| Cydar Limited | Cambridge | A rating |
| CyDen Ltd | Swansea | A rating |
| Cyera UK Ltd | London | A rating |
| Cyferd Ltd | London | A rating |
| CYGAMES EUROPE LIMITED | London | A rating |
| Cygilant UK Limited | Belfast | A rating |
| Cygnet Call Centre Ltd | Hounslow | A rating |
| Cygnet Care Ltd | Norfolk | A rating |
| Cygnet Health Care Ltd | West Malling | A rating |
| Cygnet Infotech Limited | London | A rating |
| Cygnetise Limited | LONDON | A rating |
| Cygnum Capital Group Ltd | London | A rating |
| Cygnus Academies Trust | Kent | A rating |
| Cygnus Enterprise Ltd | Bridge of Don | A rating |
| Cygnus Instruments Limited | Dorchester | A rating |
| Cygnus Tankers Limited | Brentford | A rating |
| Cygnus Tankers Limited | London | A rating |
| Cyient Europe Limited | Reading | A rating |
| Cykube Ltd | London | A rating |
| Cylindo Limited | Egham | A rating |
| Cymar Computer Ltd | London | A rating |
| CyNation Ltd. | London | A rating |
| Cynergy Bank plc | London | A rating |
| CYNETIC GLOBAL LTD | Ipswich | A rating |
| Cynomi Ltd | London | A rating |
| Cynopsis Solutions UK Limited | London | A rating |
| Cynosure UK Ltd | Cookham | A rating |
| Cyon Agency Limited | Bramley | A rating |
| CYP UK Limited | Shepperton | A rating |
| CYPAK LTD | London | A rating |
| Cypress Book Company UK Limited | London | A rating |
| Cypress Court Care Home | Crewe | A rating |
| Cypress Garden Services Limited | Northwood | A rating |
| CYPRESS LTD | Salisbury | A rating |
| CYPRESSA LIMITED | Bristol | A rating |
| Cyprus Bakery Ltd | London | A rating |
| CYPRUS CARS LTD | Ilford | A rating |
| Cyprus Fisheries Limited | LONDON | A rating |
| Cyrenians | Edinburgh | A rating |
| Cyreth Ltd T/A Strangford Arms Hotel | Newtownards | A rating |
| Cyril Leonard Ltd | London | A rating |
| Cyrrus Limited | Thirsk | A rating |
| Cyrus Capital Partners Europe LLP | LONDON | A rating |
| Cytec Engineered Materials Ltd | Wrexham | A rating |
| Cyted Ltd. | Cambridge | A rating |
| Cytel Statistical Services and Software UK Limited | London | A rating |
| Cytix Ltd | Manchester | A rating |
| Cytopath Ltd | Ledbury | A rating |
| Cytoplan Ltd | Hanley Swan | A rating |
| Cytora Limited | London | A rating |
| Cytora Ltd | London | A rating |
| CYTOSPIRE THERAPEUTICS LIMITED | London | A rating |
| CytoSwim Ltd | Coventry | A rating |
| CYTS (UK) Tours Ltd | London | A rating |
| CYVEN POETRY 2 LIMITED t/a T4 Bubble Tea Shop | Coventry | A rating |
| CYZ SOFTWARE CONSULTANCY LTD | Bristol | A rating |
| CZ Luton Ltd | Luton | A rating |
| Czajka Care Group | Bradford | A rating |
| CZAR VENTURES UK LIMITED(15345211) | London | A rating |
| CZARNIKOW GROUP LIMITED | London | A rating |
| Czech-Pol Ltd T/A Medical Dent | West Bromwich | A rating |
| CZICC UK LIMITED | London | A rating |
| CZWG Limited | London | A rating |