Did Spillovers From Europe Indeed Contribute to the 2010 U.S. Flash Crash?

Using intraday data, we study spillovers from European stock markets to the U.S. in the hours before the flash crash on 6 May 2010. Many commentators have pointed to negative market sentiment and high volatility during the European trading session before the Flash Crash. However, based on a range of vector autoregressive models, we find no robust evidence that spillovers increased at that time. On the contrary, spillovers on 6 May were mostly smaller than in the preceding days, during which there was great uncertainty surrounding the Greek sovereign debt crisis. The absence of evidence for spillovers underscores the difficulties in understanding the nature of flash events in financial markets.