Anonymous Trading in Equities

Abstract

In this paper, I explore a reform at the Oslo Stock Exchange to assess the causal
effect of post-trade trader anonymity on stock liquidity and trading volume. Using a regression discontinuity approach, I find that anonymity leads to a reduction in bid-ask spreads of 40% and an increase in trading volume of more than 50%. The increase in trading volume is accounted for largely by increased trading activity by institutional investors, while retail investors do not adjust their trading behavior in response to anonymity. The results suggest that post-trade anonymity positively affects standard measures of market quality.