| Mar-Key Group Limited | Christchurch | A rating |
| Mar-Train Heavy Haulage Ltd | Lisburn | A rating |
| Mara Invest Limited | London | A rating |
| MARA LABS UK LIMITED | London | A rating |
| Maracanda Ltd t/a Green Mosaic | London | A rating |
| MARAFA FOODS LTD | Manchester, | A rating |
| MARAFIE CONSULTANCY UK LTD. | Stockport | A rating |
| Marah Ltd T/A Maple Dental Clinic | Luton | A rating |
| Marais associates Ltd | Hornchurch | A rating |
| Maral Enterprises Limited | London | A rating |
| MARALB CONSTRUCTION LTD | Maidenhead, | A rating |
| Marama Care PVT Ltd | Plymouth | A rating |
| Maran UK Limited | London | A rating |
| Maranatha Healthcare Limited t/a Home Instead Birmingham | Birmingham | A rating |
| Marantomark Limited | Oldham | A rating |
| Marash & Kids Limited | Essex | A rating |
| MARATHON ARTISTS LTD | LONDON | A rating |
| Marathon Asset Management (Services) Ltd | London | A rating |
| Marathon Capital Ltd | London | A rating |
| Marathon Music Limited | London | A rating |
| MARATHON TRADE & CONSULTING LIMITED | London | A rating |
| Marathon Trading and Supply Services Limited | London | A rating |
| Marathonians Music Group Limited | London | A rating |
| Marble & Joinery Workshop LTD | London | A rating |
| Marble Aerospace Limited | Chippenham | A rating |
| MARBLE ARCH EXPRESS LTD | London | A rating |
| MARBLE ARCH INN | MARBLE ARCH | A rating |
| Marble Bar Asset Management LLP | London | A rating |
| Marble Direct | Glasgow | A rating |
| Marble Endeavour Ltd | London | A rating |
| Marble Hall Services Ltd t/a Radfield Home Care Camberley, Farnborough & Fleet | Camberley | A rating |
| Marble Services Limited | London | A rating |
| Marble4life LTD | Leeds | A rating |
| Marbleside Care | Margate | A rating |
| Marblism UK Ltd | London | A rating |
| Marbrook Ltd | St Neots | A rating |
| Marc & Partners Ltd | London | A rating |
| Marc Jacobs International (UK) Limited | London | A rating |
| Marc Newson Limited | London | A rating |
| MARCEGAGLIA STAINLESS SHEFFIELD LTD | SHEFFIELD | A rating |
| Marceline (Canary Wharf) Limited | Croydon | A rating |
| March Physiotherapy Clinic Ltd. | March | A rating |
| March Specsavers Ltd | March | A rating |
| March Stud Limited | Northampton | A rating |
| March Town Cricket Club | March | A rating |
| Marcham Road Health Centre Abingdon | Abingdon | A rating |
| Marchanson Ltd | London | A rating |
| MarchantCain Group Ltd | Coventry | A rating |
| Marchants & Co Limited | Leigh on Sea | A rating |
| MARCHBPGARAGE LTD T/A BP | March, | A rating |
| Marches Academy Trust | Oswestry | A rating |
| Marches Architectural Hardware Limited | Llandrindod Wells | A rating |
| Marches Construction Management Ltd | KENT | A rating |
| Marches Medical Practice | Broughton | A rating |
| Marchharv Ltd T/A The Royal Goat Hotel | Beddgelerth | A rating |
| Marcho Partners Services (UK) Limited | London | A rating |
| Marchon Group Limited | Harpenden | A rating |
| Marcia Edwards t/a ME Dance Company | Stourbrudge | A rating |
| Marcio Jorge | Marlborough | A rating |
| Marcloud Limited | Liverpool | A rating |
| Marco Angelini and Co, Ltd | London | A rating |
| Marco Botti Limited | Newmarket | A rating |
| Marco investments Limited | Manchester | A rating |
| Marco Italian Restaurant Ltd T/A Made in Italy | Chester | A rating |
| Marco Leite | Llanrwst | A rating |
| Marco Limited | Edenbridge | A rating |
| MARCOM DIGITAL SOLUTIONS LTD | COVENTRY | A rating |
