An option is just a contract: it gives you the right to buy or sell a stock at a fixed price, until a fixed date. You are not forced to use it - that's the "option" part. To keep it concrete, we'll follow one stock all the way down: Apex, trading at $100 a share. Every example below uses the same Apex.
First, the four words you need
Strike price: the fixed price the contract locks in. Premium: what you pay to buy the option (or collect if you sell one). Expiration: the date the contract dies. Contract size: one option almost always covers 100 shares, so a $3 premium really means $3 x 100 = $300.
Two sides to every contract: the buyer pays the premium and gets the right. The seller (also called the "writer") collects the premium and takes on the obligation to deliver if the buyer uses their right.
- Stock: Apex, trading at $100
- We'll use a $105 strike, one month out
- The premium for that contract is $3 per share ($300 total)
We'll keep using this same Apex, $105 strike, $3 premium below.
Call option
What it is: the right to buy the stock at the strike price. You buy a call when you think the stock will go up.
The appeal: small money controls 100 shares, and your loss is capped at the premium. The catch: the stock has to move up enough to clear the strike and the premium before you make a cent, and the clock is always running against you.
Put option
What it is: the mirror image - the right to sell the stock at the strike price. You buy a put when you think the stock will go down, or to insure shares you already own.
The appeal: profit when a stock falls, or protect what you own. The catch: like insurance, if nothing bad happens the premium is just gone.
The premium (and why it decays)
What it is: the premium is built from two parts. Intrinsic value = how much the option is already "in the money" right now. Time value = everything extra you pay for the chance the stock moves your way before expiration.
Why it matters: an option is a wasting asset. Time decay is the buyer's enemy every single day - and, as you'll see next, the seller's best friend.
Selling a covered call (collecting premium as income)
What it is: you own 100 shares and sell a call against them. You pocket the premium today. In return you agree to sell your shares at the strike if the stock rises above it. Because you already own the shares, the call is "covered" - no scary open-ended risk.
• Apex stays under $105 - the call expires worthless, you keep your shares and the $300. You can do it again next month.
• Apex rises above $105 - your shares get "called away" (sold) at $105. You still made $5 of upside plus the $3 premium, but you gave up any gain above $105.
Why it matters to a dividend investor: this is exactly how covered-call income funds (the JEPI / QYLD / covered-call CEF crowd) manufacture their big monthly payouts - they hold stocks and sell calls over and over, turning premium into "dividends." The trade-off is real: you swap the stock's upside for steady income, so in a roaring bull market these funds lag the market they're built on.
Selling a cash-secured put
What it is: the flip side. You sell a put and set aside the cash to buy the stock if you're assigned. You collect premium now, and you only end up buying if the stock falls to your strike - a price you already liked.
Why it matters: another premium-income engine some funds use. You're paid to place a "buy" order at a discount. The risk: in a real crash you're locked into buying at $95 while the stock keeps falling well below it.
In / at / out of the money, exercise & assignment
Moneyness: a call is in the money when the stock is above the strike, at the money when it's right at it, out of the money when it's below (puts are the reverse). Exercise: the buyer using their right. Assignment: the seller being forced to deliver because a buyer exercised.
Why it matters: these four words are 90% of the jargon. Once "in the money = has real value" and "assignment = the seller's bill comes due" click, the rest of options-speak reads normally.