| 10-PROJECT Controls Ltd | Construction | 2018 |
| 106 Beulah Road Management RTM Company Ltd | Households | 2012 |
| 10B Holiday Limited | Hospitality | 2021 |
| 1ST Glass Double Glazing Limited | Construction | 2003 |
| 21 ST. Philip's Road Limited | Households | 2010 |
| 22 - 24 Lower Oldfield Park Management Company Limited | Hospitality | 2004 |
| 360 Creation Ltd | Professional & scientific | 2024 |
| 444VIDEO Limited | Other services | 2024 |
| 83CNC Ltd | Manufacturing | 2026 |
| A & M Sims Ltd | Construction | 2015 |
| A V a Ecology Limited | Professional & scientific | 2013 |
| A&C Williams Ltd | Health & social care | 2016 |
| A&O Building & Carpentry Limited | Construction | 2023 |
| A.P.A.C. Limited | Professional & scientific | 2004 |
| Abbie Carpets Limited | Wholesale & retail | 2020 |
| Abdelrahman Surgical Ltd | Health & social care | 2023 |
| Abergavenny Exchange Properties Limited | Construction | 2009 |
| Ace Site Services (UK) Limited | Construction | 2009 |
| Ackland Mainwaring Limited | Professional & scientific | 2011 |
| Acrston Ltd | Professional & scientific | 2026 |
| Adastra Adventures Limited | Administrative & support | 2015 |
| Adriana Holdings Limited | Financial services | 2011 |
| Adriana Limited | Health & social care | 2001 |
| Advanced Barn Comfort Ltd | Agriculture & fishing | 2020 |
| Advanced Health Shop UK Ltd | Wholesale & retail | 2023 |
| Advanced Property Solutions (South West) Ltd | Construction | 2016 |
| Advanced TRS UK Ltd | Wholesale & retail | 2019 |
| Adventure River Ltd | Arts & recreation | 2014 |
| Advis Limited | Professional & scientific | 2013 |
| Agreeinsure Limited | Agriculture & fishing | 1995 |
| AIM Product Design Limited | Professional & scientific | 2014 |
| Akek Limited | Professional & scientific | 2003 |
| Alan Curtis Solicitors Ltd. | Professional & scientific | 2021 |
| Alan Jones & Associates Ltd | Professional & scientific | 2006 |
| Alchemy Training Group Limited | Education | 2020 |
| Allard Sports Cars Limited | Manufacturing | 2012 |
| Allied Mail Limited | Real estate | 1998 |
| Alpine Farm Agriculture Ltd | Agriculture & fishing | 2022 |
| ALR Financial Services Limited | Professional & scientific | 2018 |
| ALS Computing Limited | Information & communication | 1993 |
| Altitude Systems Ltd | Information & communication | 2019 |
| Always Essential Limited | Wholesale & retail | 2022 |
| Amabellas Ltd | Other services | 2025 |
| Amalgamated Cybernetics Limited | Professional & scientific | 2010 |
| Amanda Whiting Limited | Information & communication | 2008 |
| Amartrosa Limited | Arts & recreation | 2021 |
| AMP Monmouth CIC | Education | 2025 |
| AMP Saas Limited | Other services | 2021 |
| AMS Fire Solutions Ltd | Construction | 2021 |
| AMS Motorcycles Limited | Wholesale & retail | 1997 |
| Ancre Hill Limited | Real estate | 2024 |
| Andrew Bayliss Hairdressing Monmouth Limited | Other services | 2016 |
| Andrew Goodwin Arborist Limited | Other services | 2016 |
| Aneena Limited | Wholesale & retail | 2006 |
| Angel Nails and Spa NP Ltd | Other services | 2018 |
| Angelic HEN Limited | Wholesale & retail | 2008 |
| Anna Cowen Ltd | Professional & scientific | 2012 |
| Apimondia Limited | Administrative & support | 2015 |
| Apline Kennels & Equestrian Ltd | Agriculture & fishing | 2022 |
| Apple Tree International Ltd | Other services | 2025 |
| Arcade Sound Limited | Wholesale & retail | 2021 |
| Arch Properties (Bristol) Limited | Real estate | 2016 |
| Archer & Co (Estate Agents) Ltd | Real estate | 2014 |
| Archer & Co (Ross-On-Wye) Ltd | Real estate | 2020 |
| Architect Designs Ltd | Professional & scientific | 2024 |
| Architect O Ltd | Professional & scientific | 2025 |
| ARD Pest Control Ltd | Agriculture & fishing | 2009 |
| Arenig Energy Limited | Professional & scientific | 2015 |
| Arimathea Films Ltd | Information & communication | 2022 |
| Arkengarth Consulting Ltd | Professional & scientific | 2021 |
| Asmac & Company (Surfacing) Limited | Construction | 1975 |
| Asset Management Consultancy Ltd | Professional & scientific | 2015 |
| Astute Property Services Ltd | Real estate | 2024 |
| ATC (Monmouthshire) Limited | Construction | 1997 |
| ATC Traditional Timber Floors and Doors Ltd | Construction | 2012 |
| Atlantic Blue Marlin Ltd | Agriculture & fishing | 2015 |
| Aubin Thompson Ltd | Wholesale & retail | 2023 |
| Audit IT Limited | Information & communication | 2026 |
| Auto Spray (Monmouth) Limited | Wholesale & retail | 2006 |
| Avoca Estate Company,Limited | Construction | 1896 |
| B & R Bespoke Ltd | Manufacturing | 2022 |
| B G Landrovers Limited | Wholesale & retail | 2001 |
| Babell Restoration Limited | Professional & scientific | 2018 |
| Bancroft Wealth Ltd | Financial services | 2020 |
| Barry Island Cottage Company Limited | Construction | 1896 |
| Barry Island Investments Limited | Construction | 1962 |
| Barton Curry Ltd | Hospitality | 2024 |
| BCC Electrical Ltd | Construction | 2020 |
| BDV Stores Limited | Wholesale & retail | 2026 |
| Beaufort Mews Management (Monmouth) Limited | Real estate | 2007 |
| Beaufort Tenants Management Limited | Households | 1993 |
| Beautyology Monmouth Ltd | Other services | 2025 |
| Beckbury Lewis Limited | Health & social care | 2006 |
| Bell Street Dent Ltd | Health & social care | 2024 |
| BEN Langdon Limited | Health & social care | 2011 |
| Bentley Hair Extensions Ltd | Other services | 2024 |
| Berber Work Ltd | Construction | 2024 |
| Berwyn Morgan Carpentry Ltd | Construction | 2023 |
| Best for Entertainment Ltd | Manufacturing | 2003 |
| Beynons Dental Surgery Ltd | Health & social care | 2009 |