| Four Girls 1 BOY Ltd | Hospitality | 2017 |
| Four Oak Technologies Ltd | Professional & scientific | 2023 |
| Four Seasons (NO 9) Limited | Health & social care | 2006 |
| Four Star Pizza (NI) Limited | Hospitality | 2007 |
| Four Two Four Ltd | Construction | 2005 |
| Four Winds Aviation Ltd | Manufacturing | 2022 |
| Four Winds Manor Ltd | Households | 2010 |
| Four Winds Nails Ltd | Other services | 2026 |
| Fourcan Ltd | Real estate | 2006 |
| Foursquare Financial Management Ltd | Professional & scientific | 2021 |
| Fourstar Junguo Ltd | Manufacturing | 2024 |
| Fourth Strike CIC | Information & communication | 2021 |
| Foveo Financial Ltd | Information & communication | 2023 |
| Fowler Consulting Ltd | Professional & scientific | 2024 |
| FOX Design Thinking Limited | Manufacturing | 2020 |
| FOX Electrical Installations Ltd | Construction | 2018 |
| FOX Events Ltd | Real estate | 2024 |
| FOX Legal Costs Ltd | Professional & scientific | 2018 |
| FOX Spirits Limited | Wholesale & retail | 2021 |
| FOX Whiskey Limited | Real estate | 2016 |
| Foxano Ltd | Manufacturing | 2019 |
| Foxbrand (NI) Limited | | 1993 |
| Foxbury Management Company Ltd | Households | 2020 |
| Foxcut Waterjet Cutting Services Ltd | Other services | 2011 |
| Foxfield Park Management Company Limited | Households | 2018 |
| Foxleigh Consulting Limited | Professional & scientific | 2017 |
| Foxleigh Meadows Management Company Limited | Real estate | 2021 |
| Foxsec Limited | Wholesale & retail | 2021 |
| Foxsun Limited | Wholesale & retail | 2024 |
| Foxtech Innovation Ltd | Health & social care | 2023 |
| Foxy Kitchens Ltd | Manufacturing | 2023 |
| Foydragh Wind Ltd | Energy | 2015 |
| Fozing Co., Ltd | Wholesale & retail | 2023 |
| FP Consultants Ltd | Information & communication | 2023 |
| FP Music Ltd | Other services | 1998 |
| Fpgni Ltd | Construction | 2025 |
| FPI (NI) Limited | Professional & scientific | 2012 |
| Fpnjfm Limited | Wholesale & retail | 2024 |
| FQS Pharma UK Ltd | Wholesale & retail | 2022 |
| FR Hair Limited | Other services | 2023 |
| FR Ventures Ltd | Real estate | 2010 |
| Fra.S Industrial Limited | Other services | 2025 |
| Fract Ydfhd Limited | Wholesale & retail | 2025 |
| Fraction One Ltd | Wholesale & retail | 2023 |
| Fractional Edge Limited | Professional & scientific | 2025 |
| Fractn Money Limited | Information & communication | 2024 |
| Fraggle Rock Ltd | Wholesale & retail | 2015 |
| Fragrances of Ireland Ltd | Wholesale & retail | 2021 |
| Fraken Developments Limited | Real estate | 1994 |
| Framath Films Ltd | Information & communication | 2021 |
| Framework Construction Ltd | Construction | 2018 |
| Francey Aviation Ltd | Manufacturing | 2018 |
| Francis and Mary Dobbs Ltd | Manufacturing | 2022 |
| Francis Hanna & Co Ltd | Professional & scientific | 2026 |
| Francis Hutcheson Institute | Education | 2026 |
| Francis Lyttle Ltd | Wholesale & retail | 2025 |
| Francis Mcpeake Ltd | Information & communication | 2016 |
| Francis West Limited | Wholesale & retail | 2025 |
| Francisco Jimenez Ltd | Information & communication | 2025 |
| Frango UKI Ltd | Hospitality | 2014 |
| Frangofurious Limited | Hospitality | 2023 |
| Frank Macelhatton Solicitors Ltd | Professional & scientific | 2021 |
| Frank Neumann Ltd | Wholesale & retail | 2023 |
| Franklin Properties, Limited | Real estate | 1942 |
| Franklins Retail Limited | Wholesale & retail | 2020 |
| Franklyavon Ltd | Health & social care | 2026 |
| Franks Pets Limited | Wholesale & retail | 2019 |
| Franwick Trading Limited | Hospitality | 2021 |
| Fraser Millar (Balmoral) Ltd | Real estate | 2016 |
| Fraser Millar Contracts Limited | Construction | 2001 |
| Fraser Millar Estates (Carryduff) Limited | Construction | 2015 |
| Fraser Millar Estates Limited | Construction | 2021 |
| Fraser Nolan Shutters Ltd | Wholesale & retail | 2012 |
| Fraser Partners Ltd | Construction | 2019 |
| Fratelli (Belfast) Ltd | Hospitality | 2014 |
| Fratelli (Ormeau Road) Limited | Professional & scientific | 2017 |
| Frazer Financial Planning Limited | Financial services | 2016 |
| Frazer Kidd LLP | | 2014 |
| Frazer Kidd Properties Limited | Real estate | 2021 |
| Frazer Kidd Property Limited | Real estate | 2025 |
| Frdm Ltd | Information & communication | 2026 |
| Freak Treats Ltd | Wholesale & retail | 2018 |
| Freaky Films Ltd | Information & communication | 2022 |
| Frecuret Ltd | Wholesale & retail | 2025 |
| Fred Holdings Limited | Construction | 2021 |
| Fred. Olsen Renewables Licences Limited | Professional & scientific | 2000 |
| Freddie Hatchet Ltd | Wholesale & retail | 2019 |
| Frederick Developments Ltd | Construction | 2006 |
| Free Electricity Ltd | Construction | 2026 |
| Free House Music Ltd | Information & communication | 2023 |
| Free'Ist Limited | Extraterritorial | 2014 |
| Freedesk Ltd | Information & communication | 2024 |
| Freedom Cloud Limited | Wholesale & retail | 2025 |
| Freedom Glen Limited | Extraterritorial | 2013 |
| Freedom Method Cycles Ltd | Wholesale & retail | 2024 |
| Freedom Recruiting Ltd | Administrative & support | 2015 |
| Freeforce Limited | Wholesale & retail | 2025 |
| Freemantle Consultants Ltd | Professional & scientific | 2020 |
| Freestorm UK Ltd | Wholesale & retail | 2024 |
| Freetech Limited | Information & communication | 2022 |