| Felicity James Developments Limited | Real estate | 2007 |
| Felix (7 Counties) Construction Ltd | Construction | 2023 |
| Felyn Co Limited | Real estate | 2020 |
| Femzy Kitchen and Catering Services Ltd | Hospitality | 2026 |
| Fen-Tonality Ltd | Manufacturing | 2022 |
| Fenfire Limited | Other services | 2020 |
| Fenster Films Limited | Administrative & support | 2009 |
| Fetchtech AI Ltd | Information & communication | 2024 |
| Fettle Fitness Limited | Information & communication | 2024 |
| FG Construction Services Ltd | Other services | 2023 |
| FIA5 Homes Limited | Real estate | 2026 |
| FIA5 Medical Ltd | Health & social care | 2023 |
| Fieldcroft Management Company Limited | Households | 2011 |
| Fieldpro Technical Services Limited | Professional & scientific | 2022 |
| Fierce Creatives Limited | Professional & scientific | 2021 |
| Figure and Face Ltd | Other services | 2021 |
| Filippa K Limited | Wholesale & retail | 2017 |
| Fill Refill Co Limited | Manufacturing | 2018 |
| Film Art & Design Ltd | Arts & recreation | 2022 |
| Final Stitch Limited | Manufacturing | 2025 |
| Finecare Homes (Stevenage) Limited | Administrative & support | 2007 |
| Finest Glass Limited | Construction | 2017 |
| Finko Limited | Manufacturing | 2002 |
| Finnmade Furniture Solutions Limited | Construction | 1999 |
| Fintry Lodge Residents Association Limited | Households | 2009 |
| Fior Medical Limited | Health & social care | 2022 |
| Fire N Frost Limited | Hospitality | 2026 |
| Fire Safety London Ltd | Other services | 2012 |
| Firemaster Alarms Limited | Construction | 1999 |
| Firepit Sandwich Co. Ltd | Wholesale & retail | 2026 |
| FIRESAFETY4U Ltd | Public administration | 2021 |
| First Born Unicorn Ltd | Hospitality | 2022 |
| First Broom Barns Management Company Limited | Households | 1976 |
| First Choice Extensions Ltd | Construction | 2022 |
| First Engineering Solutions Limited | Professional & scientific | 2024 |
| First Group London Ltd | Construction | 2022 |
| First Line Logistics Ltd | Transport & logistics | 2025 |
| First Media Group Limited | Information & communication | 2018 |
| First Response Fire Safety UK Ltd | Administrative & support | 2010 |
| First Solution (UK) Ltd | Construction | 2012 |
| Fischer Developments Limited | Construction | 2016 |
| Fischer Group Limited | Financial services | 2019 |
| Fischer Rose Limited | Real estate | 2019 |
| Fish Embassy Ltd | Agriculture & fishing | 2025 |
| Fish Gourmet Limited | Wholesale & retail | 1965 |
| Fisherman's Wharf (Stevenage) Ltd | Hospitality | 2016 |
| Fishers G Ltd | Real estate | 2023 |
| Fit OUT London Group Ltd | Information & communication | 2022 |
| Fitr. Holdings Limited | Other services | 2015 |
| Fitz Scaffolding Ltd | Construction | 2013 |
| Five Elements Constructions Ltd | Construction | 2015 |
| Five Star Traders Limited | Hospitality | 2024 |
| Fizzyjen Limited | Health & social care | 2022 |
| Fjay Consulting Limited | Administrative & support | 2015 |
| Fjay Properties Limited | Real estate | 2025 |
| FK Property Development Ltd | Real estate | 2020 |
| FKR Property Development Ltd | Real estate | 2017 |
| Flaming June Consulting Limited | Administrative & support | 2017 |
| Flaming Props Ltd | Information & communication | 2022 |
| Flamingo Flowers Ltd. | Wholesale & retail | 1994 |
| Flamingo Group International Limited | Wholesale & retail | 2015 |
| Flamingo Group Midco Limited | Wholesale & retail | 2015 |
| Flamingo Holdings Limited | Wholesale & retail | 2000 |
| Flamingo Horticulture Investments Limited | Wholesale & retail | 2012 |
| Flamingo Horticulture Ltd | Wholesale & retail | 2015 |
| Flamingo Produce Investments Limited | Wholesale & retail | 2026 |
| Flamingo Produce Ltd. | Wholesale & retail | 1994 |
| Flawed Hero Movement CIC | Arts & recreation | 2024 |
| Flexible Workspace (Wellington) Limited | Real estate | 2021 |
| Flexico Developments Limited | Professional & scientific | 1954 |
| Flint Street Lettings Limited | Real estate | 2024 |
| Flint Street Limited | Real estate | 2023 |
| Flooring Restorations People Limited | Other services | 2018 |
| Floresite Ltd | Other services | 2016 |
| Florin Electrical Ltd | Construction | 2017 |
| Flow Drain & Property Soultions Ltd | Construction | 2022 |
| Fluffy Hub Ltd | Wholesale & retail | 2024 |
| Fluorocarbon Corporate Limited | Professional & scientific | 2017 |
| Fluorocarbon Group Limited | Professional & scientific | 2006 |
| Fluorocarbon Limited | Manufacturing | 1961 |
| Fluorocarbon Surface Technologies Ltd | Professional & scientific | 2007 |
| FLY One Ltd | Transport & logistics | 2026 |
| Flying Moth Ltd | Information & communication | 2006 |
| Flynn Pharma (Holdings) Limited | Professional & scientific | 2006 |
| FMC Systems Limited | Information & communication | 2011 |
| Focus Pictures Limited | Professional & scientific | 2024 |
| FOG Studio Limited | Wholesale & retail | 2024 |
| Fontenay Property Solutions Ltd | Administrative & support | 2025 |
| Footpath Media Ltd | Information & communication | 2024 |
| Forbes Young Contractor Accountants Limited | Professional & scientific | 2012 |
| Force Facilities Limited | Other services | 2026 |
| Fore Dimensions Ltd | Information & communication | 2020 |
| Forlan Enterprises Limited | Real estate | 2013 |
| Form London Ltd | Other services | 2026 |
| Forma+ Porcelain Slabs & Fabrication Limited | Wholesale & retail | 2023 |
| Formo Ltd | Manufacturing | 2012 |
| Formula Autocentres Limited | Extraterritorial | 2014 |
| Formula One Auto Centres Limited | Wholesale & retail | 1979 |
| Formula One Developments Limited | Administrative & support | 1998 |
| Formula Plus Autocentres Limited | Extraterritorial | 2014 |