| Castle Gate Residential (Nottingham) Ltd | Real estate | 2023 |
| Castle Green Real Estate Limited | Construction | 2024 |
| Castle Gym Limited | Arts & recreation | 2022 |
| Castle Heights Ltd | Real estate | 2016 |
| Castle Homes Property Group Ltd | Real estate | 2024 |
| Castle Lock (2020) Limited | Hospitality | 2020 |
| Castle Marinas Limited | Real estate | 2006 |
| Castle Marinas One Limited | Arts & recreation | 2011 |
| Castle Marinas Three Limited | Arts & recreation | 2014 |
| Castle Oak Lettings Ltd | Real estate | 2025 |
| Castle Orthopaedic Partners LLP | | 2019 |
| Castle Park View Ltd | Construction | 2023 |
| Castle Rock Brewery Ltd | Extraterritorial | 1997 |
| Castle Rock Carpentry and Construction Ltd | Construction | 2025 |
| Castle Rock Commercial Finance Ltd | Financial services | 2024 |
| Castle Rock Financial Planning Ltd | Financial services | 2019 |
| Castle Rock Projects Ltd | Real estate | 2021 |
| Castle Scaffolding Hire Ltd | Construction | 2024 |
| Castle Smart Homes Ltd | Extraterritorial | 2024 |
| Castle Sound & Vision Limited | Wholesale & retail | 1997 |
| Castle View Terrace Ltd | Hospitality | 2026 |
| Castle Wharf Limited | Real estate | 2021 |
| Castle Will Writers Ltd | Professional & scientific | 2013 |
| Castledene Property Management (Nottingham) Limited | Households | 2025 |
| Castlefield Dog Rescue CIC | Agriculture & fishing | 2022 |
| Castlefield Kennels Limited | Agriculture & fishing | 2014 |
| Castlegate 143 Limited | Extraterritorial | 1946 |
| Castlegate 587 Limited | Professional & scientific | 2010 |
| Castlegate 597 Limited | Wholesale & retail | 2010 |
| Castlegate 608 Limited | Real estate | 2010 |
| Castlegate 643 Limited | Construction | 2011 |
| Castlegate 789 Limited | Real estate | 2020 |
| Castlegate 801 Limited | Wholesale & retail | 2025 |
| Castlegate 802 Limited | Administrative & support | 2025 |
| Castlegate Capital Limited | Financial services | 2016 |
| Castlegate Financial Services Limited | Administrative & support | 2014 |
| Castlerock Developments Ltd | Real estate | 2018 |
| Castlerow Property Investments Limited | Construction | 2010 |
| Castri Ltd | Construction | 2025 |
| Castrovalva Limited | Information & communication | 2013 |
| Casual Brew Company Limited | Hospitality | 2024 |
| Casual Dining Group Limited | Hospitality | 2021 |
| Cat Autokeys Limited | Wholesale & retail | 2024 |
| Cat Catering Limited | Hospitality | 2023 |
| Cat Midlands Ltd | Construction | 2011 |
| Catalent Nottingham Limited | Professional & scientific | 1997 |
| Catalent UK Supply Chain Limited | Manufacturing | 1989 |
| Catalyst Commercial Limited | Professional & scientific | 2024 |
| Catalyst for Organisational Efficiency Ltd | Administrative & support | 2014 |
| Catalytic Recycling UK Ltd | Water & waste | 2015 |
| Catch the Vision Auto's Ltd | Wholesale & retail | 2024 |
| Catchems END Fish Bar Limited | Hospitality | 2012 |
| Catchfly (Nottingham) Limited | Professional & scientific | 2026 |
| Catdog Ltd | Wholesale & retail | 2022 |
| Cate Halstead Ltd | Health & social care | 2023 |
| Caten Ltd | Construction | 2018 |
| Catena Holding (UK) Ltd | Other services | 2014 |
| Catena Inspection & Engineering Services Limited | Manufacturing | 2009 |
| Catered Occasions Limited | Hospitality | 2025 |
| Catering by Taffy Limited | Hospitality | 2026 |
| Catering Equipment Depot Ltd | Wholesale & retail | 2020 |
| Catershield Services Limited | Hospitality | 2009 |
| Catharsis Creative Arts Therapy Ltd | Public administration | 2015 |
| Cathedral Holdings International (London) Limited | Financial services | 2020 |
| Cathedral Self Storage Ltd | Wholesale & retail | 2014 |
| Cathford Limited | Wholesale & retail | 1977 |
| Catholic Marriage Care Limited | Health & social care | 1946 |
| Catkin Enterprises Limited | Wholesale & retail | 2018 |
| Catt Composites Limited | Manufacturing | 2015 |
| Catterick Anzio Residents Company Limited | Households | 2005 |
| Caudwell Solutions Ltd | Information & communication | 2013 |
| Caudwell With Patel Properties Ltd | Real estate | 2019 |
| Caught & Bowled Ltd | Hospitality | 2017 |
| Caulfield Limited | Information & communication | 2011 |
| Caulk Estates Limited | Real estate | 1946 |
| Caulton Investment & Business Consultancy LLP | | 2022 |
| Caunton Engineering Limited | Manufacturing | 1969 |
| Caunton Holdings Limited | Financial services | 2008 |
| Caunton Investments Limited | Real estate | 1997 |
| Caunton Tennis Academy Ltd | Professional & scientific | 2016 |
| Caupo Ltd | Wholesale & retail | 2024 |
| Causality Health Ltd | Arts & recreation | 2025 |
| Cause & Effect Media Limited | Extraterritorial | 2013 |
| CAV Construction (Nottm) Ltd | Construction | 2021 |
| CAV Ltd. | Hospitality | 2014 |
| Cavalier Sheet Metal Works Limited | Manufacturing | 1978 |
| Cavalry Design Associates Limited | Professional & scientific | 2009 |
| Cavalry Design Limited | Extraterritorial | 2024 |
| Cavan Investments Limited | Real estate | 2015 |
| Cavan Properties Limited | Real estate | 2019 |
| Cavani Furniture Ltd | Extraterritorial | 2011 |
| Cavari Holdings Limited | Financial services | 2025 |
| Cavari Limited | Wholesale & retail | 2025 |
| Cave Escape Nottingham Limited | Arts & recreation | 2017 |
| Cave Justice Ltd | Professional & scientific | 2025 |
| Cave Plant Hire & Contractors Limited | Administrative & support | 2002 |
| Caveman Mapperley Ltd | Other services | 2021 |
| Caveman UK Barber Ltd | Other services | 2025 |
| Cavendish Auto Centre Limited | Wholesale & retail | 2006 |
| Cavendish Buildings (Wheeler Gate) Ltd | Construction | 2024 |