| Finchbrook Limited | Financial services | 2011 |
| Findtheircare Ltd | Information & communication | 2025 |
| Fine and Country (Wendover) Limited | Real estate | 2018 |
| Fine Design & Build Limited | Construction | 2024 |
| Fine Saas Solutions Ltd | Information & communication | 2023 |
| Finest Fossils Limited | Wholesale & retail | 2017 |
| Fingerwolf Consulting Ltd | Information & communication | 2019 |
| Finley Consultancy Limited | Professional & scientific | 2019 |
| Fintech Nucleus Limited | Information & communication | 2024 |
| Fiona Harrold PR Ltd | Health & social care | 2000 |
| Fire Door Surveys and Installations Ltd | Public administration | 2026 |
| Fire Flash Production Ltd | Information & communication | 2014 |
| Fire Mountain Productions Limited | Information & communication | 1998 |
| Fire Risk Engineering Ltd | Administrative & support | 2021 |
| Firebird Photography Limited | Professional & scientific | 2017 |
| Firs Pumping Station Limited | Water & waste | 2018 |
| First Call Facilities Services Limited | Administrative & support | 2023 |
| First Choice Capital Training Limited | Education | 2024 |
| First Choice Plumbing and GAS Limited | Construction | 2014 |
| First Class Mens Barbers Limited | Other services | 2019 |
| First Construction Finance Limited | Financial services | 2016 |
| First Creative Print and Display Packaging Ltd | Manufacturing | 2004 |
| First Nation Investment Limited | Professional & scientific | 2015 |
| First Residence Ltd | Real estate | 2025 |
| Firsthome Properties Limited | Real estate | 1998 |
| Fish Housing Limited | Real estate | 2021 |
| Fisherman’S Hook Ltd | Hospitality | 2024 |
| Fishtank Consulting & Translation Services Ltd | Professional & scientific | 2012 |
| Fit Mind Body Factory Limited | Wholesale & retail | 2023 |
| Fit to Deliver Limited | Education | 2000 |
| FIT4FUTURE Education Solutions Ltd | Education | 2019 |
| Fitch (and Fetch) Leatherwork Ltd | Manufacturing | 2013 |
| Fitlife Health Club Limited | Arts & recreation | 2015 |
| Fitness Blueprint Ltd | Arts & recreation | 2020 |
| Fitzgerald Holdings Group Ltd | Financial services | 2024 |
| Fitzgerald Surveying Services Ltd | Professional & scientific | 2024 |
| Fitzgerald UK Property Ltd | Real estate | 2023 |
| Fitzright Securuity Services Ltd | Administrative & support | 2025 |
| Five Spot Capital Limited | Professional & scientific | 2016 |
| Five Stars Fades Aylesbury Ltd | Other services | 2025 |
| Five Twos Taxis Limited | Transport & logistics | 2025 |
| FJM Healthcare Ltd | Health & social care | 2022 |
| FK Khan Ltd | Wholesale & retail | 2025 |
| Flaco Construct Ltd | Construction | 2025 |
| Flagler Technologies Limited | Administrative & support | 2023 |
| Flame & ALL (Flame Afrique) Ltd | Wholesale & retail | 2023 |
| Flame Doctor Limited | Construction | 2019 |
| Flames Aylesbury Ltd | Hospitality | 2025 |
| Flamingo Bathrooms Ltd | Construction | 2026 |
| Flamingo Installations Ltd | Construction | 2025 |
| Flamingo Services Ltd | Construction | 2025 |
| Flare Bright Ltd | Manufacturing | 2015 |
| Flavourama Limited | Manufacturing | 2017 |
| Flavoursome Foods Ltd | Hospitality | 2023 |
| Fleet Elite Vehicle Management Limited | Administrative & support | 2008 |
| Fletched Consulting Ltd | Professional & scientific | 2026 |
| Flexi Construction Services Ltd | Construction | 2011 |
| Flexible Management Limited | Information & communication | 2001 |
| Flexy Commercial Group Limited | Construction | 2020 |
| Flink Limited | Administrative & support | 1982 |
| Flint Architects Ltd | Professional & scientific | 2019 |
| Flipside Property Ltd | Real estate | 2019 |
| Flohome Ltd | Professional & scientific | 2026 |
| Flojob Limited | Administrative & support | 2025 |
| Flomut Ltd | Health & social care | 2020 |
| Flooring &More Ltd | Construction | 2023 |
| Flor Ltd | Wholesale & retail | 2012 |
| Floral Creations (Amersham) Limited | Wholesale & retail | 2010 |
| Florelle Marketing Ltd | Professional & scientific | 2024 |
| Florence Nightingale Hospice Charity | Health & social care | 2007 |
| Florence Nightingale Hospice Shops Limited | Wholesale & retail | 1993 |
| Florinahealthcare Limited | Health & social care | 2016 |
| Florys NYK Ltd | Construction | 2026 |
| Flowedge AI Ltd | Information & communication | 2025 |
| Flowlight Ltd | Manufacturing | 2018 |
| Flowright Associates Ltd | Professional & scientific | 2024 |
| Floyds Barns Management Company Limited | Real estate | 1990 |
| Flrb Ltd | Information & communication | 2025 |
| Fluent Chimneys Limited | Construction | 2007 |
| Fluent IT Solutions Ltd | Information & communication | 2012 |
| Fluent Limited | Agriculture & fishing | 2003 |
| Fluid Flooring Ltd | Construction | 2016 |
| Fluid Plumbing Ltd | Construction | 2025 |
| Fluo Limited | Administrative & support | 2009 |
| Flux Enterprise Limited | Health & social care | 2016 |
| Flux Plus Limited | Wholesale & retail | 2017 |
| FLY Taxi Limited | Transport & logistics | 2025 |
| FLY Tyre Ltd | Manufacturing | 2026 |
| Flying Stuff Ltd | Wholesale & retail | 2024 |
| Flynn Design Services Limited | Professional & scientific | 2021 |
| FM Property & Holdings Ltd | Real estate | 2026 |
| FMY One Limited | Education | 2018 |
| Focus Gym Technology Ltd | Information & communication | 2025 |
| Folarta Ltd | Construction | 2025 |
| Folkspur Flooring Limited | Construction | 1983 |
| Follow Through Services Ltd | Information & communication | 2016 |
| Fona UK Ltd | Manufacturing | 2003 |
| Food Nation AY Limited | Hospitality | 2025 |
| Foodsci Consulting Ltd | Professional & scientific | 2025 |
| Forces of Recovery CIC | Health & social care | 2024 |