| Builth Wells Rugby Football Club Limited | Builth Wells | 2001 |
| Builtlift Ltd | London | 2025 |
| Buinigauk Ltd | London | 2025 |
| Buju Limited | London | 2018 |
| Buka Ltd. | Teddington | 2015 |
| Bula Ltd | London | 2013 |
| Bulba Studio Ltd | London | 2024 |
| Bulford Associates Limited | Aylesbury | 2002 |
| Bulk Garage Nutrition Limited | Hull | 2012 |
| Bulkington Village Centre | Warwickshire | 1996 |
| Bulks Gym Ltd | Gravesend | 2009 |
| Bull and Red Flag Ltd | Kington | 2026 |
| Bull at the Gate Fleet Limited | Essex | 2024 |
| Bull Bay Golf Club Limited(The) | Amlwch, Anglesey | 1926 |
| Bull Creative Consultants Limited | Southend-On-Sea | 2015 |
| Bull F1T Ltd | Cheltenham | 2023 |
| Bull Fitness Limited | Yeadon | 2017 |
| Bull Squad Ltd | York | 2024 |
| Bull Terrier Limited | Radstock | 2012 |
| Bullard Bloodstock Limited | Fordham Ely | 2002 |
| Bulldog Bouncers Ltd | Chippenham | 2022 |
| Bulldog Club Ltd | Bellshill | 2023 |
| Bulldog Event Hire Limited | Kinmel Bay | 2019 |
| Bulldog Macro Advisors Ltd | Chesterfield | 2021 |
| Bulldog Musical Entertainments Limited | Surrey | 1982 |
| Bulldog Padel Limited | London | 2026 |
| Bulldog-Sports Ltd | Edinburgh | 2013 |
| Bulldogs Basketball C.I.C. | London | 2023 |
| Bullet Creative Limited | London | 2001 |
| Bullet Sports Management Limited | Bognor Regis | 2019 |
| Bullet Tooth Ltd | Pinner | 2025 |
| Bullet Train Music Ltd | London | 2023 |
| Bullet's Sports Bar Ltd | Yeovil | 2020 |
| Bulletproof Baller Ltd | London | 2025 |
| Bulletproof Games Ltd | Tamworth | 2015 |
| Bulletproof Studios Ltd | Airdrie | 2022 |
| Bullett Studio Ltd | London | 2015 |
| Bullfit Coaching Limited | Birmingham | 2022 |
| Bullfrog Arts C.I.C. | Leicester | 2011 |
| Bullgng Ltd | Leicester | 2018 |
| Bullhouse Fitness Limited | Millhouse Green | 2026 |
| Bullie INK Limited | Sheffield | 2018 |
| Bullish Competitions Ltd | Maesteg | 2025 |
| Bullocks 2 Limited | London | 2011 |
| Bulls News Limited | Hereford | 2005 |
| Bulls Sports Entertainment Agency Ltd | London | 2021 |
| Bullseye Dart Hub Ltd | London | 2026 |
| Bullseye Sports Bar Ltd | London | 2025 |
| Bullseyes Boxing Ltd | Filey | 2024 |
| Bully BOY Limited | Stourbridge | 2014 |
| Bullyache Ltd | Reading | 2022 |
| Bullzeye Lounge and Darts Shop Ltd | Ashton-Under-Lyne | 2026 |
| Bulmershe Gymnastics Club | Reading | 1996 |
| Bulwell Forest Golf Club Limited | Nottingham | 2004 |
| Bulwell Hall Boxing and Community Fitness Club Limited | Nottingham | 2008 |
| BUM Note Limited | London | 2005 |
| BUM Note Music Limited | London | 2019 |
| Bumble BEE Design Studio Ltd | Shipley | 2015 |
| Bumble Beez Ltd | Ramsgate | 2012 |
| Bumble-Bee Creation Corner Ltd | Chorley | 2026 |
| Bumblebees Adventures Limited | Salford | 2024 |
| Bumblescratch 2016 Ltd | London | 2016 |
| Bumblescratch Ltd | London | 2013 |
| Bump Club Limited | Bristol | 2006 |
| Bumpah Ltd | London | 2025 |
| Bumper FUN Limited | Bridlington | 2012 |
| Bumskin Limited | London | 2016 |
| Bunbea Ltd | Fareham | 2022 |
| Bunbury Banter CIC | Dumfries | 2019 |
| Bungaroosh Design Limited | Worthing | 2015 |
| Bungay & Waveney Valley Golf Club Limited | Lowestoft | 2019 |
| Bungay Arts and Theatre Society | Bungay | 1997 |
| Bungay Castle Trust | Bungay | 1987 |
| Bungee Fitness Club Limited | Stratford-Upon-Avon | 2023 |
| Bungee FLY Limited | London | 2007 |
| Bungee Leicester Ltd | Leicester | 2024 |
| Bungee Trampoline Hire Scotland Ltd | Glasgow | 2025 |
| Bungeefit Ltd | Nottingham | 2023 |
| Bungeefungee Ltd | Glasgow | 2025 |
| Bungydome (UK) Ltd. | Ayrshire | 2007 |
| Bunhill Fitness Limited | Beaconsfield | 2025 |
| Bunker 19 Ltd | Southend-On-Sea | 2023 |
| Bunker 51 Limited | Grimsby | 2010 |
| Bunker Airsoft SW Ltd | Ebbw Vale | 2023 |
| Bunker Events Limited | York | 2026 |
| BUNKER.164 Ltd | London | 2025 |
| Bunkerbay Ltd | Poole | 2024 |
| Bunkersonix Limited | Bristol | 2010 |
| Bunkfest | Wallingford | 2002 |
| Bunkr Golf Ltd | Edinburgh | 2025 |
| Bunmi Agusto Studios Ltd | London | 2024 |
| Bunn's Tagada Ltd | South Ockendon | 2026 |
| Bunnies Mobile Tattoos Limited | Middlesbrough | 2013 |
| Bunns Leys Designs Limited | Evesham | 2008 |
| Bunny Hill Farm Weddings and Events Limited | York | 2018 |
| Bunny Hoppers Ltd | Shepshed | 2015 |
| Bunny Kinney Ltd | London | 2019 |
| Bunny Productions | London | 2019 |
| Bunny Racing Ltd | Sawston | 2007 |
| Bunny Rwlk Ltd | Newcastle Upon Tyne | 2024 |