| OTAS SUPPORTED LIVING LIMITED | SHEERNESS | A rating |
| Otaski Energy Solutions Ltd | Gateshead | A rating |
| OTB Engineering Limited | London | A rating |
| OTC Direct Services LTD | Sheffield | A rating |
| OTC Europe LLP | London | A rating |
| OTDC LIMITED | Aberdeen | A rating |
| OTDS LTD | REDHILL | A rating |
| OTE PLC | London | A rating |
| OTEL SOLUTIONS LTD | London | A rating |
| OTERRA UK LIMITED | Holbeach | A rating |
| Other People's Sculpture Limited | London | A rating |
| OTHER SOLUTIONS Consulting | London | A rating |
| Otherway London Limited | London | A rating |
| OTHM QUALIFICATIONS | DARTFORD | A rating |
| Oticon Ltd | Hamilton | A rating |
| Otis Eventing Ltd | Ellesmere | A rating |
| Otis Limited | London | A rating |
| OTIS NEWS AGENT LIMITED t/a BEST ONE NEWS AGENT | Northampton, | A rating |
| Otley Cricket Club | Otley | A rating |
| OTO Technologies Limited | Blackburn | A rating |
| OTO WELLBEING LIMITED | London | A rating |
| Otodynamics LTD | Hatfield | A rating |
| Otoshi Limited | London | A rating |
| OTOVO LIMITED | LONDON | A rating |
| OTPD LTD | London | A rating |
| OTRIUM UK LIMITED | Manchester | A rating |
| Otsuka Pharmaceutical Europe Ltd | Windsor | A rating |
| Otta Technology Limited t/a Otta | London | A rating |
| Otter Bookbinding LIMITED | Midhurst | A rating |
| Otter Ferry Seafish Ltd | Tighnabruaich | A rating |
| Otterbourne Care Limited | Winchester | A rating |
| OTTERSHAW CHERTSEY LTD T/A 3 Rooms Indian Restaurant | Chertsey | A rating |
| Ottery St Mary Station | Ottery St. Mary | A rating |
| Ottewill Silversmiths & Jewellers Limited | Ashford | A rating |
| Otto Bock Healthcare PLC | Egham | A rating |
| Otto Car Limited | London | A rating |
| Otto Parade Limited | Chislehurst | A rating |
| OTTO UHA LTD | Chorley, | A rating |
| OTTO&BEK LTD | Kent | A rating |
| Ottolenghi Limited | London | A rating |
| Ottolenghi Ltd | London | A rating |
| Ottoman Whitechapel Ltd | London | A rating |
| OTUGAGA GLOBAL CONCEPTS LIMITED | Northampton | A rating |
| Otus Capital Management Limited | London | A rating |
| Oud Milano UK Ltd t/a Abdul Samad Alqurashi and Oud Milano | Hitchin | A rating |
| OUGHTIBRIDGE STORE | SOUTH YORKSHIRE | A rating |
| Oughtibridge War Memorial Cricket Club | Sheffield | A rating |
| OUI CHEF FRUIT AND PRODUCE LIMITED | London | A rating |
| OUITECH LTD | Stockport | A rating |
| Oujla Group Ltd | Glasgow | A rating |
| Ouka London Ltd | London | A rating |
| Oundle School | Peterborough | A rating |
| Oundle Town Cricket Club | Peterborough | A rating |
| Ounje Adun Ltd (Africfood) | Cambridge | A rating |
| Ouno Creative | Farnborough | A rating |
| our Daily Bread Ministries Trust | Carnforth | A rating |
| our dentist | glasgow | A rating |
| OUR FAMILY CARE HOME LIMITED TA Bescot Lodge Care Home | West Midlands | A rating |
| Our Fashion Ltd | LEICESTER | A rating |
| Our Footprints Ltd | Bristol | A rating |
| Our Health Partnership | Birmingham | A rating |
| Our Kids Nursery | Birmingham | A rating |
| Our Lady Immaculate Catholic Academies Trust | Northampton | A rating |
| Our Lady of Bethlehem Abbey Trust | Portglenone | A rating |
| Our Lady of Dolours RC Primary School | London | A rating |
| Our Lady of Fatima Catholic MAT | HARLOW | A rating |
