| Maris Interiors | London | A rating |
| Marisco Medical Practice | Mablethorpe | A rating |
| Mariso Holding Ltd | Birmingham | A rating |
| Marissa Leisure Limited | Northallerton | A rating |
| MARISU LIMITED | Hounslow | A rating |
| Maritime & Coastguard Agency | Southampton | A rating |
| Maritime + Engineering College North West (trading as the Engineering College) | Birkenhead | A rating |
| Maritime Academy Trust | London | A rating |
| Maritime Asset Partners (UK) Limited | London | A rating |
| Maritime Beds Ltd T/A Maritime Beds | Dewsbury | A rating |
| MARITIME CHRISTIAN MINISTRIES | Litherland | A rating |
| Maritime Craft Services (Clyde) Ltd | Fairlie | A rating |
| Maritime Developments Limited | Aberdeen | A rating |
| Maritime Insights & Intelligence Limited t/a Lloyd's List Intelligence | London | A rating |
| Maritime International Secretariat Services Limited | London | A rating |
| Maritime Strategies International Ltd. | London | A rating |
| Maritime Technical International Limited | London | A rating |
| Maritime Ventures UK Ltd | London | A rating |
| Marium Jeelani Limited | London | A rating |
| MARIUS WM LTD | Birmingham, | A rating |
| Mariya London Stores Limited | Mansfield | A rating |
| MARIYA THEVAKANNA T/A T.Mariya Food and Wine | Stoke on Trent | A rating |
| MARJAN FASHION LIMITED | Loughton | A rating |
| Marjan Tile Limited | London | A rating |
| Marjolo Partners Ltd | Sheffied | A rating |
| Marjoram Trading Ltd | Chelmsford | A rating |
| Marjorie McClure School | Chislehurst | A rating |
| MARK & SONS LIMITED | Ilford | A rating |
| Mark Allen Group | London | A rating |
| Mark Asplin Whiteley Ltd | Whitby | A rating |
| Mark B Properties Ltd | Harrow | A rating |
| Mark Bates Limited | Grantham | A rating |
| Mark Bennett Vogel | London | A rating |
| Mark Berryman Design Limited | Lymington | A rating |
| MARK BUILDING MAINTENANCE LTD | London | A rating |
| Mark Capital Management Limited | London | A rating |
| Mark Christopher Howarth London Limited | London | A rating |
| Mark Copper Roofing Ltd | Inverness | A rating |
| Mark Fairhurst (Architects) Limited | London | A rating |
| MARK FISHER CARSHALTON LIMITED | London | A rating |
| Mark Goucher Productions Limited | London | A rating |
| MARK IDENTITIES LIMITED | Chelmsford | A rating |
| Mark Lloyd Ltd | Hartlepool | A rating |
| MARK LOUCAS LIMITED | London | A rating |
| Mark O'Lone | Ardkeen | A rating |
| Mark Roberts Motion Control Limited | Blindley Heath | A rating |
| Mark Rubinstein Ltd | London | A rating |
| Mark Ryan Consulting | Wellingborough | A rating |
| Mark Taylor Support Ltd | Telford | A rating |
| Mark Time Care Limited | Nottingham | A rating |
| Mark Wray Architects Limited | Bath | A rating |
| Mark-Up Tools Limited | Manchester | A rating |
| MARK'ENNOVY PERSONALIZED CARE LIMITED | Romsey | A rating |
| Mark's Cotswold Bakery Ltd | Chipping Norton | A rating |
| Mark43 UK Limited | Manchester | A rating |
| Markaz Al Huda Ltd | Bury | A rating |
| MARKAZI JAMIA MASJID GHAUSIA | HUDDERSFIELD | A rating |
| markazi jamia mosque riza | huddersfield | A rating |
| MARKAZI JAMIAT AHL E HADITH | Bradford | A rating |
| Markbase Limited T/A Primrose Corner | London | A rating |
| Markcon Limited | London | A rating |
| Markel International Services Limited | London | A rating |
| Markem-Imaje Industries Limited | Nottingham | A rating |
| Marken Limited | Feltham | A rating |
