An option trading strategy that is constructed by selling a put option (short put option) at a given strike price and buying a put option (long put option) at a higher strike price, both on the same underlying and with the same expiration month. An investor would seek such a strategy when the underlying is expected to remain neutral if the higher-strike option is out of the money. This spread obligates the holder to buy the underlying at the higher strike price upon exercise by the seller, while giving him at the same time the right to sell the underlying at the lower strike price. The maximum potential profit is limited to the initial payout (the net credit) received at the start of trade. However, the maximum loss is limited to the difference between the lower and higher strikes, minus the net credit amount received when the strategy is set up.

The short put spread is alternatively called a bull put spread.