham | A rating |
| MASALA BAZAAR SMETHWICK LTD | Smethwick | A rating |
| MASALA BAZAAR SWANSEA LTD | swansea | A rating |
| MASALA BAZAAR SWINDON LTD | Cwmbran | A rating |
| MASALA CARE LIMITED T/A BADI MIRCHI | Eastleigh | A rating |
| Masala Craft Limited TA Atithi Contemporary Indian Restaurant | York | A rating |
| Masala Craft R&B Limited TA Masala Craft | York | A rating |
| Masala Creations & Events Limited T/A Masala Creations | Southall | A rating |
| Masala Dabbas Foods Ltd | Orpington | A rating |
| MASALA DERBY LIMITED | Derby | A rating |
| Masala Express Suffolk Limited | Lakenheath | A rating |
| MASALA HUT HATFIELD LTD | Hertfordshire | A rating |
| MASALA INDIAN SPICE LTD T/A Aleeza's Finest Indian Cusine | SPENNYMOOR | A rating |
| Masala One Ltd | Southminster | A rating |
| Masala Spice Ltd, T/A Curry Mahal Restaurant | Bristol | A rating |
| Masaud Solicitors Limited T/A MSD Solicitors | Manchester | A rating |
| Masaya Limited | Ascot | A rating |
| MASB Accounts Limited | London | A rating |
| MASB Group Limited | Manchester | A rating |
| Mascalls Stud | Brentwood | A rating |
| Mascolo Ltd T/A Toni & Guy | London | A rating |
| Mascot Bespoke Homes Limited | London | A rating |
| Masdar Offshore Wind UK Limited | London | A rating |
| Masdar UK Development Company Limited | London | A rating |
| MASECO LLP t/a MASECO Private Wealth | London | A rating |
| Maserati GB Limited | Slough | A rating |
| Mash Direct Limited | Comber | A rating |
| Mash Foods Ltd | Croydon | A rating |
| Mash Lift Installation LTD | LONDON | A rating |
| Mash Media Group Ltd | Kingston Upon Thames | A rating |
| Masha Popova Ltd | London | A rating |
| Mashco Limited | Watford | A rating |
| Mashreqbank psc | London | A rating |
| Mashua Ltd | London | A rating |
| Masibrook Limited T/A BUKHARA RESTAURANT | PRESTON | A rating |
| Masil Food and Wine Ltd | London | A rating |
| Masila Superstore | Birmingham | A rating |
| MASILLA FOOD & WINE LTD | London | A rating |
| Masintelligence Limited | Amersham | A rating |
| MASISO LTD | Milton Keynes | A rating |
| Masjid Al Aqsa | Bolton | A rating |
| MASJID AL-HUMERA | London | A rating |
| Masjid and Imambargah Shuhdae Karbala | London | A rating |
| Masjid Tooba (Wigan Mosque) | Wigan | A rating |
| Masjid-Al-Momineen | Blackburn | A rating |
| MASJID-E-ALI (A.S) | Luton | A rating |
| MASJID-E-NOORUL ISLAM | BOLTON | A rating |
| MASKED FRAME PICTURES LIMITED | LONDON | A rating |
| MASKOLD ENVIRONMENTAL LTD | LONDON | A rating |
| Masks Hospitality Ltd T/A Bhageecha | Elstree | A rating |
| Maslow Capital UK Limited | London | A rating |
| Mason & Carr Property Management Limited | EDINBURGH | A rating |
| Mason & M Limited | Cambridge | A rating |
| MASON ADVISORY LIMITED | London | A rating |
| Mason and Marlowe Ltd | MANCHESTER | A rating |
| Mason Clark Associates | Hull | A rating |
| Mason Events Management Ltd | london | A rating |
| Mason Jewellers Limited | Leeds | A rating |
| Mason Yardley Trust | Birmingham | A rating |
| Masons Car Service Limited | London | A rating |
| Masons Local | Birmingham | A rating |
| Masons Meats Limited | London | A rating |
| Masons Passive Fire Protection Ltd | Essex | A rating |
| Masonwood Build Ltd | Iver | A rating |
| Masood Textiles & Trimmings Ltd | Rochdale | A rating |
| Masq London Ltd | London | A rating |
| Masraf London Ltd | London | A rating |
| Masref Ltd t/a Nsave | London | A rating |
| MASRI & SONS LTD T/ATHE CHEQUERS INN | WITNEY | A rating |
| Masro Construction Ltd | London | A rating |
| Masroor Ahmad T/A Rufies Clapham | London | A rating |
| MASS (UK) LTD | Harrow | A rating |
| MASS Analytics Ltd | London | A rating |
| Mass Bespoke Furniture UK Ltd | London | A rating |
| Mass Care Momentous Ltd | Taunton | A rating |
| MASS COMPLETE PROPERTY SOLUTIONS LTD | Hertfordshire, United Kingdom | A rating |
| Mass Grill And Pizza Ltd | London | A rating |
| Mass Information Systems Ltd | Wokingham | A rating |
| MASS LUBRICANTS LIMITED | Glasgow | A rating |
| MASS PROPERTY & MANAGEMENT LTD | Cheadle | A rating |
| Mass Spectrometry Instruments Limited | Dewsbury | A rating |
| Mass&many Ltd | London | A rating |
