Exit Barrier. A barrier to exit is a factor blocking an existing firm from leaving a market quickly and at a low cost.
A major exit barrier is sunk cost. Sunk costs are costs that cannot be recovered upon exiting a market. Basically sunk costs are costs associated with advertising and cancelling contracts with suppliers, workers and buyers. The higher are sunk costs, the higher the costs of failure and the more risky it is to enter the industry. An exit barrier therefore acts as an entry barrier because it disincentivizes firms from entering a market.