The effects of data breaches on the stock price in the period 2016-2018

Event study methodology was used to study the effect of data breaches on the stock price in the period 2016-2018 for 123 firms noted on the United States stock market. In contrast to most previous works in earlier periods, no significant results were found indicating an effect in this period. This is in line with a declining trend found before when researching data breach effects. The effect of the size of a data breach on the reaction on the stock price was also studied. The size of the data breach did not have a significant effect on the stock price reaction.