RiskPicksWhat is a Dark Pool?
A dark pool is a private exchange where large investors can buy and sell stocks without their orders being visible to the public market. The name comes from the fact that orders are "dark" (hidden) until after they execute. They exist because when a fund needs to buy or sell millions of shares, showing that order on a public exchange would move the price against them before the trade is complete.
How dark pools work
- Orders are submitted to the dark pool but not displayed on any public order book
- The dark pool matches buyers and sellers internally, usually at the midpoint of the public bid and ask (NBBO)
- Once a trade executes, it is reported to the public tape, usually within seconds
- The key benefit is that nobody sees the order before it fills, which prevents front-running and market impact
Who runs dark pools
- Broker-dealer dark pools: run by major banks like Goldman Sachs (Sigma X), Morgan Stanley (MS Pool), and JP Morgan (JPM-X)
- Independent dark pools: standalone venues like Liquidnet, which focuses on matching large block trades between institutional investors
- Exchange-owned dark pools: some public exchanges operate their own dark pool venues
Why retail traders pay attention
Dark pool prints (the trade reports that become public after execution) give retail traders clues about what institutional investors are doing. A large dark pool print at a specific price level can indicate institutional accumulation or distribution.
- A series of large dark pool buys may signal that a fund is building a position
- Large prints near support or resistance levels can confirm or invalidate those levels
- Dark pool volume as a percentage of total volume can indicate how much institutional interest a stock is getting
Controversy
Critics argue that dark pools reduce transparency and give institutional investors an unfair advantage over retail traders. The SEC has fined several dark pool operators for misleading subscribers about how orders were handled. Supporters counter that dark pools provide better execution for large orders and that trade data is still publicly reported after execution.
Dark pool trading accounts for roughly 40% of all US equity volume on a typical day. When you see "dark pool print" alerts in trading tools, those are completed dark pool trades that have been reported to the public tape.