| Marcon Fit-Out Ltd | Antrim | A rating |
| Marconato Limited | Herts | A rating |
| Marcopolo Bakery | Wantage | A rating |
| Marcopolo Food Ltd TA Marco Polo | Wickford | A rating |
| MarcoPolo Learning Ltd | London | A rating |
| Marcrist International Limited | Doncaster | A rating |
| Marcura UK Limited | Worthing | A rating |
| Marcus & Marcus Limited | Enfield | A rating |
| Marcus Barnett Studio | London | A rating |
| Marcus Care Homes Ltd T/A Enstone House | Chipping Norton | A rating |
| Marcus Humphrey House | Bridge of Weir | A rating |
| MARCUS NEIMAN LIMITED | Romford | A rating |
| Marcusp Ltd | Widnes | A rating |
| Marden Medical Centre | Tonbridge | A rating |
| Marden Medical Practice | Shrewsbury | A rating |
| MARDON LIMITED | Lancaster | A rating |
| Mare Nostrum Group | Harrogate | A rating |
| Marek Wojciechowski Architects Limited | London | A rating |
| Marel Limited | Colchester | A rating |
| Marelli Automotive Systems Europe plc | Llanelli | A rating |
| Marelli Automotive Systems UK Ltd | Llanelli | A rating |
| Marex Group Plc | London | A rating |
| Marex Marine Services Limited | Aberdeen | A rating |
| MARFA STANCE LTD | London | A rating |
| MARFAST & CO LTD | MANCHESTER | A rating |
| MARFISHECO LTD | Edinburgh | A rating |
| Marfleet Group Practice (Dr J A D Weir & Partners) | Hull | A rating |
| Marg Sat Santokh Manufacturers Limited | Birmingham | A rating |
| Margalla Hills UK Ltd | Slough | A rating |
| Margaret Beaufort Institute of Theology | Cambridge | A rating |
| MARGARET HOUSE (HERTFORDSHIRE) LIMITED | Hertfordshire | A rating |
| Margaret House Residential and Dementia Care Home | Royston | A rating |
| Margaret Howell Limited | London | A rating |
| MARGARET ROAD STORES LTD | HAMILTON, | A rating |
| Margaret Rose Care Ltd T/As Warberries Nursing Home | Torquay | A rating |
| Margarets Homecare Services Ltd | Bournemouth | A rating |
| Margarot Forrest Care Management Ltd | Edinburgh | A rating |
| Margate Food Investments Ltd TA Subway | Margate | A rating |
| Margate House Limited | London | A rating |
| Margate Specsavers Limited T/A Specsavers Opticians | Broad Stairs | A rating |
| Margaux Ltd | London | A rating |
| Margaux Platforms Limited | London | A rating |
| Margav Renewables Ltd | Rugeley | A rating |
| Margetts Fund Management Limited | Birmingham | A rating |
| Margin Goods Group Ltd | LONDON | A rating |
| MARGIN SOLUTIONS LTD | Glasgow | A rating |
| Margiotta Limited | Edinburgh | A rating |
| Margo Consulting Ltd | London | A rating |
| Margot Bakery Ltd | London | A rating |
| Marhaba Charitable Trust & Masjid Al Noor | Boston | A rating |
| MARHABA SWEETS LTD | BLACKBURN | A rating |
| MARHABA TELECOMMUNICATION SYSTEMS LTD | BIRMINGHAM | A rating |
| MARIA CARE LIMITED | North Somerset | A rating |
| Maria Grachvogel Ltd | LONDON | A rating |
| Maria Luisa de Moreno International Foundation | London | A rating |
| MARIA MOMPO LIMITED | ILFORD | A rating |
| Maria Montessori Ltd T/A Maria Montessori Nursery School | London | A rating |
| Maria Montessori Nursery Limited T/A Maria Montessori Nursery School | London | A rating |
| Maria Montessori Training Organisation (The) | London | A rating |
| Maria Nila UK Limited | Warwick | A rating |
| Maria Residential Home EMI Ltd | High Wycombe | A rating |
| Maria Stolbova's Rhythmic Gymnastics Academy LLP | London | A rating |
| MariaDB UK Limited | London | A rating |
| Mariage Freres Royaume Uni | London | A rating |
| MARIAH'S COLLECTION | Bradford | A rating |
