Options Volume by Strike Chart

Direct answer: Options volume measures contracts traded on a given day; open interest counts all currently open contracts at each strike. High open interest at specific strikes reveals where large positions have accumulated, influencing market maker hedging flows that can create price stickiness or amplification near those levels. The distribution across strikes is used to calculate max pain, gamma exposure, and sentiment readings by strike.

By Swoopr Editorial Team AI tools may assist with research and drafting. Swoopr Investment is responsible for all published content. Published August 15, 2026

Volume vs. Open Interest: What Each Measures

Options volume and open interest are both reported per strike and expiration, but they measure different things:

Volume

Volume counts the number of contracts that changed hands during the current trading session. Each trade increments the volume counter regardless of whether the trade opened a new position or closed an existing one. Volume resets to zero at the start of each trading day and reflects current trading activity, making it useful for identifying strikes attracting immediate attention.

Open interest

Open interest counts the total number of contracts that are open (have not been closed, expired, or exercised) as of the previous session's close. When a buyer and seller both create new positions, open interest increases by one. When an existing contract holder closes their position by trading with someone who is also closing (not opening), open interest decreases. Open interest grows over time as more positions are established and shrinks as they are unwound or expire.

A strike with high volume but low open interest suggests short-term speculative activity with little position buildup. A strike with high open interest but low volume shows where large positions were established in prior sessions and are still held. The most significant strikes are often those with high open interest, since those positions involve the largest aggregate hedging requirements.

Max Pain: Where Option Buyers Hurt Most

Max pain is the stock price at expiration that would result in the greatest total dollar loss for all open options buyers as a group. It is found by calculating, for each possible expiration price, the total intrinsic value that would need to be paid out on all in-the-money options, then identifying the price that minimizes this total payout.

The mechanics: as the stock rises, calls gain value (costing call sellers more) while puts lose value (benefiting put sellers). As the stock falls, the reverse is true. The max pain strike is where the sum of all ITM call values plus all ITM put values is minimized, leaving the most options worth zero at expiration.

Max pain theory is controversial. Critics argue that market makers do not have the ability or incentive to manipulate prices toward this level, and that observed convergence toward max pain is often coincidence or a reflection of mean-reversion tendencies. Proponents argue that the massive delta-hedging flows around high open interest strikes create natural price gravity near expiration. Either way, max pain is worth knowing as context, not as a standalone trading signal.

Gamma Exposure (GEX) by Strike

Gamma exposure (GEX) translates open interest data into an estimate of how many dollars of stock must be bought or sold by market makers for each one-percent move in the underlying. It is calculated for each strike by multiplying gamma by open interest by shares per contract by the stock price.

GEX can be aggregated across all strikes and expirations to produce a single "net dealer gamma" figure. The sign and magnitude of this figure reveal the market's structural sensitivity to price movements:

Positive GEX (net long gamma): Dealers buy the underlying when it falls and sell it when it rises, dampening price swings. Markets with large positive GEX tend to exhibit lower intraday volatility and range-bound behavior.
Negative GEX (net short gamma): Dealers must buy the underlying when it rises and sell it when it falls (to stay delta-neutral on their short options), amplifying price movements. Markets with large negative GEX tend to exhibit higher intraday volatility and trending behavior.

GEX analysis is most useful around heavy open interest expirations (monthly and quarterly options expiries) and for highly liquid large-cap stocks and index products where options market makers are significant participants in the underlying market.

Options Pinning: Price Gravity Near Expiration

When a stock's price is near a strike with large open interest as expiration approaches, market maker hedging can create a "pinning" effect. The mechanism works as follows:

Assume dealers are short 10,000 ATM calls at the $100 strike with one day to expiration. When the stock is at $100, these calls have delta near 0.50, and dealers hold roughly 500,000 shares of stock as their delta hedge (50 delta per call, 100 shares per contract, 10,000 contracts). As the stock rises to $101, those calls become slightly ITM with delta near 0.65. Dealers must now buy additional shares to increase their hedge from 500,000 to 650,000 shares. Conversely, if the stock falls to $99, the calls become slightly OTM with delta near 0.35, and dealers must sell shares, reducing the hedge from 500,000 to 350,000 shares.

