The Triggers and Clustering Properties of Merger Waves

This paper studies the triggers and the agglomeration of M&A activity within clusters constituted by time, market and industry. Based on almost 500,000 individual transactions, we find that industry factors play a significant role in triggering activity and that M&A agglomerates strongly across related industries. While clustering in time turns out to be insignificant, stock-market effects can be either an attracting or a repelling force, depending on the type of deal examined. This supports the view that merger waves are largely driven by industry shocks.