| CF 9489 Ltd | Arts & recreation | 2023 |
| Cgsi Ltd | Hospitality | 2026 |
| Chameleon & Co UK Ltd | Wholesale & retail | 2020 |
| Champers Entertainment Services Limited | Information & communication | 2024 |
| Chapman's Piece (Burford) Residents' Association Limited | Households | 1978 |
| Chapman, Robinson & Moore Limited | Professional & scientific | 1990 |
| Charlbury One Limited | Professional & scientific | 2007 |
| Charlbury Two Limited | Professional & scientific | 2007 |
| Charles Hoare Landscape & Garden Services Limited | Administrative & support | 2014 |
| Charlton Electrical Services Limited | Construction | 2017 |
| Charlton on Otmoor Services Limited | Administrative & support | 2012 |
| Chawley Court Limited | Real estate | 2016 |
| Cherwell Collective CIC | Hospitality | 2020 |
| Cherwell Court (Banbury) Management Company Limited | Households | 2005 |
| Cherwell Finance Ltd | Wholesale & retail | 2024 |
| Cherwell-Lodge Residents Association Limited | Households | 1966 |
| Chestnut Close (Oxford) Management Company Limited | Households | 1992 |
| Chestnut Court (Oxford) Management Company Limited | Real estate | 2007 |
| Chestnut Court Freehold Limited | Households | 2020 |
| Chichester House Management Company Limited | Households | 2008 |
| Childcare Oxford Ltd | Education | 2023 |
| Chilman Fire and Security Limited | Professional & scientific | 2005 |
| Chris Lord Building and Property Maintenance Limited | Construction | 2022 |
| Cirrus Aircraft Europe Limited | Wholesale & retail | 2015 |
| City Spires Properties Ltd | Real estate | 2019 |
| Clarkson Alliance Cost Management Ltd | Financial services | 2015 |
| Clarkson Alliance Project Management Limited | Other services | 2018 |
| Clarus Construction Ltd | Construction | 2021 |
| Clear Sky Catering Consumables Limited | Professional & scientific | 2007 |
| Clever Energy Heating Ltd | Construction | 2022 |
| Clever Ideas Limited | Wholesale & retail | 2021 |
| Clever Technology Solutions Ltd | Wholesale & retail | 2013 |
| Clinical Engineering Ltd | Professional & scientific | 2009 |
| Cobbetts Close (Eynsham) Management Company Limited | Households | 2017 |
| Coinmarketboards Ltd | Wholesale & retail | 2025 |
| Colban Limited | Agriculture & fishing | 2007 |
| Coldquanta UK Limited | Professional & scientific | 2014 |
| Collins Specialist Services Ltd | Health & social care | 2024 |
| Commercialise Limited | Administrative & support | 2012 |
| Commswise Ltd | Information & communication | 2000 |
| Complete Glass and Glazing Oxford Ltd | Construction | 2025 |
| Conifer Joinery Ltd | Manufacturing | 2005 |
| Connect Intelligence Limited | Wholesale & retail | 2003 |
| Connect OIL Limited | Wholesale & retail | 2001 |
| Connexuspro Ltd | Information & communication | 2018 |
| Coozam Ltd | Information & communication | 2025 |
| Core Air Tech Limited | Wholesale & retail | 2024 |
| Core Evolution Holdings Limited | Financial services | 2014 |
| Corner to Corner Brickwork Ltd | Construction | 2022 |
| Cornerstone Land Ltd | Construction | 2017 |
| Cornerstoneone Real Estate UK Limited | Financial services | 2025 |
| Corporate Aviation UK Ltd | Transport & logistics | 2020 |
| Cot's Green Management Company Limited | Households | 1996 |
| Couling Close Residents Management Company Limited | Households | 2016 |
| County Insurance Services Limited | Financial services | 2013 |
| Covered Arts Limited | Arts & recreation | 2003 |
| Cowboymod Limited | Other services | 2011 |
| CR Fabrication Ltd | Construction | 2022 |
| Creamery Corner Limited | Manufacturing | 2025 |
| Creative Property Development Limited | Real estate | 2025 |
| Crescent Place Management Limited | Households | 2011 |
| Cristina Oliver Limited | Other services | 2017 |
| CRM Partners Limited | Real estate | 1999 |
| Crown House Properties (Oxford) Limited | Real estate | 1971 |
| CRU8 Deli Limited | Hospitality | 2016 |
| Crystalmaker Software Limited | Information & communication | 2003 |
| CSC Polo Academy Ltd | Agriculture & fishing | 2026 |
| CSC Polo Livery Ltd | Agriculture & fishing | 2026 |
| Cumberland Mews Management Company Limited | Households | 1987 |
| Cunliffe Court Association Limited | Households | 2003 |
| Curavia Ltd. | Professional & scientific | 2022 |
| Cured HAM Specialist Ltd | Wholesale & retail | 2018 |
| Cutteslowe House (Oxford) Management Company Limited | Other services | 1983 |
| Cygnet Electronics Limited | Wholesale & retail | 1984 |
| D & M Trapp Limited | Construction | 2020 |
| D J Walker Roofing Ltd | Construction | 2023 |
| D Thomas Fencing & Building Ltd | Administrative & support | 2024 |
| D.J. Green Ltd | Other services | 2010 |
| D.P.L. Electrical Services Ltd | Construction | 2018 |
| D.T. Property Maintenance Limited | Construction | 2013 |
| Dacg Limited | Financial services | 2023 |
| Daigazou Ltd. | Information & communication | 2013 |
| Daily Scroll News Limited | Information & communication | 2026 |
| Dailysmart Pack Ltd | Wholesale & retail | 2025 |
| Dakota Project Management Ltd | Construction | 2018 |
| Dakota Projects Ltd | Professional & scientific | 2014 |
| Danceworks Limited | Professional & scientific | 2000 |
| Dandylion Homes Limited | Real estate | 2020 |
| Dapperdesi Limited | Wholesale & retail | 2025 |
| Darkstars Studios Ltd | Information & communication | 2018 |
| Darnells Limited | Construction | 1991 |
| Dashwood Arms Limited | Hospitality | 2019 |
| David Mills Estates (Oxford) Limited | Real estate | 1970 |
| Davies Surfacing Limited | Construction | 2016 |
| Dayakim Ltd | Transport & logistics | 2023 |
| DB Bookkeepers Ltd | Professional & scientific | 2020 |
| DBF Banbury Limited | Wholesale & retail | 2022 |
| Ddlcd Consulting Limited | Professional & scientific | 2009 |
| Ddsm Consulting Co Ltd | Financial services | 2024 |
| DE Law Limited | Professional & scientific | 2024 |