Financial crises are often characterized by sharp reductions in liquidity followed by cascades of falling prices. Researchers are making progress in work to understand the levels of liquidity on a daily basis, but understanding the vulnerability of liquidity to market shocks remains a challenge....

During liquidity shocks such as occur when margin calls force the liquidation of leveraged positions, there is a widening disparity between the reaction speed of the liquidity demanders and the liquidity providers. Those who are forced to sell typically must take action within the span of a day,...