| Marker Diagnostics UK Limited | Edgbaston | A rating |
| Markerstudy Group Services Limited | Sevenoaks | A rating |
| Markerstudy Insurance Services Limited | Brentwood | A rating |
| Markerstudy Insurance Services Limited | Sevenoaks | A rating |
| Markes International Ltd. | Bridgend | A rating |
| Market Alley Artisan Foods Ltd | London | A rating |
| MARKET BUTCHER LTD | LONDON | A rating |
| Market Cloud Ltd | London | A rating |
| Market Deeping Cricket Club | Market Deeping | A rating |
| Market Direct Ltd | Hounslow | A rating |
| Market Drayton Dental Practice Limited | Gloucester | A rating |
| Market Harborough & Bosworth Partnesrhip | Market Harborough | A rating |
| MARKET INTELLIGENCE INTERNATIONAL | LONDON | A rating |
| Market Lane Dental Care | Selby | A rating |
| Market Lavington Surgery | Devizes | A rating |
| MARKET LINK GROUP LIMITED | London | A rating |
| MARKET MAKERS AI LIMITED | London | A rating |
| MARKET NEWS LIMITED | LONDON | A rating |
| Market of Choice LTD | Dewsbury | A rating |
| Market Quarter Medical Practice | Rugby | A rating |
| Market Rasen Surgery | Market Rasen | A rating |
| Market Resource Partners Limited | Belfast | A rating |
| Market Rocket Limited | London | A rating |
| Market Securities LLP | London | A rating |
| MARKET SHOPPY LTD | Hounslow | A rating |
| MARKET SQUARE DENTAL LTD | Bicester | A rating |
| MARKET SQUARE NEWS LTD t/a LONDIS MARKET SQUARE NEWS LTD | DOVER | A rating |
| MARKET STREET CLINIC LTD | Launceston | A rating |
| Market Street Dental Care | Nottingham | A rating |
| Market Street Health Group | Eastham | A rating |
| Market Street Medical Practice | Droylsden | A rating |
| Market2Marketers | London | A rating |
| MarketAxess Europe Ltd | London | A rating |
| Marketbridge Europe Limited | London | A rating |
| Marketcam LTD | Cambridge | A rating |
| Marketcast UK Limited | London | A rating |
| Marketglen Limited T/A Lake Vyrnwy Hotel and Spa | Oswestry | A rating |
| Markethub Technologies Ltd | London | A rating |
| Marketing and Leisure Management Limited | Poole | A rating |
| Marketing Distribution Services Ltd | London | A rating |
| Marketing Fish Ltd | London | A rating |
| Marketing Mavens (Scotland) Ltd | Glasgow | A rating |
| MARKETING MONKEYS LIMITED | Sutton | A rating |
| Marketing Options Limited | Surrey | A rating |
| Marketing Pro Limited | London | A rating |
| Marketing Ventures Limited | Leeds | A rating |
| Marketing VF Ltd | London | A rating |
| MARKETINGFLOW LIMITED | Manchester | A rating |
| marketingQED Ltd. | London | A rating |
| Marketplace Ministries Limited | Totnes | A rating |
| Marketplace Platforms Limited | London | A rating |
| Markets Group Ltd | London | A rating |
| MarketsandMarkets Limited | North Harrow | A rating |
| Markey Tyres Ltd | Portadown | A rating |
| MARKFIELD CONVENIENCE STORE LTD | LEICESTER | A rating |
| Markfield Institute of Higher Education | Markfield | A rating |
| Markhor (UK) Ltd | Enniskillen | A rating |
| Markhor Club Ltd | Middleton | A rating |
| Markides Associates Ltd | London | A rating |
| Markies LTD | Wakefield | A rating |
| Markimeld Limited trading as Lisboa Patisserie | London | A rating |
| MarkitSERV Ltd. | London | A rating |
| Markpro Trading Ltd | London | A rating |
| Marks and Clerk LLP | London | A rating |
| Marks and Spencer Group Plc | London | A rating |
| Marks Barfield Ltd | London | A rating |
