Earlier this year, markets were spooked by blow-ups in a number of volatility-linked products. But dealing with volatility is the foundation of risk management on Wall Street and there's a particular model that's become pervasive among big investors and banks -- so-called Value-at-Risk (VaR) models seek to gauge how much a portfolio might gain or lose based on historic price movements. On this week's episode of the Odd Lots podcast, we speak to one of the original creators of VaR. Till Guldimann explains how he came up with the model while at JPMorgan, plus how it works, its limitations, how it can be gamed, and what he thinks of the volatility landscape now.