DIX (Dark Pool Short Index) Explained: A Contrarian Market Indicator

What is DIX?

DIX (Dark Pool Short Index) is a metric developed by SqueezeMetrics that measures the proportion of short volume in dark pools for S&P 500 component stocks. Published daily, DIX has gained attention among traders for its counterintuitive ability to signal bullish conditions when short volume is high and bearish conditions when short volume is low.

The formula is simple: DIX equals the total short volume in dark pools divided by total dark pool volume, measured across all S&P 500 stocks. The result is a percentage, typically ranging between 40% and 50%.

## Why High Short Volume is Bullish

This is the part that confuses most traders. How can more shorting be a bullish signal? The answer lies in understanding who is doing the shorting and why.

In dark pools, the dominant participants are market makers and large institutional desks. When an institution wants to buy a large block of shares, the market maker on the other side of the trade technically "sells short" to provide that liquidity. The market maker does not hold the shares in inventory -- they sell short and then acquire the shares afterward to cover. This is a fundamental part of how market making works.

Therefore, high dark pool short volume often indicates that market makers are selling short to meet institutional demand for buying. More institutional buying demand means more market maker shorting, which means higher DIX. The signal is not that people are betting against the market -- it is that institutions are aggressively accumulating shares through dark pools.

Conversely, low DIX suggests that institutional buying has dried up. Market makers are not being asked to provide as much liquidity, so short volume drops. This absence of institutional demand can precede market weakness.

## Historical Accuracy

DIX gained widespread attention during the March 2020 COVID crash. In the days before the market bottomed on March 23, DIX surged to historically high levels, indicating massive institutional buying in dark pools even as the market was in freefall. Traders who followed the DIX signal were positioned to catch one of the most powerful rallies in market history.

Similarly, DIX has flagged several other notable turns. In late 2018, DIX spiked during the Christmas Eve selloff, correctly signaling a bottom. It also showed elevated readings before the recovery from the 2022 bear market lows.

However, DIX is not infallible. It can remain elevated for extended periods without an immediate rally, and it occasionally gives false signals. Like any indicator, it should be used as one input among many, not as a standalone trading system.

## How to Read DIX

**High DIX (above 45-46%)**: Institutions are aggressively buying through dark pools. This is a bullish signal, especially if it occurs during or after a market decline. The combination of high DIX and falling prices (institutional buying into weakness) has historically been one of the strongest buy signals.

**Low DIX (below 42-43%)**: Institutional buying has slowed. This can be bearish, especially if it occurs near market highs. The combination of low DIX and rising prices (rally without institutional participation) is a warning sign.

**DIX trend**: Beyond absolute levels, watch the direction. Rising DIX during a pullback suggests accumulation. Falling DIX during a rally suggests distribution.

## DIX and GEX Together

SqueezeMetrics publishes both DIX and GEX (gamma exposure). Together, they provide a powerful framework:

**High DIX + High GEX**: Institutions are buying, and dealer hedging is stabilizing the market. This is the most bullish combination -- expect a low-volatility grind higher.

**High DIX + Low/Negative GEX**: Institutions are buying, but the market is in a volatile regime. Expect a rally but with larger intraday swings. This often occurs at market bottoms.

**Low DIX + High GEX**: Institutions are not buying aggressively, but dealer hedging is keeping volatility low. This is a complacent market that could crack if GEX deteriorates.

**Low DIX + Low/Negative GEX**: Institutions are not buying, and the market is in a volatile regime. This is the most bearish combination and often corresponds to persistent downtrends.

## Accessing DIX on SquawkFlow

SquawkFlow integrates dark pool metrics including DIX into the dashboard, providing daily updates alongside gamma exposure data. This combination lets you quickly assess the institutional and structural backdrop without juggling multiple data sources.

Track this live on SquawkFlow

Real-time options flow, GEX dashboard, dark pool alerts, and AI narration — free.

Related Articles