| Mariam Global Limited | Manchester | A rating |
| Marian Engineering Ltd | Birtley | A rating |
| Marian Fathers Charitable Trust | London | A rating |
| Marian House Care Home | Uxbridge | A rating |
| Marian Mission for the Poor | Leyton | A rating |
| Mariana UFP LLP | London | A rating |
| Marianna Financial Services Limited | Brentford | A rating |
| Mariapolis Ltd | Welwyn Garden City | A rating |
| MARICARE LIMITED T/A BEECH HAVEN CARE HOME | Oxfordshire | A rating |
| Marick Real Estate Ltd | London | A rating |
| Marie Curie | London | A rating |
| MARIE-CHANTAL LIMITED | London | A rating |
| Marieco Care Ltd | Leytonstone | A rating |
| Maried De Louise Limited | London | A rating |
| MARIELANE GOLD LTD | Derby | A rating |
| MARIGOLD AND MANGO LTD | WEST BYFLEET | A rating |
| Marigold care Group Ltd | London | A rating |
| MARIGOLD INSULATION UK LTD | Halesowen | A rating |
| Marigold MG1 Ltd | Borehamwood | A rating |
| Marigold Services Limited | Forest Gate | A rating |
| MARIJAK LIMITED | London | A rating |
| Marilak Services Limited | Hatfield | A rating |
| Marillac Neurological Care Centre | Brentwood | A rating |
| MARIMEX INSULATION AND INTERNATIONAL TRADING LTD | LEICESTER | A rating |
| Marina Cafe Limited | Edinburgh | A rating |
| MARINA EDUCATION CONSULTANTS LTD | England | A rating |
| Marina Lodge | Scarborough | A rating |
| MARINA MASALA LTD T/A LOTUS INDIAN KITCHEN | MERCIA MARINA | A rating |
| Marina Projects Ltd | Southampton | A rating |
| MARINA RETAIL STORE LIMITED | SAINT LEONARDS -ON - SEA | A rating |
| Marina Rossmann ta Station Yard Dental Practice | Needham Market | A rating |
| MARINA SEAVIEW LTD | MILTON KEYNES | A rating |
| Marina United Limited | Swansea | A rating |
| MarinaTex | Brighton | A rating |
| Marine Capital Limited | London | A rating |
| MARINE DENTAL PRACTICE LIMITED | Worthing | A rating |
| Marine Fabrication and Engineering Limited | Truro | A rating |
| Marine Fish Bar UK Limited | Leicester | A rating |
| Marine Hotel (Ballycastle) Ltd | Ballycastle | A rating |
| Marine Ingredients Certifications Ltd | London | A rating |
| Marine Labour Services MLS Ltd | Southampton | A rating |
| Marine Management Organisation | Newcastle | A rating |
| Marine Power Systems Limited | Swansea | A rating |
| Marine Procurement Ltd | North Berwick | A rating |
| Marine Shipbuilding Company UK Ltd | London | A rating |
| Marine Stewardship Council | London | A rating |
| Marine Supply Limited | Falmouth | A rating |
| Marine Systems Technology Ltd | Winsford | A rating |
| Marine Technical Limits Limited | Kintore | A rating |
| MARINE VIEW REST HOME | HOVE | A rating |
| Marine Zero Limited | Retford | A rating |
| MarineGuard Systems Ltd | Southampton | A rating |
| Mariner Estate Limited | London | A rating |
| Mariner Europe Limited | London | A rating |
| Marino Foods Limited | Durham | A rating |
| Marinpine Transport (UK) Limited | London | A rating |
| Marinus Fuel Ltd | Andover | A rating |
| Marinus Ltd | Kent | A rating |
| MARIO COACH TRAVEL LIMITED | Nelson | A rating |
| Mario E Peppe Ltd | London | A rating |
| Mario Motors | Basingstoke | A rating |
| MARIO'S PFC LTD | London | A rating |
| Marion Lauder House | Manchester | A rating |
| MARION TRADING LTD | Birmingham | A rating |
| MARIONETE LIMITED | LONDON | A rating |
| MARIOS PIZZA AND CHICKEN LIMITED | Loughborough | A rating |
| MARIOUK LTD | Aberdeen | A rating |
| Mariposa Care Group Limited | Matlock | A rating |