Financial equilibrium with asymmetric information and random horizon

We study in detail and explicitly solve the version of Kyle’s model introduced in a specific case in Back and Baruch (Econometrica 72:433–465, 2004), where the trading horizon is given by an exponentially distributed random time. The first part of the paper is devoted to the analysis of time-homogeneous equilibria using tools from the theory of one-dimensional diffusions. It turns out that such an equilibrium is only possible if the final payoff is Bernoulli distributed as in Back and Baruch (Econometrica 72:433–465, 2004). We show in the second part that the signal the market makers use in the general case is a time-changed version of the one they would have used had the final payoff had a Bernoulli distribution. In both cases, we characterise explicitly the equilibrium price process and the optimal strategy of the informed trader. In contrast to the original Kyle model, it is found that the reciprocal of the market’s depth, i.e., Kyle’s lambda, is a uniformly integrable supermartingale. While Kyle’s lambda is a potential, i.e., converges to 0, for the Bernoulli-distributed final payoff, its limit in general is different from 0.     

No-arbitrage bounds for the forward smile given marginals

We explore the robust replication of forward-start straddles given quoted (Call and Put options) market data. One approach to this problem classically follows semi-infinite linear programming arguments, and we propose a discretisation scheme to reduce its dimensionality and hence its complexity. Alternatively, one can consider the dual problem, consisting in finding optimal martingale measures under which the upper and the lower bounds are attained. Semi-analytical solutions to this dual problem were proposed by Hobson and Klimmek [Financ. Stochastics, 2015, 19, 189–214] and by Hobson and Neuberger [Math. Financ., 2012, 22, 31–56]. We recast this dual approach as a finite-dimensional linear program, and reconcile numerically, in the Black–Scholes and in the Heston model, the two approaches.     

No-arbitrage Near-Cointegrated VAR(p) term structure models,term premia and GDP growth

The recent macro-finance literature does not agree either about the empirical properties of the expectation part and of the term premium on long-term bonds or about the importance or even the direction of the relationship between the term premium and future economic activity. This paper proposes a two-step approach to handle both problems. First, in a VAR setting, we extract a reliable measure of the term premium by means of averaging estimator techniques aiming at optimally solving prediction problems when highly persistent processes are present and, thus, providing a so called Near-Cointegrated VAR(p) approach. Second, we analyze the dynamic response of GDP to shocks to the term premium by using the New Information Response Function concept. As far as the first problem is concerned, we find that the NCVAR-based term premium measure is rather stable and counter-cyclical, as suggested by interest rates survey-based estimation of yield curve models and by its risk compensation role. Regarding the second problem, we find that an increase in the long-term spread caused by the term premium induces two effects on future economic activity: the impact is negative for short horizons (less than 1 year), whereas it is positive for longer ones.     

No-arbitrage criteria for financial markets with transaction costs and incomplete information

This note deals with criteria of absence of arbitrage opportunities for an investor acting in a market with frictions and having a limited access to the information flow. We develop a mathematical scheme covering major models of financial markets with transaction costs and prove several results including a criterion for the robust no-arbitrage property and a hedging theorem.      

No-arbitrage conditions for storable commodities and the modeling of futures term structures

One distinguishable feature of storable commodities is that they relate to two markets: cash market and storage market. This paper proves that, if no arbitrage exists in the storage-cash dual markets, the commodity convenience yield has to be non-negative. However, classical reduced-form models for futures term structures could allow serious arbitrages due to the high volatility of the convenience yield. To avoid negative convenience yield, this paper proposes a semi-affine arbitrage-free model, which prices futures analytically and fits futures term structures reasonably well. Importantly, our model prices commodity-related contingent claims (such as calendar spread options) quite differently with classical models.     

A computationally fast estimator for random coefficients logit demand models using aggregate data

This article proposes a computationally fast estimator for random coefficients logit demand models using aggregate data that Berry, Levinsohn, and Pakes ( 1995 ; hereinafter, BLP) suggest. Our method, which we call approximate BLP (ABLP), is based on a linear approximation of market share functions. The computational advantages of ABLP include (i) the linear approximation enables us to adopt an analytic inversion of the market share equations instead of a numerical inversion that BLP propose, (ii) ABLP solves the market share equations only at the optimum, and (iii) it minimizes over a typically small dimensional parameter space. We show that the ABLP estimator is equivalent to the BLP estimator in large data sets. Our Monte Carlo experiments illustrate that ABLP is faster than other approaches, especially for large data sets.     

Improving risk classification and ratemaking using mixture-of-experts models with random effects

In the underwriting and pricing of nonlife insurance products, it is essential for the insurer to utilize both policyholder information and claim history to ensure profitability and proper risk management. In this paper, we apply a flexible regression model with random effects, called the Mixed Logit-weighted Reduced Mixture-of-Experts, which leverages both policyholder information and their claim history, to categorize policyholders into groups with similar risk profiles, and to determine a premium that accurately captures the unobserved risks. Estimates of model parameters and the posterior distribution of random effects can be obtained by a stochastic variational algorithm, which is numerically efficient and scalable to large insurance portfolios. Our proposed framework is shown to outperform the classical benchmark models (Logistic and Lognormal GL(M)M) in terms of goodness-of-fit to data, while offering intuitive and interpretable characterization of policyholders' risk profiles to adequately reflect their claim history.     

