| Hylton Restaurant Ltd | Hospitality | 2025 |
| Hylton Road Autocentre Ltd | Wholesale & retail | 2023 |
| Hylton Sports Club CIC | Other services | 2012 |
| Hylton Training Limited | Education | 2014 |
| Hylton Tuition Centre Limited | Education | 2026 |
| Hype Homes Investments Limited | Real estate | 2025 |
| Hypersanni Creative Studios Ltd | Professional & scientific | 2025 |
| I & a Foods Limited | Hospitality | 2017 |
| I Drive Retail Solutions Limited | Professional & scientific | 2008 |
| I E Projects Limited | Professional & scientific | 2021 |
| I Resources Ltd | Professional & scientific | 2007 |
| I.P.G. Limited | Health & social care | 1986 |
| I6MEDIA Ltd | Information & communication | 2011 |
| Iamimportant Ltd | Education | 2015 |
| IAN James Chapman Estates Limited | Construction | 2021 |
| IAN Jeff Contract Services (NE) Limited | Administrative & support | 2016 |
| IAN Swansbury and Sons Builders Limited | Construction | 2003 |
| IAN T Publishing Limited | Information & communication | 2018 |
| IAN Turnbull Consulting Limited | Professional & scientific | 2017 |
| IAN White Motors Limited | Wholesale & retail | 1997 |
| IAN Wood Memorials Ltd | Manufacturing | 2003 |
| Iapss Ltd | Education | 2011 |
| IB Rope Access Services Ltd | Construction | 2018 |
| Ibloom Holding Ltd | Financial services | 2026 |
| Ice Kids CIC | Other services | 2022 |
| Iceborn Vikings CIC | Other services | 2024 |
| Iced Cream Ltd | Wholesale & retail | 2024 |
| Iceguys CIC | Arts & recreation | 2021 |
| ICT Educational Services Limited | Other services | 2003 |
| ICU Electronic Systems Ltd | Administrative & support | 2019 |
| ICY Price Ltd | Wholesale & retail | 2016 |
| ICY Properties Ltd | Real estate | 2025 |
| Ideg Community Interest Company | Arts & recreation | 2025 |
| Identity Consult Limited | Professional & scientific | 2005 |
| IDL Tiling Ltd | Construction | 2023 |
| Idustrialdesign Co Ltd | Wholesale & retail | 2024 |
| IDW Neptune Ltd | Construction | 2025 |
| IF Financial Limited | Financial services | 2013 |
| Ifendieze Services Limited | Health & social care | 2026 |
| IG Productions Ltd | Administrative & support | 2022 |
| Igas Direct Ltd | Wholesale & retail | 2025 |
| Igasuk Ltd | Construction | 2023 |
| Ignio Limited | Information & communication | 2013 |
| IGO Energy Ltd | Professional & scientific | 2023 |
| IGP Property and Lettings Limited | Real estate | 2021 |
| IGP Property Limited | Real estate | 2022 |
| IJ and Sons Ltd | Other services | 2026 |
| IJC Global Limited | Professional & scientific | 2016 |
| Ijez Limited | Information & communication | 2022 |
| IK Promotions Limited | Arts & recreation | 2019 |
| Ikem Window Cleaners Ltd | Administrative & support | 2025 |
| Ilhote Ltd | Hospitality | 2021 |
| Illumine Atelier Limited | Manufacturing | 2024 |
| Imadjinn Ltd | Extraterritorial | 2023 |
| Imagine Creative Solutions Limited | Administrative & support | 2013 |
| Imagine Salon Supplies Ltd | Wholesale & retail | 2019 |
| Imaging Consultancy Services Limited | Manufacturing | 2022 |
| IMD NE Limited | Extraterritorial | 2004 |
| Immediatelymocktail’D Limited | Extraterritorial | 2024 |
| Immortal Strength Co. Ltd | Wholesale & retail | 2026 |
| Impala Consulting Ltd | Professional & scientific | 2007 |
| Imperiumpartnership Ltd | Real estate | 2021 |
| IN Electrical Ltd | Construction | 2026 |
| Inceoglu Ltd | Hospitality | 2026 |
| Incredible Loft Storage Solutions Ltd | Construction | 2025 |
| Indecom Ltd | Construction | 2015 |
| Independant Advocacy Services Ltd | Health & social care | 2006 |
| Independent Live CIC | Hospitality | 2023 |
| Independent Physiotherapy Ltd | Health & social care | 2024 |
| Independent Sunderland Limited | Hospitality | 2012 |
| Independent, Advanced & Clear Ltd | Financial services | 2019 |
| Inderjeet Logistics Ltd | Transport & logistics | 2024 |
| Indiano Anderson Ltd | Professional & scientific | 2023 |
| Indigo Bathrooms Group Ltd | Construction | 2024 |
| Indigo Bathrooms Group North East Limited | Construction | 2025 |
| Indigo Sunderland Ltd | Hospitality | 2019 |
| Induk Ltd | Wholesale & retail | 2022 |
| Industrial Coatings Solutions Limited | Wholesale & retail | 2011 |
| Industrial Monitoring Systems Limited | Manufacturing | 1993 |
| Infinite Properties North East Limited | Real estate | 2016 |
| Infinity Hair & Beauty Limited | Other services | 2013 |
| Infinity Nine Limited | Hospitality | 2013 |
| Infinity Pizza RD Limited | Hospitality | 2019 |
| Infinity Wellness Clinic Ltd | Other services | 2021 |
| Influx Motion Limited | Real estate | 2010 |
| Inita | Education | 2007 |
| INJ Associates Ltd | Education | 2011 |
| Injective Engineering Limited | Professional & scientific | 2024 |
| Inka Publishing Limited | Information & communication | 1998 |
| Inn Design Services N.E. Limited | Professional & scientific | 2013 |
| Inn Place (Design Services) Limited | Construction | 1998 |
| Inner Light Photography C.I.C. | Professional & scientific | 2025 |
| Innerstand Limited | Administrative & support | 1999 |
| Innev Technologies Limited | Information & communication | 2014 |
| Innoaction Consulting Ltd | Professional & scientific | 2021 |
| Innohela Global Services Ltd | Transport & logistics | 2026 |
| Innovaprint Labs Ltd | Manufacturing | 2025 |
| Inout Cleaning Services Limited | Administrative & support | 2025 |
| Inpdr Gateway Ltd | Information & communication | 2020 |
| Insangel Limited | Arts & recreation | 2022 |