both the market's return and volatility. The results suggest that the day after the referendum, there was little evidence … of a positive effect on stock returns. However, using a longer window of three days before and after the referendum …, there was evidence of a positive effect from the referendum on the market's returns and a negative effect on its volatility …

following the surprise outcomes of the Brexit referendum and the 2016 U.S. presidential election, bid-ask spreads increase …