| Cirrostratus 3 Limited | Manchester | 2023 |
| Cirrus Assets Investments Limited | London | 2019 |
| Cirrus Connects Group Limited | Epsom | 2020 |
| Cirrus Logic International Holdings Ltd. | Newbury | 2018 |
| Cirrus Logic UK International Holding Co. Ltd. | Newbury | 2014 |
| Cirrus Trustees Limited | Harrogate | 2012 |
| CIS Africa Holdings Ltd | London | 2026 |
| CIS Group Holdings Ltd | St. Austell | 2020 |
| CIS Healthcare Limited | Oxford | 2006 |
| Cisg Distressed Holdings III Limited | Hemel Hempstead | 2024 |
| Cisive International Holdings, Ltd. | Manchester | 2018 |
| Cisl Holdings Ltd | Banstead | 2022 |
| Cisla Limited | Addlestone | 2015 |
| Cisnes Tech Holdings Ltd | London | 2020 |
| Cissac Holdings Ltd | Hemel Hempstead | 2024 |
| Cissbury Capital Ltd | Ascot | 2022 |
| Cissbury View Holdings Ltd | Penarth | 2024 |
| Cista Limited | Norwich | 2021 |
| Cisurv Group Ltd | Witney | 2026 |
| CIT (GGH) Limited | London | 2020 |
| CIT (SA) Limited | London | 2021 |
| CIT Capital Aviation (UK) Limited | London | 1996 |
| CIT Financial Services Limited | London | 1999 |
| CIT Investments Limited | London | 2015 |
| CIT Investments NO. 2 Limited | London | 2017 |
| CIT Jermyn Limited | London | 2019 |
| Cit-E Group Ltd | Birmingham | 2022 |
| Citadale Holdings Ltd | Leicester | 2024 |
| Citadel 2024-1 PLC | London | 2024 |
| Citadel Advisors Europe Limited | London | 2017 |
| Citadel Care Group Ltd | London | 2025 |
| Citadel Finance Limited | London | 1997 |
| Citadel Financial Intermediary Ltd | Croydon | 2015 |
| Citadel Financial Services Ltd | Nottingham | 2024 |
| Citadel Financial Solutions Limited | Honiton | 2009 |
| Citadel Holdings 2024-1 Limited | London | 2024 |
| Citadel Holdings PLC | London | 1997 |
| Citadel Homes (TC) Limited | Newcastle Upon Tyne | 2021 |
| Citadel International Holdings Ltd | London | 2025 |
| Citadel Property Company Ltd | Chester Le Street | 2021 |
| Citadel Risk Services UK Limited | London | 1979 |
| Citadel Securities (Europe) Limited | | 2005 |
| Citadel Securities Finance (UK) Limited | London | 2019 |
| Citadel UTB Limited | London | 2021 |
| Citara Holdings Limited | Abingdon | 2024 |
| Citation Capital Management Limited | London | 1999 |
| Citation Hero Limited | Wilmslow | 2023 |
| Citax Asset Management Limited | London | 2022 |
| Citco Custody (UK) Limited | London | 2015 |
| Citco Financial Products (London) Limited | | 2005 |
| Citco London Limited | | 1999 |
| Citco Management (UK) Limited | | 1991 |
| Citco Reif Services UK Limited | London | 1998 |
| Citcon UK Limited | Manchester | 2020 |
| Cite Investments Limited | Ipswich | 2009 |
| Citeco Group Ltd | Leeds | 2026 |
| Citex Factors Ltd | Manningtree | 2020 |
| Citi Equities Limited | London | 2020 |
| Citi Financing Ltd | Ilford | 2020 |
| Citi FX Limited | London | 2010 |
| Citi Group (Holdings) Ltd | Canterbury | 2023 |
| Citi Money Exchange London Limited | London | 2014 |
| Citi Remittance Services Ltd | London | 2021 |
| Citi Utilities Holdings Limited | Cheltenham | 2024 |
| Citi Venture Group Ltd | Harrow | 2017 |
| Citi Wealth Management Limited | London | 2022 |
| Citibank UK Limited | London | 2018 |
| Citibase Limited | London | 2020 |
| Citibid Securities Limited | London | 1987 |
| Citibox UK Ltd | London | 2024 |
| Citicapital Leasing (March) Limited | Canary Wharf | 1981 |
| Citiclient Nominees NO 9 Limited | Canary Wharf | 2006 |
| Citicorp Trustee Company Limited | Canary Wharf | 1928 |
| Citicourt & Co Limited | Fleet | 1991 |
| Citicourt Investments Limited | London | 2017 |
| Citidel Limited | London | 2014 |
| Cities Group Holdings Limited | Birmingham | 2014 |
| Cities UK Limited | Birmingham | 2004 |
| Citifinancial Europe Limited | London | 1978 |
| Citifinancial Mortgage Corporation | London | 1980 |
| Citiflex PLC | Leeds | 1997 |
| Citigroup Capital UK Limited | London | 1998 |
| Citigroup Global Markets Limited | Canary Wharf | 1983 |
| Citigroup Investment Services Limited | London | 2026 |
| Citigroup Participation Luxembourg Limited | London | 2001 |
| Citiko Ltd | London | 2026 |
| Citimount (Holdings) Ltd | Shenfield | 2024 |
| Citipark Management Limited | Leeds | 2014 |
| Citipark PLC | Leeds | 2014 |
| Citiplanners Limited | Telford | 2016 |
| Citipool Holdings Limited | Congleton | 2015 |
| Citipost Holdings Limited | Erith | 2016 |
| Citiscape Mill Ltd | Romford | 2025 |
| Citisense Holdings Ltd | London | 2022 |
| Citius Resources Limited | Rugby | 2025 |
| Citivale Group Holdings Ltd | Ripon | 2021 |
| Citiy Property UK Ltd | London | 2024 |
| Citizen Cosmetics Limited | London | 2017 |
| Citizen Holdings Limited | Kidderminster | 2016 |
| Citizen Kids Ltd. | London | 2019 |