We propose a simplified approach to mean-variance portfolio problems by changingtheir parametrisation from trading strategies to final positions. This allows us to treat,under a very mild no-arbitrage-type assumption, a whole range of quadratic optimisationproblems by simple mathematical tools...

The Markowitz problem consists of finding in a financial market a self-financingtrading strategy whose final wealth has maximal mean and minimal variance. Westudy this in continuous time in a general semimartingale model and under coneconstraints: Trading strategies must take values in a...

We study mean-variance hedging under portfolio constraints in a general semi-martingale model. The constraints are formulated via predictable correspondences,meaning that the trading strategy is restricted to lie in a closed convex set whichmay depend on the state and time in a predictable way....

Recent research has shown that relaxing the assumptions of complete informationand common knowledge in exchange rate models can shed light on a wide range ofimportant exchange rate puzzles. In this chapter, we review a number of models wehave developed in previous work that relax the strong...

For an investor with constant absolute risk aversion and a long horizon, who trades in amarket with constant investment opportunities and small proportional transaction costs, weobtain explicitly the optimal investment policy, its implied welfare, liquidity premium, andtrading volume. We...

In a market with one safe and one risky asset, an investor with a long horizon, constantinvestment opportunities, and constant relative risk aversion trades with small proportionaltransaction costs. We derive explicit formulas for the optimal investment policy, its impliedwelfare, liquidity...

The paper is the first one outside the high-frequency domain to use sentiment-signednews to directly compare news and no-news stock returns. This is done by estimatingwhether returns on positive, neutral and negative news days are significantly differentfrom the average daily return for a large...

We explore the effects of information propagation in a centralized financialmarket. Specifically, we embed search frictions within the Grossman andStiglitz (1980) framework, relying on information percolation as modeled inDuffie, Malamud, and Manso (2009). First, we show that information...

Our purpose is to show how large difference of beliefs induced by fear of crashesis amenable to large and persistent price responses to contemporaneous shocks. Weconstruct a pure exchange economy populated by two agents who estimate strictlydifferent models regarding the fundamental. In...

This paper presents an equilibrium model in a pure exchange economywhen investors have three possible sources of heterogeneity. Investorsmay differ in their beliefs, in their level of risk aversion andin their time preference rate. We study the impact of investors heterogeneityon equilibrium...