Options Trading — How Calls and Puts Work
Options are derivatives contracts giving the right to buy or sell an asset at a set price. Learn how call and put options work, pricing basics, and common strategies.
Definition
Options are derivative contracts that give the buyer the right, but not the obligation, to buy (call option) or sell (put option) an underlying asset at a predetermined price (strike price) on or before a specific date (expiration date).
The buyer pays a premium to the seller (writer) for this right. The seller, in turn, takes on the obligation to fulfill the contract if the buyer exercises. This asymmetry — the buyer has the right, the seller has the obligation — is what makes options unique among financial instruments.
Options serve three primary purposes: speculation (leveraged directional bets), hedging (portfolio insurance), and income generation (selling premium).
How It Works
Call options — the right to buy
You buy a call when you expect the price to rise.
| Scenario | If Stock at Expiration | Option Value | Profit (minus premium) |
|---|---|---|---|
| Deep ITM | EUR 150 (strike 100) | EUR 50 | EUR 50 − premium |
| ATM | EUR 100 (strike 100) | EUR 0 | −premium (loss) |
| OTM | EUR 80 (strike 100) | EUR 0 | −premium (loss) |
Maximum loss: Premium paid Maximum gain: Unlimited (stock can rise indefinitely)
Put options — the right to sell
You buy a put when you expect the price to fall or want to protect a position.
Maximum loss: Premium paid Maximum gain: Strike price − 0 (stock can fall to zero)
Option pricing components
| Factor | Effect on Call Price | Effect on Put Price |
|---|---|---|
| Stock price rises | Increases | Decreases |
| Strike price higher | Decreases | Increases |
| Time to expiration longer | Increases | Increases |
| Volatility increases | Increases | Increases |
| Interest rates rise | Increases | Decreases |
The Greeks
| Greek | Measures | Practical Meaning |
|---|---|---|
| Delta (Δ) | Price sensitivity to underlying | Delta 0.5: stock moves EUR 1 → option moves EUR 0.50 |
| Gamma (Γ) | Rate of delta change | Accelerates gains/losses near expiration |
| Theta (Θ) | Time decay per day | Option loses value daily (hurts buyers, helps sellers) |
| Vega (ν) | Sensitivity to volatility | High vega → expensive before earnings/events |
| Rho (ρ) | Sensitivity to interest rates | Minor effect for short-term options |
Moneyness
- In the Money (ITM): Call: stock > strike. Put: stock < strike. Has intrinsic value.
- At the Money (ATM): Stock ≈ strike. Maximum time value.
- Out of the Money (OTM): Call: stock < strike. Put: stock > strike. Pure time value.
Example
Strategy 1 — Protective Put (portfolio insurance):
You own 100 shares of ASML at EUR 700 (EUR 70,000 position). You worry about a short-term decline before earnings.
Buy 1 put contract (100 shares): Strike EUR 660, Expiration 45 days, Premium EUR 15/share = EUR 1,500.
| ASML Price at Expiry | Stock P&L | Put P&L | Net P&L | Without Put |
|---|---|---|---|---|
| EUR 750 | +5,000 | −1,500 | +3,500 | +5,000 |
| EUR 700 | 0 | −1,500 | −1,500 | 0 |
| EUR 650 | −5,000 | +8,500 | +3,500 | −5,000 |
| EUR 600 | −10,000 | +13,500 | +3,500 | −10,000 |
The put limits your maximum loss to EUR 5,500 (stock drops to strike + premium paid), regardless of how far ASML falls. Cost: EUR 1,500 (2.1% of portfolio value for 45 days of protection).
Strategy 2 — Covered Call (income generation):
You own 100 shares of Siemens at EUR 180. You sell 1 call contract: Strike EUR 195, Expiration 30 days, Premium received: EUR 3/share = EUR 300.
| Outcome | Result |
|---|---|
| Siemens stays below EUR 195 | Keep shares + EUR 300 premium = 1.7% monthly income |
| Siemens rises above EUR 195 | Sell shares at 195 (8.3% gain) + keep EUR 300 premium |
| Siemens drops to EUR 165 | Lost EUR 1,500 on shares, but EUR 300 premium reduces loss to EUR 1,200 |
Covered calls generate steady income (1-3% monthly) but cap your upside. It is the most popular options strategy among individual investors.
