Wyndham and WorldMark are similar programs, and both come under the Wyndham Destinations division owned by Travel + Leisure. While they are part of the same company, the difference depends on what type of timeshare product you are reviewing.
Wyndham manages deeded timeshare weeks as well as points programs such as Club Wyndham Access, so it is a hybrid operation with products dependent on when and at which resort the timeshare was purchased. Some owners may have purchased deeded timeshare weeks that are part of the Wyndham program, even though the company focuses on selling points to new owners.
WorldMark is a pure points program where points can be used at any of the more than 90 WorldMark timeshare resorts. The program operates more like a travel club, where owners book a unit at a resort within the network. The size of the unit depends on how many points they own.
The points programs for Wyndham and WorldMark operate in a similar way and both programs are intertwined in the sense that Wyndham points owners can choose to stay at either Wyndham or WorldMark resorts. WorldMark owners can also choose to vacation in a Wyndham resort, but must pay an additional fee to access those resorts.
The primary difference is that Wyndham has varying levels of programs and offers the choice of buying a deeded interest as well as a package of points, whereas WorldMark operates as a pure points program.