| Extreme Lengths Ltd | Other services | 2010 |
| Ezra Hatton Limited | Professional & scientific | 2004 |
| Ezytrade Ltd | Construction | 2025 |
| F.I.B.I. Plumbing Co Ltd | Households | 2026 |
| F.M.Cunningham Ltd | Manufacturing | 2012 |
| FAB Learning Ltd | Education | 2023 |
| Fade & Blade Ltd | Other services | 2024 |
| Fair and Square Accounts Limited | Professional & scientific | 2017 |
| Faith and Peace Limited | Health & social care | 2015 |
| False Sensitivity Limited | Construction | 2025 |
| Fanes Group Limited | Real estate | 2019 |
| Fantuz Limited | Other services | 2019 |
| Farr Investment Properties Limited | Real estate | 2026 |
| Farrer Consulting Ltd | Professional & scientific | 2025 |
| Fast Trans 2025 Ltd | Transport & logistics | 2025 |
| Fast Truck Solution Ltd | Transport & logistics | 2025 |
| Fast Turbo Ltd | Wholesale & retail | 2014 |
| Fastacare Services Limited | Professional & scientific | 2021 |
| Fastrax Conveyor Rollers Limited | Manufacturing | 2005 |
| Favorite Transport Limited | Transport & logistics | 2024 |
| Fbotezatu Ltd | Wholesale & retail | 2019 |
| FC Trucking Limited | Transport & logistics | 2018 |
| Fcmm Ltd | Construction | 2020 |
| Fcs-Accident Limited | Other services | 2009 |
| Fcsg Ltd | Transport & logistics | 2024 |
| Feldstar Plumbing & Heating LLP | | 2024 |
| Fendow Limited | Wholesale & retail | 2013 |
| Fenix Services TD Limited | Construction | 2019 |
| Fenton Precision Engineers (Finedon) Limited | Real estate | 1970 |
| Fernley Hill Limited | Professional & scientific | 2019 |
| Ferns Properties Ltd | Real estate | 2020 |
| Ferret Publishing Ltd | Information & communication | 2011 |
| FEZ Catering Ltd | Hospitality | 2025 |
| Fezc. G and Sons Ltd | Real estate | 2025 |
| FHM Healthcare Ltd | Health & social care | 2013 |
| Fidibus Limited | Real estate | 2006 |
| Fieldscot Ltd | Hospitality | 2004 |
| Figa Service Ltd | Transport & logistics | 2022 |
| Figaros Pizza Ltd | Hospitality | 2016 |
| Film and Such Ltd | Information & communication | 2021 |
| Fine Entertainments Ltd | Administrative & support | 2017 |
| Fineshade Vineyard Ltd | Agriculture & fishing | 2024 |
| Fingab.Corp Ltd | Wholesale & retail | 2025 |
| Firefighting Chemical Consultants Limited | Professional & scientific | 2024 |
| Firm Steps Limited | Public administration | 2026 |
| First Rate Developments Limited | Real estate | 2022 |
| First Rate Masonry Limited | Construction | 2020 |
| First Rate Partnership Ltd | Real estate | 2024 |
| Fisher Smith Ltd | Manufacturing | 2018 |
| Fit and Flourish Global Ltd | Other services | 2024 |
| Fit Tennis Ltd | Arts & recreation | 2022 |
| FITNESS4VIDA Ltd | Arts & recreation | 2021 |
| Fitzys Gents Hairstylists Limited | Other services | 2013 |
| Five Star Electrical Services (Corby) Limited | Construction | 1997 |
| Five Star IT Services Ltd | Construction | 2007 |
| Five Star Mortgages Limited | Financial services | 2016 |
| Fixitpro (Northants) Ltd | Wholesale & retail | 2024 |
| Fixlt TED Ltd | Construction | 2025 |
| Fixmyhome Ltd | Construction | 2026 |
| FKS Logistics Limited | Transport & logistics | 2025 |
| Flash Auto Limited | Transport & logistics | 2018 |
| Flash Cars Corby Ltd | Transport & logistics | 2019 |
| Flashbang Consulting Limited | Information & communication | 2025 |
| Fleet Mark Ltd | Manufacturing | 2026 |
| Fletcher & Archer Limited | Construction | 2008 |
| Flexfilm Limited | Manufacturing | 1997 |
| Flitwick & Ampthill Plumbing Supplies Limited | Wholesale & retail | 2010 |
| Flopur Ltd | Wholesale & retail | 2025 |
| Florashell Needle Crafts Ltd | Wholesale & retail | 2025 |
| Florence George Ltd | Construction | 2016 |
| Florin Harabor. Pesi Ltd | Wholesale & retail | 2024 |
| Flot Construction Ltd | Construction | 2022 |
| Flotrans Logistic Ltd | Transport & logistics | 2020 |
| Flourishine Ltd | Hospitality | 2024 |
| Flower & Farmer Limited | Wholesale & retail | 2018 |
| Floweress Ltd | Wholesale & retail | 2025 |
| Flowolf Ltd | Information & communication | 2019 |
| FLYD8 Ltd | Transport & logistics | 2024 |
| Flyjasper Ltd | Transport & logistics | 2019 |
| FM BID Support Ltd | Professional & scientific | 2025 |
| FMH Conveyors International Limited | Manufacturing | 1994 |
| Focussed Publications Limited | Professional & scientific | 2016 |
| Foggy Grove Limited | Wholesale & retail | 2020 |
| Foleytech Ltd | Manufacturing | 2016 |
| Folgate Safety Limited | Construction | 2011 |
| Fonk Tech Ltd | Wholesale & retail | 2016 |
| Food Nutrition Partners Limited | Manufacturing | 2017 |
| Foodie London Ltd | Manufacturing | 2019 |
| Foodmaker Limited | Manufacturing | 1968 |
| Footballcv.Com Limited | Arts & recreation | 2000 |
| Fora Partner LP | | 2014 |
| Forest Gate (Corby) Limited | Wholesale & retail | 2000 |
| Forest Gate (Corby) Property Limited | Extraterritorial | 2017 |
| Forever Bonds Limited | Health & social care | 2026 |
| Forge House RTM Company Limited | Households | 2014 |
| Forsell Forestry & Property Company Limited | Professional & scientific | 1990 |
| Forte Utilities and Highways Ltd Limited | Construction | 2020 |
| Fortress Insurance Services Limited | Financial services | 2023 |
| Fortune Dragon 29 Limited | Hospitality | 2024 |
| FORTY22 Ltd | Wholesale & retail | 2025 |