| A.R. Wentworth (Sheffield) Limited | Manufacturing | 1982 |
| A.R.F. Management Company Limited | Households | 2021 |
| A.R.Williams Consulting Ltd | Health & social care | 2024 |
| A.T Body Shop and Autos Ltd | Wholesale & retail | 2024 |
| A.W.U.L Lettings Ltd | Real estate | 2025 |
| A1 Fixings Ltd | Administrative & support | 2004 |
| A1 Foods (S) Limited | Hospitality | 2019 |
| A1 Global Solutions Limited | Wholesale & retail | 2021 |
| A1 Improvement Building Ltd | Construction | 2021 |
| A1 Laundries Ltd | Other services | 2019 |
| A1 Pallets & Timber Products Limited | Construction | 2009 |
| A1 Piling Equipment Limited | Administrative & support | 2022 |
| A1 Plumbers Merchant Limited | Wholesale & retail | 2021 |
| A1 Roper Ltd | Manufacturing | 2005 |
| A1 Taxis Sheffield Ltd | Construction | 2017 |
| A2 Advice Ltd | Financial services | 2020 |
| A2B Car & Van Sales Limited | Wholesale & retail | 2008 |
| A2B Removal & Storage Limited | Transport & logistics | 2021 |
| A2B Taxis Yorkshire Ltd | Transport & logistics | 2018 |
| A2Z Mobile Barbers Ltd | Other services | 2023 |
| A3 Property Solutions Ltd | Real estate | 2025 |
| A4 Property Maintenance Ltd | Construction | 2021 |
| A4Z Limited | Information & communication | 2024 |
| A57 Aggregates Ltd | Wholesale & retail | 2024 |
| A57 Grab Hire Ltd | Administrative & support | 2020 |
| AA Contracting Ltd | Construction | 2023 |
| AA Electrical Wholesalers and Lighting Limited | Wholesale & retail | 2001 |
| AA Grill & Peri Peri Chicken Limited | Hospitality | 2024 |
| AA Kitchens Ltd | Wholesale & retail | 2020 |
| AA Limitless Vision Ltd | Wholesale & retail | 2026 |
| AA Mechanical Insurance Services Limited | Financial services | 2006 |
| AA Tax Accountants Limited | Professional & scientific | 2015 |
| AA Tools & Engineering Group Ltd | Construction | 2026 |
| AA Tools Group Limited | Construction | 2019 |
| AA Tools Ltd | Manufacturing | 2014 |
| AAA Analytics Ltd | Professional & scientific | 2026 |
| AAA Enterprises (SY) Limited | Real estate | 2016 |
| AAA Legal Services Ltd | Wholesale & retail | 2012 |
| AAA Plus Ltd | Wholesale & retail | 2025 |
| AAA Properties (UK) Ltd | Real estate | 2011 |
| AAA Risk Consultants Ltd | Professional & scientific | 2016 |
| Aaabakarov's Ltd | Wholesale & retail | 2022 |
| AAD Architects Limited | Professional & scientific | 1981 |
| Aadams Properties Ltd | Real estate | 2023 |
| Aadipranavam Ltd | Wholesale & retail | 2014 |
| Aaeducationuk Ltd | Professional & scientific | 2024 |
| Aafj Ltd | Wholesale & retail | 2025 |
| Aais Holdings Ltd | Financial services | 2025 |
| Aais Property Ltd | Real estate | 2025 |
| AAJ Transport Ltd | Transport & logistics | 2016 |
| Aalfy Ltd | Education | 2013 |
| Aalia S H Ltd | Wholesale & retail | 2025 |
| Aamerah Energy Ltd | Mining & quarrying | 2025 |
| Aamerah Holding Ltd | Financial services | 2025 |
| Aami Property Limited | Real estate | 2026 |
| Aami Real Estate Ltd | Real estate | 2021 |
| Aamis LLP | | 2025 |
| Aaml Cafe Ltd | Hospitality | 2023 |
| AAP Metal Fabrication Services Ltd | Manufacturing | 2009 |
| Aaps Space Ltd | Real estate | 2026 |
| Aaran Mckenzie Films Ltd | Information & communication | 2022 |
| Aariz Enterprises Ltd | Transport & logistics | 2026 |
| Aarmish Ltd | Administrative & support | 2019 |
| Aaron Bott Ltd | Extraterritorial | 2020 |
| Aaron David Consulting Limited | Professional & scientific | 2017 |
| Aaron Holdings Limited | Health & social care | 2002 |
| Aaron Martin Mentoring Service Ltd | Education | 2024 |
| Aaron Roofing Supplies Limited | Extraterritorial | 1996 |
| Aarons Driving Limited | Transport & logistics | 2025 |
| Aarshad Limited | Information & communication | 2016 |
| Aaru's Kitchen Limited | Hospitality | 2026 |
| AAT Investment Co. Limited | Financial services | 2025 |
| AB & J Services Limited | Transport & logistics | 2021 |
| AB Commercial Finance Limited | Administrative & support | 2022 |
| AB Copywriting Ltd | Professional & scientific | 2024 |
| AB Digital Consulting Ltd | Administrative & support | 2025 |
| AB Electrical Install Ltd | Construction | 2023 |
| AB Graphics Ltd | Professional & scientific | 2019 |
| AB Heat Ltd | Construction | 2025 |
| AB Laine Properties Ltd | Real estate | 2024 |
| AB Mercantile Group Ltd | Real estate | 2023 |
| AB Pharmacist Ltd | Wholesale & retail | 2022 |
| AB Property Rentals Limited | Real estate | 2020 |
| AB Rendering Ltd | Construction | 2022 |
| AB Renewable Solutions Limited | Construction | 2022 |
| AB Roofing Solutions (MC) Limited | Construction | 2021 |
| AB Roofing Solutions Ltd | Construction | 2010 |
| AB Site Solutions Ltd | Wholesale & retail | 2010 |
| AB Solarfit Limited | Construction | 2013 |
| AB Transmission Protection Limited | Professional & scientific | 2011 |
| Ab&L Property Ltd | Construction | 2025 |
| ABA Architecture and Interiors Limited | Construction | 2016 |
| ABA Flat Roofing Limited | Construction | 2020 |
| ABA Global Holdings Ltd | Professional & scientific | 2018 |
| ABA Roofing Contractors Ltd | Construction | 2026 |
| Abaculi Limited | Information & communication | 2022 |
| Abacus Accountancy & Consultancy Services Limited | Professional & scientific | 2018 |
| Abacus Accounting & Payroll Services Limited | Professional & scientific | 2004 |
| Abacus Day Care Limited | Health & social care | 2025 |
| Abacus Garage Door Solutions Ltd | Construction | 2018 |