| Gyler Limited | Households | 2017 |
| Gym Humba Ltd | Health & social care | 2020 |
| Gym Outfit Ltd | Extraterritorial | 2019 |
| Gym Religion Limited | Wholesale & retail | 2019 |
| Gymate Ltd | Manufacturing | 2023 |
| Gymate UK CIC | Other services | 2023 |
| Gymvision Ltd | Other services | 2014 |
| Gynex Global Ltd | Wholesale & retail | 2025 |
| Gynopro Ltd | Health & social care | 2024 |
| Gynova Solutions Ltd | Professional & scientific | 2025 |
| Gyntrix Solutions Ltd | Information & communication | 2025 |
| Gyntronic Solutions Ltd | Information & communication | 2025 |
| Gypsies and Travellers Wales Limited | Health & social care | 1993 |
| Gypsy Threadworks Ltd | Wholesale & retail | 2025 |
| Gypt Ltd | Professional & scientific | 2025 |
| Gyros HUT Ltd | Hospitality | 2022 |
| Gyrus Medical Limited | Manufacturing | 1989 |
| GZ Adventure Ltd | Wholesale & retail | 2023 |
| GZ Entreprise Ltd | Wholesale & retail | 2023 |
| GZ Select Ltd | Wholesale & retail | 2015 |
| Gzss Trading Limited | Wholesale & retail | 2024 |
| Gōndi Lifestyle Salon Limited | Other services | 2016 |
| H & B Supplies Limited | Wholesale & retail | 1998 |
| H & D Essence Ltd | Professional & scientific | 2025 |
| H & D Residentials Limited | Real estate | 2018 |
| H & G Properties Limited | Real estate | 2017 |
| H & H Rental Properties Ltd | Real estate | 2025 |
| H & H Services Ltd | Other services | 2018 |
| H & K Accounting Services Limited | Professional & scientific | 2013 |
| H & K Corporation (London RD) Ltd | Hospitality | 2010 |
| H & M Investments (Cardiff) Limited | Real estate | 2006 |
| H & M Traders PVT Ltd | Wholesale & retail | 2020 |
| H & R LA Strada Limited | Hospitality | 2011 |
| H a for Training and Consultant Ltd | Professional & scientific | 2023 |
| H a L O P E O Processing Ltd | Information & communication | 2024 |
| H a Selley Limited | Professional & scientific | 2016 |
| H and H Avalon Holdings Limited | Administrative & support | 2020 |
| H and I Group Ltd | Administrative & support | 2017 |
| H Bainbridge Limited | Wholesale & retail | 2001 |
| H Cafe Limited | Hospitality | 2025 |
| H D Home Improvements Ltd | Construction | 2017 |
| H H Property & Finance Limited | Real estate | 1999 |
| H H Wealth Academy Ltd | Real estate | 2019 |
| H IS for Hawk Limited | Information & communication | 2024 |
| H Jones & Associates Limited | Professional & scientific | 2007 |
| H K R Family Store Limited | Wholesale & retail | 2025 |
| H K R Premier Store Limited | Wholesale & retail | 2021 |
| H Khan Limited | Financial services | 2014 |
| H Lettings Ltd | Real estate | 2025 |
| H Nails (Barry) Limited | Other services | 2021 |
| H R Classics Ltd | Manufacturing | 2024 |
| H S Bristol Cars Limited | Wholesale & retail | 2016 |
| H S DAD Ltd | Professional & scientific | 2017 |
| H S Health Solutions Limited | Health & social care | 2016 |
| H Shields Limited | Extraterritorial | 2026 |
| H Simmons Ltd | Real estate | 2025 |
| H Spec Cars Ltd | Wholesale & retail | 2024 |
| H T Motors Limited | Wholesale & retail | 2024 |
| H W & W Ltd | Extraterritorial | 2011 |
| H&A Home Market Ltd | Other services | 2025 |
| H&Ak Consultants Ltd | Information & communication | 2019 |
| H&D Techniques Limited | Professional & scientific | 2008 |
| H&H Civils Ltd | Construction | 2019 |
| H&H Collectables Ltd | Wholesale & retail | 2025 |
| H&H Holiday Homes Ltd | Real estate | 2022 |
| H&I Nova Limited | Wholesale & retail | 2025 |
| H&K Commerce Ltd | Wholesale & retail | 2025 |
| H&M Global Trades Ltd | Wholesale & retail | 2026 |
| H&N Nails Kentish Town Ltd | Other services | 2026 |
| H&S Cleaning Services Ltd | Administrative & support | 2021 |
| H&S DEO Ltd | Other services | 2025 |
| H&S Private Ltd | Hospitality | 2026 |
| H&S Softune Ltd | Wholesale & retail | 2025 |
| H&Sj Property Ltd | Real estate | 2021 |
| H&U Ecommerce Ltd | Wholesale & retail | 2025 |
| H&X Optical Co., Ltd. | Extraterritorial | 2019 |
| H-Gado Ltd | Other services | 2024 |
| H.A Bishop Ltd | Wholesale & retail | 2025 |
| H.A.P. Hydraulic Equipment Limited | | 1967 |
| H.A.T Roofing Services Limited | Construction | 2006 |
| H.B. Dairies (South Wales) Limited | Real estate | 1991 |
| H.D. Electrical Service Ltd | Construction | 2013 |
| H.Dekoration Ltd | Wholesale & retail | 2025 |
| H.E Futures Ltd | Professional & scientific | 2018 |
| H.Fox & Co Limited | Hospitality | 2015 |
| H.Herbert Plumbing Services Ltd | Construction | 2022 |
| H.O.W Travel Ltd | Administrative & support | 2026 |
| H.R.S Gami Ltd | Real estate | 2021 |
| H.T. Maddocks and SON (Whitchurch) Limited | Wholesale & retail | 1957 |
| H.T.C. Group Holding Limited | Administrative & support | 2023 |
| H.Woodley and Company,Limited | Real estate | 1938 |
| H1 Finance Ltd | Professional & scientific | 2018 |
| H1 Stores Limited | Wholesale & retail | 2025 |
| H2 Cando Ltd. | Administrative & support | 2018 |
| H2 Catering Ltd | Wholesale & retail | 2019 |
| H2 Projects Limited | Construction | 2018 |
| H20 Plumbing 'N' Heating Limited | Construction | 2018 |
| H2H Catering Ltd Limited | Hospitality | 2026 |
| H2O Active Ltd. | Wholesale & retail | 2012 |
| H2O Cardiff Ltd | Arts & recreation | 2016 |