| Cicero Holdings Limited | London | 2019 |
| Cicerone SDV Ltd | London | 2022 |
| Cicfof Limited | Cambridge | 2023 |
| Cici Lulu Limited | Stoke-On-Trent | 2025 |
| Ciconia Group Holding Ltd | Egham | 2023 |
| CID Capital Ltd | London | 2025 |
| Cida Investments Limited | Milton Keynes | 2024 |
| Cider Barn Projects Ltd | Shepton Mallet | 2026 |
| Cidron Arlberg Topco Limited | London | 2024 |
| Cidron Morrison Bidco Limited | Fareham | 2026 |
| Cidron Neptune Bidco Limited | Bolton | 2020 |
| Cidron Neptune Midco Limited | Bolton | 2020 |
| Cidron Neptune Topco Limited | Bolton | 2020 |
| Cidron Sonar Holdco Limited | London | 2026 |
| Cidron Sonar Midco Limited | London | 2026 |
| Cidron Talon Bidco Limited | London | 2026 |
| Cidron Victor Bidco Limited | Fareham | 2026 |
| Cidron Victor Midco Limited | Fareham | 2026 |
| CIE Partners Services Limited | London | 2025 |
| CIE UK (Holdings) Ltd | Grays | 1988 |
| Cie-Group Holdings Limited | Nottingham | 2022 |
| CIEF1 UK Holdings Limited | London | 2018 |
| Cielo Azul Ltd | Wallingford | 2017 |
| Cielo Bidco Limited | Cradley Heath | 2025 |
| Cielo Group Ltd | Virginia Water | 2016 |
| Cielo Holdco Limited | Cradley Heath | 2025 |
| Cielo Midco 1 Limited | Cradley Heath | 2025 |
| Cielo Midco 2 Limited | Cradley Heath | 2025 |
| Cielo Topco Limited | Cradley Heath | 2025 |
| Cien Ltd | London | 2026 |
| Cienna Limited | Leicester | 2013 |
| Ciep Spin Midco 1 Ltd | London | 2024 |
| Ciep Spin Midco 2 Ltd | London | 2024 |
| Cierco International Limited | London | 2021 |
| CIF Capital Markets Mechanism Holdco Limited | London | 2024 |
| CIF Capital Markets Mechanism PLC | London | 2024 |
| CIF Group Limited | Liverpool | 2022 |
| Cifa+ Limited | Rugeley | 2018 |
| Cifc Asset Management Europe Ltd | London | 2017 |
| Cifco Ltd | Berkhamsted | 2012 |
| Ciff General Partner Limited | London | 2020 |
| Cifo Limited | County Durham | 2024 |
| CIG (UK) Holdings and Investments Ltd | Dudley | 2024 |
| CIG (UK) Legal & Investments Ltd | Dudley | 2025 |
| CIG Group Ltd | Slough | 2025 |
| CIG Group Properties Ltd | Wrexham | 2023 |
| CIG Holdings Ltd | Wymondham | 2017 |
| Ciga Healthcare (Holdings) Limited | Ballymena | 2012 |
| Ciga Holdings Limited | Ballymena | 2025 |
| Cigara Holdings Ltd | Blackburn | 2021 |
| Ciggyjuice Group Ltd | Romsey | 2018 |
| Cigh Ltd | Leamington Spa | 2024 |
| Cigna 2000 UK Pension Limited | Greenock | 1999 |
| Cigna Chestnut Holdings, Ltd | London | 2013 |
| Cigna European Services (UK) Limited | London | 1924 |
| Cigna Insurance Services (Europe) Limited | London | 2002 |
| Cigna Legal Protection UK Ltd | London | 2010 |
| Cigna Oak Holdings Ltd | London | 2003 |
| Cigna Walnut Holdings, Ltd. | London | 2014 |
| Cigna Willow Holdings Ltd | London | 2002 |
| Cigno Holdings Ltd | Swansea | 2019 |
| Cignpost Advised Limited | Godalming | 2001 |
| Cignpost Corporate Limited | Godalming | 2024 |
| Cignpost Services Limited | Godalming | 2014 |
| CIH Enterprises Limited | Wisbech | 2024 |
| CIH Limited | Arnold | 2026 |
| CII Holdco Ltd | Rotherham | 2013 |
| CIK Financial Ltd | Daventry | 2019 |
| Ciklum Holding UK Limited | London | 2017 |
| Ciko Estates Kent Ltd | Canterbury | 2025 |
| Ciko Holding Kent Ltd | Canterbury | 2025 |
| CIL Financial Services Limited | Sutton Coldfield | 2019 |
| CIL Management Ltd | Belfast | 2023 |
| CIL UK Holdings Limited | Middlesex | 2019 |
| Cilantro Bidco Ltd | London | 2021 |
| Cilantro Holding Ltd | London | 2021 |
| Cilantro Midco Ltd | London | 2021 |
| Cilar Finance Limited | Binfield, Bracknell | 2014 |
| Cilbenrick Limited | Swansea | 2004 |
| Cildarn Limited | Coleshill | 2008 |
| Cilh Holdings Limited | Bootle | 2019 |
| Cilldara Group Holdings Ltd | Henley-In-Arden | 2019 |
| Cillion Consulting Limited | Bexley | 2017 |
| Cils Barnsley Limited | London | 2022 |
| Cils Belvedere Limited | London | 2022 |
| Cils Ellesmere Port Limited | London | 2022 |
| Cils Leighton Buzzard Limited | London | 2022 |
| Cils Milton Limited | London | 2022 |
| Cils Peterborough Limited | London | 2022 |
| Cils Sherburn Limited | London | 2022 |
| CILS1 UK Holdings Limited | London | 2022 |
| Cilvrr Investments Ltd | London | 2025 |
| CIM Global Financial Limited | London | 2026 |
| CIM Bristol Co-Living Holdings Limited | London | 2024 |
| CIM Bristol Holdings Limited | London | 2024 |
| CIM CSL GP Limited | London | 2024 |
| CIM Financial Group Limited | London | 2025 |
| CIM Group Holdings Ltd | Southampton | 2025 |
| CIM Leeds Holdings Limited | London | 2023 |
| CIM Manchester Holdings Limited | London | 2023 |