| OUR LADY OF FIDELITY | LONDON | A rating |
| Our Lady of Fidelity (Virgo Fidelis Convent) | London | A rating |
| Our Lady of Grace Catholic Academy Trust | London | A rating |
| Our Lady of Lourdes Catholic Primary School | London | A rating |
| Our Legacy (UK) Ltd | London | A rating |
| Our Motive Ltd | Margate | A rating |
| Our Place Group (Our Place Schools and Lakeside) | Malvern | A rating |
| Our Retail Limited | Romford | A rating |
| OUR SHOP 3 LIMITED | Lancaster | A rating |
| Our Studio Ltd | Manchester | A rating |
| Our Voice Legal Ltd | Basildon | A rating |
| OUR-SCENT LTD | BARKING RIVERSIDE | A rating |
| OURHOUSING LIMITED | Small Heath | A rating |
| OurNet Health Services Ltd | WALSALL | A rating |
| OURONYX LIMITED | London | A rating |
| Ourris Properties Limited | London | A rating |
| Ourris Residential Homes Ltd | London | A rating |
| Ourway Care Ltd | Raunds | A rating |
| Oury Clark Chartered Accountants | Slough | A rating |
| Ousa Limited | London | A rating |
| Oushk Pharmacy Limited | Stockport | A rating |
| Ouster UK Ltd | Edinburgh | A rating |
| Out In Tech Ltd | London | A rating |
| Out of Hours West Lancshire CIC | Skelmersdale | A rating |
| OUT SINCE TUESDAY LIMITED | Gravesend | A rating |
| Out There Media Production Limited | Salford | A rating |
| Outback Imaging UK Limited | London | A rating |
| OUTBRAIN UK LTD | London | A rating |
| OUTCO Limited | Leatherhead | A rating |
| outcome care and support limited | Wolverhampton | A rating |
| Outcome Solutions and Services Limited | London | A rating |
| Outdoor Sagacity Ltd | London | A rating |
| Outerinsight Limited | London | A rating |
| OUTERLIMIT GROUP LTD | London | A rating |
| Outernet London Limited | Greater London | A rating |
| Outernet Venue Ltd | London | A rating |
| OUTFIT CLOTHING LIMITED | Leicester | A rating |
| Outfitters Stores UK Limited (t/a ETHNC) | London | A rating |
| Outfly Innovation Ltd | London | A rating |
| Outform Group UK Limited | Camberley | A rating |
| OutFox Bio Limited | Didcot | A rating |
| OUTLANE SPICE | Huddersfield | A rating |
| Outlier Ventures Operations Ltd | London | A rating |
| OUTLOOK (UK) LIMITED | Portsmouth | A rating |
| Outlook Energy Services Ltd | Bristol | A rating |
| Outokumpu Stainless Limited | Sheffield | A rating |
| Outplay Entertainment Limited | Dundee | A rating |
| Outpost Management Ltd | London | A rating |
| Outpost Technologies Ltd | London | A rating |
| Outpost VFX Limited | Bournemouth | A rating |
| Outra Limited | London | A rating |
| Outram Fields Care Home | Sheffield | A rating |
| Outreach Care and Staffing Ltd | Slough | A rating |
| Outreach Corporation UK Limited | London | A rating |
| Outright Care Ltd | Enfield | A rating |
| Outright Games Limited | Lee-on-the-Solent | A rating |
| OutSee Limited | Cambridge | A rating |
| Outserve Ltd | Stafford | A rating |
| Outset Limited | Maidstone | A rating |
| Outside In (Cambridge) Ltd | Cambridge | A rating |
| OutsideClinic Limited | Swindon | A rating |
| OUTSIZED VENTURES LIMITED | London | A rating |
| Outsolv Ltd | BIRMINGHAM | A rating |
| Outsource Automation Solutions Ltd | Sandbach | A rating |
| Outsource Experts Ltd | Nottingham | A rating |
| Outsource Media Ltd | London | A rating |
| OUTSOURCED ACC LTD | BECKENHAM | A rating |
