| Jdtv Limited | Information & communication | 2005 |
| JE Decor Ltd | Construction | 2026 |
| Jean & Jack Ltd | Professional & scientific | 2026 |
| Jeary & Lewis Limited | Professional & scientific | 2017 |
| Jeary Investments Ltd | Financial services | 2024 |
| JEL Enterprises Limited | Information & communication | 2020 |
| Jenson Limited | Health & social care | 2002 |
| Jeremy Tyrrell Limited | Professional & scientific | 2008 |
| Jess Davies Dressage Ltd | Agriculture & fishing | 2025 |
| Jester's Adventure Play Ltd | Arts & recreation | 2010 |
| Jesurun Properties Ltd | Real estate | 2024 |
| JET Rail Ltd | Construction | 2023 |
| JET ROD Limited | Administrative & support | 1994 |
| JFR Novus Limited | Information & communication | 2021 |
| JG Fire and Security Limited | Administrative & support | 2018 |
| JG Psychology Practice Limited | Health & social care | 2026 |
| JH 4 Ltd | Information & communication | 2025 |
| JHJ Limited | Construction | 1999 |
| Jina Asian Enterprises Limited | Manufacturing | 2016 |
| Jipe Limited | Information & communication | 2023 |
| Jitaku Ltd | Real estate | 2024 |
| JJ Carey Consultants Ltd | Professional & scientific | 2017 |
| JJ Pet Supplies Ltd | Wholesale & retail | 2023 |
| JJB Holdings (SW) Ltd | Financial services | 2025 |
| JJB Maintenance Limited | Construction | 2009 |
| Jjep Services Limited | Professional & scientific | 2018 |
| Jjkh Limited | Construction | 2023 |
| JJM Electrical Contractors Ltd | Construction | 2018 |
| JJM Enterprise Ltd | Real estate | 2021 |
| JJM PUB Co Limited | Hospitality | 2022 |
| JJW Groundworks Ltd | Construction | 2020 |
| JK2L Ltd | Information & communication | 2024 |
| JKR QS Services Limited | Professional & scientific | 2016 |
| JLB Law Ltd | Professional & scientific | 2021 |
| Jlmt Property Investors Ltd | Construction | 2021 |
| JM Collings Limited | Construction | 2004 |
| JM Electrical (Wiltshire) Ltd | Manufacturing | 2021 |
| JMA Groundworks Limited | Construction | 2026 |
| Jmacs Consulting Limited | Professional & scientific | 2023 |
| JMC Quality Solutions Limited | Professional & scientific | 2013 |
| JMH Detailing Ltd | Administrative & support | 2025 |
| JML Williamson Ltd | Health & social care | 2020 |
| Jockey Lane Management Company Limited | Households | 2018 |
| JOE Mavericks Ltd | Hospitality | 2025 |
| John Benson Property Consultant Limited | Real estate | 2021 |
| John F Stevenson Limited | Other services | 2017 |
| John KAY Steel Limited | Arts & recreation | 2012 |
| John Miller (Corsham) Limited | Manufacturing | 1978 |
| John Williams Heating Services Ltd | Construction | 2004 |
| Jolyon Hobby Limited | Administrative & support | 2015 |
| JON Burchell Building Contractors Limited | Construction | 2010 |
| Jonathan Brookman Ltd | Construction | 2025 |
| Jonathan James Coxon Ltd | Extraterritorial | 2022 |
| Jonathan James Richards Ltd | Extraterritorial | 2022 |
| Jonwallacedesign Limited | Professional & scientific | 2010 |
| Jorley Ltd | Wholesale & retail | 2024 |
| Jossmite Ltd | Financial services | 2021 |
| Joyce Chanin Developments Limited | Construction | 2003 |
| JP2026 Limited | Agriculture & fishing | 2026 |
| JPE & KR Brunt Ltd | Agriculture & fishing | 2011 |
| JPN Groundwork & Building Contractor Limited | Construction | 2005 |
| JPO Studios Ltd | Information & communication | 2026 |
| JPS Renewable Energy Ltd | Construction | 2011 |
| JR Research Limited | Professional & scientific | 2014 |
| JR Taxi Chippenham Ltd | Transport & logistics | 2024 |
| Jrel Holdings Ltd | Financial services | 2025 |
| JRS Media Content Ltd | Other services | 2024 |
| Jsoi Adventures Ltd | Other services | 2025 |
| JSS Chauffeurs Ltd | Transport & logistics | 2025 |
| JT Paget & SON Limited | Wholesale & retail | 2019 |
| JT Property Development Ltd | Construction | 2025 |
| Jt&H Properties Limited | Real estate | 2025 |
| Jtai Plumbing Ltd | Construction | 2025 |
| Jtec South West Limited | Construction | 2024 |
| Jubilee TAP Property Management Ltd | Construction | 2020 |
| Judgeday Holdings Ltd | Real estate | 2016 |
| Judgeday Limited | Administrative & support | 1993 |
| Jump Films Limited | Information & communication | 2016 |
| Juneg Ltd | Wholesale & retail | 2026 |
| Juniper Construction & Groundwork's Limited | Construction | 2021 |
| Jury Developments Limited | Construction | 2012 |
| Just BE More Dog Ltd | Other services | 2021 |
| Just Bernese Ltd | Agriculture & fishing | 2026 |
| Just Fascinating Ltd | Manufacturing | 2012 |
| Just Gardening Limited | Wholesale & retail | 2016 |
| Just Labernese Ltd | Agriculture & fishing | 2026 |
| Just-So Occasions Limited | Administrative & support | 2009 |
| Justin Leighton Ltd | Professional & scientific | 2014 |
| JWD Aitken Consulting Limited | Professional & scientific | 2020 |
| JWK Brickwork&Landscapes Ltd | Construction | 2024 |
| JWR Property Management Ltd | Real estate | 2022 |
| K & K Patel Limited | Health & social care | 2023 |
| K & R Group Ltd | Construction | 2015 |
| K & S Contractor's Ltd | Agriculture & fishing | 2025 |
| K and M Masonry Holdings Limited | Financial services | 2026 |
| K M Agricultural Spares Limited | Manufacturing | 1989 |
| K Martin Ltd | Professional & scientific | 2012 |
| K T Barnsley Limited | Transport & logistics | 2014 |
| K. Worlock Homes Limited | Construction | 1987 |
| K.A.H. Kitchen Contractors Limited | Administrative & support | 2002 |