Strategy 3 — Iron Condor (range-bound market):
When you believe an asset will stay within a range, you sell both a call spread and a put spread:
- Sell EUR 190 call, buy EUR 200 call (credit: EUR 2)
- Sell EUR 170 put, buy EUR 160 put (credit: EUR 2)
- Total premium collected: EUR 4/share = EUR 400
- Max loss: EUR 600 (if stock moves beyond EUR 200 or below EUR 160)
- Win condition: stock stays between EUR 170-190 at expiration
Why It Matters
Portfolio protection
Institutional investors routinely use put options to protect large portfolios. A portfolio manager with EUR 100 million in European stocks might spend 0.5-1% annually on put protection — a small price for insuring against a 2008-style crash.
Leverage without margin calls
Buying a call option for EUR 500 can give you exposure to EUR 10,000 worth of stock (20x leverage). Unlike margin trading, your maximum loss is strictly limited to the EUR 500 premium — no margin calls, no additional deposits.
Income generation in sideways markets
In flat or slowly rising markets (common for European equities), covered call strategies generate 8-15% annually in premium income on top of dividends. This is why options-selling ETFs (like JPMorgan Equity Premium Income ETF) have attracted billions.
Price discovery and implied volatility
Option prices reveal the market's expectation of future volatility. The VIX ("fear index") is derived from S&P 500 option prices. Before major events (elections, central bank decisions), implied volatility rises, signaling uncertainty.
Risks and Pitfalls
Selling naked options — unlimited risk
Selling (writing) a call option without owning the underlying stock exposes you to theoretically unlimited losses. If the stock doubles, triples, or more, you must buy shares at market price to deliver them at the strike price.
Time decay (theta) destroys option value
Approximately 75% of options expire worthless. As a buyer, time works against you — every day your option loses value, even if the stock moves in your direction. Theta accelerates in the final 30 days before expiration.
IV crush after events
Buying options before earnings because you "know" the stock will move is a common trap. Option premiums are inflated before events (high implied volatility). After the event, IV collapses regardless of direction, often resulting in losses even when you correctly predicted the move.
Complexity leads to mistakes
Multi-leg strategies (spreads, straddles, condors) require precise execution. A misplaced strike price, wrong expiration, or incorrect quantity can transform a hedged position into an exposed one. Paper-trade first.
Liquidity on European exchanges
European options markets (Eurex) are less liquid than US markets (CBOE). Bid-ask spreads on individual stock options in Europe can be 5-15%, compared to 1-3% in the US. This makes frequent options trading significantly more expensive in Europe.
FAQ
Can I trade options through a Polish broker?
Polish brokers (Bossa, mBank) offer options on WIG20 (European-style, cash-settled) on the GPW. For options on individual stocks or US/European indices, you need an international broker like Interactive Brokers, which provides access to Eurex and CBOE.
European vs American options — what is the difference?
European options can only be exercised at expiration. American options can be exercised at any time before expiration. WIG20 options on GPW are European. Most US stock options are American. For practical purposes, early exercise of American options is rarely optimal except for deep ITM puts or before ex-dividend dates.
How much money do I need to start trading options?
Buying a single WIG20 option costs 100-500 PLN (premium). On US markets via Interactive Brokers, a single equity option costs $50-500 (premium). Start small, focus on simple strategies (buying calls/puts, covered calls), and never risk more than 2-5% of your portfolio on any single options trade.
Are options riskier than stocks?
For buyers: maximum loss is the premium (defined risk). For sellers: risk can be unlimited. Options are not inherently "riskier" — they are more complex. A protective put actually reduces portfolio risk. The risk comes from misuse, overleveraging, and lack of understanding.
Related Articles
- Put Option — detailed guide to protective puts
- Collateral — margin requirements for options
- Risk Parity — how options fit into balanced portfolios
- See the full financial dictionary for more terms
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