| Casa Management Services Limited | Administrative & support | 2022 |
| Casa Parmigiana (Bracknell) Ltd | Hospitality | 2025 |
| Cashflow Investments Limited | Information & communication | 2004 |
| Casper Holdings RG Ltd | Extraterritorial | 2022 |
| Casper Sourcing Ltd | Real estate | 2022 |
| Caspian Pegasus Enterprises Ltd | Information & communication | 2025 |
| Cast Leadership Development Ltd | Professional & scientific | 2019 |
| Castan Digital Limited | Information & communication | 2026 |
| Castle Income Plus Ltd | Information & communication | 2017 |
| Castle Rock Design & Build Ltd | Construction | 2016 |
| Castle Rock Landscapes Limited | Other services | 2019 |
| Catalin Junior Limited | Wholesale & retail | 2019 |
| Cater the Estate Ltd | Hospitality | 2025 |
| Cawood Scientific Holdings Limited | Financial services | 2021 |
| CBB Electrical Ltd | Construction | 2019 |
| Cc&B Services Ltd | Administrative & support | 2025 |
| CCG Contracts Limited | Extraterritorial | 2003 |
| Ccnb Property Ltd | Real estate | 2025 |
| CCS (SL) Ltd | Hospitality | 2019 |
| Ccts Properties Ltd | Real estate | 2023 |
| CCW Medical Services Limited | Health & social care | 2024 |
| Ceilidh Cleaning & Maintenance Services Limited | Administrative & support | 2014 |
| Celeritas Construction Ltd | Construction | 2025 |
| Celesse Ltd | Information & communication | 2023 |
| Celia Gibson QA Ltd | Professional & scientific | 2018 |
| Cell Telecom Limited | Extraterritorial | 2000 |
| Centrilogic Ltd | Information & communication | 2011 |
| Certa Safety Limited | Professional & scientific | 2015 |
| Cestrian Partnership Limited | Real estate | 2026 |
| CG Groundcare Limited | Administrative & support | 2017 |
| CG Momentum Limited | Professional & scientific | 2026 |
| CH Architech Limited | Professional & scientific | 2011 |
| CH Square Ltd | Manufacturing | 2024 |
| Chamarielle Ltd | Real estate | 2021 |
| Champion Coaching Ltd | Education | 2024 |
| Chance to Dance Stars Community Interest Company | Health & social care | 2018 |
| Chandi Care UK Ltd | Public administration | 2024 |
| Chanin Luke Limited | Education | 2020 |
| Charlie Consultancy Ltd | Professional & scientific | 2023 |
| Charpai Limited | Information & communication | 2023 |
| CHEF2TABLE Limited | Hospitality | 2017 |
| Chemtra Limited | Other services | 2018 |
| Cherix Technology Ltd | Information & communication | 2025 |
| Chic Booty Ltd | Wholesale & retail | 2025 |
| Chigley Consulting Ltd | Professional & scientific | 2014 |
| Child Autism UK | Education | 1997 |
| Chill OUT in Croatia Limited | Administrative & support | 2003 |
| Chill OUT! Event Management Ltd | Administrative & support | 2004 |
| Chilston Solutions Ltd | Arts & recreation | 2022 |
| Chiltern Referrals Limited | Professional & scientific | 2015 |
| Chimku Limited | Wholesale & retail | 2018 |
| Chin Barr Holding Limited | Financial services | 2021 |
| Chin Barr Trading Limited | Health & social care | 2021 |
| Chivers Sports and Landscapes Limited | Arts & recreation | 2004 |
| Chives Place Management Company Limited | Professional & scientific | 2003 |
| Choice Care Group 2 Limited | Health & social care | 2013 |
| Choice Care Group 3 Limited | Health & social care | 2013 |
| Choice Care Group Holdings Limited | Health & social care | 2013 |
| Choice Care Group Limited | Extraterritorial | 2003 |
| Choice Care Limited | Health & social care | 2020 |
| Choice Holdings Limited | Health & social care | 2001 |
| Choice Pathways Limited | Health & social care | 2009 |
| Choir Global Ltd | Financial services | 2026 |
| Choral Clinical Services Ltd | Health & social care | 2026 |
| Choral Performance Ltd | Wholesale & retail | 2026 |
| Chris Faerber Consulting LLP | | 2023 |
| Chris Pine Consulting Limited | Information & communication | 2009 |
| Chrome Crusaders Ltd | Arts & recreation | 2024 |
| Chrysolite Housing Limited | Real estate | 2023 |
| Church Green Residents Association Limited | Households | 1967 |
| Churchill Autoglazing Ltd | Wholesale & retail | 2023 |
| Churchill Swartz Limited | Wholesale & retail | 2025 |
| CIB Recruitment Ltd | Administrative & support | 2018 |
| Cirrac Limited | Professional & scientific | 2010 |
| Citizens Advice East Berkshire Limited | Health & social care | 1997 |
| City Scooter Ltd | Administrative & support | 2024 |
| City Technology Limited | Manufacturing | 1977 |
| Civinci II Ltd | Information & communication | 2022 |
| Civitanavi Systems UK Ltd | Professional & scientific | 2020 |
| CJJ Chauffeurs Ltd | Transport & logistics | 2017 |
| CJJ Coaches Limited | Transport & logistics | 2019 |
| CJL Technology Solutions Ltd | Information & communication | 2022 |
| Cjrtraining Ltd | Arts & recreation | 2025 |
| CJT Technologies Ltd | Information & communication | 2016 |
| Ckaf Ltd | Hospitality | 2014 |
| Clann.Io Limited | Information & communication | 2026 |
| Clarkescleaners Ltd | Administrative & support | 2024 |
| Clark’S Cutting Services Ltd | Other services | 2026 |
| Classic London Taxis Ltd | Transport & logistics | 2021 |
| Classicstone Properties Limited | Real estate | 1989 |
| Classicworth Limited | Administrative & support | 2015 |
| Claudia ANG Ltd | Construction | 2013 |
| Claudia’S Cosmetic Clinic Limited | Other services | 2021 |
| Clayton & Reichelt LLP | | 2016 |
| Cleanhome Limited | Other services | 2007 |
| Cleansuper Limited | Administrative & support | 2015 |
| Cleanups Limited | Information & communication | 2009 |
| Clearsoft Solutions Limited | Information & communication | 2016 |
| Clever Retail Ltd | Wholesale & retail | 2019 |
| CLH Roofline Limited | Construction | 2021 |