Calls and puts

An option gives you the right, but not the obligation, to buy or sell something at a fixed price before a set date. That single idea creates an instrument with a shape unlike anything else you've studied: when you buy an option, your maximum loss is known in advance, while your potential gain can be large. Options are also full of traps for beginners — most of them related to time. This lesson builds the foundation.

What you'll learn

• What calls and puts are, and the language of options
• Premium, and the difference between intrinsic value and time value
• In, at, and out of the money
• Payoffs at expiry: breakeven, maximum loss, and maximum gain
• The difference between buying and selling (writing) options

1. The basics

Buyers pay the premium and have rights. Sellers (writers) receive the premium and take on obligations — they must deliver (or buy) if the option is exercised.

2. Intrinsic value and time value

Premium = intrinsic value + time value

• Intrinsic value — what the option would be worth if exercised right now
  • Call: underlying price − strike (if positive)
  • Put: strike − underlying price (if positive)
• Time value (extrinsic value) — everything else: the value of the possibility of a favourable move before expiry

(Illustrative.) A stock trades at $105. A $100-strike call costs $7.

• Intrinsic value = $105 − $100 = $5
• Time value = $7 − $5 = $2

Time value shrinks as expiry approaches and is zero at expiry. This decay is one of the most important forces in options (see The Greeks).

3. In, at, and out of the money

OTM options are cheap because they have no intrinsic value — only time value. They need a large move to pay off, and most expire worthless.

4. Payoffs at expiry

Long call

• Maximum loss: the premium paid
• Breakeven: strike + premium
• Maximum gain: theoretically unlimited

Long put

• Maximum loss: the premium paid
• Breakeven: strike − premium
• Maximum gain: strike − premium (if the underlying falls to zero)

Worked example

(Illustrative.) A stock is at $100. You buy one $100-strike call expiring in 30 days for $5.00.

• Cost: $5.00 × 100 shares = $500 — your maximum loss
• Breakeven at expiry: $100 + $5 = $105

Note: the stock must rise more than 5% just for you to break even. Being right about direction isn't enough — you must be right about how far and how fast.

5. Selling (writing) options

The seller of an option receives the premium and takes the opposite side:

• Short call: keeps the premium if the price stays below the strike — but faces potentially unlimited losses if the price rises sharply (unless they own the shares — see Covered calls, spreads, and straddles).
• Short put: keeps the premium if the price stays above the strike — but must buy the shares at the strike if it falls.

Selling options wins often (time decay works in the seller's favour) but can suffer rare, very large losses — the same tail-risk profile as mean-reversion strategies (see Trend-following vs mean-reversion vs breakout systems).

Common beginner mistakes

• Buying cheap, far out-of-the-money options and watching them expire worthless.
• Forgetting the 100-share multiplier when calculating cost and risk.
• Being right on direction but wrong on timing — time decay erodes the premium.
• Selling naked options for "income" without understanding tail risk.
• Ignoring liquidity — wide bid-ask spreads on options can be a large share of the premium.

Key terms

Practice

1. Open an option chain for a liquid stock or ETF. Find an ATM call and an OTM call with the same expiry. Split each premium into intrinsic and time value.
2. Calculate breakeven and maximum loss for buying one contract of each.
3. Note the bid-ask spread on each as a percentage of the premium.
4. Write, in one sentence, what move — size and timing — you'd need for each to be profitable.

Quick recap

• A call is the right to buy; a put is the right to sell, at the strike, until expiry.
• Premium = intrinsic value + time value; time value decays to zero at expiry.
• Long options: maximum loss = premium; breakeven = strike ± premium.
• You need the right direction, size, and timing to profit.
• Selling options earns premium but carries large, rare losses — start with defined risk.