The ratio estimator of a firm's markup is the ratio of the output elasticity of a variable input to that input's cost share in revenue. This note raises issues that concern identification and estimation of markups using the ratio estimator. Concerning identification: (i) if the revenue...

We present cross-country empirical evidence on the role of natural resources in explaining long-run differences in private investment as a share of GDP in a sample of 72 developing countries.  Our empirical results suggest important differences between oil and non-oil resources.  While revenue...

This paper shows that, with (partial) irreversibility, higher uncertainty reduces the impact effect of demand shocks on investment. Uncertainty increases real option values making firms more cautious when investing or disinvesting. This is confirmed both numerically for a model with a rich mix...

This paper provides an empirical study of the effect of a transaction tax on share prices, using changes in the rate of stamp duty in the UK as quasi-experiments. Because the impact of a stamp duty is expected to depend on how frequently particular shares are traded, we employ a...