| MAC Management Limited | Transport & logistics | 2017 |
| Made Form Ltd | Information & communication | 2026 |
| Maesllan Limited | Hospitality | 2025 |
| Majestic Balloons Ltd | Wholesale & retail | 2025 |
| Malthouse Court Flats Management Company Limited | Households | 2003 |
| Manigod Ltd | Hospitality | 2019 |
| Mapitandgo Friends Limited | Information & communication | 2009 |
| Mapitandgo Systems Limited | Information & communication | 2008 |
| Marcross Holdings Limited | Arts & recreation | 1964 |
| Mary Edwards Limited | Real estate | 2011 |
| Mastkey Limited | Professional & scientific | 1989 |
| Matthew G Brook Limited | Arts & recreation | 2023 |
| Matthew Thomas Performance Nutrition Ltd | Other services | 2021 |
| MDJ Academy Ltd | Arts & recreation | 2021 |
| MDJ Electronics Ltd | Other services | 2020 |
| Memento Mori Publishing Ltd | Information & communication | 2024 |
| MG Stnicholas Limited | Construction | 2018 |
| Middle Street Resolutions Limited | Professional & scientific | 2015 |
| Mnemosyne Film Ltd | Information & communication | 2025 |
| Mopps Cleaning Limited | Administrative & support | 2023 |
| Morrison Maintenance Ltd | Professional & scientific | 2018 |
| Mottown Llantwit Major Ltd | Wholesale & retail | 2018 |
| Mrbe Ltd | Manufacturing | 2019 |
| MRW Support Services Limited | Professional & scientific | 2016 |
| MTJ Urology Limited | Health & social care | 2022 |
| N.T Carpentry Ltd | Manufacturing | 2019 |
| Nature Based Therapies Limited | Health & social care | 2019 |
| Navidi Events Limited | Hospitality | 2026 |
| Navidi Promotions Ltd | Professional & scientific | 2013 |
| Neal Mullis Limited | Construction | 2014 |
| Newspeed Limited | Hospitality | 2024 |
| NO Nonsense Accountancy Ltd | Professional & scientific | 2010 |
| Nomad Electronics Limited | Information & communication | 1996 |
| NPC2016 Limited | Administrative & support | 2016 |
| OD AA DO ZET CIC | Information & communication | 2025 |
| Orchard Lodge Investments Limited | Mining & quarrying | 2020 |
| Origin Capital Group Ltd | Real estate | 2025 |
| OUR Woodwell CIC | Health & social care | 2025 |
| PAE Dhillon Ltd | Wholesale & retail | 2023 |
| PAE Kaurs Ltd | Wholesale & retail | 2026 |
| Pancake World Ltd | Manufacturing | 2013 |
| Parachute Packing Services Limited | Manufacturing | 2020 |
| Peace Within Counselling Services Ltd | Health & social care | 2022 |
| Pencod Fish Bar Limited | Hospitality | 2024 |
| Peppermint Grove Stays Ltd | Hospitality | 2022 |
| PER Consulting Ltd | Professional & scientific | 2011 |
| Perdix Firearms Limited | Information & communication | 1986 |
| Personal Washroom Services Ltd | Wholesale & retail | 2008 |
| Personal Washroom Solutions Ltd | Administrative & support | 2008 |
| Phillips Engineering & Maintenance Ltd | Wholesale & retail | 2022 |
| Poetry Wales Press Limited | Information & communication | 1988 |
| Produp Ltd | Information & communication | 2021 |
| Prop Fiction Limited | Information & communication | 1997 |
| Pryderi Safety Ltd | Information & communication | 2026 |
| Qmax Consulting Ltd | Professional & scientific | 2025 |
| Quroc Limited | Wholesale & retail | 2017 |
| R.I.Davies (Civil Engineering) Ltd | Agriculture & fishing | 2006 |
| R4NDT Ltd | Professional & scientific | 2025 |
| RDR Woodchip Ltd | Water & waste | 2016 |
| Redd Studio Ltd | Wholesale & retail | 2025 |
| REDI-38 Limited | Real estate | 2000 |
| Redrow Driveways Limited | Construction | 2026 |
| Redwood Aviation Ltd | Transport & logistics | 2019 |
| Redwood Close (Boverton) Management Co Limited | Households | 2002 |
| Refine Analysis Ltd | Information & communication | 2025 |
| Regal Holidays (UK) Limited | Administrative & support | 2019 |
| Reynish Audio Limited | Information & communication | 2023 |
| Richie Property Limited | Real estate | 2021 |
| Richie Tool and Plant Hire Ltd | Administrative & support | 2025 |
| RJD Construction (South Wales) Ltd | Construction | 2022 |
| Rogers 7 Limited | Hospitality | 2021 |
| Room in the Palace Limited | Real estate | 2006 |
| Rope & RIG Ltd | Construction | 2025 |
| Rosedew Developments Limited | Construction | 2014 |
| RSO Productions Limited | Arts & recreation | 2023 |
| Rtch Ltd | Professional & scientific | 2020 |
| Run Jump FLY Limited | Professional & scientific | 2017 |
| Rung Health Ltd | Information & communication | 2026 |
| S&Jfaulky Limited | Hospitality | 2025 |
| SDA Business Rescue Limited | Financial services | 2017 |
| Seasons Art Llanelli Ltd | Education | 2022 |
| Shawsy Ltd | Construction | 2021 |
| Shot Incognito Limited | Information & communication | 2019 |
| Sian Trenberth Photography Limited | Arts & recreation | 2002 |
| Sigma QMS Ltd | Professional & scientific | 2018 |
| Silmix Limited | Manufacturing | 1999 |
| Simtec Consult Ltd | Information & communication | 2021 |
| Sionedits Ltd | Information & communication | 2017 |
| Sipp Property Investments 2 TG Ltd | Real estate | 2011 |
| Sipp Property Investments Ltd | Financial services | 2012 |
| Skirider Limited | Administrative & support | 2003 |
| SLE Media Limited | Hospitality | 2018 |
| SLG Media Limited | Hospitality | 2018 |
| Sloanranger Ltd | Administrative & support | 2023 |
| Solely Marketing Ltd | Professional & scientific | 2018 |
| Sonabuild Ltd | Manufacturing | 2024 |
| Sota Tattoo Ltd | Other services | 2011 |
| Specialist VIP Drivers UK Ltd | Professional & scientific | 2022 |
| Spiral Shore Property Ltd | Real estate | 2025 |
| ST Donats Nursery Ltd | Education | 2022 |