| Alston Hill Services Ltd | Nelson | 2026 |
| Alston Holdco Ltd | Chelmsford | 2024 |
| Alston Holdings Limited | Longridge Road Preston | 2001 |
| Alston Investments Limited | Chorley | 2014 |
| Alston Partners Consulting Limited | Dunmow | 2025 |
| Alston Studios Ltd | London | 2026 |
| Alston Trading Group Limited | Leighton Buzzard | 2022 |
| Alstone Communications Ltd | Cheltenham | 2023 |
| Alstradev Ltd | London | 2019 |
| Alsurpal Ltd | Bristol | 2026 |
| Alsurveys Limited | Leven | 2023 |
| Alsyncro Ltd | Horncastle | 2026 |
| ALT Advisors Limited | Billericay | 2021 |
| ALT Advisory Ltd | Brentwood | 2025 |
| ALT Analytica Ltd | London | 2025 |
| ALT Approach Ltd | Northampton | 2020 |
| ALT Associates Ltd | Reading | 2024 |
| ALT Atlas Ltd | London | 2021 |
| ALT BI Consultancy Limited | Wokingham | 2023 |
| ALT Business Services Limited | Liverpool | 2011 |
| ALT Business Solutions Ltd | Balmedie | 2016 |
| ALT Business Tech Ltd | Reading | 2017 |
| ALT Capital Global Ltd | London | 2019 |
| ALT Circle Ltd. | London | 2025 |
| ALT Communications Ltd | London | 2025 |
| ALT Consultants Ltd | Kington | 2023 |
| ALT Consulting Services Limited | Dunmow | 2026 |
| ALT Cruise Limited | Ilford | 2021 |
| ALT Design Partnership Limited | Warminster | 2017 |
| ALT Design Studio Ltd | Newcastle Upon Tyne | 2019 |
| ALT Digital Limited | Frome | 2023 |
| ALT Digital Marketing Ltd | London | 2016 |
| ALT Drilling Services Limited | Aboyne | 2007 |
| ALT Equities Limited | Waltham Cross | 2013 |
| ALT Fire Ltd | London | 2022 |
| ALT HAN Company Limited | London | 2016 |
| ALT Holding Investments Limited | Bristol | 2016 |
| ALT House Consulting Limited | Ipswich | 2025 |
| ALT Intelligence Ltd | London | 2026 |
| ALT IQ Consulting Ltd | Bexley | 2025 |
| ALT Laser Limited | Manchester | 2012 |
| ALT Marketing Group Ltd | Margate | 2019 |
| ALT Marketing Ltd | Tamworth | 2024 |
| ALT Media Enterprise Ltd | Colchester | 2022 |
| ALT Nexus Ltd | Tunbridge Wells | 2025 |
| ALT North Limited | Manchester | 2025 |
| ALT Nuvem Limited | Cheltenham | 2024 |
| ALT Perspective Consulting Ltd | Amersham | 2025 |
| ALT Planning and Consenting Ltd | Glasgow | 2022 |
| ALT Procurement Limited | Roslin | 2016 |
| ALT Programmes Limited | Hayling Island | 2013 |
| ALT Project Services Ltd | London | 2023 |
| ALT Quality Consulting Limited | Wantage | 2016 |
| ALT Services Limited | Bridlington | 2003 |
| ALT Surveying Limited | Aberdare | 1999 |
| ALT TEN Interactive Limited | Aberdeen | 2018 |
| ALT Theory Limited | Shipley | 2020 |
| ALT Web Design Ltd | Walsall | 2012 |
| Alt-Group Holdco Ltd | Worcester | 2026 |
| Alt-H Limited | Leicester | 2015 |
| ALT-JL1 Limited | London | 2021 |
| Alt-Legal Limited | Wetherby | 2014 |
| Alt-Nrg Ltd | London | 2025 |
| Alt-Take Ltd | London | 2026 |
| Alt-V Law Limited | London | 2024 |
| Alt-X Law Consultants Ltd | London | 2021 |
| ALT. Content Ltd | London | 2025 |
| ALT. Studio Limited | Cottingham | 2017 |
| ALT. Supply Consulting Limited | Shepperton | 2014 |
| Alta Business Improvements Ltd | Evesham | 2015 |
| Alta Concept Ltd | Weybridge | 2020 |
| Alta CPC Limited | Edinburgh | 2014 |
| Alta Digital Ltd | Warrington | 2007 |
| Alta Flora Ltd | London | 2018 |
| Alta Idea Interiors Ltd | Acton Turville | 2025 |
| Alta Innovation Ltd | Cambridge | 2024 |
| Alta International Limited | London | 2019 |
| Alta Investment Group Limited | London | 2021 |
| Alta Law Ltd | Peterborough | 2023 |
| Alta Legal Ltd | London | 2021 |
| Alta London Limited | London | 2018 |
| Alta Nova Consulting Engineers Ltd | Fulham | 2025 |
| Alta Optima Ltd | London | 2014 |
| Alta Performance Materials Holdings Company (UK) Limited | London | 2019 |
| Alta Performance Materials India Partner Limited | London | 2019 |
| Alta Scientia Ltd. | Oxford | 2009 |
| Alta Semita Ltd | Harrow | 2019 |
| Alta Solutions Limited | Spalding | 2013 |
| Alta Stet Limited | Farnham | 2016 |
| Alta Studio Ltd | Grimsby | 2017 |
| Alta Transform Ltd | Radlett | 2025 |
| Alta Vecta Limited | Liverpool | 2023 |
| Alta Vera Limited | London | 1992 |
| Alta Vista Consultancy Ltd | Berkhamsted | 2025 |
| Alta Vista Consulting Limited | Braintree | 2019 |
| Alta Vista Partners Limited | Cardiff | 2025 |
| Alta VUE Limited | Pudsey | 2017 |
| Alta Zenith Limited | York | 2021 |
| Altaan Medic Ltd | Manchester | 2025 |
| Altacor Limited | Birmingham | 2005 |