| Outsourcing and Marketing Limited | London | A rating |
| Outsourcing UK Limited | London | A rating |
| OutSystems Limited | London | A rating |
| OutThink Ltd | London | A rating |
| Outverse Limited | London | A rating |
| Outward Capital LLP | London | A rating |
| Outwood Grange Academies Trust | Wakefield | A rating |
| Ouvra Ltd | Sale | A rating |
| OVAL CARE HOMES LTD | LONDON | A rating |
| OVAL CONSORTIUM LIMITED T/A PEPE'S PIRI PIRI | SHEFFIELD | A rating |
| Oval Convenience Ltd T/A Premier | Doncaster | A rating |
| Oval Insights Ltd | London | A rating |
| Oval Invincibles Ltd | London | A rating |
| Oval Spice Ltd | London | A rating |
| Oval Systems Limited t/as Oval Business Solutions | Godalming | A rating |
| Ovalhouse Theatre Ltd trading as Brixton House | London SW9 8GL | A rating |
| Ovalhouse Theatre Ltd Trading as Brixton House | London | A rating |
| OVARRO LIMITED | Sheffield | A rating |
| Ovation | Oakham | A rating |
| Ovation Bidco Ltd | Cambridge | A rating |
| OVATIONDATA LTD | ST PAULS CRAY | A rating |
| Ove Arup and Partners International Ltd | London | A rating |
| OVELSHIELD LIMITED | LONDON | A rating |
| OVEN SHINERS LIMITED | South Godstone | A rating |
| Ovenden Off Licence Ltd | Halifax | A rating |
| Over the Rainbow | Manchester | A rating |
| Over The Rainbow Day Nursery | Romford | A rating |
| Over There Ltd | Tameside | A rating |
| Over-Deliver Ltd | London | A rating |
| Overbury Plc | London | A rating |
| Overbury Stallions Ltd T/A Overbury Stud | Tewkesbury | A rating |
| OVERCHAIN HOLDINGS LIMITED | London | A rating |
| OVERDRIVE MOTOR REPAIRS LTD | Batley | A rating |
| Overington and Roberts LTD | York | A rating |
| Overley Hall Limited | Telford | A rating |
| Overmind | London | A rating |
| OVERNIGHT OPS LIMITED | London | A rating |
| OvernightSite Ltd | London | A rating |
| OVERPAID TAX LTD | HUDDERSFIELD | A rating |
| Oversea-Chinese Banking Corporation Ltd | London | A rating |
| OVERSEAS CAREER GURU LTD | Hounslow | A rating |
| Overseas Immigration LTD | Hounslow | A rating |
| Overseas Immigration Services UK Ltd | Southall | A rating |
| Overseas Interpreting Ltd | London | A rating |
| Overseas Tutorial Centre Ltd | London | A rating |
| Oversight Board UK | London | A rating |
| Overslade care limited T/A Right at Home (Bedford) | Kempston | A rating |
| Overstone Park School Limited | Northampton | A rating |
| Overthrow Digital Ltd | London | A rating |
| Overton Grange School | Sutton | A rating |
| Overton Park Surgery | Cheltenham | A rating |
| Overtoun House | Dumbarton | A rating |
| Overview Ltd | Woking | A rating |
| OVERZEST LTD | Ilford, London | A rating |
| OVG Europe Limited | London | A rating |
| OVH Ltd | London | A rating |
| Ovil Group of Companies Limited | London | A rating |
| OVIS HOSPITALITY LIMITED | London | A rating |
| Oviva UK Limited | London | A rating |
| OVIVO UK Ltd | Wolverhampton | A rating |
| Oviya Food and Wine LTD | BRADFORD | A rating |
| Ovo Consulting Limited | Watford | A rating |
| OVO Group LTD | Bristol | A rating |
| OW Hospitality Ltd | Kidderminster | A rating |
| Owadally and King | Surrey | A rating |
| Owen & Owen Retirement Developments Ltd | Radcliffe on Trent | A rating |
| Owen Associates | Cardiff | A rating |