In many credit risk and pricing applications, credit transition matrix is modeled by a constant transition probability or generator matrix for Markov processes. Based on empirical evidence, we model rating transition processes as piecewise homogeneous Markov chains with unobserved structural...

Markowitz's celebrated mean--variance portfolio optimization theory assumes that the means and covariances of the underlying asset returns are known. In practice, they are unknown and have to be estimated from historical data. Plugging the estimates into the efficient frontier that assumes known...

In this paper, we argue that economists can learn a great deal from the design principles implemented in medical research. We develop a theoretical model to show the logic of adaptive sequential experiment design in the presence of uncertainty over negative effects and discuss how to choose...

Many longitudinal studies involve relating an outcome process to a set of possibly time-varying covariates, giving rise to the usual regression models for longitudinal data. When the purpose of the study is to investigate the covariate effects when experimental environment undergoes abrupt...

This paper establishes a general result on the existence of non-trivial quasi-equilibria for economies with infinitely many commodities, in which consumers’ preferences are assumed to be lower semi-continuous, but not necessarily to have open lower sections nor to be open valued. Such...

We propose a dynamic auction mechanism for efficiently allocating multiple heterogeneous indivisible goods. These goods can be split into two distinct sets so that items in each set are substitutes but complementary to items in the other set. The seller has a reserve value for each bundle of...

This article proposes an efficient and incentive compatible dynamic auction for selling multiple complementary goods to finitely many bidders. The goods are traded in discrete quantities. The seller has a reserve price for every bundle of goods and determines which bundles to sell based on...

This article proposes an efficient and incentive compatible dynamic auction for selling multiple complementary goods. The seller has reserve prices. The auctioneer announces a current price for every bundle of goods and a supply set of goods, every bidder responds with a set of goods demanded at...

We propose a new Walrasian tatonnement process called a double-track procedure for efficiently allocating multiple heterogeneous indivisible items in two distinct sets to many buyers who view items in the same set as substitutes but items across the two sets as complements. In each round of the...

This paper studies the problem of how to distribute a set of indivisible objects with an amount M of money among a number of agents in a fair way. We allow any number of agents and objects. Objects can be desirable or undesirable and the amount of money can be negative as well. In case M is...