Our Indexes

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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How to Read the Position Sizer

Vol-Targeted Position Sizer · Foundations

Free to read

How to Read the Position Sizer

Enter the underlying, your vol target, and your capital. The tool returns a regime-adjusted size in shares or notional. Here's how to work every number on the screen.

The Position Sizer has three inputs and one output. The inputs drive the calculation; the output is the number you actually trade. The regime panel in between is the most important thing to understand before you enter the first trade.

The three inputs

At the top of the tool: Underlying — the ticker you're sizing. Below it, Volatility Target — the annualized vol contribution you want this position to represent, expressed as a percentage of capital (a typical starting point is 0.5%–1.5% per position). Finally, Account Capital — the dollar base the percentage applies to. These three numbers are all the tool needs to produce a first-pass size before the regime adjustment.

The tool layout UnderlyingSPY ▾ Vol Target1.0 % ▾ Capital$100,000 REGIME PANEL Realized vol (1yr pctile): 92nd VolDex® 30d: 14.8% RiskDex®: 3.33 Regime: STRESSED OUTPUT Size multiplier: ×0.45 Adj. size: 81 shares / $34,083 Full (unscaled) size: 180 shares / $75,740

Left column: three inputs. Right top: the live regime panel — realized-vol percentile, VolDex® 30d, and RiskDex® combine to classify the regime and set the multiplier. Right bottom: the output — regime-adjusted share count and notional.

Reading the regime panel

The regime panel is the most important section of the tool. It shows three live readings: the underlying's realized-vol percentile over its trailing year, today's VolDex® 30-day implied vol, and the RiskDex® reading. Together they classify the current regime — Calm, Elevated, or Stressed — and set the size multiplier that scales your inverse-vol result. A Stressed regime with a 92nd-percentile realized vol might deliver a multiplier of ×0.45; a Calm regime at the 20th percentile runs near ×1.0.

What the output numbers mean

The tool shows two sizes side by side: the full (unscaled) size — what the inverse-vol formula alone would deliver without any regime adjustment — and the regime-adjusted size, which is the number you trade. The multiplier is the ratio between them. Seeing both helps you understand how much the regime filter is cutting your gross exposure relative to a naive vol-targeting approach. In a calm market the two numbers converge; in a stressed market the adjusted size may be less than half the unscaled figure.

Two things to check before trading

Check — Is the realized-vol percentile pulled from an adequate history? If the underlying is newly listed, the trailing year may be thin. The tool flags this when fewer than 252 trading days of history are available.
Check — Does the vol target match the rest of your book? Sizing one position to 1% and another to 3% defeats the equalizing purpose of the framework. Use a consistent target across all positions, then vary it only deliberately.
Do it live

Reading the layout is free. To calculate live sizes: ETFs with ETF Analytics, single stocks with ETF + Equities. The full regime-multiplier table and Nations-index feed require Everything.

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Educational content from Nations Indexes. VolDex® and RiskDex® are registered marks of Nations Indexes. Diagrams are schematic. Nothing here is investment advice.

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