What it is. dark pool prints: Dark pools are private, off-exchange venues (ATSs) where large institutional block orders execute without displaying pre-trade quotes to the public market. Trades still print to the FINRA Trade Reporting Facility (TRF), but with a delay and no venue attribution beyond the aggregated TRF tape.
How to read it. Watch dark-pool share of total volume (typically 40-50% market-wide) and specific large prints, especially blocks 100k+ shares executed near or above the ask. A rising dark share on a stock during a downtrend often signals institutional accumulation; a spike during a rally can signal distribution.
Why it matters. Roughly half of all US equity volume trades off-exchange. Tracking dark-pool prints lets retail traders infer institutional positioning that's invisible on Level 2. Combined with SEC 13F filings (quarterly, lagged) and Form 4 insider transactions, dark-pool tape gives a real-time proxy for smart-money flow.