| Inchuition Ltd | Administrative & support | 2018 |
| Industrial Interiors Limited | Manufacturing | 2022 |
| Industrial Supplies Service Ltd | Wholesale & retail | 2017 |
| Ineson Payroll Services Ltd | Administrative & support | 2004 |
| Infinity Gomersal Ltd | Other services | 2024 |
| Infinity Optics Limited | Administrative & support | 2017 |
| Innovative Structures Ltd | Construction | 2020 |
| Insideout Cleaning Solutions Limited | Administrative & support | 2013 |
| Inspired Project Management Solutions Ltd | Professional & scientific | 2012 |
| Inspiring Futures Care and Support Services Ltd | Other services | 2025 |
| Intelec Electrical Contractors Ltd | Construction | 2014 |
| Interior Design Partnership Limited | Professional & scientific | 2021 |
| International Furniture Solutions Limited | Wholesale & retail | 2023 |
| Intrepid Coaching Limited | Education | 2024 |
| IP Quality Solutions Limited | Administrative & support | 2019 |
| IPA Support Services Limited | Health & social care | 2023 |
| IPM Workshop Services Limited | Manufacturing | 2008 |
| Iraq Heritage Ltd | Extraterritorial | 2013 |
| Irealtors Ltd | Real estate | 2019 |
| IRM Trenchless Solutions Ltd | Construction | 2026 |
| Iron Pixel Ltd | Information & communication | 2026 |
| ITS NOT Rocket Science Limited | Professional & scientific | 2001 |
| Ivershomes Ltd | Extraterritorial | 2024 |
| Iwmep Ltd | Professional & scientific | 2026 |
| J & J Ventures Ltd | Real estate | 2019 |
| J & L Creative Limited | Real estate | 2023 |
| J & L Springlock Washer Limited | Manufacturing | 2012 |
| J & M Consultants Limited | Professional & scientific | 2017 |
| J and JM Mcculloch Limited | Manufacturing | 2003 |
| J Davies Property Services Limited | Real estate | 2021 |
| J Harris Professional Services Ltd | Households | 2025 |
| J Pro Media Limited | Information & communication | 2024 |
| J R Mens Hairdressing Ltd | Administrative & support | 2014 |
| J Whitley Limited | Hospitality | 2021 |
| J&L Property Group Limited | Real estate | 2024 |
| J&M Assets LLP | | 2012 |
| J&M Bradford Limited | Professional & scientific | 1995 |
| J. Coote Engineers Limited | Manufacturing | 2003 |
| J. Scott Construction Ltd | Construction | 2021 |
| J.J. Stainless Limited | Wholesale & retail | 1998 |
| J25 Holdings Ltd | Real estate | 2022 |
| Jack Hammerton Limited | Wholesale & retail | 1973 |
| Jackwake Ltd | Transport & logistics | 2025 |
| Jain International (UK) Limited | Wholesale & retail | 2025 |
| James Harris Associates Limited | Professional & scientific | 1988 |
| James Wood Estate Agent Limited | Real estate | 2025 |
| Jamie Careless Limited | Real estate | 2024 |
| Jamun Global Ltd | Wholesale & retail | 2019 |
| Jangur Ltd | Financial services | 2026 |
| Jason Clark Roofing Limited | Construction | 2017 |
| Jawbone Plant Hire Ltd | Construction | 2015 |
| JB & Sons Drylining and Plastering Ltd | Construction | 2019 |
| JB Construction & Landscapes Limited | Administrative & support | 2017 |
| JB Developments Harrogate Ltd | Construction | 2023 |
| JB Plant & Machinery Hire Limited | Administrative & support | 2017 |
| JB Training Partners Ltd | Professional & scientific | 2020 |
| JCT Building Developments Ltd | Construction | 2024 |
| JCT Contractors Ltd | Construction | 2024 |
| JDL10 Limited | Real estate | 2020 |
| JDR Estates Limited | Real estate | 2014 |
| Jeff Wright Locum Services Limited | Health & social care | 2007 |
| Jenson Blue Group Ltd | Professional & scientific | 2026 |
| Jericho Restoration Limited | Manufacturing | 2023 |
| Jgmaltas Electrical Ltd | Construction | 2021 |
| JH Aggregates Limited | Transport & logistics | 2016 |
| JH Wills Limited | Other services | 2019 |
| Jigsaw Property Solutions (Yorks) Limited | Construction | 2021 |
| Jillian Harry Estates Ltd | Real estate | 2026 |
| Jimbo RN Ltd | Real estate | 2025 |
| JJC Groundworks Limited | Construction | 2013 |
| Jkhl Investments Limited | Financial services | 2023 |
| JMB the Sunflower Kitchen Ltd | Hospitality | 2025 |
| JMC Surfacing Limited | Construction | 2023 |
| JMP Mechanical & Process Pipework Ltd | Professional & scientific | 2023 |
| JNT Joinery Contractors Limited | Manufacturing | 2019 |
| JNT Pest Control Ltd | Agriculture & fishing | 2023 |
| Joanne’S Childminding Ltd | Health & social care | 2023 |
| Joey and Friends Ltd | Hospitality | 2022 |
| John Richard (Hair) Ltd | Other services | 2024 |
| Johnston Pension Trustees Limited | Financial services | 2006 |
| JON WAH Clothing Limited | Wholesale & retail | 2026 |
| Jones Masonry Group Ltd | Real estate | 2020 |
| Jordan Wake Limited | Wholesale & retail | 2017 |
| Josem Ltd | Wholesale & retail | 2023 |
| Joseph Killingbeck (Estates) Limited | Professional & scientific | 1939 |
| Joshua Adams Limited | Wholesale & retail | 2012 |
| Joy & Comfort Ceremonies Limited | Other services | 2025 |
| JPM EA Limited | Real estate | 2019 |
| JR Hair Academy Ltd | Other services | 2025 |
| Jrny Travel Ltd | Administrative & support | 2026 |
| JS3 Investments Ltd | Real estate | 2020 |
| JSS Software Limited | Information & communication | 2018 |
| Just Simple Quality Ltd | Professional & scientific | 2025 |
| JW Electrical Services Yorkshire Ltd | Construction | 2025 |
| K&R Groundworks Ltd | Construction | 2018 |
| K8 & Partners Limited | Information & communication | 2021 |
| K9BEDS Limited | Wholesale & retail | 2024 |
| Kadco Fashion & Textiles Ltd | Wholesale & retail | 2012 |
| Kadco Investments Ltd | Real estate | 2016 |
| Kadco IT & BPO Solutions Ltd | Information & communication | 2013 |