Given that financial series are poorly described by Gaussian distributions, how can the volatility behavior of such series be explained? Here we put forward a possible explanation to add the existing ones. We focus on a class of reduced variables that are independent and identically distributed....

We revisit the finding that crashes can be deterministic and governed by log-periodic formulas [D. Sornette, A. Johansen, Significance of log-periodic precursors to financial crashes, Quant. Finance 1 (2001) 452–471; D. Sornette, W.X. Zhou, The US 2000–2002 market descent: how much longer and...