| Fair Fire Ltd | Manufacturing | 2014 |
| Fairlie Mckenzie International Limited | Professional & scientific | 2015 |
| Fairway Lakes Maintenance Limited | Real estate | 2021 |
| Fairway Plumbing and Heating Services Ltd | Construction | 2019 |
| Faithwalk Ministries | Health & social care | 2021 |
| Falco Subbuteo FC Ltd | Education | 2022 |
| Falcon Residential Trailer Parks Limited | Real estate | 1961 |
| Famida Ltd | Real estate | 2021 |
| Famida Management & Services Ltd | Real estate | 2026 |
| Famida Properties Ltd | Hospitality | 2022 |
| Family Amour Contact Services Limited | Health & social care | 2026 |
| Family Attractions Ltd | Information & communication | 2026 |
| Fane Protap Haiducesc Ltd | Hospitality | 2017 |
| Farden Services Ltd | Construction | 2025 |
| Farndon Harbour Moorings Limited | Transport & logistics | 1973 |
| Farrelly GAS Services Limited | Construction | 2022 |
| Farrington Oils Limited | Manufacturing | 2005 |
| Fasie Ltd | Other services | 2017 |
| Fast & Fjori Ltd | Transport & logistics | 2025 |
| Fast Enterprises Ltd | Wholesale & retail | 2025 |
| Fawe Architectural Design Ltd | Administrative & support | 2019 |
| Fazal Consultancy Ltd | Health & social care | 2020 |
| Fazed Films Limited | Professional & scientific | 2012 |
| FBY Operations Ltd | Construction | 2025 |
| FC Roadlink Ltd | Transport & logistics | 2026 |
| FCH Care Ltd | Health & social care | 2018 |
| FCH Recruitment Ltd | Transport & logistics | 2020 |
| FCO - Accountancy Limited | Professional & scientific | 2010 |
| Fcsb Limited | Transport & logistics | 2015 |
| FD Plant Ltd | Wholesale & retail | 2021 |
| FDB Electrical Limited | Manufacturing | 1971 |
| Feakins of Kettering Limited | Wholesale & retail | 2013 |
| Feather N’ Grey Group Ltd | Professional & scientific | 2025 |
| Felicity Ingram Ltd | Professional & scientific | 2019 |
| Felton Healthcare Solutions Ltd | Health & social care | 2025 |
| Fence IT (Northants) Limited | Construction | 2023 |
| Feniks Utilities Limited | Construction | 2021 |
| Fenn Holdings Ltd | Real estate | 2015 |
| Fenton Precision Engineering Limited | Manufacturing | 2000 |
| Feol Limited | Construction | 2020 |
| Fernley Arnold Limited | Professional & scientific | 2019 |
| Ferrers & Vine Ltd | Hospitality | 2025 |
| Fescom Consultants Limited | Wholesale & retail | 2023 |
| Festo Building & Property Services Limited | Other services | 2016 |
| Festo Care Solutions Ltd | Health & social care | 2023 |
| Festsafe Ltd | Real estate | 2025 |
| FFA Property Ltd | Real estate | 2023 |
| FG Transport Ltd | Transport & logistics | 2022 |
| Field Chemicals Limited | Water & waste | 1987 |
| Fiendon Transport Ltd | Transport & logistics | 2025 |
| Fight Club 13 Ltd | Professional & scientific | 2026 |
| Filinarsen Ltd | Extraterritorial | 2017 |
| Finch Signs Ltd | Manufacturing | 2011 |
| Findstock Limited | Agriculture & fishing | 1996 |
| Finedon Building Services Limited | Construction | 2012 |
| Finedon Road Fitness Club Limited | Health & social care | 2011 |
| Finewell Limited | Construction | 2008 |
| Fingerlimes Consulting Limited | Information & communication | 2025 |
| Firbanks Supported Living Ltd | Health & social care | 2022 |
| Firbanks Transport Ltd | Health & social care | 2021 |
| Fire Safe Consulting Ltd | Professional & scientific | 2025 |
| Firecrow Ltd | Arts & recreation | 2024 |
| Fireproof Impact Ltd | Professional & scientific | 2025 |
| First Care Plus Five Limited | Health & social care | 2022 |
| First Choice Heating Northampton Limited | Construction | 2016 |
| First Choice Recovery and Motor Sales Ltd | Wholesale & retail | 2024 |
| First Digital Events Limited | Professional & scientific | 2016 |
| First for Plant Safety Training Limited | Education | 2024 |
| First Option Care Services Ltd | Health & social care | 2010 |
| First Rate Window Cleaning Ltd | Administrative & support | 2026 |
| Fisher Mortgages Limited | Financial services | 2024 |
| Fitter Body Ladies Kettering Limited | Arts & recreation | 2020 |
| Fitter Body Ladies Newport Pagnell Limited | Arts & recreation | 2022 |
| Fitter Body Ladies Wellingborough Limited | Arts & recreation | 2018 |
| Fittings & Fixtures Ltd | Manufacturing | 2019 |
| Fitzhugh Property Group Ltd | Real estate | 2019 |
| Five Oak Capital Limited | Real estate | 2025 |
| Five Star Irthlingborough Ltd | Hospitality | 2024 |
| Five Star Kebab Ltd | Hospitality | 2025 |
| Five Star Pizza Kebab Ltd | Hospitality | 2026 |
| Five-Nine Consulting Ltd | Professional & scientific | 2025 |
| Fivestars Management Ltd | Real estate | 2026 |
| Fixit Property Solutions Ltd | Construction | 2020 |
| FK Inns Ltd | Hospitality | 2018 |
| FK Restoration Limited | Construction | 2000 |
| FKR Holdings Ltd | Real estate | 2019 |
| Flair Hair Design Limited | Other services | 2015 |
| Flames Pizza Ltd | Hospitality | 2019 |
| Flaunt Beauty Academy Limited | Education | 2021 |
| Flava Digital Ltd | Information & communication | 2017 |
| Flavors of Africa Ltd | Hospitality | 2016 |
| Fleetpark Limited | Real estate | 2004 |
| Fletcher European Containers Limited | Manufacturing | 1997 |
| Fletchers Heating & Plumbing Ltd | Construction | 2018 |
| Flexifix Solutions Ltd | Administrative & support | 2024 |
| FLO Accounting Limited | Administrative & support | 2017 |
| FLO Flexi Services Limited | Construction | 2026 |
| Flo's Automotive Ltd | Wholesale & retail | 2022 |
| Flo's Garage Ltd | Wholesale & retail | 2018 |
| Florand Ltd | Transport & logistics | 2017 |