| Hydroclean Solutions Ltd | Administrative & support | 2018 |
| Hydrocleaning Solutions Ltd | Administrative & support | 2024 |
| Hygeia Locum Ltd | Health & social care | 2010 |
| Hyperion Imaging & Intervention Limited | Health & social care | 2023 |
| I Love Kitchens Ltd | Construction | 2004 |
| I M I J Property Holdings Limited | Real estate | 2002 |
| I SPY Racing Syndicate Ltd | Arts & recreation | 2022 |
| I-Fone Care Ltd | Information & communication | 2015 |
| Iampr Consultancy Limited | Professional & scientific | 2021 |
| IAN Bainton Plumbing & Heating Limited | Construction | 2005 |
| IAN Reynolds Training Limited | Professional & scientific | 2018 |
| Icare Residential Social Work Consultancy Limited | Professional & scientific | 2022 |
| ICL (Properties) Limited | Real estate | 2015 |
| ICL Freight Limited | Transport & logistics | 2021 |
| Ignite Marketing and Sales Limited | Administrative & support | 2015 |
| II / AC Holdings Limited | Administrative & support | 2017 |
| Iipenev Ltd | Construction | 2020 |
| IJK Partners Limited | Professional & scientific | 2016 |
| ILH Holdings Ltd | Construction | 2024 |
| Illume Wealth Management Limited | Professional & scientific | 2025 |
| IM Food Tech Ltd | Professional & scientific | 2020 |
| Image 2000 Systems Limited | Construction | 1996 |
| Imagen Photography Limited | Professional & scientific | 2001 |
| IMI Auto Care Ltd | Wholesale & retail | 2026 |
| Impact Leadership Consultancy Ltd | Professional & scientific | 2026 |
| Improv Systems (U.K.), Inc. | | 2002 |
| Inbound Electrical Ltd | Construction | 2025 |
| Independent Shipping Survey Ltd | Transport & logistics | 2024 |
| Independent Skincare Consultancy Limited | Extraterritorial | 2015 |
| Indicoll Limited | Information & communication | 2010 |
| Indigo Tangerine Limited | Professional & scientific | 2016 |
| Infinitum Enterprises Limited | Professional & scientific | 2024 |
| Infinity Blinds of Hull Limited | Wholesale & retail | 2014 |
| Infogencer Limited | Administrative & support | 2008 |
| Infoplai Limited | Information & communication | 2022 |
| Ingicality Ltd | Information & communication | 2020 |
| Inglemire Club Limited | Hospitality | 2026 |
| INNOV8 9 10 Limited | Administrative & support | 2007 |
| Innovatek Limited | Professional & scientific | 2004 |
| Inspire Vivariums Ltd | Wholesale & retail | 2014 |
| Inspire-Ignite Limited | Extraterritorial | 2016 |
| Inspired Angling Ltd | Wholesale & retail | 2021 |
| Inspired Technology (Yorkshire) Limited | Information & communication | 2002 |
| Instrument Control & Electrical Engineering Limited | Professional & scientific | 2017 |
| Inter K9 Limited | Administrative & support | 2017 |
| International Estuarine & Coastal Specialists Ltd | Professional & scientific | 2019 |
| Internova Consulting Ltd | Professional & scientific | 2025 |
| Intimate Enhancements Ltd | Other services | 2025 |
| Intrapreneur International Ltd | Extraterritorial | 2016 |
| Invest Scarborough LLP | | 2020 |
| Ioer Limited | Construction | 2011 |
| Ippi (UK) Ltd | Manufacturing | 2012 |
| IR Fabrication Ltd | Manufacturing | 2023 |
| Iron Cloud Limited | Information & communication | 2015 |
| ISL Travel Limited | Administrative & support | 2008 |
| Islay Capital Limited | Financial services | 1989 |
| Islay Technology Limited | Financial services | 2022 |
| Ispring Limited | Information & communication | 2003 |
| ITH Wind Limited | Manufacturing | 2025 |
| ITS Doozie Limited | Information & communication | 2024 |
| Itsm Assist Limited | Information & communication | 2011 |
| Ivanta Limited | Information & communication | 2026 |
| IVY House Racing Ltd | Agriculture & fishing | 2023 |
| IXQ Consulting Limited | Professional & scientific | 2000 |
| J & J L Flanagan Motor Engineers Limited | Wholesale & retail | 2003 |
| J & J Mallinson Limited | Other services | 2016 |
| J & K Leisure York Ltd | Hospitality | 2021 |
| J Bouncetastic Limited | Arts & recreation | 2023 |
| J Byass & Sons Limited | Agriculture & fishing | 2012 |
| J Drew & SON Limited | Construction | 2007 |
| J Holtby Limited | Real estate | 2017 |
| J M & E Ovington & SON (Funeral Directors) Limited | Other services | 1999 |
| J M P Partnership (Holdings) Limited | Extraterritorial | 2007 |
| J R Jackson & Sons Limited | Construction | 2014 |
| J&E Marketing Ltd | Professional & scientific | 2026 |
| J&G Aria Solutions Limited | Information & communication | 2026 |
| J. Naylor (Funeral Directors) Limited | Other services | 1994 |
| J. Pidgeon & SON Limited | Other services | 1944 |
| J. S. Hedges Funeral Service Limited | Other services | 2000 |
| J.A.W.Scaffolding Ltd | Construction | 2026 |
| J.H.Family Butcher Limited | Wholesale & retail | 2008 |
| J.W.P. Building and Solar Services Ltd | Construction | 2011 |
| Jack Price CDG Ltd | Construction | 2022 |
| Jacks Renewables Ltd | Manufacturing | 2026 |
| Jackson Agri Ltd | Financial services | 2022 |
| Jacquelines Ltd | Wholesale & retail | 2012 |
| JAL IT Services Limited | Information & communication | 2011 |
| James Buxton Ltd | Wholesale & retail | 2019 |
| James Close Properties Ltd | Real estate | 2024 |
| James England ENT Services Ltd | Health & social care | 2023 |
| James Joseph Commercial Limited | Real estate | 2019 |
| James Raymond Homes Limited | Real estate | 2015 |
| James Slee Developments Limited | Construction | 2013 |
| James Thompson Electrical Services Limited | Construction | 2003 |
| James White Butchers Limited | Wholesale & retail | 2009 |
| Jarvis Property Developments Limited | Administrative & support | 2012 |
| Jasiral Limited | Professional & scientific | 2017 |
| Jasminet Limited | Hospitality | 2022 |
| Jayday Ltd | Wholesale & retail | 2014 |
| Jayne Hampshire Limited | Hospitality | 2011 |