We develop a new methodology to estimate the impact of a financial transaction tax (FTT) on informational efficiency, liquidity and volatility. In our sequential trading model there are price elastic noise traders and traders with private information of heterogeneous quality. We estimate the...

We propose new methods for estimating the bid-ask spread from observed transaction prices alone. Our methods are based on the empirical characteristic function instead of the sample autocovariance function like the method of Roll (1984). As in Roll (1984), we have a closed form expression for...

Many controversies that beset the digital economy turn on the role of advertising and its use of personal data. We examine the trade-off between privacy and ad targeting accuracy from the advertisers' perspective. By exploiting Apple's gradual restriction, and ultimately the abolition of ad...