| Green Machine Loughton Limited | Wholesale & retail | 2020 |
| Green Machine South Woodford Limited | Wholesale & retail | 2020 |
| Green Machine Southgate Limited | Extraterritorial | 2020 |
| Green Machine Stoke Newington Limited | Wholesale & retail | 2020 |
| Green Pepper Renewable Energies Limited | Construction | 2013 |
| Green Tea Productions Ltd | Information & communication | 2024 |
| Greenacres Yard Ltd | Real estate | 2024 |
| Greener Heating Ltd | Professional & scientific | 2007 |
| Greenfield Technology Limited | Wholesale & retail | 1994 |
| Greenheart Developments Limited | Construction | 1997 |
| Greenhinton Limited | Financial services | 2015 |
| Greenshoot Limited | Water & waste | 2009 |
| Greenside View Management Company Ltd | Households | 2016 |
| Greg Williams Limited | Professional & scientific | 2010 |
| Greg Williams Photography Limited | Professional & scientific | 2002 |
| Grey Scale Consultancy Ltd | Professional & scientific | 2017 |
| Grid Logistics Company (GLC) Ltd | Transport & logistics | 2021 |
| Griffiths Eccles Capital Limited | Administrative & support | 2007 |
| Griffiths Eccles LLP | | 2002 |
| Grip Tate Limited | Information & communication | 2012 |
| Gripsfix.Com Ltd | Other services | 2024 |
| Grit Investments Ltd | Real estate | 2020 |
| Groundline Engineering Limited | Construction | 2014 |
| Grove Court Properties (Beaconsfield) Limited | Real estate | 1961 |
| Grove Court Properties (Holdings) Limited | Financial services | 1955 |
| Grove Mews Limited | Real estate | 2016 |
| Grow Digital Care Ltd | Information & communication | 2024 |
| Growing Confident Minds Ltd | Education | 2022 |
| GSA Property Management Limited | Real estate | 2013 |
| GST Property Maintenance Ltd | Construction | 2023 |
| Guardian Electrical Holdings Limited | Manufacturing | 2019 |
| Guardian Electrical Limited | Manufacturing | 2019 |
| Guido Palau Hair Limited | Other services | 1998 |
| Guillaume Janssen UK Limited | Manufacturing | 2026 |
| GX Business Support Limited | Professional & scientific | 2019 |
| GX Cleaning Services Limited | Administrative & support | 2026 |
| GX Constructions Limited | Construction | 2019 |
| GX Estate Services Limited | Administrative & support | 2020 |
| GX Healthcare Ltd | Health & social care | 2015 |
| GX Investments Ltd | Professional & scientific | 2015 |
| GX IT Consultants Ltd | Information & communication | 2022 |
| GX Liberate Ltd | Real estate | 2017 |
| GX Local Express Ltd | Wholesale & retail | 2023 |
| GX Nail Lounge Limited | Other services | 2023 |
| GX Physio Limited | Other services | 2008 |
| GX Tree Care & Fencing Ltd | Water & waste | 2026 |
| GX Tuition Ltd | Education | 2023 |
| GX WAX Lounge Limited | Other services | 2023 |
| Gxdentist Ltd | Health & social care | 2021 |
| Gxoptical Ltd | Wholesale & retail | 2017 |
| H Mitchell Landscapes Limited | Other services | 2013 |
| H&S Tyres Ltd | Wholesale & retail | 2025 |
| H-Dev Limited | Other services | 2006 |
| H. L. R. Limited | Wholesale & retail | 1979 |
| H.I. (Health International) Limited | Professional & scientific | 1983 |
| Hadencroft Ltd | Water & waste | 2019 |
| Hallco 308 Limited | Construction | 1999 |
| Hallway Simmentals Limited | Agriculture & fishing | 2023 |
| Halo Training Academy Limited | Education | 2024 |
| Halo Tuition Academy Limited | Administrative & support | 2024 |
| Hamelins Investments Limited | Real estate | 2019 |
| Hamelins Properties Limited | Construction | 2019 |
| Hamelins Property Limited | Construction | 2019 |
| Hamilton Energi Ltd | Other services | 2024 |
| Hammer N Chizel Carpentry Ltd | Manufacturing | 2026 |
| Handscomb & Hook Limited | Construction | 2009 |
| Handy Mini Stores Ltd | Wholesale & retail | 2025 |
| Hannan Property Services Ltd | Construction | 2005 |
| Happy Home Improvement Solutions Limited | Construction | 2012 |
| Harbham.K Limited | Other services | 2023 |
| Harefield Carriage Company Limited | Other services | 2015 |
| Harefield Garage Limited | Other services | 2009 |
| Harehill Investments Limited | Real estate | 1973 |
| Harlesden Carpets Ltd | Wholesale & retail | 2010 |
| Harley Servicing Ltd | Wholesale & retail | 2011 |
| Harleyy Construction Limited | Information & communication | 2021 |
| Harold Hill Limited | Hospitality | 2013 |
| Harrington Boyd Ltd | Administrative & support | 2010 |
| Harrisons Associates Ltd | Other services | 2017 |
| Harry's Halal Ltd | Extraterritorial | 2021 |
| Hartley Court Maintenance Company Limited | Households | 2011 |
| Hartley Ross Ltd | Financial services | 2020 |
| Hastings Lettings Limited | Real estate | 2018 |
| Hatteker Group Ltd | Real estate | 2024 |
| Havard & Hunter Ltd | Real estate | 2023 |
| Have YOU MET MS Jones Ltd | Professional & scientific | 2019 |
| Hawkswood Children's Nursery Limited | Education | 2024 |
| Hawthorn Court (Pinner) Limited | Households | 1977 |
| Hayat Investments Ltd | Real estate | 2017 |
| Haybridge Homes Limited | Real estate | 2019 |
| Haycroft Farms Limited | Agriculture & fishing | 1995 |
| Hayden Electrical Contractors Limited | Construction | 2021 |
| Hazelgrove Investment Limited | Real estate | 2017 |
| HC Pharma Consultancy Ltd | Professional & scientific | 2014 |
| HCF Management Services Limited | Professional & scientific | 2020 |
| HD Automotive Limited | Wholesale & retail | 2019 |
| Hdma Vertical Ltd | Professional & scientific | 2025 |
| HE Himself Ltd | Construction | 2023 |
| HE Himself One Ltd | Real estate | 2025 |
| Headroom Health Ltd | Professional & scientific | 2025 |