Abstract
One measure of the ex ante cost of disasters is the welfare gain from shorten-ing their expected duration. We introduce a stochastic clock into a standard disaster model that summarizes information about progress (positive or negative) toward disaster resolution. We show that the stock market response to duration news is essentially a sufficient statistic to identify the welfare gain to interventions that alter the state. Using information on clinical trial progress during 2020, we build contemporaneous forecasts of the time to vaccine deployment, which provide a measure of the anticipated length of the COVID-19 pandemic. The model can thus be calibrated from market reactions to vaccine news, which we estimate. The estimates imply that ending the pandemic would have been worth from 5% to 15% of total wealth as the expected duration varied in this period.