| Green Light Insurance Services Limited | Financial services | 1996 |
| Green Maple Properties Ltd | Real estate | 2025 |
| Green Serpent Medical Limited | Professional & scientific | 2024 |
| Green Shade Investments Limited | Real estate | 2017 |
| Greenfast & Furious Limited | Financial services | 2023 |
| Greenfast Limited | Professional & scientific | 2022 |
| Greenonline Logistics Ltd | Transport & logistics | 2021 |
| Greens Cottages Management Limited | Households | 2019 |
| Greens Farm Lane Stores Limited | Wholesale & retail | 2023 |
| Greyn Ltd | Professional & scientific | 2022 |
| Greystone Training Solutions Ltd | Education | 2026 |
| Griphon Capital Limited | Professional & scientific | 2022 |
| Ground Control Evergreen Investments Ltd | Agriculture & fishing | 2020 |
| Ground Control Holdings Limited | Professional & scientific | 2004 |
| Ground Control Limited | Administrative & support | 1984 |
| Group A1 Limited | Water & waste | 2025 |
| Group Asset Solutions Limited | Wholesale & retail | 2015 |
| Group Capital Holdings Limited | Administrative & support | 2017 |
| Group Haulage Limited | Transport & logistics | 2007 |
| Grove Road E3 Limited | Construction | 2025 |
| Growing Minds Learning Centre Limited | Education | 2025 |
| Growing Minds LP | | 2025 |
| GRP Communications Limited | Information & communication | 2022 |
| Grumpyvapers Limited | Wholesale & retail | 2018 |
| GSD Enterprises Ltd | Administrative & support | 2020 |
| Guaranteed Motors Limited | Wholesale & retail | 2017 |
| Guarding & General Security Services Limited | Administrative & support | 2014 |
| Guildprime Partnership LLP | | 2019 |
| Guildprime Specialist Contracts Ltd | Construction | 2004 |
| Gupta Healthcare Limited | Health & social care | 2021 |
| Gym U Ltd | Arts & recreation | 2026 |
| H & H Property Ventures Ltd | Real estate | 2021 |
| H & J L Consultancy Ltd | Administrative & support | 2012 |
| H & M Roofing Contractors Limited | Construction | 2019 |
| H a Eagle Investments Limited | Real estate | 2015 |
| H Berkeley Electrical Ltd | Construction | 2018 |
| H Design Studios London Limited | Professional & scientific | 2023 |
| H Green Interiors Ltd | Administrative & support | 2017 |
| H J Riley Services Ltd | Construction | 2022 |
| H&W Protect ME Today Ltd | Other services | 2024 |
| H. Quirk Properties Limited | Real estate | 2012 |
| H.R. Philpot & SON (Barleylands) Limited | Agriculture & fishing | 1964 |
| H.R. Philpot & SON (Great Hayes) Limited | Agriculture & fishing | 1955 |
| H.R. Philpot & SON (Holdings) Limited | Agriculture & fishing | 1987 |
| H.W. Pickrell Limited | Wholesale & retail | 1965 |
| H20 Solutions & Civils Ltd | Construction | 2016 |
| H2O Recruitment & Training Services Limited | Administrative & support | 2012 |
| Habitabit Arcem Ltd | Information & communication | 2013 |
| Habm Ltd | Wholesale & retail | 2015 |
| Hagrid Investments Limited | Administrative & support | 2020 |
| Hair & Beyond Limited | Other services | 2026 |
| Hair @ 108 Limited | Other services | 2017 |
| Hakabi Limited | Professional & scientific | 2024 |
| Hallmark Care Homes (Amersham) Limited | Real estate | 2020 |
| Hallmark Care Homes (Angmering Grange) Limited | Health & social care | 2021 |
| Hallmark Care Homes (Angmering) Limited | Real estate | 2018 |
| Hallmark Care Homes (Banstead) Limited | Health & social care | 2016 |
| Hallmark Care Homes (Bath) Limited | Real estate | 2020 |
| Hallmark Care Homes (Billericay) Limited | Health & social care | 2008 |
| Hallmark Care Homes (Brentwood) Limited | Real estate | 2019 |
| Hallmark Care Homes (Brighton) Ltd | Health & social care | 2011 |
| Hallmark Care Homes (Bromley) Limited | Real estate | 2020 |
| Hallmark Care Homes (Bromsgrove) Limited | Real estate | 2025 |
| Hallmark Care Homes (Bute Town) Limited | Health & social care | 2004 |
| Hallmark Care Homes (Cambridge) Limited | Health & social care | 2018 |
| Hallmark Care Homes (Cardiff) Limited | Health & social care | 1998 |
| Hallmark Care Homes (Chalfont ST Giles) Limited | Construction | 2023 |
| Hallmark Care Homes (Eastbourne) Limited | Real estate | 2020 |
| Hallmark Care Homes (Girton) Limited | Real estate | 2014 |
| Hallmark Care Homes (Henley Manor) Limited | Health & social care | 2019 |
| Hallmark Care Homes (Henley) Limited | Real estate | 2017 |
| Hallmark Care Homes (Hutton Mount) Limited | Real estate | 2019 |
| Hallmark Care Homes (Hutton View) Limited | Health & social care | 2019 |
| Hallmark Care Homes (Ingatestone) Limited | Real estate | 2020 |
| Hallmark Care Homes (Ipswich) Limited | Health & social care | 2009 |
| Hallmark Care Homes (Leigh-On-Sea) Limited | Health & social care | 2011 |
| Hallmark Care Homes (Lightwater) Ltd | Health & social care | 2011 |
| Hallmark Care Homes (Midford Manor) Limited | Health & social care | 2021 |
| Hallmark Care Homes (Pentwyn) Limited | Health & social care | 2004 |
| Hallmark Care Homes (Penylan House) Limited | Health & social care | 2024 |
| Hallmark Care Homes (Penylan) Limited | Real estate | 2024 |
| Hallmark Care Homes (Porth) Limited | Health & social care | 2017 |
| Hallmark Care Homes (Rugby) Limited | Health & social care | 2013 |
| Hallmark Care Homes (Sonning) Limited | Real estate | 2020 |
| Hallmark Care Homes (ST Mellons) Limited | Construction | 2020 |
| Hallmark Care Homes (SW19) Limited | Health & social care | 2009 |
| Hallmark Care Homes (Tunbridge Wells) Limited | Health & social care | 2015 |
| Hallmark Care Homes (Willingdon Park Manor) Limited | Health & social care | 2021 |
| Hallmark Care Homes (Wokingham) Limited | Health & social care | 2009 |
| Hallmark Care Homes (Woodford Green) Limited | Real estate | 2020 |
| Hallmark Care Homes Developments (NO. 2) Limited | Construction | 2013 |
| Hallmark Care Homes Group Limited | Professional & scientific | 2003 |
| Hallmark Care Homes Holdings Limited | Professional & scientific | 2003 |
| Hallmark Garden Solutions Limited | Administrative & support | 2017 |
| Hallmark Healthcare (Blandford Forum) Limited | Construction | 2008 |
| Hallmark Healthcare (Rochdale) Limited | Extraterritorial | 1994 |
| Hallmark Travel London Limited | Administrative & support | 2008 |
| Hamber Safes Limited | Administrative & support | 2018 |
| Hamcor Construction Services Limited | Professional & scientific | 2006 |
| Hamelin Trust | Wholesale & retail | 1991 |