| Avusta Limited | Real estate | 1987 |
| AW Prop Ltd | Administrative & support | 2016 |
| Awelon CYF | Energy | 2016 |
| Axon Brown Investments Ltd | Financial services | 2025 |
| AY Rooflines Limited | Construction | 2022 |
| Aynimr Ltd | Wholesale & retail | 2026 |
| Balmoral Apartments (Llandudno) Management Ltd | Real estate | 2015 |
| Balmyle Limited | Real estate | 1993 |
| Bambw Film Limited | Information & communication | 2012 |
| Barcallan Limited | Other services | 2006 |
| Bathers Self Storage Limited | Real estate | 2002 |
| Bathhouse Grooming Ltd | Other services | 2025 |
| Baytree Hotel Limited | Hospitality | 2013 |
| BDC Laundry Limited | Administrative & support | 2017 |
| BDR2 Ltd | Hospitality | 2022 |
| Beach Cafe Bar Ltd | Hospitality | 2022 |
| Beach Lawns Management Company (Llandudno) Limited | Other services | 1998 |
| Beaumont Apartments Management Company Limited | Households | 2004 |
| Ben's Bakery Limited | Manufacturing | 2018 |
| Benmax Construction Ltd | Construction | 2018 |
| Bertalot Medical Services Ltd | Health & social care | 2013 |
| Berwyn Medical Services Ltd | Health & social care | 2014 |
| Bespoke Scaffold Design Limited | Professional & scientific | 2011 |
| Beyond 90 Analysis Limited | Information & communication | 2026 |
| Bisby Accountancy Ltd | Professional & scientific | 2023 |
| Bistro Bach Limited | Hospitality | 2018 |
| Bizon Geological Consulting Limited | Professional & scientific | 2017 |
| BLAKES03 IT Services Ltd | Information & communication | 2015 |
| Blink Optical Limited | Extraterritorial | 2014 |
| Bloci Ltd | Information & communication | 2021 |
| Block 7 Management Company Limited | Households | 2024 |
| Blue Claw Rugs Ltd | Manufacturing | 2025 |
| Blue FOX Technology Limited | Information & communication | 2006 |
| Blue Turtle Group Ltd | Wholesale & retail | 2022 |
| Bluegrid Services Ltd | Energy | 2025 |
| Bluerock Automation Ltd | Manufacturing | 2014 |
| BMK Creation Limited | Extraterritorial | 2015 |
| BOB Parry (Survey & Valuation) Limited | Real estate | 2001 |
| BOD Diddan (Llandudno) Management Company Limited | Households | 2016 |
| Bodafon Properties Limited | Real estate | 2025 |
| Bodhyfryd Road 1967 Limited | Extraterritorial | 2014 |
| Bondfigure Projects Limited | Real estate | 1993 |
| Boots Hearingcare Limited | Health & social care | 1964 |
| Borras DRY Cleaners & Laundrette Limited | Other services | 2015 |
| Botanical Babe Ltd | Wholesale & retail | 2023 |
| Boughen & Edwards Limited | Wholesale & retail | 2026 |
| Boulton Financial Services Limited | Administrative & support | 2007 |
| Boulton Wealth Management Ltd | Real estate | 2013 |
| Bowclass Limited | Households | 1985 |
| Box Manchester Limited | Other services | 2015 |
| BP Dews Building Contractors Limited | Construction | 2017 |
| BR Care Ltd | Health & social care | 2022 |
| Brass TAP Holdings Ltd | Hospitality | 2025 |
| Brazen Body Piercings Limited | Other services | 2021 |
| Breach Block Ltd | Information & communication | 2024 |
| Broadway Court (Craig Y DON) Management Company Limited | Administrative & support | 2012 |
| Broadway Enterprises Limited | Real estate | 1972 |
| Brock & Co Accounting Ltd | Professional & scientific | 2015 |
| Brucecarey Ltd | Manufacturing | 2026 |
| Bryn Dowsi Limited | Real estate | 2008 |
| Bryn Estyn Badminton Centre Limited | Arts & recreation | 1986 |
| Bryn Mawr Limited | Professional & scientific | 2012 |
| Bryn Vardre Management Company Limited | Real estate | 1995 |
| Bryn Y BIA Management Company Limited | Households | 2001 |
| Buckley's Mobile Crane Service Ltd | Extraterritorial | 2009 |
| Burrow Estates Limited | Real estate | 2018 |
| Butterflies of Deganwy Limited | Education | 2004 |
| Butterworths Accountants Limited | Extraterritorial | 2004 |
| Butts Clough Limited | Real estate | 1990 |
| C 'N' C Crafts Ltd | Wholesale & retail | 2006 |
| C Lloyd Window Cleaning Ltd | Administrative & support | 2025 |
| C P Services (North Wales) Limited | Professional & scientific | 2011 |
| C S Audio Limited | Information & communication | 2016 |
| C Tile Limited | Construction | 2003 |
| C V Cottages Ltd | Hospitality | 2025 |
| C. LM Marine Services Limited | Manufacturing | 2011 |
| C.Anh. Properties Limited | Real estate | 2017 |
| Cadfan Computing Limited | Information & communication | 1989 |
| Caer Arianrhod CYF | Health & social care | 2023 |
| Calon LAN Community Care Ltd | Health & social care | 2005 |
| Cambiar Tech Limited | Information & communication | 2023 |
| Cambria Lodge Ltd | Education | 2013 |
| Cambrian Business Park Ltd | Real estate | 2023 |
| Cambrian Property Holdings Limited | Professional & scientific | 1987 |
| CAN Y BAE Hotel Limited | Hospitality | 2023 |
| Cape Wrath Capital Limited | Financial services | 2015 |
| Car Hub Wales Ltd | Wholesale & retail | 2022 |
| Caravan Letting Services (NW) Ltd | Real estate | 2016 |
| Caravanalia Ltd | Manufacturing | 2017 |
| Caravans Direct (NW) Limited | Wholesale & retail | 2006 |
| Carbon Account Ltd | Information & communication | 2022 |
| Carbon Nexus Group Ltd | Financial services | 2017 |
| Carey Enterprise Ltd | Manufacturing | 2025 |
| Cariad Cottages Ltd | Households | 2023 |
| Carlyn Management Limited | Households | 2006 |
| Carmens Asian Mini Market Limited | Wholesale & retail | 2009 |
| Casanova Italian Restaurant Ltd | Hospitality | 2010 |
| CASH28 Ltd | Wholesale & retail | 2025 |
| Cateuk Ltd | Health & social care | 2023 |
| Cayaran Ltd | Hospitality | 2016 |