Multifractal analysis of stock exchange crashes

► Strong multifractal properties meaning that temporal correlations play a substantial role during an extreme event. ► Aftershock periods exhibit richer and more complex dynamics than the foreshock period. ► The 1929 and 1987 events display strong antipersistent behavior, rejecting the Efficient Market Hypothesis. ► 1929 crash display greater degree of mulitfractality than the 1987 event.