| Cibn UK Branch | London | 2022 |
| Cibon Limited | London | 2010 |
| Cibrone Ltd | London | 2025 |
| Cibum Limited | Tunbridge Wells | 2014 |
| Cica and Co LDN Limited | Enfield | 2026 |
| Cicatrices Research Consulting Limited | Melton Mowbray | 2017 |
| Cicek Consultancy Ltd | Liverpool | 2005 |
| Cicero League of International Lawyers | Sutton | 2013 |
| Cicero's Hair Company Limited | Littlehampton | 2009 |
| Cicerone Ltd | Gateshead | 2025 |
| Cici Hair Salon Ltd | London | 2021 |
| Cici Nails and Spa Ltd | Penwortham | 2022 |
| Cici Salon Limited | Edinburgh | 2022 |
| Cici's Nail Bar Limited | Darlington | 2016 |
| Cici’S Beauty Lounge Ltd | Huddersfield | 2019 |
| Cicp Ltd | Manchester | 2019 |
| CID Beauty Ltd | Gloucester | 2026 |
| CID Lifestyle Ltd | London | 2020 |
| Cida Canine Training Ltd | Alresford | 2024 |
| Cidacrown Limited | London | 2002 |
| Cidarise-Euchariahorvarthne Ltd | Scunthorpe | 2023 |
| Ciddano Ltd | Dagenham | 2014 |
| CIE Management Services Limited | Fareham | 2014 |
| Cieax Limited | Birmingham | 2025 |
| Ciege Limited | London | 2018 |
| Ciekurs Ltd | Wishaw | 2024 |
| Ciel Aesthetics Limited | Windsor | 2025 |
| Cielepak Logistics Ltd | London | 2022 |
| Ciercle Ltd | London | 2025 |
| Cierco Holding Limited | Aberdour | 2018 |
| CIF (London) Ltd | Liverpool | 2020 |
| Cife Limited | London | 2021 |
| CIG Limited | Brough | 2025 |
| Cigaronne International Limited | Croydon | 2000 |
| Cigirex Limited | London | 2010 |
| Cigna Ltd | London | 2025 |
| Cignia Consulting Limited | Colchester | 2013 |
| Cigsal Beauty & Hair Ltd | London | 2025 |
| CIH Northwest Limited | Chester | 1984 |
| CIH South East Limited | Tadworth | 2012 |
| Cihan Werrington Ltd | London | 2024 |
| Cijc (Employers) Limited | Teddington | 2010 |
| Cikarts Ltd | Morden | 2023 |
| Cikizwa Ltd | Colchester | 2025 |
| CIL (It-Consulting) Limited | Reigate | 2017 |
| Cila Hairdressing Ltd | London | 2018 |
| Cilcennin Cyntaf | Lampeter | 2007 |
| Cilex Regulation Limited | Bedford | 2008 |
| Cilialight Ltd | Cardiff | 2024 |
| Cilip Pathways Limited | London | 2020 |
| Cill Mhanach Wellness CIC | Bathgate | 2017 |
| Cillamallia Hair & Beauty Ltd | Bedford | 2024 |
| Cilliacious Ltd | Northfleet / Gravesend | 2017 |
| Cillian Nails Ltd | Salford | 2017 |
| Cillus Ltd | Wrexham | 2017 |
| Cilos UK Services Ltd | Sutton | 2025 |
| CIM Enterprises Ltd | Maidenhead | 2004 |
| CIM Hair & Beauty Limited | Glasgow | 2026 |
| Cimacraft Limited | London | 2001 |
| Cimc Universal Tank Technologies (UK) Ltd | Skelmersdale | 2020 |
| Cimex Lectularius Limited | Stamford | 2013 |
| Cimexuk Ltd | Bishop Auckland | 2013 |
| CIN Ltd | Chatham | 2021 |
| Cina Barber Ltd | Nottingham | 2022 |
| Cinar Barber Ltd | Portsmouth | 2020 |
| Cinarali Ltd | Egham | 2022 |
| Cinch Outdoors Ltd | Morecambe | 2019 |
| Cinder's Gowns & Tailoring Ltd. | Newcastle Upon Tyne | 2015 |
| Cinderella Cardiff Limited | Bridgend | 2016 |
| Cinderella Nails and Beauty Ltd | Enfield | 2019 |
| Cinderella's Beauty Salon Ltd | London | 2006 |
| Cinderella's Cleaning Services (Oxford) Limited | Oxford | 2004 |
| Cinderella's Glasgow Ltd | Glasgow | 2019 |
| Cinderellalam Ltd | London | 2026 |
| Cinderellas Beauty Rooms Ltd | London | 2025 |
| Cinderella’S Laundry Ltd | Bognor Regis | 2022 |
| Cinderford Area Neighbourhood Development Initiative (C.A.N.D.I.) | Cinderford | 1996 |
| Cinderford Nails Ltd | Cinderford | 2021 |
| Cinders Beauty Clinic Ltd | Ashton-Under-Lyne | 2021 |
| Cindies Student Nights Ltd | Hitchin | 2021 |
| Cindy Hair Limited | Birmingham | 2026 |
| Cindy Nails & Beauty Limited | Burnley | 2018 |
| Cindy Nails (Attleborough) Ltd | Attleborough | 2021 |
| Cindy Nails Cleethorpes Ltd | Grimsby | 2024 |
| Cindy Nails Limited | Enfield | 2023 |
| Cindys Smiles and Aesthetics Ltd | Oldham | 2022 |
| Cinema Acoustic Panel Systems Limited | Maidstone | 1998 |
| Cinema Technology Community C.I.C. | London | 2017 |
| Cinemotion Pictures Limited | London | 2023 |
| Cinergi Ltd | Romsey | 2020 |
| Cingilli Collection Limited | London | 2015 |
| Cinico Limited | Woodbridge | 2021 |
| Cinnabarre Limited | Wishaw | 2014 |
| Cinnamon (UK) Limited | London | 1995 |
| Cinnamon Beauty Ltd | Hemel Hempstead | 2026 |
| Cinnamon Grove GIN Limited | Haverfordwest | 2011 |
| Cinnamon Management Ltd | Coventry | 2021 |
| Cinos Beauty Ltd | Colwyn Bay | 2026 |
| Cinpres GAS Injection Limited | Chesterfield | 1984 |
| Cinque Ports Canine Ltd | Hertford | 2026 |