| Hyfuels Limited | London | 2021 |
| Hygena Limited | Harrogate | 2011 |
| Hyggea Ltd | London | 2021 |
| Hyggea Property Venture Group Ltd | London | 2021 |
| Hygienaclad Ltd | Loughton | 2008 |
| Hygiene SUE Limited | Tunbridge Wells | 2014 |
| Hygienic Concepts Limited | Cannock | 2013 |
| Hygienic Solutions (UK) Limited | Leicester | 2009 |
| Hygienox Limited | Norwich | 1997 |
| Hygiplas (Containers) Limited | Northampton | 1978 |
| Hygrove Homes Limited | Swansea | 2008 |
| Hyhebrides Ltd | Stornoway | 2021 |
| Hyhurst Group Limited | Westerham | 2020 |
| Hyla Properties Ltd | Norwich | 2018 |
| Hylam Limited | Ely | 2013 |
| Hyland Software Solutions UK Ltd. | Maidenhead | 1994 |
| Hyland Software UK Ltd | Maidenhead | 2012 |
| Hylands Property (HP) Limited | Harrow | 2019 |
| Hyle Trading Co., Ltd. | Beckenham | 2015 |
| Hylite (UK) Limited | Flint | 2010 |
| Hylite Security Limited | Flint | 2010 |
| Hylton Ross (UK) Ltd | New Eltham | 1999 |
| Hymans Limited | | 2002 |
| Hymans Robertson IP Holding Limited | London | 2021 |
| Hymans Robertson Limited | London | 2020 |
| Hymerford Ltd | Yeovil | 2013 |
| Hymie Ltd | Harrogate | 2015 |
| Hynefield Properties Limited | Oxford | 1993 |
| Hynes Electrical Services Limited | St. Albans | 2026 |
| Hyoung Hockey Co., Ltd | Beckenham | 2024 |
| Hypar Tank Panels Limited | Wellingborough | 1984 |
| Hype Facilities Limited | Harrogate | 2025 |
| Hype Securities Limited | Harrogate | 2025 |
| Hype Signs Ltd | Luton | 2018 |
| Hyper Drive Ltd | Harrogate | 2012 |
| Hyper Logical Limited | Farnham | 2025 |
| Hyper Loop Ltd | Harrogate | 2013 |
| Hyper Ltd | Reading | 2022 |
| Hyper Value Barry Island Ltd | Barry | 2023 |
| Hyperagile Ltd | London | 2019 |
| Hypercars Limited | Wilmslow | 2005 |
| Hypercloud Professionals Limited | Borehamwood | 2015 |
| Hyperdrive Lubricants Limited | Birchwood | 2009 |
| Hypericum RTM Company Limited | Bushey | 2026 |
| Hyperion C-Ied Limited | Hungerford | 2023 |
| Hyperion Property Services Ltd | Brentwood | 2021 |
| Hyperium Medical Ltd | London | 2020 |
| Hyperlight Ltd | London | 2011 |
| Hyperlux Technology Company Ltd | London | 2024 |
| Hypermagnetic Ltd | Liverpool | 2022 |
| Hyperpolymath Productions Ltd | London | 2024 |
| Hypersain Ltd | Newport | 2023 |
| Hyperscale Limited | Birmingham | 2016 |
| Hyperscale Music Limited | Birmingham | 2016 |
| Hypership Holdings Limited | Belfast | 2026 |
| Hypersurface Technologies Limited | London | 2016 |
| Hypertek (Trust) Holding Limited | London | 1984 |
| Hypharm Limited | Chester | 2015 |
| Hyphen International Limited | Maidenhead | 2017 |
| HYR EN MAN Limited | London | 2024 |
| Hyson Green Youth Club | Nottingham | 2008 |
| Hyspeed Racing Limited | Wotton-Under-Edge | 2021 |
| Hythe Crescent Limited | Seaford | 2023 |
| Hytheway Limited | Middlesex | 1983 |
| Hytyme Limited | London | 2014 |
| Hyve Developments Limited | Loughborough | 2016 |
| Hyvs Ltd | London | 2020 |
| Hyzen Ltd | Swadlincote | 2023 |
| HZA Management Ltd | Edinburgh | 2012 |
| HZA Services Ltd | Bolton | 2021 |
| HZF Marine Ltd | London | 2026 |
| HZZ Light Industrial Co., Ltd. | London | 2007 |
| I & E Plumbing Limited | Worcester | 2025 |
| I & H Developments Limited | Harrow | 2002 |
| I & K Enterprises Ltd | Lockerbie | 2024 |
| I & M Smith Properties Limited | Aberdeen | 2014 |
| I & M Warner Properties Limited | Birmingham | 2001 |
| I Ahmed (Rigg Street) Limited | Blackburn | 2019 |
| I AM a Graduate Limited | Chipping Norton | 2006 |
| I AM I.T. Limited | Bristol | 2008 |
| I AM Investment & Asset Management Limited | Ipswich | 2014 |
| I AM IT 4 Limited | Bristol | 2010 |
| I AM IT for U Limited | Bristol | 2010 |
| I AM Legal Limited | Liverpool | 2013 |
| I AM NOT a Solicitor Limited | Watford | 2011 |
| I AM NOT Holding Limited | Cambridge | 2017 |
| I AM NOW Ltd | London | 2023 |
| I AM Shisha Ltd | London | 2018 |
| I AM Swagger Ltd | London | 2025 |
| I AM TIM Hilton Limited | Basildon | 2012 |
| I and a Investments Limited | Peterborough | 1996 |
| I and J Captive Services Limited | London | 2020 |
| I and M Cooke Limited | London | 2024 |
| I Bill U Limited | Watford | 2011 |
| I C B Consultancy Services Limited | London | 2006 |
| I C Mathison Limited | Bristol | 2009 |
| I C Services Limited | Perth | 2002 |
| I Care 1826 Limited | Welwyn Garden City | 2013 |
| I Care Pharma Limited | Brentford | 2016 |
| I Create Experience Ltd | Margate | 2018 |