Why would someone buy an option?
Begin with a person, a concern, and a choice—not market vocabulary.
Example brokerage position
SPY Nov 20, 2026 $95 Put
Assigned · must fulfill promise
How a platform might label it
- Action
- SELL TO OPENStart a new position as the option seller
- Quantity
- 1 contractOne options agreement
- Type
- PUTHolder has a right to sell shares
- Strike
- $95.00Agreed price per share
- Expiration
- Nov 20, 2026Contract's final date
- Multiplier
- 100 sharesShares represented by one contract
- Premium
- +$3.00/share · +$300Option price received by this seller
- Collateral
- $9,500 cash reservedCash supporting the promise to buy
What that means in plain English
You were paid $300 to promise that you would buy 100 SPY shares for $95 each if assigned before the option expires.
What happened
SPY fell to $90. A holder exercised. Clearing assigned this account.
Cash at assignmentNot settled yet
Premium-adjusted resultNot calculated yet
Imagine Maya owns 100 shares
Maya owns 100 shares worth $100 each
She likes the investment and does not want to sell it today.
She worries the shares could fall soon
She wants protection for the next three months while keeping the shares.
Her choice in plain English
Pay $300 today for the temporary right to sell her 100 shares for $95 each.
If the market falls to $90, she can still sell for $95. If it stays above $95, she can keep the shares and let the protection end unused. Either way, the $300 cost is hers to pay.
Market translation
Maya buys one $95 put for a $3 premium per share. The put is the contract that gives her that temporary selling right.
Someone may buy an option to gain a temporary choice without immediately buying or selling the shares.
Market terms:
Two sides of the same contract
The holder may use the contract, sell it, or let it expire.
The seller must perform if the contract is exercised and assigned.
Plain English → market language
The person who pays for the choice is the buyer or holder. The person paid to accept the other side is the seller. The holder owns a right; the seller accepts an obligation.
Holder chooses. Seller is obligated.
Review:
What actually moves when an option is used?
The call buyer may choose to buy 100 shares at the agreed price.
💵 Holder pays cash to the assigned seller
📈 Assigned seller sends 100 shares to the holder
Market translation: a call gives its holder the right to buy at the strike.
The put buyer may choose to sell 100 shares at the agreed price.
📈 Holder sends 100 shares to the assigned seller
💵 Assigned seller pays cash to the holder
Market translation: a put gives its holder the right to sell at the strike.
Exercise is a transaction: cash moves one way and shares move the other way.
Review:
Read the contract before the outcome
The agreed transaction price if the option is exercised.
The share quantity controlled by this standard example contract.
The holder receives it and the assigned put seller pays it.
Option's price · “premium”:
Buyer pays $3 × 100 = $300; seller receives $300
Seller-side safety setup:
A cash-secured put seller reserves $9,500 so the account can buy the shares if assigned. The reserved support is called collateral.
Premium is the option's price. Collateral supports the seller's obligation. They are not the same money.
Review:
Exercise and assignment are opposite views
Market term: the holder exercises.
The market stands between the accounts and processes settlement.
Market term: the selected short account is assigned.
Expiration is the deadline.
An unexercised option can expire with no remaining right or obligation. Early exercise can also occur for American-style equity options, but this lesson uses expiration settlement only.
Review:
How this seller-side account reached assignment
Holder-side action
Exercises the right to sell
Clearing action
Allocates assignment
Your account
Receives the obligation
The current holder and your account are economically opposite, but they are not permanently paired with each other.
Market terms:
Which way does the 💵 $9,500 assignment cash move?
💵 $9,500 cash
Choose a direction. The asset begins in a neutral question tray.
Which way do the 📈 100 shares move?
Settlement complete
Long-holder-side settlement
💵 Cash+$9,500
📈 Shares−100
Option position0
Your account settlement
💵 Cash−$9,500
📈 Shares+100
Option position0
Premium received+$300
Assignment cash−$9,500
Shares worth at $90+$9,000
Net result−$200
Your effective cost was $92 per share: the $95 strike minus the $3 premium. The shares are worth $90, so the result is −$2 × 100.
Hypothetical educational expiration example—not a current SPY quote. Excludes transaction costs, taxes, liquidity, broker-specific margin, and interim option value.