On moments of the supremum of normed weighted averages

Let {X, X_n; n ≥ 1} be a sequence of real-valued iid random variables, 0 < r < 2 and p > 0. Let D = { A = (a_nk; 1 ≤ k ≤ n, n ≥ 1); a_nk, ? R and sup_{n, k} |a_n,k| < ∞}. Set S_n( A ) = ∑ⁿ_k=1a_{n, k}X_k for A ? D and n ≥ 1. This paper is devoted to determining conditions whereby E{sup_{n ≥ 1}, |S_n( A )|/n^1/r}^p < ∞ or E{sup_{n ≥ 2} |S_n( A )|/2n log n)^1/2}^p < ∞ for every A ? D. This generalizes some earlier results, including those of Burkholder (1962), Choi and Sung (1987), Davis (1971), Gut (1979), Klass (1974), Siegmund (1969) and Teicher (1971).     

Nonparametric function estimation from inversely sampled record-breaking data

Often, in industrial stress testing, meteorological data analysis, and other similar situations, measurements may be made sequentially and only values smaller than all previous ones are recorded. When the number of records is fixed in advance, the data are referred to as inversely sampled record-breaking data. This paper is concerned with nonparametric estimation of the distribution and density functions from such data (successive minima). For a single record-breaking sample, consistent estimation is not possible except in the extreme left tail of the distribution. Hence, replication is required, and for m such independent record-breaking samples, the estimators are shown to be strongly consistent and asymptotically normal as m ∞ →. Computer simulations are used to investigate the effect of the bandwidth on the mean squared errors and biases of the smooth estimators, and are also used to provide a comparison of their performance with the analogous estimators obtained under random sampling for record values.     

Uniform validity of saddlepoint expansion on compact sets

This paper shows that Daniels's (1954) saddlepoint expansion for the density of a sample mean is, for all practical purposes, always uniformly valid on compact subsets in the interior of the domain of the mean. This uniform validity is the key for establishing the relation between the saddlepoint expansion for the density function and Lugannani and Rice's expansion for the tail probability, and for establishing the validity of a high-order asymptotic expansion for the density of a standardized mean.     

Uniqueness of the least-distances estimator in regression models with multivariate response

In a regression model with univariate response, the quantities derived from the least-absolute-deviations method need not be unique. In this note, we show that, contrary to the univariate case, in a regression model with multivariate response, the least-distances method typically yields quantities that exhibit uniqueness properties that are similar to those obtained by the least-squares method.     

The Role of Entrepreneurship in the Context of Career Trajectories: Moving Back into Wage Employment or into Unemployment?

This study investigates patterns of movement from self‐employment to wage employment or to unemployment in Belgium. Non‐parametric techniques and complimentary log–log analyses are used to determine the significance of stable individual traits (e.g. gender) and of time‐dependent characteristics (e.g. family and organizational context, labour market mobility) in moving back to wage employment or to unemployment. Evidence is provided on the possibility of entrepreneurship acting as a ‘steppingstone’ between long‐term unemployment and paid work. Yet, significant relationships also emerge between ex‐ante time spent in unemployment and the possibility of continued unemployment upon self‐employment exit.     

SYSTEMIC AND IDIOSYNCRATIC SOVEREIGN DEBT CRISES

The theoretical literature on sovereign defaults has focused on adverse shocks to debtors' economies, suggesting that defaults are of an idiosyncratic nature. Still, sovereign debt crises are also of a systemic nature, clustered around panics in the financial center, such as the European Sovereign Debt Crisis in the aftermath of the US Subprime Crisis in 2008. Crises in the financial centers are rare disasters and, thus, their effects on the periphery can only be captured by examining long episodes. In this paper, we examine sovereign defaults from 1820 to the Great Depression, with a focus on Latin America. We find that 63% of the crises are of a systemic nature. These crises are different. Both the international collapse of liquidity and the growth slowdown in the financial centers are at their core. These global shocks trigger longer default spells and larger losses for investors.     

SOVEREIGN DEBT RESTRUCTURINGS: PREEMPTIVE OR POST‐DEFAULT

Sovereign debt restructurings can be implemented preemptively—prior to a payment default. We code a comprehensive new data set and find that preemptive restructurings (i) are frequent (38% of all deals 1978–2010), (ii) have lower haircuts, (iii) are quicker to negotiate, and (iv) see lower output losses. To rationalize these stylized facts, we build a quantitative sovereign debt model that incorporates preemptive and post‐default renegotiations. The model improves the fit with the data and explains the sovereign's optimal choice: preemptive restructurings occur when default risk is high ex ante, while defaults occur after unexpected bad shocks. Empirical evidence supports these predictions.