There are three possible outcomes at expiration. The stock price can be at or above the higher strike price, below the higher strike price but not below the lower strike price or below the lower strike price. If the stock price is at or above the higher strike price, then both puts in a bull put spread expire worthless and no stock position is created. If the stock price is below the higher strike price but not below the lower strike price, then the short put is assigned and a long stock position is created. If the stock price is below the lower strike price, then the short put is assigned and the long put is exercised. The result is that stock is purchased at the higher strike price and sold at the lower strike price and the result is no stock position.

If assignment is deemed likely and if a long stock position is not wanted, then appropriate action must be taken. Before assignment occurs, the risk of assignment can be eliminated in two ways. First, the entire spread can be closed by buying the short put to close and selling the long put to close. Alternatively, the short put can be purchased to close and the long put open can be kept open