If a company or organisation needs to be established and headquartered within an EU state, then UK firms may not be able to access EU markets post-Brexit. This has consequences for broadcasters and companies such as Virginmedia, the BBC and Sky,that offer online services to Europe via satellite, cable and, increasingly, the internet and mobile phones. It also affects UK-domiciled online games companies operating in Europe.
Source: How will Brexit affect copyright legislation? | LSE Media Policy Project