| Castle Wharf Management Limited | Real estate | 2021 |
| Castle Yard Management Company Limited | Real estate | 2008 |
| Castlebell Limited | Professional & scientific | 1999 |
| Castlebond Limited | Real estate | 1983 |
| Castlebuild Limited | Other services | 2018 |
| Castleby Ltd | Real estate | 2024 |
| Castlefield Advisory Partners Limited | Financial services | 2008 |
| Castlefield Assets Limited | Real estate | 2015 |
| Castlefield Commercial Property Services Ltd | Households | 2021 |
| Castlefield Commercial Property Storage Ltd | Transport & logistics | 2025 |
| Castlefield Developments (Manchester) Limited | Construction | 2013 |
| Castlefield Distillery Limited | Manufacturing | 2021 |
| Castlefield Estates Limited | Real estate | 1981 |
| Castlefield Gallery | Arts & recreation | 1984 |
| Castlefield Gate Management Company Limited | Households | 2001 |
| Castlefield Holdings Limited | Financial services | 2015 |
| Castlefield Hospitality Limited | Hospitality | 2023 |
| Castlefield House Properties Limited | Real estate | 2016 |
| Castlefield Investment Partners LLP | | 2002 |
| Castlefield Locks Management Limited | Households | 2003 |
| Castlefield Media Ltd | Professional & scientific | 2012 |
| Castlefield Partners Limited | Financial services | 2009 |
| Castlefield Property Limited | Construction | 2017 |
| Castlefield Secretaries Limited | Extraterritorial | 1996 |
| Castlefield Warehousing Ltd | Transport & logistics | 2023 |
| Castlefield Wealth Management Limited | Extraterritorial | 2007 |
| Castleland Ltd | Real estate | 2003 |
| Castlepark Estates Ltd | Real estate | 2018 |
| Castlesprings Limited | Manufacturing | 2012 |
| Castletech Maintenance Ltd | Real estate | 1997 |
| Castlethorn Trading Limited | Wholesale & retail | 2019 |
| Castleton Property Ventures Ltd | Real estate | 2025 |
| Castleton Shawarma Ltd | Hospitality | 2025 |
| Castleview Estates UK Ltd | Real estate | 2004 |
| CASTLEVIEW09 Limited | Professional & scientific | 2022 |
| Castramrc Ltd | Wholesale & retail | 2020 |
| Casual Associates Ltd | Professional & scientific | 2011 |
| Casual Classic Ltd | Wholesale & retail | 2023 |
| Casual Restaurants Limited | Hospitality | 2013 |
| Casualking Ltd | Wholesale & retail | 2017 |
| Casuall Fashion Co., Ltd | Extraterritorial | 2019 |
| Casually Active Limited | Wholesale & retail | 2025 |
| Caswell Training Ltd | Information & communication | 2019 |
| Cat 1 (NW) Ltd | Administrative & support | 2015 |
| Cat O'Nine Tails Limited | Professional & scientific | 2025 |
| Cat of the EYE Ltd | Extraterritorial | 2025 |
| Cat Properties Ltd | Real estate | 2015 |
| Cat Settle Limited | Education | 2016 |
| Cat Settle Properties Ltd | Real estate | 2016 |
| Cat's Whiskers Productions Limited | Information & communication | 2008 |
| Catalina Swimwear Ltd | Wholesale & retail | 2025 |
| Catalloy Limited | Manufacturing | 1977 |
| Catalyse Global Ltd | Professional & scientific | 2024 |
| Catalysis Hubs Limited | Information & communication | 2025 |
| Catalyst 12 Ltd | Professional & scientific | 2025 |
| Catalyst Asset & Office Solutions Limited | Other services | 2003 |
| Catalyst Business Development Limited | Professional & scientific | 2002 |
| Catalyst Development Group Ltd | Education | 2026 |
| Catalyst Education (Lancashire) Limited | Professional & scientific | 2005 |
| Catalyst Education Limited | Professional & scientific | 2005 |
| Catalyst for International Services Limited | Extraterritorial | 2026 |
| Catalyst Healthcare (Manchester) Financing PLC | Health & social care | 2004 |
| Catalyst Healthcare (Manchester) Holdings Limited | Professional & scientific | 2002 |
| Catalyst Healthcare (Manchester) Limited | Professional & scientific | 2002 |
| Catalyst Healthcare (Romford) Financing PLC. | Health & social care | 2003 |
| Catalyst Healthcare (Romford) Holdings Limited | Health & social care | 2003 |
| Catalyst Healthcare (Romford) Limited | Health & social care | 2003 |
| Catalyst Higher Education (Sheffield) Holdings Limited | Real estate | 2005 |
| Catalyst Higher Education (Sheffield) PLC | Education | 2005 |
| Catalyst Informatics Ltd | Information & communication | 2025 |
| Catalyst Information Services Ltd | Professional & scientific | 2008 |
| Catalyst Otis Limited | Financial services | 2003 |
| Catalyst People Development Limited | Professional & scientific | 2003 |
| Catalyst Quail Limited | Financial services | 2001 |
| Catalyst Realm for Investment Ltd | Extraterritorial | 2025 |
| Catalyst Talent Ltd | Administrative & support | 2025 |
| Catalyst X Ltd | Information & communication | 2023 |
| Catatumbo Housing Ltd | Real estate | 2026 |
| Catch Properties Ltd | Real estate | 2019 |
| Catch the Mice Limited | Professional & scientific | 2019 |
| Catchmix Ltd | Wholesale & retail | 2022 |
| Catchpro Limited | Extraterritorial | 2008 |
| Catella Apam Capital Partners Limited | Financial services | 2023 |
| Catella Capital Limited | Financial services | 2023 |
| Catering Concessions Ltd | Hospitality | 2024 |
| Catering Fresh Limited | Wholesale & retail | 2025 |
| Catering Lily on Diet UK Ltd | Hospitality | 2016 |
| Cateringforu Ltd | Hospitality | 2016 |
| Cateringsupplier Ltd | Hospitality | 2022 |
| Catermatch Solutions Ltd | Administrative & support | 2006 |
| Caterpillars Day Nursery Ltd | Health & social care | 2013 |
| Caterpro Engineering Services Ltd | Manufacturing | 2018 |
| Cathay Industrial Ltd | Extraterritorial | 2012 |
| Cathcart & Co Consultancy Ltd | Professional & scientific | 2026 |
| Cathcart Catering & Events Ltd | Hospitality | 2023 |
| Cathedral Arches Limited | Hospitality | 2011 |
| Cathedral Jewellers Manchester Limited | Wholesale & retail | 2013 |
| Cathedral Park Developments Ltd. | Real estate | 2007 |
| Catherine Court Property Management Limited | Administrative & support | 1995 |
| Catherine Mackey - Travel Counsellors Limited | Administrative & support | 2025 |