Investors who anticipate that a stock won't trade below a certain price for a set time period can generate income by selling a put option. One such option trading strategy is selling a cash covered put option. This entails selling a put at a certain strike price while also posting cash as collateral in case the put option is exercised and shares are obligated to be purchased. The risk to this option strategy is that you may be forced to buy shares at a price above what the stock is currently worth. In addition, this means that the value of stock you’re obligated to purchase may fall to zero.