| Christening Corner Ltd | Wholesale & retail | 2022 |
| Christian Hope Ministries International Church Ltd | Other services | 2024 |
| Christianarianna Limited | Health & social care | 2026 |
| Chromium Construction Limited | Construction | 2024 |
| Chubb's House Limited | Extraterritorial | 2006 |
| Chuckit UP Scaffolding Ltd | Construction | 2026 |
| Chudleigh Construction Limited | Construction | 2003 |
| Chunk Media Ltd | Information & communication | 2025 |
| Chunky Traders Ltd | Hospitality | 2025 |
| Churchgate Estates Limited | Professional & scientific | 1996 |
| Churchgate Land Limited | Construction | 2011 |
| Churchgate Woking Ltd | Construction | 2017 |
| Churchill & Mathews Property Investments Ltd | Real estate | 2018 |
| Churchthing Limited | Other services | 2014 |
| Churn Services Limited | Information & communication | 2012 |
| Chycrest Developments Limited | Construction | 2014 |
| CI Elite Electrical Ltd | Construction | 2020 |
| Ciaan Ltd | Real estate | 2021 |
| Cian Glazing & Maintenance Ltd | Construction | 2022 |
| Ciana Investment Limited | Real estate | 2018 |
| CIJ Groundworks Limited | Construction | 2025 |
| CIN Ground Work Ltd | Construction | 2021 |
| Cinct Ltd | Information & communication | 2018 |
| Cinnacare Limited | Wholesale & retail | 2025 |
| Cinnaminna Limited | Wholesale & retail | 2023 |
| Cinox Enterprise Ltd | Real estate | 2017 |
| Cinox Healthcare Ltd | Health & social care | 2018 |
| Cinox Healthcare Recruitment Ltd | Administrative & support | 2024 |
| Cinox Housing Community Interest Company | Health & social care | 2024 |
| Ciobanu Property Improvements Ltd | Construction | 2017 |
| Ciobanu Property Investment Ltd | Real estate | 2025 |
| Cipa Solutions Ltd | Transport & logistics | 2016 |
| Ciprian Ghenta Ltd | Construction | 2015 |
| Circle Circle Films Limited | Information & communication | 2017 |
| Circle of Care Ltd | Health & social care | 2026 |
| Circular Networks Ltd | Information & communication | 2016 |
| Cirronex Ltd | Information & communication | 2025 |
| Cital Consultancy Services Limited | Professional & scientific | 2026 |
| Citi Capital Ltd | Real estate | 2020 |
| Citi Holdings Group Ltd | Real estate | 2024 |
| Citi Holdings Ltd | Administrative & support | 2021 |
| Citi Residences Ltd | Real estate | 2026 |
| Cities on Hills Ltd | Arts & recreation | 2022 |
| Citiscape Developments Limited | Construction | 2002 |
| Citiscape Mill Ltd | Financial services | 2025 |
| Citizens Wellbeing Intervention Limited | Health & social care | 2024 |
| City 44 Properties Limited | Real estate | 2020 |
| City Capital Management Ltd | Real estate | 2017 |
| City Care and Support Limited | Health & social care | 2024 |
| City Castle Ltd | Real estate | 2025 |
| City Data Services Technology Limited | Professional & scientific | 2015 |
| City Fire Proofing Ltd | Other services | 2016 |
| City Goddess Limited | Manufacturing | 2003 |
| City Law Chambers (London) Ltd | Professional & scientific | 2025 |
| City Media London Limited | Information & communication | 2026 |
| City of London Education Centres Ltd | Education | 2016 |
| City on a Hill Consul Ltd | Health & social care | 2021 |
| City on a Hill Propriétés Limited | Real estate | 2024 |
| City Paws Ltd | Other services | 2021 |
| City Place Ltd | Hospitality | 2019 |
| City Plumbers & Constructions Ltd | Construction | 2021 |
| City Rope Access Ltd | Construction | 2017 |
| City Services (London) Ltd | Real estate | 2019 |
| City Smart Cruise Limited | Transport & logistics | 2025 |
| CITY2STAY Ltd | Real estate | 2020 |
| Citycomfort Ltd | Hospitality | 2024 |
| Cityease International Ltd | Education | 2024 |
| Cityglen Investment Group Limited | Real estate | 2019 |
| Cityglen Limited | Hospitality | 2000 |
| Cityglen Properties Ltd | Real estate | 2024 |
| Cityglen PUB Co. Limited | Hospitality | 2001 |
| Citymize Estates Ltd | Real estate | 2023 |
| Cityprime Developments Limited | Construction | 2026 |
| Citysite Construction Limited | Construction | 2007 |
| Citywide Garages & Recovery Limited | Wholesale & retail | 2025 |
| Cityzen Rentals Ltd | Real estate | 2024 |
| Civistra Ltd | Information & communication | 2025 |
| Cizservices Ltd | Administrative & support | 2022 |
| CJ & AW Smith Holdings LLP | | 2016 |
| CJB Decorators Ltd | Construction | 2024 |
| CJL Arts Ltd | Arts & recreation | 2015 |
| CJX Premier Consulting Ltd | Information & communication | 2010 |
| Ckan Solutions Limited | Information & communication | 2016 |
| CKS Services Group Ltd | Administrative & support | 2024 |
| CKU Care Ltd | Health & social care | 2024 |
| CL Glazing Surveyors Limited | Construction | 2012 |
| CL Shipping London Ltd | Other services | 2026 |
| Claassen Limited | Real estate | 2020 |
| Clad Service Ltd | Construction | 2023 |
| Claddagh Care Ltd | Health & social care | 2026 |
| Claddinstall Limited | Construction | 2020 |
| Claire Trade Ltd | Wholesale & retail | 2025 |
| Clandel UK Limited | Professional & scientific | 2012 |
| Clara Locus Ltd | Construction | 2019 |
| Clara Wells Limited | Administrative & support | 2025 |
| Clarence Green College Ltd | Education | 2022 |
| Clarence Healthcare Services Ltd | Administrative & support | 2022 |
| Clarity Counselling Ltd | Health & social care | 2018 |
| Clarity Housing Limited | Households | 2021 |
| Clarity Property Care Ltd | Administrative & support | 2026 |