This continuous rebalancing creates opposing flows that tend to push the stock back toward $100. Buys above the strike (dealers adding to hedge as calls gain delta) and sells below the strike (dealers reducing hedge as calls lose delta) both work to compress the stock's range around the high open interest strike near expiration.

FAQ

What is the difference between options volume and open interest?

Options volume is the number of contracts traded during the current trading session. Open interest is the total number of open (not yet closed or expired) contracts at a given strike and expiration. Volume resets to zero each day and reflects current activity, while open interest accumulates over time and shows where positions have been established. High volume at a strike signals current trading interest; high open interest signals where large positions have been built up over days or weeks.

What is the max pain theory in options?

Max pain theory holds that stock prices tend to move toward the strike price at which the total dollar value of open options contracts (both calls and puts) would be minimized, causing the maximum financial pain to options buyers as a group. This max pain strike is where the aggregate payout to all option holders would be lowest. The theory posits that market makers, who typically hold net short options positions, have incentive or ability to guide the stock toward this level near expiration. Max pain is a contested concept and not a reliable predictive tool on its own.

What is options pinning near expiration?

Options pinning refers to the tendency for a stock's price to gravitate toward a strike with large open interest as expiration approaches. When a stock is near a strike with massive open interest, market makers holding large delta exposures must continuously buy or sell the underlying to stay delta-neutral. This rebalancing creates a self-reinforcing dynamic: a stock near the strike gets pushed back toward it each time it moves slightly away, because of the opposing hedging flows triggered at that level. Pinning is most pronounced in heavily traded, liquid options with weekly or monthly expirations.

How is gamma exposure (GEX) by strike calculated?

Gamma exposure (GEX) at each strike is calculated by multiplying the gamma per contract by the open interest at that strike, by the number of shares per contract (typically 100), and by the current stock price. The result, often expressed in dollar terms, estimates how many dollars of stock market makers must buy or sell for each one-percent move in the stock. Positive GEX (dealers net long gamma) tends to suppress price volatility. Negative GEX (dealers net short gamma) can amplify moves. Summing GEX across all strikes gives total market GEX.

How can the put/call ratio by strike be used as a sentiment indicator?

The put/call ratio at each strike compares the open interest or volume of puts to calls. High put/call ratios at strikes below the current price can indicate hedging demand (investors protecting long stock positions) or bearish speculation. High call/put ratios above the current price suggest call buying (bullish bets or covered call selling). Unusually high put volume at a specific strike may signal institutional hedging at that level, which can act as an informal support indication. These are signals to consider alongside other context, not standalone predictors.

Why do large open interest strikes sometimes act as support or resistance?

Strikes with large open interest attract hedging activity. When a stock approaches a strike where market makers are short many calls, those dealers must buy the underlying as it rises (to stay delta-neutral on their short call exposure), creating buying pressure that can slow the advance. Similarly, approaching a strike where dealers are short many puts creates selling pressure as they sell the underlying to stay neutral. This dealer hedging behavior around large open interest strikes can produce temporary price stickiness, though it does not reliably act as hard support or resistance.

What does a sudden spike in options volume at a single strike indicate?

A sudden spike in volume at a single strike, particularly in calls far above the current price or puts far below it, can indicate several things: large speculative positioning ahead of an expected catalyst, institutional hedging of an equity position, or a block trade from a sophisticated market participant. Unusual options activity at a specific strike is sometimes monitored as a sentiment signal, though it can also reflect routine hedging by a large stockholder. Without knowing whether the contracts were bought or sold, and whether to open or close positions, the directional interpretation is ambiguous.

References

Disclaimer

This article is for educational and informational purposes only. It does not constitute personalized investment, financial, or tax advice. Options trading involves significant risk, including the possible loss of the entire premium paid. All numerical examples are hypothetical and for illustration only. Consult a qualified financial professional before making trading decisions.

Options Volume by Strike: Reading the Open Interest Chart