# Dark Pool Prints Also known as: DIX. A Breadth, Sentiment & External Data reference entry (Positioning & flows) in the LuxAlgo Library: explained, not implemented as a chart indicator. ## What are dark pool prints? Dark pool prints are trades executed on off-exchange venues, alternative trading systems that display no public order book, and then reported to the consolidated tape through FINRA's trade reporting facilities. The 'print' is the after-the-fact report; the pre-trade interest was never visible. Institutions use these venues to work large orders with less market impact. Off-exchange trading is a large slice of the US equity market: in recent years roughly 40% or more of share volume has executed away from exchanges, though much of that is retail flow filled by wholesalers rather than institutional dark pool blocks. FINRA publishes venue-level ATS volume weekly, on a delay. The best-known derived gauge is the Dark Index (DIX) from SqueezeMetrics, which aggregates off-exchange short-marked volume in S&P 500 constituents. Because market makers filling customer buy orders often report their own side short under the marking conventions, a high share of short-marked off-exchange volume is interpreted, in this framework, as passive buying pressure. High DIX readings are read as quiet accumulation. ## How to read dark pool data Public and vendor sources exist, each with sharp caveats. 1. FINRA's OTC transparency site shows weekly share volume per ATS and per stock, useful for seeing where off-exchange trading happens, weeks late. 2. FINRA's daily short sale volume files give the short-marked share of off-exchange volume, the raw ingredient of DIX-style gauges. 3. Vendor dashboards flag unusually large single prints; treat these as footprints of institutional interest without assuming direction, since a print does not reveal the aggressor. 4. For aggregate sentiment, compare a gauge like DIX against its own history and against what market breadth is doing, not as a standalone trigger. ## Why there's no indicator for this The consolidated tape a charting platform receives does not attribute prints to specific venues in a way an OHLCV indicator can use, and the datasets behind dark pool analysis live elsewhere entirely: FINRA's daily short sale volume files, its weekly ATS transparency statistics published on a two-to-four week lag, and proprietary aggregations such as DIX, whose exact construction belongs to its vendor. Even with that data, interpretation rests on reporting conventions rather than observed intent: a short-marked print shows how a trade was reported, not who initiated it or why. Proxies built this way can summarize off-exchange activity, but no honest chart indicator can extract 'dark pool buying' from price and volume. ## How traders use it - Accumulation reads: elevated dark-pool buying gauges during pullbacks are taken as a sign that passive buyers are absorbing supply, which some traders weigh alongside the vendor's paired [gamma exposure](https://www.luxalgo.com/library/concept/gamma-exposure/) measure. - Single-name block hunting: unusually large prints at notable sizes or prices are logged as evidence an institution is active, and those price levels are then watched as references. - Confirmation with internals: because dark pool signals are slow and ambiguous, desks cross-check them against [advance/decline internals](https://www.luxalgo.com/library/concept/advance-decline-internals/) and intraday gauges like the [TICK Index](https://www.luxalgo.com/library/concept/tick-index/). - Sentiment mosaics: DIX-style readings get combined with composites such as the [Fear & Greed Index](https://www.luxalgo.com/library/concept/fear-and-greed-index/) to judge whether visible fear is matched by hidden buying. ## Dark pool gauges vs other sentiment reads - **Gamma Exposure** (https://www.luxalgo.com/library/concept/gamma-exposure/): GEX infers dealer hedging pressure from options open interest; DIX infers passive buying from off-exchange prints. Published together by the same vendor, they answer different questions: constraint versus accumulation. - **Fear & Greed Index** (https://www.luxalgo.com/library/concept/fear-and-greed-index/): Composite sentiment indices blend visible market statistics into one dial; dark pool gauges try to read the flow those statistics miss. The first publishes its components, the second rests on proprietary inference from reporting conventions. ## FAQ ### Are dark pools legal? Yes. They are SEC-regulated alternative trading systems. Trades must be reported to the tape promptly after execution; only the pre-trade order book is hidden. ### What is the DIX? SqueezeMetrics' Dark Index: a sentiment gauge built from short-marked off-exchange volume in S&P 500 stocks, where higher readings are interpreted as more passive dark-pool buying. Its precise construction is proprietary. ### Does a big dark pool print mean someone is buying? Not by itself. A print records a completed trade between two parties and does not show which side initiated it. Direction is inferred, often shakily, from marking conventions or subsequent price behavior. ### Why is dark pool data delayed? Venue-level detail comes from FINRA's transparency program, which publishes ATS volumes weekly on a two-to-four week lag. Only aggregated daily short-volume files and vendor estimates are available sooner. ## Related concepts - COT Analysis: https://www.luxalgo.com/library/concept/cot-analysis/ - Margin Debt: https://www.luxalgo.com/library/concept/margin-debt/ - Short Interest: https://www.luxalgo.com/library/concept/short-interest/ - Insider Transactions: https://www.luxalgo.com/library/concept/insider-transactions/ - Buyback Flows: https://www.luxalgo.com/library/concept/buyback-flows/ - Fund Flows: https://www.luxalgo.com/library/concept/fund-flows/ - 13F Concentration: https://www.luxalgo.com/library/concept/13f-concentration/ - Odd-lot Activity: https://www.luxalgo.com/library/concept/odd-lot-activity/ --- Source: https://www.luxalgo.com/library/concept/dark-pool-prints/ (LuxAlgo Library, the encyclopedia of trading & technical analysis). Free to use with attribution: https://www.luxalgo.com/library/license/