| Houghtons Foodservice Ltd | Wholesale & retail | 2023 |
| Houghtons of Edinburgh Ltd | Wholesale & retail | 2023 |
| Hound of Ulster Limited | Hospitality | 2026 |
| House of Beauty Retail Ltd | Wholesale & retail | 2015 |
| House of Chilli & Spice Ltd | Hospitality | 2026 |
| Hoveblend Limited | Hospitality | 1989 |
| Howapped Ltd | Information & communication | 2018 |
| Howe NOW Brown COW Ltd | Wholesale & retail | 2011 |
| Howland Quay Residents Company Limited | Households | 1995 |
| HQ Automotive Ltd | Extraterritorial | 2016 |
| HR With YOU Ltd | Administrative & support | 2023 |
| Hrande Consulting Limited | Professional & scientific | 2019 |
| HRH Developments (Surrey) Ltd | Construction | 2025 |
| HTH Partnership Limited | Wholesale & retail | 2021 |
| Hudson Scaffolding Ltd | Construction | 2014 |
| Hukins Health Ltd | Health & social care | 2024 |
| Humberstone Court Residents Company Limited | Households | 2003 |
| Hunted Food Limited | Hospitality | 2022 |
| Hunter Group Investments Limited | Construction | 2015 |
| Huntlets Ltd | Households | 2022 |
| Hurtwood House School LLP | | 2008 |
| Hush Investments Group Limited | Financial services | 2023 |
| Huxford Creations Ltd | Professional & scientific | 2024 |
| Hydrocracker Theatre Company | Arts & recreation | 2010 |
| HYJ Consultants Ltd | Professional & scientific | 2025 |
| I Gruber Limited | Other services | 2010 |
| I&M Dream Interiors Ltd | Construction | 2023 |
| IAN Marlow Safety Services Ltd | Professional & scientific | 2017 |
| IAN Mcardle Architects Limited | Professional & scientific | 2003 |
| Ibtec Ltd | Manufacturing | 2013 |
| ICG Real Estate Limited | Real estate | 2026 |
| Iconic Existence Limited | Arts & recreation | 2001 |
| Icyfans Ltd | Wholesale & retail | 2021 |
| Ide&S Dorking Ltd | Professional & scientific | 2017 |
| Idiosyncratic Works of Art Limited | Professional & scientific | 2001 |
| Idmr Digital Ltd | Professional & scientific | 2022 |
| IDP Procurement Ltd | Professional & scientific | 2005 |
| Ifbe Limited | Manufacturing | 2022 |
| Iggi UK Limited | Professional & scientific | 2004 |
| IM Aesthetics Surrey Limited | Other services | 2024 |
| Imagecat Limited | Professional & scientific | 2006 |
| Immediate Investments | Financial services | 2018 |
| Imrr Ltd | Arts & recreation | 2018 |
| IN Ladywell Limited | Real estate | 2016 |
| Indagine Limited | Information & communication | 2025 |
| Indemand Consulting Limited | Wholesale & retail | 2016 |
| Indev Consulting Limited | Professional & scientific | 2023 |
| INFL8IVE Events Structures Limited | Administrative & support | 2016 |
| Infospectra Ltd | Information & communication | 2025 |
| Inichio Solutions Limited | Professional & scientific | 2023 |
| Inispire Ltd | Real estate | 2019 |
| Inka Rose CAM Ltd | Real estate | 2025 |
| Innovate Apps Ltd | Information & communication | 2026 |
| Innovate London Ltd | Construction | 2023 |
| Innside Edge Limited | Hospitality | 2023 |
| Inside Leap Limited | Professional & scientific | 2006 |
| Insight Diagnostic Solutions Ltd | Health & social care | 2024 |
| Insource Research Limited | Professional & scientific | 2021 |
| Inspex Services Limited | Professional & scientific | 2017 |
| Inspiring Accountants Ltd | Professional & scientific | 2008 |
| Instep AI Limited | Information & communication | 2025 |
| Institute of Legacy Management | Education | 2001 |
| Int-Apta Ltd | Professional & scientific | 2001 |
| Integral Leadership Dynamics Limited | Professional & scientific | 2011 |
| Integral Leadership Ltd | Professional & scientific | 2024 |
| Integrandus Limited | Professional & scientific | 2008 |
| Intelligent Asset Management Ltd | Professional & scientific | 2002 |
| Intelligent Design Ltd | Construction | 2019 |
| Intelligent Paws Limited | Wholesale & retail | 2017 |
| Interesting Times Ltd | Information & communication | 1998 |
| Interior Advantage Limited | Construction | 1997 |
| International Forecourt Standards Forum Ukeig | | 1997 |
| International Maritime Services Limited | Agriculture & fishing | 1997 |
| Internity.Life Ltd | Education | 2019 |
| Into the New Ltd | Professional & scientific | 2025 |
| Intratik Limited | Construction | 2013 |
| Invario Ltd | Construction | 2019 |
| Inverwest Ltd | Administrative & support | 2020 |
| Investwise Mortgages Limited | Financial services | 2005 |
| ION Electrical Contractors Ltd | Construction | 2019 |
| Iontaoibh Limited | Real estate | 2024 |
| IP London Ltd | Professional & scientific | 2013 |
| IP Marketing Solutions Ltd | Professional & scientific | 2021 |
| Irepair Phone (Dorking) Ltd | Wholesale & retail | 2025 |
| Irepair Phone Vape Ltd | Wholesale & retail | 2018 |
| Ironing Bored Limited | Other services | 2019 |
| Irvine Arboriculture Ltd | Administrative & support | 2025 |
| Isaac Family LLP | | 2016 |
| Isabella & Co. Kidswear Ltd | Wholesale & retail | 2025 |
| Isola DEL Sole (Sheen) Limited | Hospitality | 2014 |
| IT IT IT Ltd | Manufacturing | 2012 |
| ITC Europe Ltd | Information & communication | 2023 |
| IVY & Parker Limited | Information & communication | 2014 |
| IVY Resourcing & Associates Limited | Administrative & support | 2017 |
| Ivys Fine Art Ltd | Professional & scientific | 2021 |
| J B Promotions Limited | Administrative & support | 2017 |
| J Banwell Investments Limited | Households | 2009 |
| J C Cope Marketing Ltd | Professional & scientific | 2012 |
| J Chenery Limited | Professional & scientific | 1997 |
| J D Riverside Construction Ltd | Construction | 2014 |