| GI-3 Growth Partners Limited | Professional & scientific | 2023 |
| GI-3 Holdings Limited | Manufacturing | 2025 |
| GI-3 Marketing Services Limited | Professional & scientific | 2026 |
| GI-3 Operations Limited | Professional & scientific | 2026 |
| Giacoia Facilities Ltd | Administrative & support | 2023 |
| Giacopazzi Testing Limited | Information & communication | 2011 |
| Giaman F Ltd | Transport & logistics | 2019 |
| Giaman Services Ltd | Transport & logistics | 2021 |
| Giant Designs Limited | Real estate | 2010 |
| Giants at Play Ltd | Arts & recreation | 2022 |
| Giau Limited | Information & communication | 2017 |
| Gibbard & Gibbard Ltd | Manufacturing | 2024 |
| Gibbins Development Ltd | Real estate | 2020 |
| Gibbo Marketing Limited | Information & communication | 2019 |
| Gibbons Recruitment Ltd | Administrative & support | 2025 |
| Gibbs Land Limited | Real estate | 2023 |
| Gibbs Services Ltd | Wholesale & retail | 2002 |
| Gibbsco Limited | Hospitality | 2008 |
| Gibin Ltd | Transport & logistics | 2024 |
| Gibrellex Limited | Professional & scientific | 2025 |
| Gibson Watts Global Ltd | Professional & scientific | 2020 |
| Gibson's Landscaping Services Ltd | Administrative & support | 2024 |
| Gidan Asher Properties Ltd | Real estate | 2024 |
| Giddyup Performance Ltd | Professional & scientific | 2014 |
| Gideon Consultancy Services Limited | Construction | 2015 |
| Gidge Newton Property Limited | Construction | 2015 |
| Gidicom Limited | Professional & scientific | 2022 |
| Gido Transport Ltd | Transport & logistics | 2025 |
| Giduc Ltd | Professional & scientific | 2019 |
| GIE Homes Ltd | Real estate | 2021 |
| Gifar Ltd | Health & social care | 2011 |
| Gift Guys Group Ltd | Wholesale & retail | 2026 |
| Giftcloud Limited | Information & communication | 2024 |
| Giftgopher Property Ltd | Real estate | 2020 |
| GIG Buddies Bristol Limited | Health & social care | 2023 |
| Giga Ltd | Wholesale & retail | 2020 |
| Gigaserve Services Limited | Wholesale & retail | 2024 |
| Gigawatt Electrical Services Ltd | Construction | 2021 |
| Gigballot Ltd | Arts & recreation | 2025 |
| Giggabit Ltd | Information & communication | 2023 |
| Gigi Logistics Limited | Transport & logistics | 2025 |
| Gigi's Pizza Ltd | Hospitality | 2024 |
| Gigyani Group Limited | Wholesale & retail | 2024 |
| Gilan Kitchen Limited | Hospitality | 2018 |
| Gilbert Printing Enterprises Limited | | 1982 |
| Gilbert Road Apartments Management Company Limited | Households | 2024 |
| Gilboy Mechanical & Catering Services Ltd | Manufacturing | 2022 |
| Gilbride Shimizu Limited | Administrative & support | 2010 |
| Gilcrest Manufacturing Limited | Manufacturing | 2002 |
| Gildav Properties UK Ltd | Real estate | 2023 |
| Gilded Rune Games Limited | Information & communication | 2022 |
| Gilder Muller Limited | Professional & scientific | 2017 |
| Gildersome Design Associates Ltd | Construction | 2021 |
| Giles Consulting Limited | Other services | 2020 |
| Giles LEE Management Company Ltd | Real estate | 2023 |
| Giles LEE Properties Ltd | Real estate | 2021 |
| Giles Roofing and Property Maintenance Ltd | Construction | 2016 |
| Giles Terry Building Ltd | Construction | 2022 |
| Gilks Holdings Limited | Professional & scientific | 2020 |
| Gill PM Limited | Construction | 2025 |
| Gillard Brothers Limited | Construction | 2005 |
| Gillard Electrical Services Limited | Construction | 2023 |
| Gillespie Rentals Ltd | Real estate | 2021 |
| Gillham House Management Company Limited | Households | 2001 |
| Gillingstool Laundry Limited | Other services | 1967 |
| Gillingstool Limited | Wholesale & retail | 2024 |
| Gillvray Health Ltd | Health & social care | 2023 |
| Gilly Macmillan Ltd | Arts & recreation | 2017 |
| Gilmartin Ground Works Ltd | Construction | 2023 |
| Gilroy Contracts & Groundswork Ltd | Extraterritorial | 2022 |
| Gilroy Design Limited | Professional & scientific | 2023 |
| Gilstead Hall Limited | Households | 1988 |
| Gimson Robotics Ltd | Manufacturing | 2013 |
| GIN Tonic & Ice Ltd | Hospitality | 2018 |
| Gina Burns Consulting Limited | Professional & scientific | 2022 |
| Gina Tigwell Hair Limited | Other services | 2016 |
| Ginge Tours Ltd | Administrative & support | 2022 |
| Ginger & Rose Ltd | Professional & scientific | 2017 |
| Ginger (Employment Services) Limited | Administrative & support | 2015 |
| Ginger Brown Ltd | Information & communication | 2016 |
| Ginger Brown Property Limited | Hospitality | 2021 |
| Gingerbeard's Preserves Ltd | Manufacturing | 2019 |
| Gingerbread (Holdings) Limited | Professional & scientific | 2012 |
| Gingerhairfavourite Ltd | Real estate | 2020 |
| Gingerneering Ltd | Professional & scientific | 2009 |
| Gingersnap Creative Management Limited | Administrative & support | 2005 |
| Ginjah Piece Ltd | Hospitality | 2025 |
| Ginko Investments Limited | Professional & scientific | 2006 |
| Gino's Grub Ltd | Hospitality | 2025 |
| Ginormous Solutions Limited | Information & communication | 2015 |
| GIO & Co Barbers Ltd | Other services | 2025 |
| Giovanni Food & Wine Limited | Wholesale & retail | 2007 |
| Giraffe Bookkeeping Ltd | Professional & scientific | 2019 |
| Giraffe Design & Build Ltd | Construction | 2021 |
| Girdhil Design Limited | Professional & scientific | 2021 |
| Girish Ltd | Health & social care | 2020 |
| Girl Moss Ltd | Information & communication | 2024 |
| Girl Power Brands Ltd | Wholesale & retail | 2025 |
| Girlhood Reclaimed CIC | Education | 2024 |
| Girls Camera Club CIC | Professional & scientific | 2025 |