| A & J Jennings Limited | Other services | 2025 |
| A & K Beauty Salon and Skin Clinic Limited | Health & social care | 2025 |
| A 2 C Holdings Limited | Financial services | 2007 |
| A 2 C Services Limited | Information & communication | 1997 |
| A B Spray Finishings Ltd | Administrative & support | 2018 |
| A Bligh Exterior Cleaning Ltd | Administrative & support | 2025 |
| A D & L Media Ltd | Professional & scientific | 2026 |
| A F Roofing Ltd | Construction | 2021 |
| A Frost Design Limited | Other services | 2016 |
| A H Rahmani Ltd | Administrative & support | 2014 |
| A Interior Systems Ltd | Construction | 2016 |
| A J Wheeler Limited | Professional & scientific | 2005 |
| A J Williams Ltd | Information & communication | 2016 |
| A K Automation and Control Limited | Construction | 2002 |
| A L Engineering Works Ltd | Professional & scientific | 2019 |
| A P Goddard Limited | Administrative & support | 2009 |
| A Page Ltd | Construction | 2017 |
| A R B Glass Services Limited | Construction | 1995 |
| A Rated Boilers Limited | Construction | 2010 |
| A S Newton Tape and Jointing Specialists Limited | Construction | 2018 |
| A Star Home Improvements (Portsmouth) Limited | Construction | 2021 |
| A Star Products Ltd | Wholesale & retail | 2022 |
| A Star Properties Southern Ltd | Real estate | 2022 |
| A Sterling Developments Ltd | Construction | 2026 |
| A Stone's Throw Event Co Limited | Administrative & support | 2014 |
| A Taberna Limited | Hospitality | 2020 |
| A to Z General Services Ltd | Administrative & support | 2012 |
| A Touch of Glass Hampshire Limited | Construction | 2018 |
| A Word to the Wise Ltd | Administrative & support | 2005 |
| A&Acorp Limited | Professional & scientific | 2025 |
| A&B Accountancy Solutions Ltd | Professional & scientific | 2018 |
| A&E Holdings (Southsea) Limited | Financial services | 2021 |
| A&G Family Limited | Hospitality | 2026 |
| A&P BUL Ltd | Construction | 2021 |
| A&Z Cove Ltd | Wholesale & retail | 2026 |
| A'Becket Consulting Limited | Professional & scientific | 2022 |
| A-Boss Scaffolding Ltd | Construction | 2015 |
| A-Data Limited | Professional & scientific | 2003 |
| A-Voyage Limited | Transport & logistics | 2024 |
| A. B. Plant Shipping (NL) Ltd | Extraterritorial | 2017 |
| A. R. Groundworks & Construction Limited | Construction | 2011 |
| A.Archer Property Group Ltd | Real estate | 2025 |
| A.B. Bar One Ltd | Hospitality | 2020 |
| A.B.C. Glass Processing Employees Trustee Limited | Other services | 2023 |
| A.B.C. Glass Processing Limited | Manufacturing | 1999 |
| A.D. Mechanical Services Limited | Construction | 2000 |
| A.D.N. Financial Solutions Ltd | Financial services | 2008 |
| A.E. Van Laun Limited | Real estate | 1981 |
| A.G. Rutter (Holdings) Limited | Real estate | 1995 |
| A.G. Rutter Limited | Wholesale & retail | 1991 |
| A.G.M Steel Fabrication Ltd | Extraterritorial | 2024 |
| A.H.A.Labour Services Ltd | Construction | 2025 |
| A.J Auto Solutions Ltd | Wholesale & retail | 2025 |
| A.K.E.K Property Ltd | Real estate | 2025 |
| A.P.S.K Ltd | Hospitality | 2025 |
| A.R. Evans Limited | Health & social care | 2013 |
| A.R.T. Construction Ltd | Construction | 2024 |
| A.S. Bates Medical Services Limited | Health & social care | 2010 |
| A.S.L (GB) Ltd | Administrative & support | 2014 |
| A.T. Construction Services Limited | Construction | 2007 |
| A.V.Harris & SON Limited | Manufacturing | 1941 |
| A1 Automac Ltd | Wholesale & retail | 2011 |
| A1 Body Works Ltd | Wholesale & retail | 2017 |
| A1 Brickwork Limited | Construction | 2005 |
| A1 Car Centre Ltd | Wholesale & retail | 2024 |
| A1 Profi Blast Limited | Administrative & support | 2019 |
| A1 Tyres Services Ltd | Wholesale & retail | 2026 |
| A10 Statics Ltd | Real estate | 2025 |
| A1R Limited | Manufacturing | 2018 |
| A2B Rapid Response Electrical Ltd | Construction | 2024 |
| A2B Rapid Response Groundworks and Landscaping Ltd | Construction | 2025 |
| A2B Rapid Response Maintenance Ltd | Construction | 2022 |
| A2B Rapid Response Property Services Ltd | Construction | 2026 |
| A2B Tax Consultancy Limited | Professional & scientific | 2026 |
| A2E Solutions Ltd | Information & communication | 2015 |
| A2R Holdings Limited | Financial services | 2025 |
| A2R Moulding Limited | Manufacturing | 2025 |
| A2R Tooling Limited | Professional & scientific | 2016 |
| A3 Air Limited | Other services | 2004 |
| A3 Leisure Limited | Manufacturing | 2022 |
| A360 Ltd | Public administration | 2018 |
| AA Beauty 192 Ltd | Hospitality | 2024 |
| AA Events and Travel Ltd | Administrative & support | 2020 |
| AA Operations (South) Ltd | Construction | 2018 |
| AA Window Services Installations Ltd | Construction | 2022 |
| AAC Hampshire Limited | Transport & logistics | 2022 |
| Aadhi Services Limited | Financial services | 2023 |
| Aalamoyo Ltd | Administrative & support | 2012 |
| Aalia Capitals and Investment Limited | Construction | 2025 |
| AAM Exeter Ltd | Wholesale & retail | 2021 |
| Aanuore Services Limited | Administrative & support | 2025 |
| Aaron Farndell Building Services Ltd | Construction | 2022 |
| Aaron Grab and Skip Hire Ltd | Water & waste | 2015 |
| AB & R Teeth Care Ltd | Health & social care | 2022 |
| AB Assets Limited | Construction | 2007 |
| AB Kebab and Grill Limited | Hospitality | 2026 |
| AB MFC Construction Limited | Construction | 2017 |
| Ab's Star Limited | Health & social care | 2018 |
| ABA Domestic Appliances Limited | Other services | 2023 |
| Abacus Building Services (Hants) Ltd | Construction | 2011 |