| Irobot Automation Ltd | Professional & scientific | 2011 |
| Iron Padel Ltd | Arts & recreation | 2026 |
| Isabran Drilling and Sawing Limited | Construction | 2025 |
| Isavey Limited | Administrative & support | 2011 |
| Island Flavaz Ltd | Hospitality | 2020 |
| Isoftware Solutions Limited | Information & communication | 2014 |
| Isoman Limited | Arts & recreation | 2014 |
| IT Careers Academy Ltd | Manufacturing | 2004 |
| Itanex Limited | Professional & scientific | 2008 |
| Itec Electronics Ltd | Professional & scientific | 2009 |
| Itide Limited | Professional & scientific | 2023 |
| Ivypen Ltd | Manufacturing | 2026 |
| Iwantacaricature.Co.Uk Limited | Wholesale & retail | 2009 |
| J & a Refrigeration Limited | Professional & scientific | 2003 |
| J & C Hale Property Ltd | Real estate | 2021 |
| J & R Catering (Midlands) Limited | Hospitality | 2022 |
| J a Griffin Plumbing & Heating Limited | Construction | 2013 |
| J a Statham Ltd | Construction | 2016 |
| J and L D Hayes Limited | Health & social care | 1994 |
| J B Place & SON (Welders) Limited | Administrative & support | 2003 |
| J C Consulting Limited | Professional & scientific | 2017 |
| J C Electro Services Limited | Administrative & support | 2009 |
| J C Glazing & Repairs Limited | Construction | 2012 |
| J C Heating & Plumbing Ltd | Construction | 2021 |
| J Chawner Orthopaedics Ltd | Health & social care | 1994 |
| J H Refurbishments Limited | Construction | 2026 |
| J Kelly Developments Ltd | Construction | 2025 |
| J Maddocks Limited | Professional & scientific | 2023 |
| J O Management Consultancy Ltd | Construction | 2026 |
| J P Harbon Ltd | Construction | 2026 |
| J Samuel Properties Limited | Real estate | 2021 |
| J Sutor Roofing Ltd | Construction | 2014 |
| J Tech Limited | Manufacturing | 2016 |
| J Vatish Breast Surgery Ltd | Health & social care | 2023 |
| J W Holdings and Investments Limited | Financial services | 2022 |
| J W Industrial Equipment Limited | Wholesale & retail | 2023 |
| J Warwick Holdings Limited | Financial services | 2019 |
| J&M International Ltd | Hospitality | 2025 |
| J. T. Finance Ltd | Professional & scientific | 2010 |
| J.J Nest Property Ltd | Real estate | 2024 |
| J.K.B. Healthcare Limited | Wholesale & retail | 2007 |
| J.Lester Bespoke Carpentry Ltd | Manufacturing | 2025 |
| J.T. Pearce (Springs) Limited | Manufacturing | 1998 |
| J.Uznanski Ltd | Other services | 2017 |
| J.W. Beddows & SON (Holdings) Limited | Manufacturing | 1971 |
| J.W. Beddows & SON Limited | Extraterritorial | 2015 |
| J10 Investment Group Ltd | Real estate | 2026 |
| Jach Ecomm Ltd | Wholesale & retail | 2024 |
| Jack Hawksworth Racing Limited | Arts & recreation | 2013 |
| Jacob Anthony Limited | Other services | 2014 |
| Jacob Sheep Society Limited(The) | Other services | 1979 |
| Jacqui Smith Advisory Ltd | Other services | 2015 |
| Jadesey Enterprise Ltd | Information & communication | 2022 |
| Jaff Ltd | Other services | 2023 |
| JAH Construction Projects Ltd | Construction | 2014 |
| Jahed's Takeaway Limited | Hospitality | 2016 |
| Jaime Such Ltd | Hospitality | 2022 |
| Jaljam Bookkeeping Ltd | Financial services | 2022 |
| JAM Beoley Limited | Professional & scientific | 2025 |
| James Brennan Surveyors Limited | Professional & scientific | 2007 |
| James Group Investments Limited | Financial services | 2018 |
| James Nutt Cars Limited | Wholesale & retail | 2020 |
| Jamproductions.Co.Uk Ltd | Administrative & support | 2008 |
| Jane Hemingway Limited | Professional & scientific | 2017 |
| Jarvis Construction Group Limited | Construction | 2002 |
| Jason Forrester Ltd | Transport & logistics | 2017 |
| JAY Jeavons Limited | Administrative & support | 2024 |
| JB Heath Limited | Agriculture & fishing | 2013 |
| JB Interior Services Limited | Construction | 2019 |
| JBR Financial Services Ltd | Real estate | 2014 |
| JBR Real Estate Ltd | Real estate | 2024 |
| Jbrd Properties Ltd | Real estate | 2021 |
| JC Kirby Properties Ltd | Real estate | 2018 |
| JC Medical Consulting Ltd | Health & social care | 2015 |
| JCE Electrical Installations Ltd | Construction | 2021 |
| JCG Land Limited | Professional & scientific | 2008 |
| JD Transmissions Limited | Wholesale & retail | 2026 |
| JDA Logistics Solutions Ltd | Information & communication | 2017 |
| JDB Studios Ltd | Information & communication | 2024 |
| JDC Electrical Contracting Services Limited | Construction | 2014 |
| JDE Pubs Ltd | Hospitality | 2018 |
| JDG Evesham Limited | Wholesale & retail | 2007 |
| JDP Group Ltd | Administrative & support | 2023 |
| Jdrh Offices Limited | Real estate | 2016 |
| JDS Consultancy Services Ltd | Professional & scientific | 2016 |
| Jdsurveying (Property) Ltd | Real estate | 2021 |
| JE and PA Dillon Limited | Administrative & support | 2001 |
| JE Carpentry & Maintenance Services Ltd | Construction | 2024 |
| Jeav Ltd | Arts & recreation | 2014 |
| Jeff Annand Contracting Limited | Administrative & support | 2004 |
| Jellycat Digital Limited | Information & communication | 2016 |
| JEM Electrical Services (West Midlands) Ltd | Construction | 2022 |
| Jeneva Consulting Limited | Professional & scientific | 2018 |
| Jens Moeller Consulting Limited | Professional & scientific | 2006 |
| JEO Consulting Limited | Administrative & support | 2003 |
| Jeremy & Co (Stratford) Limited | Real estate | 2019 |
| Jeremy & Co Limited | Real estate | 2008 |
| Jeremy Duckham (Scenic Artist) Limited | Arts & recreation | 2002 |
| Jestaminute Community Theatre CIC | Education | 2011 |
| JET Vehicle Finance Limited | Administrative & support | 2005 |