What DIX is
FINRA publishes, every session, how much of each stock's off-exchange volume was reported as a short sale. SqueezeMetrics turns that into a per-stock dark pool short share and averages it across S&P 500 members, weighted by dollar volume. The result is DIX: one number per session, usually between 40% and 50%.
How to read it, and what it is not
Most short volume in these files is market makers and liquidity providers selling short to fill customer purchases, then covering. That is why SqueezeMetrics argues a higher DIX reflects more buying demand routed through dark pools, the opposite of what the word "short" suggests. It remains a derived index: it shows no individual trade, size, venue or price, and a reading says nothing certain about what the market does next.
This page describes each reading by where it ranks in its own window of about one trading year: high at or above the 80th percentile, low at or below the 20th, typical in between. That is a description of the series, not a buy or sell signal.
Source and timing
Source: the SqueezeMetrics DIX series, built from FINRA daily short sale volume files. It updates once per session after the close; each reading is dated by the session it describes. When the source does not answer, this page keeps the last published reading with its own date.
DIX explained covers the method in more depth. The dark pool flow page shows a clearly labeled modeled activity view; none of it is real trade data, and none of it is used here.
COMMON QUESTIONS
- What is the dark pool index (DIX)?
- DIX is a daily index published by SqueezeMetrics: the dollar-weighted share of off-exchange (dark pool) volume in S&P 500 stocks that FINRA reports as short sales. It is around 40 to 50 percent on most days.
- Is a high DIX reading a bullish sign?
- This page does not call any reading bullish or bearish. Short volume in these files is mostly market makers selling short to fill customer purchases, so a high reading says where volume was printed, not who was buying. Each reading is described by where it ranks in its own one-year window: high, typical or low.
- When is DIX updated?
- Once per trading session, after the close, when FINRA publishes its daily short sale volume files and SqueezeMetrics updates the series. Every reading on this page carries the session date it describes.
- Is DIX the same as a dark pool print?
- No. DIX is a derived daily index across the S&P 500. It does not show individual trades, sizes, venues or prices, and SquawkFlow does not publish dark pool prints.