| Big BOY Public Relations Limited | Sandhurst | 2022 |
| Big Branding Limited | Haverfordwest | 2014 |
| Big Cat Brewery Limited | St Albans | 2012 |
| Big Cat Trading Company Limited | East Sussex | 1997 |
| Big Century Co., Ltd. | Kenilworth | 2017 |
| Big Church Productions Limited | Edinburgh | 2023 |
| Big Dude's Big Deals Ltd | Bristol | 2025 |
| Big Face TV Limited | St. Albans | 2015 |
| Big Fast Trading Co., Ltd. | London | 2015 |
| Big Finish Holdings (UK) Limited | Maidenhead | 2019 |
| Big Five Investment Norway Limited | London | 2024 |
| Big Five. Altcd Limited | London | 2024 |
| Big Frog Limited | Bury | 2020 |
| Big Game Productions Ltd. | Iver Heath | 2001 |
| Big Global Investment Ltd | London | 2019 |
| Big Green Surf School Ltd | Newquay | 2022 |
| Big Gymwear Ltd | Warminster | 2026 |
| Big Innovation Hub Limited | London | 2013 |
| Big Kidz Karting Limited | Spalding | 2010 |
| Big Life Records Limited | Warrington | 2020 |
| Big Light Holdings Limited | Ipswich | 2002 |
| Big Lola's Taqueria Ltd | Liverpool | 2022 |
| Big Love Int'L Ltd | Kenilworth | 2011 |
| Big M Small C Ltd | Leeds | 2016 |
| Big Money Ltd | Dartford | 2006 |
| Big Moon Limited | Manchester | 2021 |
| Big Nanny's Hair Products Ltd | London | 2018 |
| Big Ocean Ventures Limited | Ware | 2022 |
| Big Picture Holdings Limited | London | 1996 |
| Big Pine Trail Ltd | Northumberland | 2022 |
| Big Pink Studio Limited | Leeds | 2012 |
| Big Q Limited | Northwich | 2001 |
| Big Rock Limited | Milton Keynes | 2017 |
| Big SIS Productions Limited | Romford | 2010 |
| Big Softies Ltd | Birmingham | 2022 |
| Big Solar Ltd | Sunderland | 2013 |
| Big Spender Limited | Salisbury | 2003 |
| Big Spirit Media Limited | Moreton-In-Marsh | 2022 |
| Big Stuff Delivery Ltd | Stretford | 2021 |
| Big Styles Health and Property Ltd | London | 2022 |
| Big T'S Metal Finishing Ltd | Heckmondwike | 2025 |
| Big Textile Co., Ltd | London | 2016 |
| Big TOE Films Limited | London | 2012 |
| Big Trading World Ltd | Sittingbourne | 2025 |
| Big Wheel International Co., Ltd | Stafford | 2019 |
| Big Wide Grin Limited | Leicester | 2020 |
| Big WIN Boom Limited | Kenilworth | 2021 |
| Big World IT Solutions Limited | Liverpool | 2024 |
| Big X Limited | Sheffield | 2004 |
| Big Yellow Tractor Ltd | Aldershot | 2011 |
| BIG5-CHINA Ltd | Mildenhall | 2012 |
| Bigbenconstruction Ltd | Purfleet | 2020 |
| Bigbury Golf Club Limited | Bigbury | 1945 |
| Bigfire Limited | London | 2025 |
| Bigfoot Services Ltd | Cardiff | 2003 |
| Bigg-In Words Ltd | Polegate | 2007 |
| Bigg-Wither Limited | Barnet | 2013 |
| Biggar Biomass Ltd | Biggar | 2013 |
| Biggcompdoor Limited | Coventry | 2023 |
| Biggenius Limited | Potters Bar | 2010 |
| Bigger on the Inside Limited | London | 2026 |
| Biggin 1959 Limited | Hull | 2013 |
| Bigginair Limited | Westerham | 1988 |
| Biggles Aviation Limited | Sutton Coldfield | 1998 |
| Biggmo Ltd | London | 2024 |
| Biggs Developments Limited | Hailsham | 2024 |
| Biggs Management Ltd | Edinburgh | 2012 |
| Bighouse Furniture Ltd | Hayes | 2015 |
| Bigkicks Limited | Watford | 2002 |
| Biglaw Services Limited | Rochdale | 2022 |
| Biglikegroup Ltd | London | 2025 |
| Biglo Art Limited | Manchester | 2023 |
| Bigloo Ltd | Cinderford | 2019 |
| Bigly Ltd | Bristol | 2024 |
| Bigstg Limited | Tarporley | 2023 |
| Bigtecks Limited | London | 2025 |
| Bigway Trade Co., Ltd. | London | 2020 |
| Bigwood Fine Art Auctioneers Ltd | Stratford-Upon-Avon | 2021 |
| BIH Wreningham Limited | Norwich | 2015 |
| BII Asset Management Limited | London | 1999 |
| BII Group Limited | London | 2003 |
| BII Nominee NO.1 Limited | London | 2013 |
| BIJ IT Consulting Limited | London | 2016 |
| Bijay Kumar Mahrra Ltd | Irthlingbrough | 2022 |
| Bijoutier London Limited | London | 2020 |
| Bike Assist Legal Limited | Egham | 2023 |
| Bike Assist Limited | Egham | 2023 |
| Bike Devil Limited | Romford | 2019 |
| Bike Track Limited | Chesterfield | 2006 |
| Bikejobs Limited | Higham Ferrers | 2008 |
| Bikemarshals Group Ltd | Skelmersdale | 2018 |
| Biker at Heart Ltd | Llanelli | 2021 |
| Bikers Claims Ltd | Glasgow | 2024 |
| Bikes & Bits Ltd | Leigh-On-Sea | 2024 |
| Bikes Electric Limited | Christchurch | 2012 |
| Bikes of Brighton Limited | Burgess Hill | 2007 |
| Bikewise Limited | Uxbridge | 2013 |
| BIL Maskin Trading Limited | London | 2025 |
| Bilanz Services Ltd | Worksop | 2025 |
| Bilayer Solutions Ltd | Bristol | 2026 |