| Alro Engineering Services Limited | Belfast | 2025 |
| Alroboss Limited | Coventry | 2013 |
| Alrog Investments Ltd | Stafford | 2019 |
| Alrosmil Design Services Ltd | Gateshead | 2024 |
| Alround Services Ltd | Dundee | 2021 |
| Alrp Ltd | Glasgow | 2014 |
| Alru Ltd | Tadcaster | 2020 |
| Alruna Consulting Ltd | London | 2021 |
| Alry Cutting Technology Ltd | Lochgelly | 2017 |
| ALS & AL Nominees Limited | London | 2001 |
| ALS Accountancy Services Limited | Stowmarket | 1997 |
| ALS Albion Limited | London | 2002 |
| ALS Architects Limited | London | 1997 |
| ALS Associates Limited | Brighton | 2013 |
| ALS Coaching Ltd | London | 2024 |
| ALS Consult Limited | Colchester | 2011 |
| ALS Consulting Services Limited | Llanelli | 2015 |
| ALS Contract Limited | Eastleigh | 2017 |
| ALS Corporate Solutions Limited | Leeds | 2011 |
| ALS Digital Ltd | Southampton | 2020 |
| ALS Enterprise Ltd | Birmingham | 2022 |
| ALS Financial Consultants Ltd | Bradford | 2007 |
| ALS Freelance Ltd | Chester | 2021 |
| ALS Future Limited | London | 2024 |
| ALS Group Assayers Limited | Prescot | 2009 |
| ALS Inspection UK Limited | Prescot | 1975 |
| ALS Laboratories (UK) Limited | Coventry | 1989 |
| ALS Law Limited | Rochdale | 2019 |
| ALS Legal Limited | Swindon | 2017 |
| ALS Life Sciences Limited | Coventry | 2000 |
| ALS Managed Services (Holdings) Limited | Hengoed | 2018 |
| ALS Managed Services (Topco) Limited | Hengoed | 2021 |
| ALS Managed Services Limited | Hengoed | 2013 |
| ALS Optical Services Ltd | Sudbury | 2025 |
| ALS Pest Solutions Limited | South Shields | 2017 |
| ALS Photographic Ltd | Basildon | 2025 |
| ALS Professional Limited | Hengoed | 2023 |
| ALS Projects Limited | Shrewsbury | 2024 |
| ALS RBC Limited | Edgware | 2015 |
| ALS Retail Ltd | Doncaster | 2020 |
| ALS Surveyors Ltd | Redruth | 2020 |
| ALS Technical Solutions Limited | Hatfield | 2012 |
| Alsa Business Solutions Ltd | London | 2023 |
| Alsa Consultancy Ltd | Thornton Cleveleys | 2023 |
| Alsa Consultancy Services Limited | Rushden | 2019 |
| Alsa PH Ltd | Hull | 2018 |
| Alsaalim Ltd | Manchester | 2025 |
| Alsaaty Ltd | London | 2021 |
| Alsace Bidco Limited | Stevenage | 2023 |
| Alsaffara Technical Services Ltd | London | 2018 |
| Alsafwa Ltd | Shrewsbury | 2024 |
| Alsager Skip Hire Limited | Stoke-On-Trent | 2005 |
| Alsager VETS4PETS Limited | Handforth | 2015 |
| Alsahli Law Firm Ltd | London | 2025 |
| Alsala Gambling Compliance Consultancy Ltd | Leeds | 2026 |
| Alsan Legal Limited | London | 2026 |
| Alsans Furnishings Limited | London | 1999 |
| Alsap Ltd | Luton | 2022 |
| Alsash Construction Ltd | Chatham | 2018 |
| Alsaso Consulting Limited | London | 2025 |
| Alsat Digital Services Limited | Dunfermline | 2008 |
| Alsation Investments Limited | Douglas | 1996 |
| Alscass Limited | London | 2026 |
| Alscot Architectural Associates Limited | Redditch | 2014 |
| Alseamus Limited | Whyteleafe | 2017 |
| Alset Digital and AI Solutions Ltd | Aberdeenshire | 2025 |
| Alsf Ltd | London | 2025 |
| Alsg Ltd | London | 2019 |
| Alshamari Limited | Leeds | 2018 |
| Alshareef Scientific Academy Ltd | London | 2019 |
| Alsheraz Consultants Ltd | Ilford, London | 2014 |
| Alshifa 5 Ltd | Bradford | 2013 |
| Alsiak Services Limited | Tarporley | 2026 |
| Alsienaz Ltd | London | 2025 |
| Alsil Consulting Ltd | London | 2026 |
| Alsinead Ltd | Cottingham | 2024 |
| Alsisa Limited | Shenfield | 2024 |
| Alsium Limited | Mansfield | 2018 |
| Alsk Limited | Luton | 2023 |
| Also Agency Ltd | London | 2016 |
| Also Communications Ltd | Etchingham | 2018 |
| Alsoco Ltd | London | 2021 |
| Alsop & Co. Limited | Winchester | 2015 |
| Alsop Verrill Limited | London | 2011 |
| Alsper Consultancy Ltd | Peebles | 2026 |
| Alss Accounting & Consulting Ltd | Spalding | 2021 |
| Alsten Kōchi Homes Ltd | Diss | 2019 |
| Alster Group Ltd | Kingston Upon Thames | 2026 |
| Alstern Solicitors Ltd | London | 2022 |
| Alsters Kelley Solicitors Limited | Leamington Spa | 2013 |
| Alstertor Rail UK Limited | Bromsgrove | 2002 |
| Alstom Academy for Rail | Derby | 1934 |
| Alstom Electrical Machines Ltd | Street Birmingham | 1951 |
| Alstom Traction Ltd | Warwickshire | 1927 |
| Alstom Transport UK (Holdings) Limited | Derby | 2013 |
| Alston + Donnelly Architecture Limited | Lancaster | 2013 |
| Alston + Partners Limited | Norwich | 2019 |
| Alston Acquisitions Limited | Chorley | 2013 |
| Alston Asquith Limited | Hatfield | 2018 |
| Alston Engineering Services Ltd | Bedford | 2022 |