Andersen and Bondarenko's paper “VPIN and the Flash Crash” is essentially a comment on our 2011 Journal of Portfolio Management paper using our measure of order toxicity, VPIN. Andersen and Bondarenko dispute our empirical findings and argue that VPIN essentially does not work. This is...

In the current credit crisis there is little or no trade in a variety of financial assets, even though bids and asks exist for many of these assets. We develop a model in which this illiquidity arises from uncertainty, and we argue that this new form of illiquidity makes bid and ask prices...

The ‘flash crash' of May 6th 2010 was the second largest point swing (1,010.14 points) and the biggest one-day point decline (998.5 points) in the history of the Dow Jones Industrial Average. For a few minutes, $1 trillion in market value vanished. In this paper, we argue that the ‘flash...

Order flow is toxic when it adversely selects market makers, who may be unaware they are providing liquidity at a loss. We present a new procedure to estimate flow toxicity based on volume imbalance and trade intensity (the VPIN toxicity metric). VPIN is updated in volume-time, making it...