Options Trading: How Calls and Puts Actually Work

An option is a contract. It gives you the right, but not the obligation, to buy or sell 100 shares of a stock at a fixed price, on or before a fixed date. You pay a premium for that right.

That structure makes options useful: you can define risk precisely, profit from a stock falling without short selling, or generate income from shares you already hold. It also makes them the fastest way to lose money in the market, because you can be completely right about direction and still lose everything.

The four things that define every option

1. Type: a call (right to buy) or a put (right to sell).
2. Strike price: the fixed price at which you may transact.
3. Expiry date: after which the contract ceases to exist.
4. Premium: what the contract costs, quoted per share, so multiply by 100.

A "TSLA 250 call expiring March 20" is the right to buy 100 Tesla shares at $250 any time before March 20. If it is quoted at $4.20, one contract costs $420.

Calls and puts

	Buying a call	Buying a put
You expect	The stock to rise	The stock to fall
You gain the right to	Buy 100 shares at the strike	Sell 100 shares at the strike
Maximum loss	The premium paid	The premium paid
Maximum gain	Theoretically unlimited	Strike minus premium, per share
Works against you	Time decay	Time decay

Notice the last row. Whichever direction you pick, time is the opponent for a buyer. That asymmetry is the heart of options trading, and it is what the marketing leaves out.

Why premium is not just direction

An option's price has exactly two components:

• Intrinsic value: what the contract would be worth if exercised right now. A $250 call with the stock at $268 has $18 of intrinsic value. If the stock is below $250, intrinsic value is zero.
• Extrinsic value: everything else. It is the market's price for the possibility that the option becomes more valuable before expiry, and it is driven by time remaining and implied volatility.

Extrinsic value decays to zero at expiry, always. Every day you hold, a little evaporates, and the decay accelerates sharply in the final weeks. This is why a stock can rise and your call still lose money: the gain in intrinsic value was smaller than the loss in extrinsic value.

Implied volatility, and why options get cheaper after good news

Implied volatility is the market's expectation of future movement, and it is baked into the premium. When a big event is coming, such as earnings or an FDA decision, IV rises and options get expensive. Once the event passes, IV collapses.

The result catches people out constantly: you buy a call before earnings, the company beats, the stock jumps 6%, and your option is worth less than you paid. The move was already priced in, and the volatility crush took more than the direction gave. This is known as IV crush, and it is the reason buying short-dated options into earnings is close to a coin flip with a negative edge.

The Greeks, briefly

The Greeks measure how an option's price responds to each variable.

Greek	Measures	What it means day to day
Delta	Sensitivity to the stock's price	0.50 delta means the option moves about $0.50 per $1 of stock
Gamma	How fast delta changes	High near the strike and near expiry; makes positions swing violently
Theta	Time decay per day	Negative for buyers, positive for sellers; your daily rent
Vega	Sensitivity to implied volatility	Why your option lost value after earnings despite being right

You do not need to calculate these. You do need to know that four separate forces act on your position, and only one of them is whether you picked the right direction.

Strategies, from safest to least

• Covered call: you own 100 shares and sell a call against them. Collects premium, caps your upside. The most conservative options strategy that exists.
• Cash-secured put: you sell a put while holding enough cash to buy the shares if assigned. You get paid to agree to buy a stock lower. Only sensible on stock you would genuinely be happy to own.
• Long call / long put: defined risk, but time decay works against you every day. Give yourself more expiry than you think you need.
• Vertical spread: buy one option, sell another further out. Caps both risk and reward, and reduces the cost of time decay.
• Naked short options: collecting premium with undefined risk. Not a beginner strategy under any circumstances.

Before you trade your first contract

1. Learn the underlying first. If you cannot trade the shares profitably, options will not fix that; they will amplify it. Start with stock trading.
2. Understand assignment. Know what happens if you are assigned, and what it will cost.
3. Buy more time than feels necessary. Most beginner losses come from being right too late.
4. Check liquidity. Wide bid-ask spreads on thin contracts can cost more than the trade makes.
5. Size in dollars, not contracts. One contract controls 100 shares. Apply the same risk rules you would to the equivalent share position.