Dark Pools: Where the Size Trades

Imagine needing to buy two million shares. Post that on the open market and the price runs away from you before you're a tenth done — everyone sees you coming. Dark pools let institutions match large trades privately, at prices tied to the public market, without broadcasting intent. Less spooked prey, better fills. It's rational, not sinister.

Off-exchange trades must still be reported after execution — the prints reach the public record, just without the advance warning an open order gives. That's the crack in the curtain: you can't see the size coming, but you CAN see where it landed. Reading those after-the-fact prints is the actual skill here.

One big off-exchange print means little — remember, everything has innocent explanations. The interesting pattern is a name whose dark-pool share of volume runs far above its own normal for days, especially near one price level. That smells like a campaign: someone large, patient, and price-sensitive, accumulating or distributing. Still a lead, not a verdict — but a strong lead.

A print tells you size changed hands, not which side was eager. Serious readers infer direction from context — where the trade priced relative to the public quote, what the stock did after, whether options flow leans the same way. This inference is genuinely hard, which is why our engine scores dark-pool pressure as one ingredient among many rather than treating any print as gospel.

You don't need a terminal to keep the concept: when a stock moves on light VISIBLE volume, ask what the invisible 40% was doing. When our dashboard flags unusual off-exchange activity, you now know exactly what that means — the big fish moved, the ripples are public, and it's one clue in the stack.