| Fibre Marketing | Gloucestershire |
| Fibre Technologies Ltd | Berkshire |
| Fibrelec Ltd | Northamptonshire |
| Fibrus ISP (NI) Ltd | |
| Ficode Technologies Ltd | |
| Fidelity Group | |
| Fidelity International Strategic Ventures | |
| Fidelity Systems plc | East Riding of Yorkshire |
| Fidomoney | |
| FidoNet Registration Services Ltd | |
| Field | |
| Field.io Ltd | |
| FieldHouse Associates | |
| Fields Data Recovery | Bridgend |
| Fife College | |
| Fifium | |
| Fifosys Ltd | Greater London |
| Fifteen Design Ltd | |
| Fifteen Design Ltd | |
| Fifth Dimension AI | |
| Figment Agency | |
| Filament AI | Greater London |
| FileCOPA | Devon |
| FileOasis | Hampshire |
| Filestream Ltd | Surrey |
| FilmFolk Ltd | |
| Filmily | |
| FiLOS Software | |
| Filter Digital Ltd | |
| Filtronic plc | West Yorkshire |
| Filwood Green Business Park | |
| FIMA Digital Ltd | |
| Fin-eX Outsourcing | |
| Finage Ltd | |
| Final DESIGN Studios | |
| Finalhit Ltd | East Sussex |
| FINALLY Agency Ltd | |
| Finally Software | Essex |
| Finalsite UK | Greater London |
| Finance System Consulting Ltd | |
| Financial Conduct Authority | |
| Financial Markets Standards Board | |
| Financial Times | |
| Finboot | |
| FINBOURNE Technology | |
| Finchetto Ltd | |
| FinCrime Dynamics Ltd | |
| Find Digital | |
| Find Web3 | |
| Findernest | |