| UK Company Name | Partial Address |
| O'Boyle Brothers Limited | NORTH HYKEHAM, LINCOLN |
| O'Boyle Civil Engineering Limited | LINCOLN, LINCOLNSHIRE |
| O'Boyle Property Limited | KNOCKLOUGHRIM, MAGHERAFELT |
| O'Brien & Daughters Management Ltd | LONDON |
| O'Brien & Son Builders | DUNTOCHER, CLYDEBANK |
| O'Brien Construction Limited | THURSO, CAITHNESS |
| O'Brien Construction Works Ltd | BELLEEK, CO FERMANAGH |
| O'Brien Contractors Limited | CUBBINGTON, LEAMINGTON SPA |
| O'Brien Fine Foods Investments Limited | 3 BEDFORD SQUARE, BELFAST |
| O'Brien Holdings Ltd | LOW FIELD LANE, GOLDSBOROUGH |
| O'Brien Limited | TOTNES, DEVON |
| O'Brien Property Services Limited | New Milton, Hampshire |
| O'Brien Racing Limited | CREWE, CHESHIRE |
| O'Brien Security Systems Limited | SKETTY, SWANSEA |
| O.B.Y.Limited | CULCHETH, WARRINGTON |
| Ob Construction ( Northern ) Ltd | Lostock, Bolton |
| Ob Developments Limited | WITNEY, OXON |
| Ob Plant Ltd | MANSFIELD ROAD, NOTTINGHAM |
| Ob/Gyn Services Limited | 2 SHERIFFS ORCHARD, COVENTRY |
| Oban Holdings Limited | OBAN, ARGYLL |
| Obarcs (Holdings) Limited | NEWTOWNARDS |
| Obelisk Networks (Uk) Limited | NEWRY, CO. DOWN |
| Oberoi Consulting Limited | PRIDE PARK, DERBY |
| Oberon Investments Limited | 2ND FLOOR, LONDON |
| Obg Pharmaceuticals Limited | COMMERCE WAY, LIVERPOOL |
| Objective 1 Limited | BLACKHORSE HILL, BRISTOL |
| Objective Travel Safety Limited | NEAR DAVENTRY, NORTHAMPTONSHIRE |
| Obligate Ltd | WITHAM |
| Obm Architectural Management Limited | WEYMOUTH, DORSET |
| Obm Properties Limited | CHELMSFORD, ESSEX |
| Obr Construction Limited | CRESSEX BUSINESS PARK, HIGH WYCOMBE |
| Obrela Limited | FINCHLEY, LONDON |
| Obroc General Partner Limited | 9 HAYMARKET SQUARE, EDINBURGH |
| Obsidian Resources Limited | MILLTIMBER, ABERDEEN |
| Obvious Limited | GREAT BOOKHAM |