Due to the ability of cell phone providers to use cell phone towers to pinpoint users' locations, federal E911 requirements, the increasing popularity of GPS-capabilities in cellular phones, and the rise of cellular phones for Internet use, a plethora of new applications have been developed that...

We show that an increase in aggregate uncertainty - measured by stock market volatility - reduces productivity growth more in industries that depend heavily on external finance. The mechanism at play is that during periods of high uncertainty, firms that are credit constrained switch the...