Stats › Active, passive and flows › Off exchange trading

Off exchange trading and dark pools

Flows/market structure · 2025 and 2026 · Cboe and SEC · 4 sources · data as of 31 Jul 2026

When you press buy in your broker's app, you probably picture your order flying off to an exchange and meeting somebody else's sell order. For most retail orders in US shares, that isn't what happens. More than half of US equity volume now executes without touching a public exchange at all, 50.6% across 2025.

The word people reach for here is dark pools, and that's the part I most wanted to correct. Dark pools are the small piece. Of all that off exchange volume, only 18.7% went through what a dark pool actually is, an alternative trading system. The other 81.3% went to principal dealers, better known as wholesalers, which are market making firms that simply take the other side of your order out of their own inventory.

So the page covers three things: how much trading happens off exchange and how that's moved, what the split between pools and wholesalers actually is, and how concentrated the wholesaler side is. On that last point, four firms handled 94% of retail marketable orders in a Federal Reserve study. Thirty registered exchanges compete for the public half of the market. Four firms handle almost all the retail flow that doesn't go there. Fair warning on the numbers: they move around by several points depending on who published them and which month, and I've kept that visible rather than smoothing it. Four sources, each dated, all at the bottom.