| Marks Baughan Securities UK, LLP | London | A rating |
| Marks Gate Health Centre | Romford | A rating |
| Marks Heeley Ltd | Bishops Stortford | A rating |
| Marks Tey Hotel | Colchester | A rating |
| MARKS-V LIMITED | HATFIELD | A rating |
| Marksman Roofing + Cladding Ltd | Nottingham | A rating |
| Markson Pianos Limited | London | A rating |
| Markson Pianos Ltd | London | A rating |
| Marktlink North UK M&A Limited | Manchester | A rating |
| MarktoMarket Valuations | Edinburgh | A rating |
| Markup Design Ltd | Bury St Edmunds | A rating |
| MARKWEBIT LTD | Crawley | A rating |
| Markyate Grill Ltd | ST. Albans | A rating |
| Marl Ltd | London | A rating |
| MARL PARTNERS LLP | LONDON | A rating |
| Marlan Maritime Technologies Ltd | Liverpool | A rating |
| Marlborough (UK) Ltd T/A Hills Pharmacy | London | A rating |
| Marlborough Bakeries (1942) Limited | Mottingham | A rating |
| MARLBOROUGH CHARCOAL GRILL LTD | Wiltshire | A rating |
| Marlborough Clinic Belfast Ltd | Belfast | A rating |
| Marlborough Club Limited | Newmarket | A rating |
| Marlborough College | Marlborough | A rating |
| Marlborough Dental Centre | Ilfracombe | A rating |
| MARLBOROUGH HIGHWAYS LIMITED | Chelmsford | A rating |
| Marlborough House Advisors Ltd | London | A rating |
| Marlborough House Partners LLP | Chelmsford | A rating |
| Marlborough House School Trust Ltd | Cranbrook | A rating |
| Marlborough House Vinehall School Ltd | Robertsbridge | A rating |
| Marlborough School | Sidcup | A rating |
| Marlborough Surgery | Seaham | A rating |
| Marldon | London | A rating |
| Marldon Joinery | London | A rating |
| MARLEY COURT CARE HOME LIMITED | Chorley | A rating |
| Marley Health Limited | London | A rating |
| Marley Limited | Burton upon Trent | A rating |
| Marlin Equity Partners Limited | London | A rating |
| Marlin Hawk Limited | London | A rating |
| MARLIYAH T4 LIMITED T/A T4 Tea For You | Hackney | A rating |
| Marloco Limited | Leeds | A rating |
| MARLOU CONSULTANCY LIMITED | London | A rating |
| Marlow C of E Infant School | Marlow | A rating |
| Marlow Education Trust | Marlow | A rating |
| Marlow Foods Limited | Stokesley | A rating |
| MARLOW POST OFFICE | MARLOW | A rating |
| Marlow Ropes Ltd | Hailsham | A rating |
| Marlow Vets | Chepstow | A rating |
| Marlowe Limited | London | A rating |
| MARLYN RECRUITMENT LTD | Essex, | A rating |
| Marmaduke Street | Liverpool | A rating |
| Marmadukes Cafe Deli Ltd | Sheffield | A rating |
| Marmalade Restaurants Limited | Worcester | A rating |
| Marmalade Schools | LONDON | A rating |
| MARMAR TEXTILES LTD | Birmingham | A rating |
| Marmarekas Grill Ltd | Rotherham | A rating |
| MARMARIS KEBAB (ABERDEEN) LIMITED | Aberdeen | A rating |
| Marmaris Whitehaven Limited | Whitehaven | A rating |
| MARMELO KITCHEN LTD | LONDON | A rating |
| Marmora Ltd T/A Marmora Care Home | Essex | A rating |
| MARNI CONSULTANCY LTD | Birmingham | A rating |
| Maro Construction Limited | London | A rating |
| MAROK CONSTRUCTIONS LTD | WOLVERHAMPTON | A rating |
| MAROKH BRICKWORK LTD | Wolvehampton | A rating |
| Maron System Limited | Swansea | A rating |
| Maronsett Limited T/A Impact | Greenford | A rating |
| Marosa Ltd. | Liverpool | A rating |
| Maroush Co Limited | LONDON | A rating |
| Maroush Group Limited | London | A rating |
| Marown Holdings Limited | Richmond, London | A rating |
| Marpal Ltd | Derby | A rating |
| MARPLE NEWS LTD | Stockport | A rating |