How Do Different Trading Venues (E.g. Dark Pools) Affect Volume and Spread?

Dark pools are private exchanges that allow institutional investors to trade large blocks of securities anonymously, without impacting the public bid-offer spread. While they reduce the visible volume on public exchanges, they can improve overall market quality by executing large orders without widening the public spread.

However, the fragmentation of volume can also reduce the depth of the public order book.

Are Dark Pools Used in Cryptocurrency Markets to Prevent Information Leakage?
How Does Delta Hedging Relate to the Need for Large, Non-Public Trades in the Underlying Asset?
In a Dark Pool, How Does the Execution of a Limit Order Differ from a Public Exchange?
How Can a Large Market Order Affect the Bid-Offer Spread Itself?
Does the Trading Volume on a Dark Pool Contribute to the Public’s Perception of Market Liquidity?
What Are “Dark Pools” and How Do They Affect the Calculation of the Effective Spread?
How Does Batching Relate to the Concept of a ‘Block Trade’ in Traditional Finance?
What Are the Main Differences between Executing a Large Trade via an Iceberg Order versus in a Dark Pool?

Glossar