When you buy a call, you pay the option premium in exchange for the right to buy shares at a fixed price (strike price) on or before a certain date (expiration date). Investors most often buy calls when they are bullish on a stock or other security because it offers lever. For example, assume ABC Co. trades for $50. A one-month at-the-money call option on the stock costs $3. Would you rather buy 100 shares of ABC for $5,000 or one call option for $300 ($3 × 100 shares), with the payoff being dependent on the stock’s closing price one month from now? Consider the graphic illustration of the two different scenarios below.