| Carpetfix Ltd | Wholesale & retail | 2021 |
| Carplounge UK Ltd | Wholesale & retail | 2020 |
| Carr Wealth Management Limited | Financial services | 2007 |
| Carr's Psychology Services Ltd | Health & social care | 2024 |
| Carrera Projects Limited | Professional & scientific | 2021 |
| Carriage Express Ltd | Transport & logistics | 2021 |
| Carriage Solutions Ltd | Administrative & support | 2016 |
| Carrick Thomson Limited | Manufacturing | 2014 |
| Carringtons Law Ltd | Professional & scientific | 2012 |
| Carroll Noon Group Ltd | Manufacturing | 2026 |
| Carry My Cross Ltd | Health & social care | 2020 |
| Cars & Wheels Ltd | Wholesale & retail | 2024 |
| Cars 4 Less (Derbyshire) Limited | Wholesale & retail | 2004 |
| Cars Empire Ltd | Wholesale & retail | 2022 |
| Cars Plant Commercial Ltd | Wholesale & retail | 2019 |
| Cars R US Notts Ltd | Wholesale & retail | 2026 |
| Carsignal Ltd | Information & communication | 2021 |
| Carsons Property Maintenance Ltd | Real estate | 2021 |
| Carta Real Estate (Bedford) Limited | Construction | 2018 |
| Carta Real Estate (Boston) Limited | Construction | 2017 |
| Carta Real Estate (Brackley) Limited | Construction | 2017 |
| Carta Real Estate (Tuxford) Limited | Construction | 2019 |
| Cartenna Holdings Ltd | Real estate | 2026 |
| Carter Advisory Ltd | Professional & scientific | 2026 |
| Carter Bond & Co Ltd | Administrative & support | 2014 |
| Cartilac Limited | Hospitality | 2017 |
| Cartmell Drive Management Limited | Households | 2017 |
| Cartolanos Ltd | Hospitality | 2019 |
| Carton Design Limited | Professional & scientific | 2010 |
| Cartwheel Coffee Roasters Ltd | Manufacturing | 2020 |
| Cartwheel Recruitment Limited | Administrative & support | 2006 |
| Cartwright PR Limited | Professional & scientific | 2009 |
| CAS Contracting Ltd | Construction | 2023 |
| CAS Engineering Services (UK) Limited | Professional & scientific | 2023 |
| Casa & Grill Ltd | Hospitality | 2026 |
| Casa Agave Ltd | Wholesale & retail | 2015 |
| Casa Bake Ltd | Manufacturing | 2026 |
| Casa Crystal Limited | Wholesale & retail | 2021 |
| Casa DEL Pluto Ltd | Hospitality | 2023 |
| Casa Dwellings UK Ltd | Real estate | 2023 |
| Casa Grange Limited | Real estate | 2024 |
| Casa Hair & Beauty Limited | Other services | 2004 |
| Casa Mairena Limited | Real estate | 2025 |
| Casa Mamma Maria Ltd | Hospitality | 2023 |
| Casa Nottingham Ltd | Hospitality | 2019 |
| Casa Nueva Music Ltd | Arts & recreation | 2025 |
| Casa Serenity Ltd | Health & social care | 2023 |
| Casa Silva Ltd | Real estate | 2024 |
| Casa UK Mortgages Ltd | Financial services | 2025 |
| Casa Uniqua Limited | Wholesale & retail | 2013 |
| Casa VO Ltd | Real estate | 2023 |
| Casa-Grange a Ltd | Real estate | 2024 |
| Casagwa Limited | Health & social care | 2023 |
| Casanots Enterprises Limited | Information & communication | 2006 |
| Casapalla Ltd | Real estate | 2025 |
| Casbridge (Notts) Ltd | Real estate | 2009 |
| Casca Limited | Extraterritorial | 2013 |
| Casciani Evans Wood Limited | Information & communication | 2003 |
| Case Canvas Ltd | Wholesale & retail | 2026 |
| Case Management Enterprises Ltd | Education | 2025 |
| Case Management Society UK | Health & social care | 2001 |
| Cash & Cash Properties Ltd | Wholesale & retail | 2016 |
| Cash Clothing Ltd | Wholesale & retail | 2021 |
| Cash GEN Arnold Ltd | Administrative & support | 2024 |
| Cash Shop Ltd | Financial services | 2004 |
| Casper Building Limited | Construction | 2021 |
| Casper-I Ltd | Wholesale & retail | 2016 |
| Caspian Takeaway Limited | Hospitality | 2022 |
| Cassandra Tenkorang Ltd | Health & social care | 2023 |
| Cassco Holdings Limited | Professional & scientific | 2005 |
| Cassco Investments Limited | Hospitality | 2003 |
| Cassco Ortongate Limited | Administrative & support | 2023 |
| Cassell Holdings Ltd | Financial services | 2024 |
| Casserole House Limited | Hospitality | 2024 |
| Cassey Landscapes Ltd. | Construction | 2005 |
| Cassidy Consultants Limited | Administrative & support | 2020 |
| Cassonder Limited | Administrative & support | 2024 |
| Cast Angling Projects Community Interest Company | Education | 2014 |
| Castcsi Limited | Information & communication | 2009 |
| Castec Consulting Limited | Professional & scientific | 2017 |
| Castelano Ltd | Manufacturing | 2023 |
| Castillo Corporation Ltd | Real estate | 2024 |
| Castle & Spire Properties Ltd | Real estate | 2022 |
| Castle Accounting Limited | Professional & scientific | 2017 |
| Castle Alliances Limited | Administrative & support | 2011 |
| Castle Associates Employment Law Limited | Administrative & support | 2011 |
| Castle Bar Properties Limited | Construction | 2001 |
| Castle Boulevard Holdings Limited | Real estate | 2014 |
| Castle Brewery (Newark) RTM Company Limited | Households | 2023 |
| Castle Brewery Management Company Limited | Households | 2002 |
| Castle Catering Engineers Ltd | Manufacturing | 2016 |
| Castle Catering Equipment Ltd | Wholesale & retail | 2018 |
| Castle Donington Eyecare Limited | Health & social care | 2022 |
| Castle Electromagnetic Compatibility Ltd | Construction | 2020 |
| Castle Engineering Co. (Bolsover) Limited | Manufacturing | 1988 |
| Castle Estates (Nottingham) Holdings Limited | Financial services | 2026 |
| Castle Estates (Nottingham) Limited | Real estate | 2009 |
| Castle Financial Solutions Ltd | Financial services | 2011 |
| Castle Gate House (Nottingham) Ltd | Construction | 2024 |
| Castle Gate Legal and Commercial Limited | Professional & scientific | 2014 |