| Massage Harmony LTD | Surbiton | A rating |
| Massala Express Limited | Yeovil | A rating |
| MASSALA JUNCTION LTD T/A MASSALA JUNCTION | Kettering | A rating |
| MASSALA LTD | Middlesbrough | A rating |
| MASSALA SPICE LIMITED t/a CINNAMON TREE | CHEADLE | A rating |
| Massala Takeaway Indian Limited | Leicestershire | A rating |
| MASSALLA CLUB (WOLVERHAMPTON) LIMITED T/A Massalla Club | Wolverhampton | A rating |
| Massari Ltd | LONDON, | A rating |
| MASSCAPITAL LTD | Bristol | A rating |
| Masses TV Limited | London | A rating |
| MASSI'S KITCHEN LTD | Ilford | A rating |
| Massilly UK Limited | Swansea | A rating |
| MASSIMO LONDON LTD | London | A rating |
| MASSIO LIMITED | London | A rating |
| MASSIVE DESIGN STUDIO LTD | London | A rating |
| Massive Rocket Limited | Hertfordshire | A rating |
| MASSIVE TRADERS LTD | FARNBOROUGH | A rating |
| MASSOLIT Online Education | London | A rating |
| Masstock Arable (UK) Limited | Cheltenham | A rating |
| MASSY ENTERPRISES LTD | Gateshead | A rating |
| MAST UK LTD | Manchester | A rating |
| Mast-Jaegermeister UK Limited | London | A rating |
| Masta Limited | London | A rating |
| Mastaa-Care Pharmacy Ltd | DAGENHAM | A rating |
| Mastek (UK) Limited | Reading | A rating |
| Mastek Systems Company Limited | London | A rating |
| MASTER & CO INVESTMENTS LTD | Bradford | A rating |
| Master Akmol Hussain Trust | London | A rating |
| master and fellows of peterhouse | cambridge | A rating |
| MASTER AUTO GLASS LIMITED | LONDON | A rating |
| MASTER AUTOS LTD | Barking | A rating |
| Master Bakers Ltd T/A Cakes & Bakes Original | London | A rating |
| MASTER BAO CATERING MANAGEMENT LTD | London | A rating |
| Master Builders VS Limited | London | A rating |
| MASTER CARE LTD | NORWICH | A rating |
| MASTER CUT KENT LTD | Margate | A rating |
| MASTER DWELLINGS CONSTRUCTION LTD | London | A rating |
| Master Electronic Technology Ltd | Bilston | A rating |
| Master Fryer | Barry | A rating |
| MASTER HEATING & ELECTRICAL LTD | Wembley | A rating |
| MASTER HOME DISCOUNT WAREHOUSE LTD | Coventry | A rating |
| Master Joinery & Woodworks Ltd | Ruislip | A rating |
| MASTER KEBAB HOUSE LTD | Banbury | A rating |
| MASTER MASSAGE EQUIPMENT LIMITED | Fareham | A rating |
| Master Mindz Ltd | Buckinghamshire | A rating |
| Master Motors MCR LTD | Manchester | A rating |
| Master Pens Ltd | Bicester | A rating |
| MASTER SOFTWARE SOLUTIONS LTD | READING | A rating |
| MASTER STUDIES WORLDWIDE | London | A rating |
| MASTER TRADE NETWORK LTD T/A MFG | London | A rating |
| MASTER'S TAILORING & FASHION SHOP LIMITED | Walsall | A rating |
| Mastercard UK Management Services LTD | London | A rating |
| Masterchef Ventures Limited | Manchester | A rating |
| Masterclass Properties Limited | London | A rating |
| Masterclean Drycleaner Service Ltd | London | A rating |
| MasterControl Global Ltd | Basingstoke | A rating |
| Mastercraft Construction (UK) Limited | Co.Derry | A rating |
| Mastered Studios | London | A rating |
| Masterguild Limited | Hayes | A rating |
| Masterinnominds Limited | Welwyn Garden City | A rating |
| Mastermedicine Limited | Ilford | A rating |
| MASTERMIND ELECTRICAL LIMITED | London | A rating |
| MASTERMIND SPV6 LTD | Halifax | A rating |
| MasterMover Ltd | Derby | A rating |
| MASTERNAUT LIMITED | LEEDS | A rating |
| MASTERPRINT PACKAGING LTD | Dewsbury | A rating |
| Masters UK Ltd. | Birmingham | A rating |
| MASTERTINT UK LIMITED | Bolton | A rating |
| MASTRICK SMILE CARE | ABERDEEN | A rating |
| MASUKH LTD T/A MABROOR BY NESATH | Upminster | A rating |
| Masumin Ltd T/A Abbeleigh House | Romford | A rating |
| Masuri Group Ltd | Winchester | A rating |
| MASUTAKI LIMITED | London | A rating |
| Maswell Park Food & Wine Ltd | Hounslow,Middlesex | A rating |
| MASZ TECHNOLOGIES LIMITED | Leicester | A rating |
| Mat Zero Heat Ltd | Hexham | A rating |
| MATA Architects Limited | London | A rating |
| MATA CHINTPURNI MANDIR LTD TRADING AS | WOLVERHAMPTON | A rating |
| Mata Sahib Kaur Educational Trust | Leicester | A rating |
| Matadar Investments Limited | Lancashire | A rating |
| MATAI STONE LTD | Chobham | A rating |