| High Horizon Digital Ltd | Professional & scientific | 2020 |
| High Security Locking Limited | Manufacturing | 2010 |
| Highgate Hills Wholesales Ltd | Wholesale & retail | 2025 |
| Hilton Banks Group Limited | Real estate | 2014 |
| Hilton Banks Holdings Limited | Real estate | 2001 |
| Hilton Banks Ltd | Wholesale & retail | 1985 |
| Hilton Rider | Professional & scientific | 1960 |
| Hitch Ltd | Administrative & support | 2025 |
| Hmbj Limited | Professional & scientific | 2018 |
| Holicity Health Ltd | Health & social care | 2006 |
| Holicity Ltd | Extraterritorial | 2011 |
| Holistic Collections Ltd | Wholesale & retail | 2020 |
| Hollywood Box Ltd | Information & communication | 2022 |
| Hoquado Ltd | Professional & scientific | 2006 |
| Horiginal Property Management Ltd | Real estate | 2024 |
| Hotsnap Ltd | Wholesale & retail | 2020 |
| House Certain Limited | Real estate | 2024 |
| Hu-Zo Ltd | Transport & logistics | 2023 |
| HUN Quality Building Ltd | Extraterritorial | 2016 |
| Hungarian Handmade Bites Limited | Manufacturing | 2015 |
| Hunport Limited | Transport & logistics | 2019 |
| Hunters & Co Developments Ltd | Real estate | 2026 |
| Hypercell Energy Ltd | Manufacturing | 2025 |
| I&F Bespoke Joinery Ltd | Construction | 2025 |
| I.C.J Building Services Ltd | Construction | 2024 |
| IAN Dennis Francis Limited | Extraterritorial | 2025 |
| ICEFOX69 Ltd | Information & communication | 2020 |
| Icsec Ltd | Information & communication | 2010 |
| Ideas Made Simple Ltd | Other services | 2020 |
| IDI International Ltd | Health & social care | 2019 |
| Ignatius Media Ltd | Information & communication | 2024 |
| Ignite Maintenance Ltd | Construction | 2025 |
| IN Unisense Limited | Wholesale & retail | 2024 |
| Increasing Black Representation Ltd | Education | 2020 |
| Indie Child Ltd | Manufacturing | 2020 |
| Ineast Services Ltd | Real estate | 2020 |
| Inhouse Creative Studio Ltd | Professional & scientific | 2025 |
| Integrated Acoustics Limited | Professional & scientific | 2009 |
| Introll Service Limited | Wholesale & retail | 2018 |
| Isaac W. Sales Ltd | Wholesale & retail | 2025 |
| Ispot IP Limited | Other services | 2018 |
| Ispot Tech Limited | Manufacturing | 2018 |
| Itaja Ltd | Hospitality | 2024 |
| Itdwx Ltd | Information & communication | 2019 |
| J & M Sales Limited | Wholesale & retail | 2023 |
| J Aldridge Utilities Limited | Energy | 2018 |
| J K Chimney Services Ltd | Administrative & support | 2026 |
| J P Sports Limited | Wholesale & retail | 2011 |
| J Prem Services Ltd | Construction | 2022 |
| J.A.S Carpentry & Building Services Ltd | Manufacturing | 2022 |
| JA Lambert Properties Limited | Real estate | 2022 |
| JAR Investment Holdings Limited | Financial services | 2023 |
| Jaxon Coaching Ltd | Professional & scientific | 2025 |
| JB Environmental Engineering Limited | Construction | 2004 |
| Jbosz Apex Ltd | Real estate | 2026 |
| Jbosz Group Ltd | Real estate | 2025 |
| Jbosz Holdings Ltd | Financial services | 2026 |
| Jimmy's CAB Services Limited | Transport & logistics | 2016 |
| JJY Limited | Wholesale & retail | 2025 |
| JJY Property Limited | Real estate | 2025 |
| Jmedstar Limited | Health & social care | 2014 |
| Joci's Renovations Ltd | Construction | 2023 |
| Jodi Sims Holdings Ltd | Real estate | 2019 |
| JOE Grande Art Ltd | Construction | 2026 |
| JOE Grande Ltd | Manufacturing | 2024 |
| Jolly Fryer Fish and Chips Ltd | Hospitality | 2024 |
| JSA Partners London Ltd | Professional & scientific | 2019 |
| JSV Autoparts Ltd | Wholesale & retail | 2021 |
| JT Courier Services Ltd | Transport & logistics | 2026 |
| Just Smile Dental Ltd | Health & social care | 2023 |
| K & D Electrical Services Ltd | Construction | 2021 |
| K. J. Jurak Transport Ltd | Transport & logistics | 2019 |
| K.J.S Roofing Limited | Construction | 2015 |
| Kapolcsi Driving Services Ltd | Transport & logistics | 2019 |
| KC Associates Ltd | Health & social care | 2025 |
| Kemco Properties Limited | Real estate | 1987 |
| Kensington Property Limited | Real estate | 1962 |
| KER Trans Ltd | Transport & logistics | 2025 |
| Khill Limited | Manufacturing | 2012 |
| Kiln Services Limited | Manufacturing | 1992 |
| Kings Road Wharf Management Limited | Households | 1990 |
| Kiss Data & Management Ltd | Information & communication | 2024 |
| Klaproth Associates Limited | Financial services | 2018 |
| KMF Builders Ltd | Construction | 2024 |
| Kokastrans Ltd | Transport & logistics | 2025 |
| Koko Trans Ltd | Transport & logistics | 2019 |
| Kolasonic Engineering Ltd | Professional & scientific | 2022 |
| KONO88 Ltd | Manufacturing | 2018 |
| Kristinanikou Ltd | Professional & scientific | 2019 |
| KS RAD Limited | Professional & scientific | 2019 |
| Kucko Ltd | Transport & logistics | 2019 |
| Kulics Ltd | Transport & logistics | 2018 |
| Kuru Properties Ltd | Real estate | 2026 |
| L & J Groundworks Ltd | Construction | 1997 |
| L and R Hospitality Ltd | Hospitality | 2020 |
| L&M Best Choice Ltd | Wholesale & retail | 2025 |
| L66 Transport Ltd | Transport & logistics | 2024 |
| LA Scatola Pizza Ltd | Hospitality | 2026 |
| Lasmollo Ltd | Wholesale & retail | 2024 |
| Lauren’S Ladies & Babies Boutique Limited | Wholesale & retail | 2025 |