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The world's leading
independent volatility indexes.

Five precision-engineered indexes that strip away the distortions of legacy vol measures — giving you a clean, real-time read on what options are actually pricing.

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VolDex®
A better way to measure option volatility
VolDex® focuses on the options that matter most—at-the-money (ATM) options with near-term expirations—giving a cleaner, more accurate view of implied volatility.

By isolating these highly liquid and actively traded contracts, VolDex avoids the distortion caused by less relevant, far out-of-the-money options. The result is a more precise snapshot of market expectations for price movement and investor sentiment—without the noise.
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CallDex®
A clearer signal of bullish sentiment & expected volatility
CallDex® tracks the cost of out-of-the-money call options to gauge market sentiment for the next 30 days. It uses call options that are one standard deviation out-of-the-money to measure what investors are expecting in terms of both volatility and potential price direction.

Higher CallDex values generally suggest traders are anticipating bigger moves or a possible market rally. Lower values indicate a calmer outlook or reduced interest in upside exposure.
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PutDex®
Focused on downside risk pricing
PutDex® delivers a clear, strike-specific measure of implied volatility by concentrating on one key data point: the normalized cost of a 30-day, one standard deviation out-of-the-money (OTM) SPY put option.

This approach isolates the segment of the options market most directly associated with downside protection, removing the noise from less relevant strike prices. The result precisely indicates market sentiment around tail risk, hedging activity, and bearish positioning.

By zeroing in on these put options—widely used by institutional investors to protect against market declines—PutDex offers valuable insight into how much investors are willing to pay to insure against losses over the next month.
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RiskDex®
A Clear Signal of Expected Market Direction
RiskDex® measures investor sentiment by comparing the normalized cost of 30-day, one standard deviation out-of-the-money (OTM) SPY put and call options. This simple ratio reveals whether the market is more focused on downside protection or upside opportunity — offering a direct view of expected equity direction over the next month.

Unlike traditional volatility indexes, which reflect overall price movement, RiskDex highlights directional bias. A rising RiskDex indicates OTM put prices are increasing at a faster rate than OTM call prices and suggests growing concerns about potential declines; a lower reading signals confidence or complacency.

This makes RiskDex a valuable tool for traders and risk managers seeking clarity on where the market thinks it's headed—not just how volatile it might be.
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TailDex®
A smarter signal for downside risk & tail hedging demand
TailDex® measures the price of deep out-of-the-money put options to assess bearish sentiment and demand for tail risk protection over the next 30 days. By focusing on puts that are three standard deviations OTM, it reflects how concerned traders are about a major downside move, often called a 'tail event'.

Higher TailDex values suggest rising demand for crash protection or increased fear of large selloffs. Lower values imply a calmer market tone and less urgency to hedge against tail risk.
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What the Heck is Option Dispersion?

by | Feb 19, 2026 | Education

Option Dispersion is a Powerful Tool but What the Heck is It?

Dispersion trading is a powerful strategy for option traders but what the heck is it? Let’s find out.

Dispersion Trading

Stock option dispersion trading is an advanced strategy that exploits differences between index options and options on individual stocks within that index. It lets traders speculate on how much stock returns will “spread out” or diverge from each other, without predicting overall market direction.

Core Idea
Imagine the S&P 500 index, made up of 500 stocks (okay, it actually has more than 500 stocks but that’s not important). The index moves little if stocks cancel each other out—one rises 5%, another falls 5%, averaging near zero (assuming they have similar weightings in the S&P 500). But individual stocks can swing wildly. Dispersion measures this spread in returns: high dispersion means stocks diverge a lot as in our example; low means they move together. The goal of dispersion trading is, usually, for the trader to profit when individual stock options rise or fall significantly while those moves cancel each other out so that the index doesn’t move and index options don’t move.

Basic Trade Setup
The classic “long dispersion” trade sells options on the index (like the SPY straddle) and buys options on its stocks (e.g., straddles on top 10 components, weighted by size). You collect premium from the “cheap” index volatility as the index doesn’t move much but pay for “richer” stock volatility in expectation of the individual stocks moving. If stocks disperse (high individual vol, low correlation), stock options explode in value offsetting the index loss. Reverse it (“short dispersion”) for when stocks herd together, like in crashes.

Why It Works
Index implied volatility often overprices correlation—markets expect stocks to move in lockstep more than they do. Realized dispersion often beats expectations, creating an opportunity for profit.

Risks
The risk is that individual stocks don’t move enough and the long straddles on those names erode away while the erosion collected from the short index option position doesn’t pay enough to cover this loss. Another risk revolves around the fact that a true dispersion trade would short index volatility and get long volatility in each of the names in the S&P 500 (weighted appropriately which is not easy since each name will have a different implied volatility, etc.). That’s not realistic for a couple of reasons including that once you get below the top 100 names in the S&P 500 the corresponding option markets are really wide making the bid/ask spread prohibitively expensive. Correlation spikes (e.g., market panic) are another risk because they hurt long dispersion—index vol soars but the individual components move in tandem as correlation increases.

In practice, dispersion trades have to select the right constituents of the underlying index to get a fair representation of the index that isn’t over weighted in some sector while selecting few enough names to make the trade feasible. Then the trader can “gamma scalp” the individual names profitably while paying the price for being short the index volatility by scalping that gamma. Since the trader is short index vol these index gamma scalps will cost money.

Dispersion is an interesting trade and while the average trader will never execute it, understanding the how and why of dispersion trading will deepen your understanding of option markets in general.

All our index values are available in real-time at NationsIndexes.com where our goal is to make you a better trader by providing objective data so you don’t have to rely on a hunch or guess.

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