Call Options
Market MechanicsA contract that gives you the right — but not the obligation — to buy 100 shares at a fixed price before a set expiry date.
A call option is a derivative contract that grants the holder the right, but not the obligation, to purchase 100 shares of the underlying security at the strike price on or before the expiration date. The buyer pays a premium for this right; the seller (writer) receives the premium and assumes the obligation to deliver shares if the option is exercised. Call options are priced using models such as Black-Scholes, which incorporates the underlying price, strike price, time to expiration, risk-free rate, and implied volatility. Delta (rate of change of option price relative to underlying price), gamma, theta (time decay), and vega (sensitivity to volatility) are the primary Greeks used to manage options positions. Long calls provide leveraged upside exposure with defined maximum loss equal to the premium paid.
The strike price is the price at which you can buy the stock. In-the-money (ITM) calls have strikes below the current price and cost more. Out-of-the-money (OTM) calls have strikes above the current price, are cheaper, but require a bigger move to profit. Expiry determines how much time the stock has to move in your favour.
The premium is what you pay for the contract. One contract = 100 shares, so a $5 premium costs you $500. This is your maximum possible loss — unlike selling options or shorting stock, buying calls has defined, limited downside.
Delta tells you how much the option price moves for every $1 move in the stock. An ATM call has roughly 0.50 delta — if the stock rises $1, the option gains ~$0.50 per share. As the stock moves higher, delta increases (approaching 1.0 deep ITM), so gains accelerate. This is the leverage.
Most options traders never exercise their contracts — they sell the option itself for a profit (or loss) before expiry. As expiry approaches, theta decay accelerates sharply, destroying value even if the stock is flat. Weekly options lose value fastest; longer-dated LEAPS decay more slowly.
Stock XYZ is trading at $100. You buy a $110 strike call expiring in 30 days for a $3 premium ($300 total for 100 shares). If XYZ rises to $120, your option is worth at least $10 intrinsically ($120 − $110), turning your $300 into $1,000+ — a 233%+ return on the premium while the stock only moved 20%. If XYZ stays at $100 or falls, your option expires worthless and you lose the full $300.
Options expire worthless more often than most retail traders expect — studies suggest 70–80% of options held to expiry expire worthless. The combination of needing the right direction, the right magnitude of move, AND the right timing creates three simultaneous hurdles. Buying cheap OTM weekly options ('lottery tickets') is one of the most reliable ways to slowly bleed capital in markets. Implied volatility also means you can be right about direction but still lose if you overpaid for the option.