What the TSR refers to as the primary timeshare market is really the traditional forms of selling and marketing a timeshare product. The primary market companies include branded companies or those who are still in active sales.
The secondary market refers to timeshare companies who are active in the marketplace, for example selling or renting timeshares, but who aren’t associated with a developer directly. There are many different types of companies that are associated with the secondary timeshare market.
Besides just the obvious renters or resellers, there are also transfer and title companies, travel clubs, exchange companies, advertising companies, and many others.