| Belmore Services Limited | Real estate | 2022 |
| Benbnk Ltd | Professional & scientific | 2023 |
| Benjamin Ross Ltd | Other services | 2016 |
| Benny International Limited | Administrative & support | 2009 |
| Berthon Boat Company Limited | Manufacturing | 1877 |
| Berthon International Limited | Arts & recreation | 1993 |
| Berthon RIB Solutions Limited | Manufacturing | 2018 |
| Betty's Sparkle and Shine Ltd | Administrative & support | 2020 |
| Beyond Broadcasting Ltd | Professional & scientific | 2012 |
| BHG Marine Limited | Manufacturing | 2002 |
| BHG Service Limited | Wholesale & retail | 2008 |
| BHP Studio Ltd | Professional & scientific | 2026 |
| BHS (BD) Limited | Hospitality | 2023 |
| Bicycle Jack's Ltd | Manufacturing | 2021 |
| Big 5 Holdings Limited | Financial services | 2021 |
| Big BAD Books Limited | Administrative & support | 2012 |
| Big Hello Design Limited | Information & communication | 2006 |
| Billswheels Transport Limited | Transport & logistics | 2017 |
| BIO Treatment Ltd | Water & waste | 2009 |
| Bio-Health Limited | Manufacturing | 1981 |
| Bionautix Ltd | Wholesale & retail | 2021 |
| Birchy Consulting Limited | Professional & scientific | 2024 |
| Bishops Brokers LLP | | 2025 |
| Bishops Financial Services Limited | Financial services | 1986 |
| Black Racing Team Ltd | Manufacturing | 2013 |
| Bleibtreu Communications Limited | Information & communication | 2017 |
| Blockchain Security Services Ltd | Information & communication | 2018 |
| Blockchain Technology Holdings Ltd | Financial services | 2016 |
| Bloombridge Fulfilment Ltd | Wholesale & retail | 2026 |
| Blueberry Lymington Boutique Franchise Limited | Wholesale & retail | 2019 |
| Bluebit Limited | Information & communication | 2009 |
| Boalhouse Ltd | Professional & scientific | 2025 |
| Boat House 27 Ltd | Wholesale & retail | 2020 |
| Boat Safety Stickers Limited | Extraterritorial | 2014 |
| Bodybest Ltd | Health & social care | 2023 |
| Boko Properties Limited | Real estate | 2024 |
| Bold & Spirited Ltd | Wholesale & retail | 2022 |
| Boldre Projects Ltd | Construction | 2009 |
| BOO BOO Limited | Administrative & support | 2006 |
| Boocas Ltd | Information & communication | 2025 |
| Boocas Records Ltd | Information & communication | 2025 |
| Bootle Estates Ltd | Real estate | 2025 |
| Borough Arms Ltd | Hospitality | 2020 |
| Boundway Property Ltd | Extraterritorial | 2021 |
| Box House Antiques Ltd | Wholesale & retail | 2018 |
| Boyce and Devoil Services Limited | Professional & scientific | 2011 |
| Bracken Mead Management Company Limited | Households | 2007 |
| Braemaar Limited | Professional & scientific | 2025 |
| Brain Haulage Limited | Transport & logistics | 2021 |
| Bram Lymington Ltd | Wholesale & retail | 2018 |
| Bramble Business Services Limited | Professional & scientific | 1989 |
| Brand Mantra Ltd | Professional & scientific | 2021 |
| Brandingsi Ltd | Information & communication | 2019 |
| Bransway Agri Limited | Agriculture & fishing | 2017 |
| Bravertech Limited | Professional & scientific | 2023 |
| Bread and Butter Software Limited | Information & communication | 2008 |
| Brick by Brick Brickwork & Building Ltd | Construction | 2019 |
| Bridgeworks Ltd. | Information & communication | 1987 |
| Brinken Wood Consulting Limited | Professional & scientific | 2023 |
| Brit-Phil Enterprise Limited | Manufacturing | 2012 |
| Britannia Thai Ltd | Hospitality | 2013 |
| Broadmead Associates Ltd | Professional & scientific | 2024 |
| Broadwater Developments Limited | Real estate | 2016 |
| Broadway Education Limited | Professional & scientific | 2019 |
| Broadway Holdings Limited | Financial services | 2022 |
| Brockenhurst Masonic Centre Limited | Other services | 2007 |
| Broomhill Conservatories Limited | Extraterritorial | 2001 |
| Broomhill Garden Buildings Limited | Wholesale & retail | 2001 |
| Brown Brothers Securities (2011) Limited | Professional & scientific | 2011 |
| Brown Lamb Limited | Real estate | 2022 |
| Bryant Associates Contractors Limited | Construction | 2008 |
| Bryce Building Projects Limited | Construction | 2005 |
| Buckland Granaries Management Company Limited | Households | 2018 |
| Buckland Place Associates Limited | Professional & scientific | 2013 |
| Buckland View Management Company Limited | Health & social care | 1988 |
| Built by Basil Limited | Manufacturing | 2026 |
| Bull Cleaning Solutions Ltd | Administrative & support | 2026 |
| Bure Investments Limited | Real estate | 1964 |
| Burkmar Limited | Real estate | 2003 |
| Burtonwood Property Limited | Manufacturing | 2020 |
| Business Architecture Ltd | Professional & scientific | 2020 |
| BW Consulting Group Ltd | Administrative & support | 2025 |
| BY the Sea PUB Company Limited | Hospitality | 2025 |
| C - Pro Holdings Limited | Professional & scientific | 2009 |
| C J T Accountancy Services Limited | Professional & scientific | 2004 |
| C Parkes Limited | Professional & scientific | 2026 |
| C Smith Accounting Ltd | Professional & scientific | 2023 |
| C.V.S. (Heathrow) Limited | Wholesale & retail | 2006 |
| Cablesure Technology Ltd. | Professional & scientific | 2001 |
| Cadco Limited | Professional & scientific | 1997 |
| Cafe 3 LLP | | 2013 |
| Caget Limited | Real estate | 2026 |
| Calder & Hannam Limited | Education | 2016 |
| Caldwells (Lymington) Limited | Real estate | 1996 |
| Call Maintenance Ltd | Construction | 2019 |
| Callaura Management Company Limited | Households | 2012 |
| Camirtec Ltd | Real estate | 2016 |
| Campervolt Limited | Manufacturing | 2024 |
| CAMPUS2CORPORATE LLP | | 2012 |
| Cancer Support Service Limited | Other services | 2024 |