| Ideal Music Communications Limited | Manufacturing | 2003 |
| Ideal Music Media Limited | Manufacturing | 1999 |
| IDO HQ Ltd | Other services | 2023 |
| IFM Design Limited | Professional & scientific | 2011 |
| Ifortunate Handyman Services Ltd | Construction | 2020 |
| IGL Commerce Ltd | Wholesale & retail | 2021 |
| Igniting Excellence Ltd | Education | 2025 |
| Ihdm Limited | Professional & scientific | 2016 |
| Ihem Software Limited | Information & communication | 2020 |
| IHI Ltd | Real estate | 2014 |
| IHT Advice Limited | Professional & scientific | 2025 |
| IKR Medical Limited | Health & social care | 2026 |
| IL Mondo Travel Limited | Administrative & support | 2017 |
| Ilex Farm Holdings Limited | Professional & scientific | 2002 |
| Ilocked Limited | Arts & recreation | 2015 |
| Images Costumes Limited | Manufacturing | 2005 |
| Images HBT Ltd | Other services | 2020 |
| Images Textiles Limited | Manufacturing | 2011 |
| Imagesound Limited | Manufacturing | 2000 |
| Imagesound Retail Music and Media Limited | Manufacturing | 1997 |
| IMAGIN3 Ltd | Construction | 2023 |
| Imdigital Ltd | Administrative & support | 2017 |
| Imeme Holdings Limited | Health & social care | 2022 |
| IMF Kitchens Limited | Construction | 2003 |
| Impact & Ascent Stunts Limited | Education | 2025 |
| Impact Signs (Chesterfield) Limited | Administrative & support | 2008 |
| Impending Tech Limited | Information & communication | 2023 |
| Imperial Despatch Ltd | Transport & logistics | 2023 |
| Imperial Taste Limited | Hospitality | 2026 |
| Improvair (Air Conditioning) Limited | | 1987 |
| Impulse Training Ltd | Professional & scientific | 2020 |
| Imran's Diner Ltd | Hospitality | 2023 |
| IMS Bidco Limited | Professional & scientific | 2016 |
| IMS Midco Limited | Professional & scientific | 2016 |
| IMS Topco Limited | Professional & scientific | 2016 |
| IN Food Solutions Ltd | Wholesale & retail | 2010 |
| IN Good Company Limited | Arts & recreation | 1993 |
| IN HER Hands Limited | Administrative & support | 2022 |
| IN the Works PR Ltd | Professional & scientific | 2011 |
| IN2FRAMES Limited | Manufacturing | 2012 |
| Inari Studios Limited | Information & communication | 2017 |
| Inclusive Pedals CIC | Education | 2017 |
| Incomol Estates Limited | Construction | 1997 |
| Independent Power Connections Limited | Energy | 2019 |
| Independent Rail Engineering Ltd | Construction | 2019 |
| Independent Railway Services Ltd | Transport & logistics | 2017 |
| Independent Sewing Services Limited | Manufacturing | 2005 |
| Indian Blues Ltd | Hospitality | 2019 |
| Indian Delight Chesterfield Ltd | Hospitality | 2026 |
| Indieversity Limited | Arts & recreation | 2021 |
| Individual Homecare Services Ltd | Health & social care | 2018 |
| Industrial Ancillaries Limited | Wholesale & retail | 1973 |
| Industrial Logistics Limited | Transport & logistics | 2021 |
| Industrial Paper Converters Limited | Manufacturing | 2003 |
| Industrial Tooling Products (UK) Limited | Wholesale & retail | 1985 |
| Infinite Endeavours Ltd | Other services | 2018 |
| Infinite Systems Limited | Construction | 2024 |
| Infiniti Holdings Ltd | Financial services | 2021 |
| Infinity Wealth Management Ltd | Financial services | 2014 |
| Infirmary Road Estates Ltd | Real estate | 2020 |
| Informed Programming Limited | Information & communication | 2023 |
| Infotec Systems Holdings Limited | Financial services | 2022 |
| Infotec Systems Ltd | Information & communication | 2008 |
| Infrared Group Ltd | Wholesale & retail | 2023 |
| Ingen Group Ltd | Real estate | 2025 |
| Ingleby Nursing Homes Limited | Extraterritorial | 1993 |
| Ingmans Cobbler Footwear Clothing Limited | Wholesale & retail | 2018 |
| Ingmans International Insignias Limited | Wholesale & retail | 2017 |
| Inhd Services Ltd | Construction | 2020 |
| Inicio 365 Ltd | Information & communication | 2024 |
| Inigo Developments Limited | Professional & scientific | 2001 |
| Inizio Hair Limited | Other services | 2008 |
| Inkerman Business Solutions Limited | Professional & scientific | 2007 |
| Inkxpress Chesterfield Limited | Wholesale & retail | 2004 |
| Inky Xpress Ltd | Hospitality | 2024 |
| Inland Holdings (Leek) Limited | Financial services | 2021 |
| Inleef Holdings Ltd | Financial services | 2026 |
| Inleef IP Ltd | Professional & scientific | 2026 |
| Inleef OP Co Ltd | Information & communication | 2026 |
| Innatus Limited | Administrative & support | 2023 |
| INOV8 Medical Solutions Limited | Wholesale & retail | 2010 |
| Inox Pipework Limited | Construction | 2017 |
| Insidetrack England Limited | Real estate | 2015 |
| Insight Coatings Midlands Ltd | Construction | 2022 |
| Inspire Cruise Ltd | Administrative & support | 2023 |
| Inspire Fire Consultancy and Training Ltd. | Education | 2005 |
| Inspire Joinery & Renovations Ltd | Construction | 2017 |
| Inspire Medical Services Limited | Health & social care | 2016 |
| Inspire Medical SERVICES-1 Ltd | Health & social care | 2026 |
| Inspire Permanent Resourcing Limited | Extraterritorial | 2012 |
| Inspire Resourcing Limited | Administrative & support | 2009 |
| Inspire Utility Solutions Ltd | Construction | 2022 |
| Inspired Audio Limited | Manufacturing | 2009 |
| Inspired Financial Solutions Limited | Financial services | 2005 |
| Inspired Property Holdings Ltd | Real estate | 2019 |
| Inspired Wellness Mansfield Ltd | Wholesale & retail | 2023 |
| Inspirit Drinks Ltd | Extraterritorial | 1998 |
| Instant Installations Limited | Manufacturing | 1990 |
| Instant Modular Solutions Ltd | Construction | 2020 |
| Instrudef Studios Ltd | Information & communication | 2023 |