Liquidity Cost Premia

The purpose of the paper is to find out the borrowing cost premia for those individuals who are liquidity-constrained, or who are first-time buyers of real estate. The analysis uses the similarity of a leveraged purchase with the exercise of a call option to defer the purchase of the asset. Sensible parameters are selected for the option, and simulations are run to identify the cost premia. The main conclusion is that these borrowing costs are prohibitive in central tendency and in dispersion. This means that liquidity-constrained individuals may be given borrowing quotations, but these quoted rates are so high and variable that these individuals are unwilling to borrow.     

Food crisis and export taxation: the cost of non-cooperative trade policies

This paper aims to assess the rationales for export taxes in the context of a food crisis. First, we summarize the effects of export taxes using both partial and general equilibrium theoretical models. When large countries aim to maintain constant domestic food prices, in the event of an increase in world agricultural prices, the optimal response is to decrease import tariffs in net food-importing countries and to increase export tariffs in net food-exporting countries. The latter decision improves national welfare, while the former reduces national welfare: this is the price that must be paid to keep domestic food prices constant. Small net food-importing countries are harmed by both decisions, while small net food-exporting countries gain from both. Second, we illustrate the costs of a lack of regulation and cooperation surrounding such policies in a time of crisis using a global computable general equilibrium (CGE) model, mimicking the mechanisms that appeared during the recent food price surge (2006–2008). This model illustrates the interdependence of trade policies, as well as how a process of retaliation and counter-retaliation (increased export taxes in large net food-exporting countries and reduced import tariffs in large net food-importing countries) can contribute to successive augmentations of world agricultural prices and harm small net food-importing countries. We conclude with a call for international regulation, in particular because small net food-importing countries may be substantially harmed by those policies that amplify the already negative impact of a food crisis.     

The log-moment formula for implied volatility

We revisit the foundational Moment Formula proved by Roger Lee fifteen years ago. We show that in the absence of arbitrage, if the underlying stock price at time T admits finite log-moments $\mathbb{E}[|\log S_T{|}^q]$ for some positive q, the arbitrage-free growth in the left wing of the implied volatility smile for T is less constrained than Lee's bound. The result is rationalized by a market trading discretely monitored variance swaps wherein the payoff is a function of squared log-returns, and requires no assumption for the underlying price to admit any negative moment. In this respect, the result can be derived from a model-independent setup. As a byproduct, we relax the moment assumptions on the stock price to provide a new proof of the notorious Gatheral–Fukasawa formula expressing variance swaps in terms of the implied volatility.