Though selling premium services that are related by ownership as a package is common, that may not always be the situation: for example, in the United States, Cinemax and Encore are optionally sold separately from or in a single package with their respective parent networks HBO and Starz, depending on the service provider. The Movie Channel and Flix meanwhile, are usually sold together with Showtime (all three channels are owned by ViacomCBS); though subscribers are required to purchase Showtime in order to receive Flix, The Movie Channel does not have such a restriction as a few providers optionally sell that service without requiring a Showtime subscription.