| Fitzgerald Engineering Ltd | Construction | 2023 |
| Fitzwilliam Court Residents Association Limited | Households | 2011 |
| Fitzwilliam Gate (Sheffield) Management Company Limited | Households | 1999 |
| Fitzwilliam House Management Company Limited | Households | 2007 |
| Fitzwilliam Maintenance Ltd | Administrative & support | 2025 |
| Five Boroughs Ltd | Hospitality | 2019 |
| Five Lives Limited | Real estate | 2022 |
| Five One Two (Sheffield) Limited | Transport & logistics | 1996 |
| Five Property Consultants Limited | Professional & scientific | 2021 |
| Five River Estates Ltd | Construction | 2019 |
| Five Rivers Cohousing Company Limited | Real estate | 2012 |
| Five Rivers Multi Academy Trust | Education | 2016 |
| Five Seventy Three Ltd | Professional & scientific | 2017 |
| Five Star Barber S5 Ltd | Other services | 2023 |
| Five Star Barber Salon Ltd | Other services | 2025 |
| Five Star Properties (SY) Ltd | Real estate | 2025 |
| Five Star Trade Ltd | Transport & logistics | 2018 |
| Five-Fifteen Limited | Arts & recreation | 2025 |
| Fivesix Solutions Ltd | Information & communication | 2023 |
| Fiveways Therapies Limited | Households | 2022 |
| Fixation Skincare Ltd | Other services | 2022 |
| Fixbox Limited | Construction | 2016 |
| Fixmycar I&G Ltd | Wholesale & retail | 2025 |
| Fizzology Ltd | Wholesale & retail | 2025 |
| Fizzy APE Ltd | Hospitality | 2023 |
| Fizzy Software Limited | Information & communication | 2010 |
| FJ Pinnock & SON Ltd | Other services | 2020 |
| FJB Construction Ltd | Real estate | 2016 |
| FJD Housing Ltd | Real estate | 2026 |
| FJK Electrical Ltd | Construction | 2022 |
| FK & SON Ltd | Wholesale & retail | 2021 |
| FK Building Services Limited | Construction | 2007 |
| FK Services NW Ltd | Administrative & support | 2016 |
| FKZ Catering Limited | Hospitality | 2016 |
| FKZ Retail Limited | Wholesale & retail | 2026 |
| Flair Healthcare Ltd | Public administration | 2022 |
| Flamboyant Healthcare Services Ltd | Health & social care | 2022 |
| Flame Cutting Contracts Limited | Construction | 2022 |
| Flame Hardeners Limited | Manufacturing | 1945 |
| Flame Lily Equity Investments Ltd | Information & communication | 2007 |
| Flamelily Care Ltd | Health & social care | 2018 |
| Flames Grill SY Ltd | Hospitality | 2024 |
| Flamesx Limited | Hospitality | 2025 |
| Flamez Sheff Limited | Hospitality | 2021 |
| Flamsteed Asset Capital Limited | Financial services | 2016 |
| Flanagan & Partners Limited | Other services | 2025 |
| Flanagan Financial Services Ltd | Financial services | 2024 |
| Flare Design Services Ltd | Professional & scientific | 2022 |
| Flash Fleet Express Limited | Wholesale & retail | 2024 |
| Flash NO. 1 Limited | Extraterritorial | 1969 |
| Flash NO. 2 Limited | Extraterritorial | 1986 |
| Flash NO. 3 Limited | Extraterritorial | 1921 |
| Flash-Dash Ltd | Wholesale & retail | 2025 |
| Flashgard Limited | Extraterritorial | 2021 |
| Flashlight Leisure Limited | Hospitality | 2013 |
| Flashwing Ltd | Information & communication | 2013 |
| Flashyscience Ltd | Information & communication | 2017 |
| Flat CAP Collars Limited | Wholesale & retail | 2024 |
| Flat Jacks Limited | Real estate | 2010 |
| Flats 5/8 Bessacar Court RTM Company Limited | Households | 2020 |
| Flatsharp Records Ltd | Information & communication | 2017 |
| Flavour Choices Ltd | Hospitality | 2019 |
| Flavours Desserts Ltd | Hospitality | 2017 |
| Flavours Vape Shop Ltd | Wholesale & retail | 2026 |
| Flawless Cleaning and Property Services Ltd | Administrative & support | 2024 |
| FLB Tanning & Cosmetics Ltd | Other services | 2025 |
| FLB Ventures Ltd | Real estate | 2004 |
| Fleet Street Kitchen (1) Limited | Hospitality | 2016 |
| Fleetbusters Limited | Other services | 2012 |
| Fleetfold Couriers UK Limited | Transport & logistics | 2025 |
| Fleetica Group Ltd | Financial services | 2025 |
| Fleetup Ltd | Transport & logistics | 2026 |
| Fleetwood Cadtek Ltd | Professional & scientific | 2011 |
| FLEMING69 Ltd | Hospitality | 2024 |
| Fletcher Consult Ltd | Professional & scientific | 2014 |
| Fletcher Holdco Limited | Financial services | 2026 |
| Fletcher Lodge Ltd | Real estate | 2015 |
| Fletcher Plant Limited | Water & waste | 2013 |
| Fletcher's Beauty and Aesthetics Ltd | Health & social care | 2025 |
| Fletchers Waste Management Limited | Financial services | 2019 |
| Fleur DE MAI Ltd | Wholesale & retail | 2026 |
| Flex Accountants Limited | Extraterritorial | 2011 |
| Flex-R Limited | Extraterritorial | 2000 |
| Flexi Car Hire Ltd | Administrative & support | 2025 |
| Flexi Inc Ltd | Administrative & support | 2020 |
| Flexi Security Ltd | Administrative & support | 2025 |
| Flexible Staffing Solutions Limited | Administrative & support | 2021 |
| Flexpenny Ltd | Administrative & support | 1999 |
| Flexy Health Care Ltd | Health & social care | 2021 |
| Flexyfuels Ltd | Wholesale & retail | 2026 |
| FLF Holdings Limited | Professional & scientific | 2021 |
| FLH Investments Limited | Real estate | 2026 |
| FLH Precision Engineering Ltd | Manufacturing | 2026 |
| Flight Junction Travel Services Limited | Administrative & support | 2007 |
| Flingomation Limited | Financial services | 2021 |
| Flinn & Steel Ltd | Wholesale & retail | 2021 |
| Flinn Retail Ltd | Other services | 2024 |
| Flint and FOX Ltd | Professional & scientific | 2024 |
| Flint Solutions Ltd | Professional & scientific | 2022 |
| Flintwood Property (South Yorkshire) Ltd | Real estate | 2024 |