| JAZ Bar (Hull) Limited | Hospitality | 2009 |
| JB Country Stores and Feed Ltd | Wholesale & retail | 2021 |
| JB Horse Boxes Limited | Wholesale & retail | 2020 |
| JB Property and Roofing Limited | Construction | 2016 |
| Jb's Bar and Grill Flamborough Ltd | Hospitality | 2026 |
| JCO Commercial Limited | Real estate | 2022 |
| JCS Motor Services Limited | Wholesale & retail | 2017 |
| JD Autotech Beverley Ltd | Wholesale & retail | 2025 |
| Jeev Mantotta Consulting Ltd | Professional & scientific | 2019 |
| Jellytots Properties Limited | Real estate | 2015 |
| Jenneson Holdings Ltd | Construction | 2020 |
| Jenneson Thompson Investments Limited | Real estate | 2020 |
| JES (Beverley) Limited | Professional & scientific | 1998 |
| Jessica Laud Mortgages Limited | Financial services | 2024 |
| Jewel Health & Safety Limited | Administrative & support | 2018 |
| JG Harborne Ltd | Professional & scientific | 2003 |
| JGP Ventures Ltd | Households | 2025 |
| JH Retail Services Ltd | Wholesale & retail | 2025 |
| JHD (CS) Limited | Wholesale & retail | 2007 |
| JHD Assets Limited | Administrative & support | 2025 |
| JHD Holdings Limited | Administrative & support | 2009 |
| JIM Crisp Limited | Construction | 2011 |
| Jithin Property Limited | Construction | 2023 |
| Jiva Parts UK Ltd | Wholesale & retail | 2024 |
| Jiva Trade UK Ltd | Wholesale & retail | 2018 |
| Jjdk Properties Limited | Real estate | 2025 |
| Jjj&L Holdings Limited | Real estate | 2020 |
| Jjma Freeholds Limited | Real estate | 2024 |
| Jjma Investments Limited | Real estate | 2019 |
| Jki(Hessle) Ltd | Construction | 2024 |
| Jlas Properties Limited | Real estate | 2014 |
| JLJ Design Ltd | Professional & scientific | 2007 |
| JM Barratt Holdings Ltd | Financial services | 2022 |
| Jmac Care Limited | Health & social care | 2014 |
| JMN Yorkshire Ltd | Financial services | 2023 |
| JMO Property Management Ltd | Real estate | 2020 |
| JMR Investments Limited | Financial services | 2020 |
| JMS Hull Ltd | Hospitality | 2022 |
| JN Plumbing & Heating Limited | Construction | 2026 |
| Jntassociates Ltd | Wholesale & retail | 2023 |
| Joaltec Ltd | Information & communication | 2025 |
| Joanne Joveini Ltd | Health & social care | 2015 |
| Joey's Drinks Ltd | Wholesale & retail | 2025 |
| John Edmond Limited | Professional & scientific | 2010 |
| John Hannard Personal Training Limited | Other services | 2004 |
| John Parkin & SON (Funeral Directors) Limited | Other services | 1997 |
| John Walker (Plumbing) Limited | Construction | 2003 |
| Jolly and Howarth Ltd | Real estate | 2024 |
| Jones Locum Services Ltd | Professional & scientific | 2019 |
| Joshma Limited | Hospitality | 2006 |
| JP Technical Ltd | Professional & scientific | 2021 |
| Jpac Limited | Education | 2000 |
| JPN (Property) Limited | Real estate | 2016 |
| JPN Holdings Ltd | Real estate | 2022 |
| JR & Sons Roofing Ltd | Construction | 2024 |
| JR Bar Beverley Ltd | Hospitality | 2026 |
| JRP Blades Global Ltd | Professional & scientific | 2025 |
| JRP Construction Ltd | Construction | 2014 |
| JS Conversions Ltd. | Manufacturing | 2016 |
| JS Windows and Doors Ltd | Construction | 2025 |
| Julie Ball Designed Interiors Limited | Professional & scientific | 2014 |
| Julie Rogerson Limited | Other services | 2022 |
| Juliet Property Management Ltd | Real estate | 2018 |
| Juliogiulietta Limited | Wholesale & retail | 2021 |
| Junico Ltd | Hospitality | 2020 |
| Junk Bar Beverley Limited | Hospitality | 2025 |
| Junk Soul Smothered Ltd | Hospitality | 2020 |
| Junk Soul York Ltd | Hospitality | 2025 |
| Jupiter Farming Company Limited | Agriculture & fishing | 1996 |
| Jupiter Security Ltd | Financial services | 2025 |
| Just NOW Financial Services Ltd | Financial services | 2020 |
| Justin Carpenter Fisheries Ltd | Wholesale & retail | 2011 |
| JY Wind Ltd | Manufacturing | 2026 |
| K. Stahl Ltd | Health & social care | 2022 |
| K. Stahl Properties Ltd | Real estate | 2022 |
| K.A Home Care Ltd | Health & social care | 2025 |
| K2 Residential Hull Limited | Households | 1972 |
| K9-UK Ltd | Administrative & support | 2017 |
| Karma Feeling UK Ltd | Manufacturing | 2025 |
| Karmwills Ltd | Real estate | 2021 |
| Karpadm Ltd | Real estate | 2016 |
| Kate Drury Independent Social Works Services Ltd | Health & social care | 2016 |
| Kaygee Engineering Limited | Manufacturing | 1982 |
| KB & SON Property Investment Ltd | Real estate | 2026 |
| KB Property Yorkshire Ltd | Real estate | 2024 |
| KC Gyms Ltd | Arts & recreation | 2025 |
| KC Petro-Analytics Ltd | Professional & scientific | 2023 |
| KC24HEALTHCARE Ltd | Health & social care | 2014 |
| KCS Holdings Limited | Financial services | 2021 |
| Keda Property Limited | Real estate | 2021 |
| Keel Electrical Services Ltd | Construction | 2024 |
| Keldgate Properties Limited | Real estate | 2025 |
| Kelvic Ltd | Transport & logistics | 2024 |
| Kemal Faruk Gunduz Ltd | Wholesale & retail | 2024 |
| Kevin Parsons Limited | Manufacturing | 2003 |
| Key Camper Conversions Ltd | Manufacturing | 2014 |
| Key Group Vehicle Solutions Limited | Real estate | 2023 |
| Key Growing Green Limited | Real estate | 2024 |
| Key Growing Limited | Real estate | 1988 |
| KHP Developments Ltd | Real estate | 2016 |