Voluntary pre-trade anonymity and market liquidity

Abstract

This paper analyses the effects on liquidity of voluntary pre-trade anonymity in the trading process. We confirm previous studies showing that market liquidity improves immediately after anonymous trading. Using the daily percentage of effective volume traded anonymously, we show that the anonymity-liquidity relationship presents a non-linear U-shape. We focus on the voluntary concealment of broker identification introduced by the Spanish Stock Exchange in October 2015. We conclude that, in our sample, anonymity increases stock liquidity but at a decreasing rate; when a considerable part of the effective volume is traded anonymously, additional percentages of anonymous trading deteriorates stock liquidity.