| A Simmons Consulting Limited | Professional & scientific | 2024 |
| A Simon AFA Mipa Fabrp Limited | Professional & scientific | 2011 |
| A Simple Logic Ltd | Information & communication | 2018 |
| A Simple Process Limited | Information & communication | 2023 |
| A Simplicity Upload Ltd | Information & communication | 2025 |
| A SIN Electrical Limited | Construction | 2023 |
| A Single Line Productions Ltd | Arts & recreation | 2024 |
| A Sky Legal Ltd | Professional & scientific | 2023 |
| A Slice Cakes Limited | Hospitality | 2017 |
| A Small Place Ltd | Hospitality | 2024 |
| A Small Studio Ltd | Professional & scientific | 2010 |
| A Small Triangle Ltd | Wholesale & retail | 2020 |
| A Small Victory Limited | Financial services | 2021 |
| A Smarter Future Limited | Real estate | 2020 |
| A Smile Ltd | Health & social care | 2018 |
| A Smiles London Ltd | Health & social care | 2024 |
| A Smith Exterior Services Ltd | Administrative & support | 2025 |
| A Smith Property Solutions Ltd | Real estate | 2024 |
| A Social Arts Practice Ltd | Construction | 2024 |
| A Solution 4 U Alcohol Licence Consultancy Ltd | Administrative & support | 2024 |
| A Soni Ltd | Real estate | 2025 |
| A Sound Move Ltd | Professional & scientific | 2025 |
| A Souvenir Ltd | Wholesale & retail | 2026 |
| A Spark in the Dark Ltd | Health & social care | 2021 |
| A Spoonful of Moonlight Ltd | Manufacturing | 2024 |
| A Spoonful of Sugar | Extraterritorial | 2012 |
| A Spring Forward Ltd | Information & communication | 2024 |
| A Sprinkle of Deco & Art Ltd | Wholesale & retail | 2015 |
| A Squad Ltd | Construction | 2021 |
| A Square Capital Limited | Real estate | 2024 |
| A Square Global Consulting Limited | Financial services | 2024 |
| A Square London Limited | Manufacturing | 2024 |
| A Square Property Group Limited | Real estate | 2025 |
| A Square Virtual Designs Ltd | Professional & scientific | 2021 |
| A Squared Business Solutions Limited | Professional & scientific | 2024 |
| A Squared Commercial Services Ltd | Professional & scientific | 2024 |
| A Squared Consultants Ltd | Professional & scientific | 2020 |
| A Squared Healthcare Ltd | Health & social care | 2020 |
| A Squared Labs Limited | Information & communication | 2025 |
| A Squire Limited | Arts & recreation | 2023 |
| A Srid Ltd | Health & social care | 2022 |
| A Srour Comodities Ltd | Wholesale & retail | 2025 |
| A Star Accommodations Ltd | Hospitality | 2025 |
| A Star Beauty & Cosmetics Limited | Other services | 2025 |
| A Star Builders Merchant Ltd | Construction | 2026 |
| A Star Care Agency Ltd | Health & social care | 2023 |
| A Star Cleaning Srvs Ltd | Administrative & support | 2023 |
| A Star Clothing Ltd | Wholesale & retail | 2024 |
| A Star Collection Limited | Wholesale & retail | 2024 |
| A Star Copy + Branding Ltd | Professional & scientific | 2021 |
| A Star Cuisine Ltd | Hospitality | 2025 |
| A Star Cutz Limited | Other services | 2025 |
| A Star Deliveries Ltd | Transport & logistics | 2016 |
| A Star Diamonds Ltd | Wholesale & retail | 2016 |
| A Star Driving Ltd | Education | 2025 |
| A Star Essentials Ltd | Transport & logistics | 2024 |
| A Star Food & Wine Ltd | Wholesale & retail | 2025 |
| A Star Games Ltd | Information & communication | 2024 |
| A Star HCW Ltd | Administrative & support | 2025 |
| A Star Heating and Plumbing Ltd | Construction | 2026 |
| A Star Homewares Ltd | Wholesale & retail | 2024 |
| A Star Inc Ltd | Health & social care | 2014 |
| A Star IS Born Limited | Financial services | 2019 |
| A Star Kitchen Ltd | Hospitality | 2024 |
| A Star Kitchens and Bathrooms Ltd | Construction | 2013 |
| A Star Liquid Limited | Other services | 2017 |
| A Star London Scaffolding Limited | Construction | 2019 |
| A Star Maths and Physics Limited | Education | 2012 |
| A Star Noble House Ltd | Other services | 2024 |
| A Star Plumbing Ltd | Construction | 2020 |
| A Star Plus Ltd | Wholesale & retail | 2018 |
| A Star Properties Watford Limited | Real estate | 2022 |
| A Star Property Services Ltd | Real estate | 2019 |
| A Star Relocation Ltd | Real estate | 2025 |
| A Star Rental Limited | Administrative & support | 2019 |
| A Star Russian School Ltd | Other services | 2019 |
| A Star Services Ltd | Professional & scientific | 2015 |
| A Star Solutions Ltd | Professional & scientific | 2018 |
| A Star Sound Hire Ltd | Hospitality | 2023 |
| A Star Student Recruits Ltd | Education | 2022 |
| A Star Studios Limited | Professional & scientific | 2007 |
| A Star Tech Agency Ltd | Administrative & support | 2026 |
| A Stars Group Ltd | Construction | 2021 |
| A Stars Media Ltd | Wholesale & retail | 2024 |
| A State of Nature Ltd | Wholesale & retail | 2020 |
| A Step Ahead CIC | Public administration | 2025 |
| A Step Ahead Mentors LLP | | 2020 |
| A Step Forward Limited | Professional & scientific | 1997 |
| A Stevenson Electrical Ltd | Construction | 2015 |
| A Stewart and Daughters Limited | Administrative & support | 2020 |
| A Stitch in Time Studio C.I.C. | Education | 2026 |
| A Stitch in Timecode Ltd | Information & communication | 2014 |
| A Stitching Room Ltd | Manufacturing | 2019 |
| A Storry Ltd | Arts & recreation | 2019 |
| A Story of Flowers Ltd | Wholesale & retail | 2024 |
| A Story Worth Telling Ltd | Information & communication | 2023 |
| A Strategy Art Consulting Ltd. | Public administration | 2018 |
| A Stronger Britain Ltd | Administrative & support | 2025 |
| A Studio Between Ltd | Professional & scientific | 2022 |
| A Studio Limited | Professional & scientific | 2006 |