Exchange Companies are NOT timeshares. Rather, they are third-party companies in place to enhance your timesharing experience. These companies allow owners to trade their time at their "home resort" (the resort which is deeded or contracted to them) for time at any resort within the company's extensive, international network. It may sound confusing, but the process is really quite simple. When an owner has a week that he or she wont' be able to use, or would like to trade for another week, he or she can deposit it with their exchange company. The week then becomes part of a bank from which other owners who've deposited their time may choose.
The largest exchange company is Resort Condominiums International (RCI), followed by Interval International (II). Each of these companies is affiliated with thousands of resorts all over the world, giving owners an almost unlimited number of trade options. If a resort is affiliated with an exchange company, owners at that particular resort are given the option to join. Membership within one of these corporations does cost a fee, but many allow owners to pay in blocks of years, rather than annually. A week's exchange value is established based on the demand for each week, the rating of the particular resort, the size of the unit and various other factors. The higher the trade value of a particular week or resort, the more luxurious or desirable a resort you can expect to get in exchange for it.