While herding has long been suspected to play a role in financial market booms and busts, theoretical analyses have struggled to identify conclusive causes for the effect. Recent theoretical work shows that informational herding is possible in a market with efficient asset prices if information...

We undertook the first market trading experiments that allowed heterogeneously informed subjects to trade in endogenous time, collecting over 2000 observed trades. Subjects’ decisions were generally in line with the predictions of exogenous-time financial herding theory when that theory is...