What are you actually buying when you buy an option?

Every instrument you have met so far is a thing you own or a promise you hold. An option is stranger than both: it is a choice, bought and sold like a commodity, with a deadline attached.

A right, not an obligation

An option is a contract giving its buyer the right — but never the duty — to trade a specific asset at a specific price by a specific date. Four fields define any option completely:

• Underlying — what it is written on (a share, an ETF, an index).
• Strike — the price you may transact at.
• Expiry — the date the right dies.
• Type — a call (the right to buy) or a put (the right to sell).

One more field hides in the plumbing: the multiplier. A standard US listed equity option covers 100 shares, so every premium quoted per share is multiplied by 100 in your account. A contract quoted at "$3.00" costs $300.

The asymmetry that makes it a separate instrument

Own a share at $100 and your outcome is roughly symmetric: up $10 is +$10, down $10 is −$10.

Buy a call with a $105 strike for a $3.00 premium and it is not symmetric at all:

• Stock at $120 at expiry → you exercise, pay $105 for something worth $120. That is $15 of value, minus the $3 you paid = +$12 per share (+$1,200 per contract).
• Stock at $80 at expiry → you simply do not exercise. Nobody can force you to buy at $105. Your loss is the $3 you paid ($300), and not a cent more.

That is the entire invention. The buyer's downside is capped at the premium — the price of the contract — while the upside stays open. You bought optionality: the ability to walk away.

Somebody sold you that right

Every option that exists was written by somebody who took the opposite side. They collected your $3 and accepted the obligation: if you exercise, they must deliver at $105 whatever the stock is doing. Their profile is the mirror image — a capped gain and an uncapped loss. That inversion is important enough to get its own lesson at the end of this unit.

Why the premium is not free

Because the asymmetry is valuable, it is priced. The premium is what the market charges for the choice, and it is set by two things you will spend the next unit dissecting: how far the stock would have to travel to make the right worth exercising, and how much time and expected movement it has to get there.

So the honest one-line description of buying an option is not "a cheap way to control 100 shares." It is: you paid a non-refundable fee for a decision you may never want to make, and the fee is gone whether or not you make it.

In the data

Apple's options chain is below, in the EODHD Terminal, one expiry at a time. Chains are marketplace data, so they are read there rather than reproduced on this page.

Open AAPL.US — options in the EODHD Terminal

Every contract on it is fixed by four things: the underlying, the expiry, the type and the strike. The exchanges' standard contract symbol packs all four into one name: AAPL271217C00420000 is Apple, expiring 17 December 2027, a call (C; a put would be P), strike 420.000. What the chain does not print is the multiplier. Every price on it is quoted per share of the underlying, and a standard US contract covers 100 shares, so a position totalled straight off the quoted prices is out by a factor of a hundred.

Try it now

1. In the chain above, pick a single call and read its four identity coordinates out loud: underlying, strike, expiry, type.

2. Note the quoted premium and multiply by 100. That is the real cash amount, and it is the maximum a buyer of that contract can lose.

3. Write the sentence in full: "I paid $X for the right — not the duty — to buy 100 shares of ___ at $Y before ___. If I am wrong, I lose the $X." If any blank is fuzzy, you do not yet understand the contract.

A note on what we do here. EODHD Academy teaches how instruments work. Nothing in this course is a recommendation to buy, sell, or write anything. Options are a high-risk instrument, and every structure shown here is a mechanics illustration, presented with its downsides attached.