How to Read an Options Chain
To read an options chain, filter to one expiry first, locate the strike nearest the current price of the underlying, and read outward from there. Calls sit on one side, puts on the other, and each row is one contract with its own bid, ask, volume and open interest.
The chain is a grid: every strike, at every expiry, for both calls and puts. Displayed in full it is several thousand rows, which is why nobody reads it in full and everybody filters it first.
Before you start
One expiry chosen before the chain is opened, because the full grid is unreadable. The expiry is a decision about time, and it should be made away from a screen showing forty of them.
The current price of the underlying, so strikes can be placed relative to it. Every reading of a chain is relative to that number.
A decision about which single column you are actually there to read. Price, liquidity or implied volatility. Three different questions with three different columns.
The steps
1. Filter to one expiry
Every expiry is a separate market with its own liquidity and its own pricing. Comparing across them at a glance is comparing different instruments.
2. Locate the strike nearest the underlying
This row is the reference point. Strikes above it and below it behave differently, and calls and puts swap roles as you cross it.
3. Read the bid and ask, not the last price
The last traded price on a quiet contract can be from yesterday. What you can actually transact at is the bid and the ask, and on options that gap is frequently wide.
4. Check open interest before considering the contract
Open interest counts contracts currently outstanding. A strike with almost none is one you can enter and then struggle to leave, which is a different risk from the one you were analysing.
5. Read volume as a separate question
Volume is today’s activity, open interest is the accumulated position. High volume with low open interest means positions opened and closed the same day.
6. Use implied volatility to explain price differences
When two contracts look comparable and are priced differently, this column is usually the reason. On this site’s shared series an implied volatility of 7.9% reproduces both measured leverage results within 0.03 percentage points.
7. Hide every column you are not using
Bid, ask, open interest and implied volatility answer most questions. The rest can be added back when you have a question that needs them.
How to tell it worked
Exactly 1 expiry is displayed.
The strike nearest the underlying is identified, and you can say which rows sit above and below it.
Every contract considered has traded on at least 1 of the last 5 days, so it can be left as well as entered.
And at most 4 columns are visible, each of which you can name a use for.
What the chain does not tell you
It does not show what you will actually pay. The displayed spread is for a small order; a larger one fills across it. On this site’s shared series a round trip on the underlying measures about 2% of the median bar range of 0.493, and an options spread is routinely a multiple of that in percentage terms.
It presents an untraded strike with the same confidence as an active one. Only the open interest and volume columns distinguish them, which is why they are not optional.
The columns worth knowing
Bid and ask are what you can transact at, and their midpoint is a reasonable estimate of fair value for a liquid contract and a fiction for an illiquid one.
Open interest is how many contracts exist, which is the closest thing the chain has to a liquidity measure.
Implied volatility is the market’s price for movement, expressed as a rate. It is the field that explains most otherwise puzzling price differences between similar contracts.
And the Greeks describe sensitivity — how the contract’s price responds to the underlying moving, to time passing and to that volatility figure changing.
Reading the two halves
Calls and puts sit on opposite sides of the same strike column. The strike is shared; everything else on the row belongs to one side or the other.
Above the current price, calls are the cheaper side and puts the expensive one. Below it, that reverses. The strike nearest the underlying is where the two are closest, which is why it works as the anchor for reading outward.
The same strike and expiry on both sides are linked by arithmetic, not by sentiment. A large price difference between them that is not explained by where the underlying sits is usually a stale quote rather than an opportunity.
Reading one side at a time is faster than reading across. Pick the side your view needs and ignore the other entirely until you have chosen a strike.
The original data
Of the 24,971 unique videos in research/search-study-corpus.jsonl, 3 mention the options chain in
the title, at a median of 1,440 views across 3 channels — and none of the 3 is instruction-shaped. Call
options appear in 13 at 77,171 and puts in 23 at 56,794. The counts come from site/corpus_count.py.
3 videos on reading the chain against 36 on the contracts it lists. The screen every options trade is placed from has effectively no instructional coverage, while the instruments displayed on it have a combined audience in the millions.
The answer to the question on that chart is that cheap and untraded usually mean the same thing. A contract with almost no open interest can be bought and then has no natural counterparty when you want out. The price you analysed and the price you could exit at are different numbers.
When it fails
The failure is reading the chain as a shopping list, and the cheap rows are the trap. Strikes far from the underlying show small numbers, which reads as a small cost rather than as a low probability of ever being worth anything. The chain displays them identically to every other row, sorted neatly by price, with nothing on the screen indicating that the number is small because the outcome is unlikely.
The second failure is reading last price. On a quiet contract it is stale.
A third is ignoring open interest. Entering is not the difficulty; leaving is.
A fourth is comparing across expiries at a glance. They are separate markets.
A fifth is leaving every column on. The grid stops being readable.
And a sixth is treating the midpoint as a fill. On a wide spread, nobody is there.
Related
Options covers what the contracts are. Strike price is the field the whole grid is organised around. And open interest is the column that separates a tradeable strike from a listed one.
What made it readable was ignoring almost every column. The chain shows a dozen fields because different people need different ones, not because any one person needs them all. Bid, ask, and open interest answer most of what I want, and adding the rest back only when I have a question they answer.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.