| Foodjoint Limited | Hospitality | 2023 |
| Foodstock Ltd | Health & social care | 2021 |
| Foolishdev Limited | Information & communication | 2026 |
| Football Fortunes Limited | Manufacturing | 2018 |
| Football Management Company (NI) Ltd | Education | 2014 |
| Footprint WFM Ltd | Information & communication | 2021 |
| Footprint Work Flow Management Limited | Information & communication | 2017 |
| Footprints Womens Centre | Other services | 1999 |
| Foras One Ltd | Information & communication | 2026 |
| Forbairt Feirste Limited | Education | 2003 |
| Forbairt Studios Ltd | Information & communication | 2026 |
| Forbidden Industries UK Ltd | Wholesale & retail | 2019 |
| Forbidden Quest Limited | Arts & recreation | 2023 |
| Forecourt Systems Limited | Financial services | 1996 |
| Forefront Commercial Solutions Limited | Professional & scientific | 2016 |
| Forest & Fika Ltd | Wholesale & retail | 2025 |
| Forest Fish Limited | Wholesale & retail | 2024 |
| Forest Gate (Newforge) Ltd | Households | 2018 |
| Forest Grove Management Company Limited | Households | 1998 |
| Forest Hill Estates Limited | | 1996 |
| Forest Park Management Company Limited | Households | 2008 |
| Forest Park Services Ltd | Health & social care | 2015 |
| Forestgrove Property Management Company Limited | Households | 2006 |
| Foresthillview Management Co Ltd | Households | 2000 |
| Forestside Acquisitions Limited | Real estate | 2014 |
| Forestside Estates Limited | Real estate | 2004 |
| Forestside Management Company Limited | Households | 2010 |
| Forestwood Agencies Limited | Wholesale & retail | 1995 |
| Forestwood Timber Limited | Wholesale & retail | 2018 |
| Forever Forest Group Ltd | Wholesale & retail | 2024 |
| Forever Goose Limited | Wholesale & retail | 2023 |
| Forever Home Property Partners Limited | Real estate | 2021 |
| Forever Luck Limited | Wholesale & retail | 2024 |
| FOREVERLOVE521 Ltd | Health & social care | 2020 |
| Forfey Ltd | Other services | 2010 |
| Forge Properties (NI) LLP | | 2007 |
| Forge Software Ltd | Information & communication | 2016 |
| Forgeham Ltd | Wholesale & retail | 2026 |
| Forgemasters TMC Animation Studios Ltd | Information & communication | 2024 |
| Forkas Trading Ltd | Wholesale & retail | 2025 |
| Form Native Limited | Professional & scientific | 2016 |
| Formational Leadership Limited | Professional & scientific | 2025 |
| Forme Studio Ltd | Manufacturing | 2012 |
| Formestudiouk Ltd. | Health & social care | 2026 |
| Formsal Limited | Real estate | 2025 |
| Formwork Supplies Ltd | Construction | 2009 |
| Forsight Ltd | Wholesale & retail | 2020 |
| Forstmile Partners L.P. | | 2017 |
| Forsythe Financial Limited | Financial services | 2014 |
| Fortfield & Brown Limited | Professional & scientific | 2021 |
| Fortfield Mews Management Limited | Households | 2005 |
| Fortfield Motors (Carrickfergus) Limited | Construction | 1975 |
| Fortfield Properties Limited | Real estate | 1976 |
| Fortfields Beauty & Fitness Club Limited | Arts & recreation | 1998 |
| Fortify Financial Solutions CIC | Financial services | 2025 |
| Fortis Works Ltd | Public administration | 2024 |
| Fortium Personal Development Limited | Extraterritorial | 2016 |
| Fortius Strength & Conditioning Ltd | Arts & recreation | 2015 |
| Fortnight Publications Limited | Information & communication | 1970 |
| Fortuna Inns Limited | Hospitality | 2013 |
| Fortune Cookie Asian Cuisine Ltd | Wholesale & retail | 2024 |
| Fortus Hardware Limited | Wholesale & retail | 2015 |
| Fortwillam Consulting Ltd | Professional & scientific | 2021 |
| Fortwilliam Court Management Limited | Households | 1985 |
| Fortwilliam Developments Limited | Construction | 2025 |
| Fortwilliam Estates Limited | Real estate | 1983 |
| Fortwilliam Grange N.I. Management Limited | Real estate | 2010 |
| Fortwilliam Management Company Limited | Real estate | 2002 |
| Fortwilliam Management Company NO. 2 Limited | Real estate | 2004 |
| Fortwilliam Merchant Securities Ltd | Professional & scientific | 2013 |
| Forty SIX Club Ltd | Wholesale & retail | 2026 |
| Forty-One Thirty LLP | | 2017 |
| FORTY8 North Business Park Management Limited | Real estate | 2006 |
| Forum Spaces Ltd | Real estate | 2026 |
| Forward Emphasis Limited | Administrative & support | 1998 |
| Forward Emphasis NI Limited | Administrative & support | 2008 |
| Forward Function OT Ltd | Health & social care | 2025 |
| Forward South Partnership | Other services | 1999 |
| Forwardfocused Consultancy (NI) Ltd | Professional & scientific | 2019 |
| Forwon Shop Limited | Wholesale & retail | 2025 |
| Forwork Technology Limited | Wholesale & retail | 2025 |
| Forza Studio Ltd | Arts & recreation | 2024 |
| Forze-Strength Through Football Ltd | Arts & recreation | 2023 |
| Foscor Limited | Real estate | 2015 |
| Fosper E-Commerce Co. Ltd | Wholesale & retail | 2023 |
| Foster Care Associates (Northern Ireland) Limited | Health & social care | 2014 |
| Foundation (Northern Ireland) | Professional & scientific | 2008 |
| Foundation Church | Other services | 2017 |
| Founder Trading Limited | Wholesale & retail | 2025 |
| Founders Coffee Limited | Wholesale & retail | 2024 |
| Foundrypath Ltd | Information & communication | 2026 |
| Foundrytech Holdings Ltd | Financial services | 2026 |
| Fountain Accounting Ltd | Professional & scientific | 2018 |
| Fountain Publishing Limited | Information & communication | 1995 |
| Four Captains Productions Ltd | Arts & recreation | 2026 |
| Four Counties Essential OIL Company Limited | Wholesale & retail | 2025 |
| Four D Management Services Limited | Extraterritorial | 2015 |
| Four FOX Ltd | Wholesale & retail | 2025 |
| Four G Ltd | Health & social care | 2022 |
| Four Gears Ltd | Professional & scientific | 2020 |