Nonparametric identification and estimation of random coefficients in multinomial choice models

We show how to nonparametrically identify the distribution of unobservables, such as random coefficients, that characterizes the heterogeneity among consumers in multinomial choice models. We provide general identification conditions for a class of nonlinear models and then verify these conditions using the primitives of the multinomial choice model. We require that the distribution of unobservables lie in the class of all distributions with finite support, which under our most general assumptions, resembles a product space where some of the product members are function spaces. We show how identification leads to the consistency of a nonparametric estimator.     

Efficient exchange rate forecasts: Lagged models better than the random walk

The evidence of Meese amd Rogoff (1983) on the out-of-sample forecasting performance of structural exchange rate models in comparison to the random walk model portrays a disappointing picture of structural models. This paper re-considers the issue for the German mark for an updated period to include a larger set of structural models and lagged adjustment. Besides out-of-sample evidence, in-sample evidence is also examined. We conclude that while some stuctural models dominate the random walk, a lagged adjustment consideration can contribute towards better performance.     

Testing for long horizon UIP using PPP-based exchange rate expectations

This paper revisits the uncovered interest parity relation. It supplements existing work in two ways: It focuses on long instead of short-term interest rates, and, related to that, employs exchange rate expectations derived from purchasing power parity (PPP) instead of actual outcomes. Among the major floating currencies over the period 1975–1997, the paper cannot support the notion of further increases in UIP-validation beyond that associated with the wave of financial market liberalization and deregulation in the early 1980s.     

马蔚华冷静面对全面开放

近日《中华人民共和国外资银行管理条例》的颁布让本来就是热门话题的中外资银行如何竞争的讨论更趋白热化,招商银行马蔚华也多次在公开场合被媒体及有关人士问及中资银行如何应对、招行如何应对的问题。在喊了多年的“狼来了”后,当“狼”真来到“家门口”时,马蔚华表示中资银行已冷静面对,外资银行的确会带     

A simple mechanism for financial bubbles: time-varying momentum horizon

Building on the notion that bubbles are transient self-fulfilling prophecies created by positive feedback mechanisms, we construct the simplest continuous price process whose expected returns and volatility are functions of momentum only. The momentum itself is measured by a simple continuous moving average of past prices over a given time horizon. We introduce a simple dynamics of the time horizon used by the representative investor, which is motivated by the race of trend following agents to forerun their competitors. We provide the full set of solutions, which includes an explosive regime where the price and momentum explodes stochastically in finite time to infinity, transient price dynamics escaping to infinity and recurrent behaviors, where the momentum remains either strictly positive or undergoes instantaneous reflections at the origin. The proposed price generating process produces price dynamics that are in agreement with the main qualitative properties of empirical financial time series. Moreover, it produces realistic regime shifts between non bubble and bubble regimes. We construct a quasi-likelihood methodology to calibrate the model to empirical financial time series, which is applied to an Internet index and a ‘brick and mortar’ index, over the period of the dotcom bubble and its subsequent crash, from Jan. 1998 to Dec. 2002. The Wilks test of nested hypotheses shows a very strong skill in diagnosing the bubble of the Internet index and in disqualifying a bubble in the ‘brick and mortar’ index.     

Measuring up to sustainability

As a concept sustainability has captured our imaginations and aspirations. As a tangible and identifiable goal it eludes us. Having developed indicators to measure and monitor economic, social and environmental conditions, we want now to measure sustainability. Our emphasis on the physical, the objective, and the rational, however, sees only the external manifestations of sustainability. The internal manifestations of sustainability, the non-material, the subjective, and the experiential, are put to one side, since they are messy, interpretive and time-consuming—the world of hermeneutics. Sustainability, however, is more than a `thing' to be measured, since it is about ecological integrity, quality of life and transformation or transcendence. Rather than ask how we can measure sustainability, it may be more appropriate to ask how we measure up to sustainability.     

Calibration of Gaussian heath, Jarrow and Morton and random field interest rate term structure models

We show how the recently introduced Gaussian random field interest rate term structure models can be calibrated accurately and quickly to market caps and swaptions prices. We show how the calibrated random field model can be approximated arbitrarily closely with a multi-factor Gaussian Heath, Jarrow and Morton model. We argue that the Gaussian random field model is easier to calibrate and can be used as an indirect way to calibrate multi-factor Gaussian Heath, Jarrow and Morton interest rate models.This work was carried out when the author was at the Financial Options Research Centre, Warwick Business School, University of Warwick. I wish to thank Stewart Hodges for many helpful discussions and comments and Martin Cooper of Tokai Bank, Europe, for supplying the data used in this paper. I also wish to thank the Economic and Social Research Council and FORC for funding. An earlier version of this paper entitled Multi-Factor Gaussian HJM Approximation to Kennedy and Calibration to Caps and Swaptions Prices was presented at the 9th Annual Conference, FORC., Warwick Business School, September 1996. Another version also appears in the author's Ph.D. thesis. I am grateful to the helpful comments provided by Marti Subrahmanyam and the two anonymous referees. All errors are my own and the views expressed in no way reflect the opinion of my employer.     

对失业者再就业激励机制的探索

现行的社会保障制度缺陷之一是某种程度上降低了失业者正常渠道再就业的积极性，许多失业者不得不从事较为普遍的隐性就业。本文探索引入“负所得税”的方法，建立更加有效的社会保障制度，既减轻了国有企业和政府的负担，又保护了下岗职工再就业的积极性。