Identifying thresholds in aid effectiveness

In this paper, the author focuses on the nonlinear nature of the aid to growth relationship to show that the “Big Push” hypothesis is consistent with capacity constraints in the understanding of aid effectiveness. The Big Push hypothesis proposes the existence of one threshold below which aid is not effective, whereas the constraints inferred by the concept of absorptive capacity suggest the existence of a second threshold above which aid is no longer effective. This paper addresses the issue of these thresholds which characterize the aid to growth relationship. Using a semi-parametric econometric method, the author finds that aid becomes effective only above a critical level, but what is more it becomes detrimental to growth at high aid flows. The author also investigates how the quality of institutions and economic vulnerability modify the level of these two thresholds. He finds that economic vulnerability is a key factor conditioning aid effectiveness.     

The pernicious effects of contaminated data in risk management

Banks hold capital to guard against unexpected surges in losses and long freezes in financial markets. The minimum level of capital is set by banking regulators as a function of the banks’ own estimates of their risk exposures. As a result, a great challenge for both banks and regulators is to validate internal risk models. We show that a large fraction of US and international banks uses contaminated data when testing their models. In particular, most banks validate their market risk model using profit-and-loss (P/L) data that include fees and commissions and intraday trading revenues. This practice is inconsistent with the definition of the employed market risk measure. Using both bank data and simulations, we find that data contamination has dramatic implications for model validation and can lead to the acceptance of misspecified risk models. Moreover, our estimates suggest that the use of contaminated data can significantly reduce (market-risk induced) regulatory capital.     

A view of the European Union as an evolving country portfolio

We apply portfolio theory to assess the consequences in terms of risk sharing of the evolution of the industry mix of European Union countries between 1986 and 1997, and of the changes in the membership configurations of both economic and monetary unions. We compute a measure of risk-return performance for EU countries, by considering countries as collections of industries, and observe that risk-return performance improved in most countries. We find that the EU9 is marginally more efficient than the other historical EU groupings and that the Euro Zone might slightly benefit from the inclusion of the United Kingdom.     

Equal opportunity and poverty reduction: How should aid be allocated?

This paper analyzes a model of aid allocation equalizing the opportunity between recipient countries to reach a common poverty reduction goal. We propose a fair and efficient aid allocation based on a multicriteria principle. The model considers structural handicaps in recipient countries in terms of lack of human capital and economic vulnerability, their initial poverty, and the natural gap between the growth rate required to reach a development goal and the observed one. We show that our proposed aid allocation favors poor and vulnerable countries with our multicriteria principle. It substantially differs from the observed allocation. Analyses also shed light on the impact of the donors' aversion to the low natural growth gap in recipient countries on the optimal aid allocation and the marginal efficiency of aid.     

Assessing horizontal mergers under uncertain efficiency gains

The analysis of horizontal mergers hinges on a tradeoff between unilateral effects and efficiency gains. We examine the role of uncertainty in this tradeoff. In theory, the attitude towards uncertainty depends on the curvature of the social objective function. On the one hand, adjustment effects, both on the consumers' and firms' sides, tend to make consumers' surplus and firms' profits convex. On the other hand, pass-through effects may act in the opposite direction. We show that convexity prevails in a number of situations, including the most general linear demand model. Implications for empirical merger analysis are exposed.