| Fortis Productions Limited | London | 2007 |
| Fortis Sport Limited | Hamilton | 2021 |
| Fortis Training Ltd | Stoke Poges | 2026 |
| Fortis Training Systems Ltd | Derry | 2025 |
| Fortitude BJJ Ltd | Ipswich | 2026 |
| Fortitude by SP Ltd | London | 2024 |
| Fortitude Dance Company Limited | London | 2012 |
| Fortitude Fitness and Training Limited | Manchester | 2023 |
| Fortitude Fitness Centre Ltd. | Caldecote | 2013 |
| Fortitude Fitness Ltd | Orpington | 2022 |
| Fortitude Fitness Wyre Limited | Poulton-Le-Fylde | 2023 |
| Fortitude Health and Performance Limited | Lydney | 2016 |
| Fortitude Health Ltd | Portsmouth | 2019 |
| Fortitude Ipswich Limited | Colchester | 2023 |
| Fortitude Limited | Tonbridge | 2006 |
| Fortitude Martial Arts Ltd | Stowmarket | 2024 |
| Fortitude Performance Ltd | Uxbridge | 2017 |
| Fortitude Promotions Ltd | Gateshead | 2023 |
| Fortitude Strength Ltd | Ashford | 2014 |
| Fortitude Training Collective Ltd | Leeds | 2026 |
| Fortitude WS Ltd | Williton | 2021 |
| Fortitudefit Limited | Edenbridge | 2023 |
| Fortitudex Ltd | Crawley | 2025 |
| Fortius Strength & Conditioning Ltd | Belfast | 2015 |
| Fortnocks Limited | West Midlands | 1995 |
| Forton Riding Limited | Shrewsbury | 2008 |
| Fortress Boxing: Fight for Change CIC | Dickens Heath | 2025 |
| Fortress Event & Safety Ltd | Trimdon Station | 2023 |
| Fortress Gym Ltd | Stroud | 2023 |
| Fortress of Gains Ltd | London | 2025 |
| Fortress Sounds Ltd | Liverpool | 2015 |
| Fortress Sports Solutions Ltd | Oxford | 2015 |
| Fortris Ltd | Poole | 2025 |
| Fortunate SON Creations Ltd | London | 2014 |
| Fortune Draw Ltd | Bury St. Edmunds | 2025 |
| Fortune for Good Ltd | Redditch | 2025 |
| Fortune Vault Competitions Ltd | Standish | 2026 |
| Fortune's CAP Productions Ltd | Teddington | 2022 |
| Fortunebirds Limited | Cambridge | 2025 |
| Forty Five Pilates Ltd | Exeter | 2025 |
| Forty Nine Agency Limited | London | 2019 |
| Forty Winks Bloodstock Limited | London | 2024 |
| Forty Winks Racing Limited | London | 2011 |
| Forty-Five Limited | Reigate | 2008 |
| FORTY40 Racing Ltd | Camberley | 2019 |
| Fortytwo Automotive Ltd | Sutton | 2019 |
| Fortytwo Marketing Limited | Leighton Buzzard | 2008 |
| Fortytwo Studio Ltd | Ellon | 2015 |
| Fortytwolove Limited | London | 2025 |
| Forum Fitness Limited | Ferndown | 2022 |
| Forum Sports Management Limited | Doncaster | 2022 |
| Forvie Outdoors Ltd | Ellon | 2023 |
| Forward Fitness Ltd | West Horsley | 2025 |
| Forward Football CIC | Birmingham | 2025 |
| Forward Gallery Ltd | Birmingham | 2011 |
| Forward Live Presents Limited | Smethwick | 2025 |
| Forward Movement Limited | London | 2014 |
| Forward Music Limited | Leeds | 2014 |
| Forward Operating Base Ltd | Huddersfield | 2012 |
| Forward Sports Coaching Ltd | Bedford | 2021 |
| Forward Thinking Movement and Dance CIC | Leicester | 2013 |
| Forza Consultants Limited | Peterborough | 2012 |
| Forza Enterprises Limited | Peterborough | 2018 |
| Forza Fitness Ltd | Montrose | 2023 |
| Forza Football UK Limited | Cobham | 2024 |
| Forza Historic Racing Ltd | York | 2016 |
| Forza Invicta Group Ltd | London | 2025 |
| Forza Padel Limited | Bradford | 2026 |
| Forza Pilates Ltd | Motherwell | 2025 |
| Forza Studio Ltd | Belfast | 2024 |
| Forza Stunts Ltd | Prestatyn | 2023 |
| FORZA90 Ltd | London | 2022 |
| Forze-Strength Through Football Ltd | Belfast | 2023 |
| FOS Branding Ltd | Margate | 2020 |
| FOS Hull Limited | Hull | 2026 |
| FOS Limited | Radlett | 1994 |
| FOS Skateboards Limited | Maidstone | 2003 |
| Fosdyke Yacht Haven Limited | Pinchbeck | 2006 |
| Foshy Productions Limited | London | 2026 |
| Fosse Fitness 365 Limited | Leicester | 2012 |
| Fosse Hill Caravan Park Limited | Driffield | 2004 |
| Fossett International Ltd | Newtownards | 2019 |
| Fossette Records Limited | London | 2024 |
| Fosseway Fields Ltd | Moreton-In-Marsh | 2023 |
| Fossoway Community Development Trust Limited | Kinross | 2023 |
| Foster Bingo Limited | 191 West George Street | 1977 |
| Foster Farms Sporting Ltd | Driffield | 2025 |
| Foster Phelps (Alconbury) Limited | Huntingdon | 2023 |
| Foster Phelps (Holdings) Limited | Huntingdon | 2023 |
| Foster Phelps (Online) Limited | Huntingdon | 2023 |
| Foster Phelps Limited | Huntingdon | 2013 |
| Foster Studios Ltd | Hornchurch | 2019 |
| Fostering Imagination CIC | Barnsley | 2024 |
| Fostival Ltd | Sandwich | 2025 |
| Fotocom Limited | London | 2017 |
| Fotodisk Ltd | London | 2022 |
| Fotografiska UK Ltd | London | 2026 |
| Fotonow SW Community Interest Company | Plymouth | 2009 |
| Fotos for Art Ltd | Newcastle Upon Tyne | 2022 |
| Fotsn Limited | Sevenoaks | 2014 |