| A Branch & Co. Ltd | Professional & scientific | 2025 |
| A Brand Fantastic Limited | Information & communication | 2013 |
| A Brands Koncepts Limited | Wholesale & retail | 2026 |
| A Brands Limited | Information & communication | 2013 |
| A Bridge to Living Limited | Health & social care | 2021 |
| A Briggs Production Ltd | Information & communication | 2023 |
| A Bright Care Ltd | Financial services | 2018 |
| A Brighter Tomorrow Limited | Financial services | 2020 |
| A Bro's Property Services Ltd | Construction | 2019 |
| A Bromberg (Exporters) Limited | Wholesale & retail | 1954 |
| A Brookes Limited | Manufacturing | 2024 |
| A Brooks Construction Limited | Construction | 2020 |
| A Brooks Consultancy Ltd | Information & communication | 2018 |
| A Brooks Decorators Ltd | Construction | 2023 |
| A Bros Halal Meat (London) Limited | Wholesale & retail | 2024 |
| A Brothers Construction Limited | Construction | 2016 |
| A Brown & Co. (Mitcham) Limited | Wholesale & retail | 1992 |
| A Brown and Company Ltd. | Professional & scientific | 2017 |
| A Brown Girl Recommends Limited | Arts & recreation | 2024 |
| A Browne Ltd | Professional & scientific | 2026 |
| A Brushstroke Away Ltd | Construction | 2023 |
| A Builders Team Limited | Construction | 2015 |
| A Building Construction Limited | Construction | 2014 |
| A BUS Could Run Ltd | Information & communication | 2015 |
| A C Avalon Advisory Ltd | Professional & scientific | 2017 |
| A C Bromley Limited | Hospitality | 2019 |
| A C Carpet Planners | | 1995 |
| A C Direct Limited | Manufacturing | 1992 |
| A C Dominic Limited | Administrative & support | 2017 |
| A C Europe Limited | Extraterritorial | 1991 |
| A C F Distance Learning Limited | Education | 1991 |
| A C F Financial Technology Limited | Information & communication | 1991 |
| A C Holdom Surveyors Limited | Professional & scientific | 1997 |
| A C Houghton-Boyle Limited | Education | 2023 |
| A C Management Associates Ltd | Professional & scientific | 1999 |
| A C PLC | Construction | 2008 |
| A C Pope Holdings Limited | Financial services | 2021 |
| A C Properties & Investments Ltd | Financial services | 2025 |
| A C Richards Consulting Limited | Professional & scientific | 2009 |
| A C Sujevic Limited | Professional & scientific | 2013 |
| A C Union Limited | Professional & scientific | 2008 |
| A C/O F Group Ltd | Transport & logistics | 2025 |
| A Cafe Society Limited | Hospitality | 2010 |
| A Cahill Limited | Construction | 2003 |
| A Campbell Healthcare Ltd | Health & social care | 2022 |
| A Capital Group Ltd | Financial services | 2023 |
| A Card KO Ltd | Wholesale & retail | 2025 |
| A Carefree Life CIC | Information & communication | 2025 |
| A Carolan Consulting Limited | Information & communication | 2016 |
| A Carr Properties Limited | Real estate | 2026 |
| A Cat Called Rover Ltd | Arts & recreation | 2014 |
| A Catering Canteen Limited | Hospitality | 2009 |
| A Cavanagh Ltd | Households | 2025 |
| A CBN Limited | Professional & scientific | 2021 |
| A Chain of Events Ltd | Administrative & support | 2007 |
| A Champs Ltd | Administrative & support | 2022 |
| A Chapman Properties Limited | Real estate | 2018 |
| A Chappell Landscaping and Building Alterations Ltd | Construction | 2024 |
| A Chauffeurs Ltd | Transport & logistics | 2010 |
| A Cheeky Little Holding Company Ltd | Financial services | 2024 |
| A Chokra Films Ltd | Information & communication | 2025 |
| A Chowdhury Holding Ltd | Financial services | 2021 |
| A Christmas Twist Limited | Information & communication | 2021 |
| A Cigar IS Just a Cigar Limited | Information & communication | 2023 |
| A Circle Agency Ltd | Wholesale & retail | 2014 |
| A Class Beauty Ltd | Education | 2021 |
| A Class Cleaners and Labourers Limited | Construction | 2024 |
| A Class Dental Limited | Health & social care | 2021 |
| A Class Foods Ltd | Wholesale & retail | 2024 |
| A Class Group UK Ltd | Financial services | 2026 |
| A Class Interiors Limited | Construction | 2019 |
| A Class Nursery Ltd | Education | 2018 |
| A Class Polishers Limited | Construction | 2021 |
| A Class Removals & Clearance Limited | Transport & logistics | 2025 |
| A Class Services Ltd | Health & social care | 2020 |
| A Class Sessions Limited | Arts & recreation | 2024 |
| A Class Transport Ltd | Transport & logistics | 2021 |
| A Cleaner (London) Limited | Administrative & support | 2014 |
| A Cleaner Experience Ltd | Administrative & support | 2026 |
| A Cleanup UK Ltd | Administrative & support | 2026 |
| A Clear Way Ltd | Health & social care | 2025 |
| A Close Shave UK Limited | Information & communication | 2019 |
| A Coda Residences Limited | Real estate | 2024 |
| A Coffee Project Ltd | Hospitality | 2023 |
| A Collected MAN Limited | Wholesale & retail | 2014 |
| A Collection Limited | Wholesale & retail | 2020 |
| A Collection of Hope Ltd | Wholesale & retail | 2019 |
| A Collection of Pixels Ltd | Professional & scientific | 2025 |
| A Collyer Consulting Ltd | Professional & scientific | 2020 |
| A Commercial Catering Equipment & Bars Company London Limited | Manufacturing | 2004 |
| A Commercial Ltd | Real estate | 2020 |
| A Common Endeavour Ltd | Professional & scientific | 2018 |
| A Common Purpose Ltd | Professional & scientific | 2021 |
| A Common Thread Limited | Professional & scientific | 2020 |
| A Company of Wild Things Limited | Professional & scientific | 2016 |
| A Connected Future Limited | Professional & scientific | 2015 |
| A Conscious Interruption Limited | Manufacturing | 2021 |
| A Consept Limited | Wholesale & retail | 2023 |
| A Considered Curiosity Ltd | Professional & scientific | 2026 |
| A Consultancy Limited | Professional & scientific | 2002 |