Reading an Option Chain Without Getting Lost

The first time you open an option chain it is overwhelming. Hundreds of rows, a dozen columns, numbers in colours nobody explained, and somewhere in there is the one contract you came to sell.

Underneath, it is a simple table with a fixed layout. Once you know the layout you can read any broker's version. Here is one you can click.

The layout is always the same

Every chain on every platform is built the same way: one expiration at a time, strikes down the middle, calls on one side and puts on the other. Usually calls on the left and puts on the right, with the middle of the table near where the stock is trading.

The layout is doing some work for you. Read across a row and you get the call and the put at the same strike, which the moneyness lesson showed are always in opposite states. Read down a column and you see how one number changes as you move away from the money.

What each column is for

Bid and ask. The bid is what someone will pay you right now. The ask is what someone will sell to you for. Selling premium, you care about the bid, because that is the price you can hit immediately. The gap between the two is the spread, and it costs you real money.

Delta. The most useful column for picking a strike. It measures how far out of the money a strike is in a way that works across any stock, and gives you a rough sense of assignment odds. “Sell the 20 delta” is an instruction anyone can follow. “Sell the $92.50” is not.

Implied volatility. The volatility number that makes the model agree with the market price. Notice in the widget that it is not the same across strikes, and that downside strikes carry more of it. That is skew, which has its own lesson.

Volume and open interest. Volume is contracts traded today. Open interest is contracts currently outstanding. Both tell you about liquidity, not direction. A strike with high open interest is easy to trade; it is not a forecast. Real chains show both. The widget above leaves them out because synthetic volume would be made up.

Last. The price of the most recent trade, which on a quiet strike may have been hours ago. It is the least reliable column on the screen and the one beginners read first. Use the bid and ask instead.

Reading it as a seller, in order

There are hundreds of rows and you need one. This sequence gets you there without wandering around.

1. Pick the expiration first. Platforms show one at a time for a reason. Thirty to forty-five days is the usual starting point, and theta explains why.
2. Go to the put side. Cash-secured puts are sold below the current price, so you want the rows below the money.
3. Find your delta. Scan the delta column for about 0.16 to 0.30, per the strike selection lesson.
4. Check you would own the stock at that strike. Multiply by 100. If that number makes you uncomfortable, nothing else on the row matters.
5. Check the spread is tight. A wide bid-ask turns a good trade into an average one.
6. Read the bid, not the mid or the last. That is the credit you can count on.

Same strike, same delta, same obligation. The second row pays $145 instead of $185 because the market for it is thin, and it will cost you again on the way out. The delta column would never have told you that.

What can go wrong

Trading off the last price. It is stale by definition.

Picking the wrong expiration. Chains for adjacent weeks look almost identical. Check the date before you send the order, every time.

Mixing up the call and put sides. Some platforms put calls on the right. Confirm which side you are on before you pick a strike.

Reading high open interest as a good trade. It means a liquid one, and nothing else.