| Housebrands Toolkits Ltd | Wholesale & retail | 2019 |
| Household Spares Limited | Wholesale & retail | 2011 |
| Housett Ltd | Hospitality | 2020 |
| Housing Ltd | Extraterritorial | 2025 |
| Hove Services Ltd. | Administrative & support | 2022 |
| Howard Coan Precious Metals Ltd | Wholesale & retail | 2021 |
| Howard House ABC Limited | Real estate | 2014 |
| Hoxton DCP Limited | Construction | 2014 |
| Hoxyfy Ltd | Wholesale & retail | 2025 |
| HR Studios Ltd | Information & communication | 2019 |
| HRP Global Ltd | Construction | 2022 |
| HS Foundation | Other services | 2016 |
| HS PM Services Ltd | Professional & scientific | 2025 |
| HS3T Limited | Information & communication | 2019 |
| Hsair Ltd | Wholesale & retail | 2022 |
| HSB Power & Data Ltd | Other services | 2017 |
| HSK Trading London Ltd | Wholesale & retail | 2026 |
| Hstv Anaesthetics Limited | Health & social care | 2018 |
| Hubbard Pegler Limited | Professional & scientific | 2006 |
| Hubbard Pegler Management Limited | Real estate | 2015 |
| Hughes Design and Build London Limited | Construction | 2021 |
| Hughes JAY & Panter Limited | Professional & scientific | 2010 |
| Humans Versus AI Ltd | Information & communication | 2026 |
| Humaz Nail & Beauty Limited | Other services | 2022 |
| Humbubble Limited | Administrative & support | 2004 |
| Humming Moon Ltd | Wholesale & retail | 2026 |
| Hummingbird@Care Ltd | Administrative & support | 2017 |
| Hungry Limited | Information & communication | 2001 |
| Hungry Recycling Limited | Information & communication | 2005 |
| Hunna a H Holdings Limited | Financial services | 2018 |
| Hunt Roofing Limited | Construction | 2009 |
| Hunterz Spice Ltd | Hospitality | 2022 |
| Hunting Gate Properties Limited | Real estate | 2015 |
| Hurlingham Electrical Ltd | Construction | 2026 |
| Hushcitystudios Ltd | Information & communication | 2026 |
| Huson Limited | Real estate | 2009 |
| Hustle Clothing Limited | Wholesale & retail | 2021 |
| HVB of Surrey Ltd | Construction | 2025 |
| Hwesa Care Services Limited | Health & social care | 2018 |
| Hyam Consulting Ltd | Information & communication | 2023 |
| Hybrid Fitness Franchise Ltd | Arts & recreation | 2018 |
| Hybrid Fitness Hull Ltd | Arts & recreation | 2025 |
| Hycen Apollo Limited | Professional & scientific | 2003 |
| Hyder Solutions Ltd | Real estate | 2022 |
| Hydra Aesthetics Limited | Other services | 2018 |
| Hydro Response Ltd | Construction | 2025 |
| Hygge Design Ltd | Professional & scientific | 2020 |
| Hyland Heating Limited | Construction | 2017 |
| Hylite Limited | Wholesale & retail | 2005 |
| Hype Fitness Limited | Arts & recreation | 2015 |
| I - KEW Service Ltd | Construction | 2017 |
| I a K Electrical Services Limited | Other services | 2017 |
| I D Foods Ltd | Hospitality | 2013 |
| I Dayal Services Ltd | Construction | 2019 |
| I N a C I T I Limited | Professional & scientific | 2016 |
| I One Four Ltd | Professional & scientific | 2020 |
| I Stevens Carpentry Ltd | Construction | 2026 |
| I&B Construction Services Limited | Construction | 2017 |
| I&K Investments London Ltd | Real estate | 2026 |
| I&S Medical Services Limited | Health & social care | 2013 |
| I-Build Design and Construction Limited | Construction | 2015 |
| I-Kew M&E Limited | Professional & scientific | 2020 |
| I-Tumz Limited | Wholesale & retail | 2021 |
| IAG Professional Tiles Ltd | Construction | 2023 |
| Iain Casey Engineering Ltd | Construction | 2016 |
| IAM Engineers Limited | Information & communication | 2025 |
| IAN Day Decorators Limited | Construction | 2007 |
| IAN Jeavons Creative Services Ltd | Arts & recreation | 2013 |
| IB Property & Investments Ltd | Real estate | 2026 |
| Ibsl Consultancy Limited | Administrative & support | 2012 |
| IC Engineering Consultants Ltd | Professional & scientific | 2018 |
| Icaresocialworksolutions Ltd | Health & social care | 2026 |
| Icionyx Technologies Limited | Information & communication | 2014 |
| Iclear Property Services Ltd | Water & waste | 2024 |
| Icon Accountants Limited | Professional & scientific | 2007 |
| Icon Paralegal Limited | Professional & scientific | 2012 |
| Iconic Hairdressing Limited | Other services | 2009 |
| Iconic Inns Ltd | Hospitality | 2026 |
| Iconsult Advisory Ltd | Professional & scientific | 2021 |
| IDA FM Ltd | Administrative & support | 2025 |
| Idabyte Ltd | Information & communication | 2018 |
| Ideal Shopping Direct Limited | Wholesale & retail | 1980 |
| Identity Consulting Limited | Professional & scientific | 1999 |
| Identra Consulting Limited | Information & communication | 2026 |
| IDJ Consulting Ltd | Professional & scientific | 2020 |
| IF I Believed Ltd | Arts & recreation | 2020 |
| Ifuture Solutions Limited | Information & communication | 2009 |
| Ignis Laser Therapy Ltd | Wholesale & retail | 2025 |
| Ignis Medical Ltd | Wholesale & retail | 2020 |
| Ignite HR Consultancy Limited | Professional & scientific | 2025 |
| Igr-R Ltd | Administrative & support | 2016 |
| IJS Property Maintenance Limited | Construction | 2021 |
| IK Meher Limited | Health & social care | 2025 |
| IKA Woods Limited | Construction | 2024 |
| IKD Property Ltd | Real estate | 2003 |
| IL Buon Vino Ltd | Wholesale & retail | 2025 |
| IL DUO DEI Gatti CLG | Education | 2018 |
| Ilford Cellular Ltd | Wholesale & retail | 1999 |
| Ilford Holdings Limited | Real estate | 2014 |
| Iliyanico Ltd | Transport & logistics | 2025 |