| Financial Control (Consultants) Limited | Financial services | 1999 |
| Finedon Road Leisure Limited | Health & social care | 2017 |
| Fineshade Engineering Limited | Professional & scientific | 2016 |
| Fineshade Services Limited | Public administration | 2025 |
| Finesse Groundworks Ltd | Professional & scientific | 2016 |
| Finewood Finishing Ltd | Other services | 2019 |
| Fingerpow Ltd | Professional & scientific | 2011 |
| Fintech Marketing Services Ltd | Financial services | 2020 |
| Finton Civil Engineering Limited | Construction | 2013 |
| Finton Construction Ltd | Construction | 2007 |
| Fire Designs Limited | Wholesale & retail | 2004 |
| Fire Doors Installer Ltd | Construction | 2026 |
| Fire Extinguisher Training Associates Limited | Other services | 2010 |
| Firebrick Partnership Limited | Administrative & support | 2015 |
| First Class Envelopes Limited | Professional & scientific | 2022 |
| First Class Mortgages Ltd | Financial services | 2014 |
| First for Heating Services Ltd | Manufacturing | 2015 |
| Firstname Communications Ltd | Administrative & support | 2010 |
| FIS LOG Limited | Construction | 2024 |
| Fisgard Ltd | Professional & scientific | 2024 |
| Fish Later Life Planning Ltd | Financial services | 2013 |
| Fitzys Ladies and Gents Hairstylists Limited | Other services | 2016 |
| Five Star Skills Ltd | Education | 2020 |
| Five Willows Limited | Professional & scientific | 2007 |
| Fivewyse Commercial Services Limited | Professional & scientific | 2017 |
| Fix-It Property Services Limited | Construction | 2025 |
| Fkeir Limited | Construction | 2025 |
| Flash Decorating Ltd | Construction | 2023 |
| Flash Digital Global Ltd | Wholesale & retail | 2025 |
| Flash Road Couriers Ltd | Transport & logistics | 2018 |
| Flaviu Trans Limited | Transport & logistics | 2015 |
| Flazmatazz Services Ltd | Information & communication | 2016 |
| Flexitalent Ltd | Administrative & support | 2025 |
| Flexpress Holdings Limited | Financial services | 2024 |
| Flexpress Limited | Manufacturing | 1999 |
| Flihi Limited | Administrative & support | 2009 |
| Flindell Ltd | Professional & scientific | 2018 |
| Flitton Commercial Limited | Extraterritorial | 2006 |
| Float Makers.Com Ltd | Professional & scientific | 2023 |
| Flomatic Holdings Limited | Other services | 2019 |
| Floriella Ltd | Wholesale & retail | 2021 |
| Flossbox Ltd | Hospitality | 2022 |
| Flower Associates International Limited | Health & social care | 2003 |
| Flowpath Consulting Ltd | Professional & scientific | 2024 |
| Fluffy Pets Creations Limited | Wholesale & retail | 2021 |
| Flyte Associates Limited | Professional & scientific | 2011 |
| FM Systems Ltd | Information & communication | 2023 |
| Focus NPD Ltd | Professional & scientific | 2022 |
| Fone Warehouse Limited | Wholesale & retail | 2022 |
| Food Technical Services Limited | Professional & scientific | 2013 |
| Foot Master Ltd | Health & social care | 2021 |
| Football FUN Factory (Community 040) Limited | Arts & recreation | 2021 |
| Footyfrenzy Ltd | Information & communication | 2026 |
| For-Shaw Innovation Ltd | Wholesale & retail | 2018 |
| Foress Trading Ltd | Wholesale & retail | 2023 |
| Foresyte Digital Ltd | Information & communication | 2026 |
| Forever Strong Fitness Ltd | Real estate | 2024 |
| Forged Experiences Ltd | Manufacturing | 2026 |
| Forgeflare Ltd | Information & communication | 2025 |
| Forkez Ltd | Construction | 2024 |
| Forktrain Limited | Education | 2019 |
| Formationdata Systems Ltd | Professional & scientific | 2025 |
| Forta Group Holdings Ltd | Financial services | 2023 |
| Forta Property Investments Ltd | Real estate | 2021 |
| Forta Studio Ltd | Information & communication | 2025 |
| Fortress U.K. Limited | Other services | 2024 |
| Fosbrook Limited | Professional & scientific | 2026 |
| Fosters Farms (Ringstead) Limited | Agriculture & fishing | 1969 |
| Foundations Pathways Limited | Health & social care | 2025 |
| Four Smiths Property Ltd | Real estate | 2018 |
| FOX J Express Ltd | Transport & logistics | 2015 |
| FOX Property Investments Ltd | Financial services | 2017 |
| FOX Recruitment Holdings Ltd | Financial services | 2024 |
| Foxhall Assembly Centre Ltd | Agriculture & fishing | 2013 |
| Foxhall Trading Limited | Agriculture & fishing | 2016 |
| Foxhall Ventures Limited | Professional & scientific | 2008 |
| Foxtrot Seven Ltd | Arts & recreation | 2021 |
| Frametek Ltd | Construction | 2025 |
| Frampton Housing CIC | Real estate | 2014 |
| Frank's Butchers (Rothwell) Limited | Wholesale & retail | 2005 |
| Franklins of Corby Limited | Wholesale & retail | 2002 |
| Freedom Property M&C LLP | | 2017 |
| Freedomroofing&Construction Ltd | Construction | 2025 |
| Freeman Consultants Ltd | Administrative & support | 2024 |
| Freeman Country Inns Limited | Hospitality | 2017 |
| Freeman Court Management Company Limited | Real estate | 2007 |
| Fresh Fast Food Ltd | Hospitality | 2025 |
| Fresh Wheelie Bins Ltd | Administrative & support | 2025 |
| Freshfoodcanteen Limited | Hospitality | 2026 |
| Friendly People Limited | Administrative & support | 2002 |
| Frozen Developments Ltd | Real estate | 2019 |
| Frydays of Kettering Limited | Hospitality | 2024 |
| FS (First AID) Training Limited | Education | 2010 |
| Fuel + Fire Films Ltd | Information & communication | 2019 |
| FUEL2GO Fuel Services Ltd | Wholesale & retail | 2025 |
| Full Circle Creative Packaging Limited | Administrative & support | 2024 |
| Full Circle Design Solutions Limited | Administrative & support | 2025 |
| Full Support Group Limited | Administrative & support | 2016 |
| Full Support Healthcare Limited | Health & social care | 2002 |
| Fullerton Enterprises Limited | Transport & logistics | 2024 |