Strategic default,workout, and commercial mortgage valuation

This paper extends existing equilibrium commercial mortgage pricing models by endogenizing negotiated workout into the usual noncooperative lending game. Workout is a feasible subgame strategy for the lender to play whenever foreclosure transaction costs exist for either party to a loan transaction. In particular, negotiated workout solutions Pareto dominate the foreclosure alternative when default occurs. To obtain our results, we embed a cooperative bargaining game within a noncooperative mortgage loan/default game. We also address the valuation wedge problem that occurs when foreclosure transaction costs are introduced. Through the notion of replacement game equilibrium, we find symmetric mortgage pricing solutions that eliminate the valuation wedge and thus suggest that lending will occur in commercial real estate mortgage markets even when foreclosure transaction costs exist.     

区块链在我国资本市场领域核心场景应用研究

在分析区块链金融行业应用价值及境外经验的基础上,本文立足我国资本市场发展实际,以问题和需求为导向,思考利用区块链规划构建我国资本市场的核心场景应用,包括面向泛金融资产交易的新型基础设施,及以之为基础的统一债券交易平台、交易所场外交易平台、“云链一体化”新型证券信息服务平台、证券监管数据共享平台等。本文建议:一是由金融监管部门统筹建设国家级区块链泛金融新型交易基础设施;二是鼓励可行性较高的区块链应用场景以概念验证项目先行先试;三是加强区块链金融科技投入和相关人才培养;四是重视区块链交流合作和区块链知识产权。     

Optimizing the terminal wealth under partial information: The drift process as a continuous time Markov chain

We consider a multi-stock market model where prices satisfy a stochastic differential equation with instantaneous rates of return modeled as a continuous time Markov chain with finitely many states. Partial observation means that only the prices are observable. For the investors objective of maximizing the expected utility of the terminal wealth we derive an explicit representation of the optimal trading strategy in terms of the unnormalized filter of the drift process, using HMM filtering results and Malliavin calculus. The optimal strategy can be determined numerically and parameters can be estimated using the EM algorithm. The results are applied to historical prices.Received: March 2004, Mathematics Subject Classification (2000): 91B28, 60G44JEL Classification: G11Supported by NSERC under research grant 88051 and NCE grant 30354.     

The effects of credit default swaps on corporate investment

ABSTRACT

This paper examines how credit default swaps (CDS) affect the corporate investment of the referenced entities. We document a significant reduction in corporate investment after CDS trading, a result that is robust to alternative model specifications and a set of endogeneity tests. Our findings of the increased firm risk and cost of capital support the costly external capital channel. The cross-sectional variations in CDS effects demonstrate that both reduced monitoring and the empty creditor problem might be the underlying forces driving the costly external capital channel. Our additional analysis implies that CDS trading is associated with an enhancement in investment efficiency for firms that are prone to overinvestment.     

Robust utility maximization for complete and incomplete market models

We investigate the problem of maximizing the robust utility functional . We give the dual characterization for its solution for both a complete and an incomplete market model. To this end, we introduce the new notion of reverse f-projections and use techniques developed for f-divergences. This is a suitable tool to reduce the robust problem to the classical problem of utility maximization under a certain measure: the reverse f-projection. Furthermore, we give the dual characterization for a closely related problem, the minimization of expenditures given a minimum level of expected utility in a robust setting and for an incomplete market.Received: September 2004, Mathematics Subject Classification (2000): 62C20, 62O05, 91B16, 91B28JEL Classification: D81, G11I thank Hans Föllmer for his help when writing this paper. Furthermore, I thank Alexander Schied for discussing the topic with me and Michael Kupper and the referees for their helpful remarks.     

The space of outcomes of semi-static trading strategies need not be closed

Semi-static trading strategies make frequent appearances in mathematical finance, where dynamic trading in a liquid asset is combined with static buy-and-hold positions in options on that asset. We show that the space of outcomes of such strategies can have very poor closure properties when all European options for a fixed date \(T\) are available for static trading. This causes problems for optimal investment, and stands in sharp contrast to the purely dynamic case classically considered in mathematical finance.     

MARGIN TRADING: A RISK-RETURN ANALYSIS

This paper attempts to present an integrated valuation analysis of investment options involving margin trading. The analysis is based on valuation theories such as Modigliani and Miller's capital structure model, the capital asset pricing model and the option pricing model. It is shown (i) that in margin trading, the return on equity is given by the return on investment plus a risk premium which increases proportionally with the margin-trading rate; (ii) that both the total risk (variance) and systematic risk (beta) of the return on equity increases proportionally with those associated with the return on investment; and (iii) that, when the option pricing model is applied to the case of margin trading, a more precise valuation formula can be employed.     

医疗费用世界难题最优解的博弈论分析

医疗费用控制是世界难题，原因在于现行医疗费用支付方式下医保和医院的博弈不存在医疗资源配置帕累托最优的均衡解。当医保按服务项目支付时，医院会选择过多服务策略；当医保按总额预算支付时，医院会选择过少服务策略。如果医保在支付周期的期末确定医疗费用支付方式，则医院会选择按预算总额提供服务策略，医疗资源配置也不能实现帕累托最优。改变动态博弈模式为静态博弈模式，并且医保以随机方法决定医疗费用支付方式，则只要支付方式的概率分布选择合理，博弈的均衡总能够实现医疗资源配置的帕累托最优。     

Satisfying convex risk limits by trading

A random variable, representing the final position of a trading strategy, is deemed acceptable if under each of a variety of probability measures its expectation dominates a floor associated with the measure. The set of random variables representing pre-final positions from which it is possible to trade to final acceptability is characterized. In particular, the set of initial capitals from which one can trade to final acceptability is shown to be a closed half-line . Methods for computing are provided, and the application of these ideas to derivative security pricing is developed.Received: May 2004, Mathematics Subject Classification (2000): 91B30, 60H30, 60G44JEL Classification: G10Steven E. Shreve: Work supported by the National Science Foundation under grants DMS-0103814 and DMS-0139911.Reha Tütüncü: Work supported by National Science Foundation under grants CCR-9875559 and DMS-0139911.     

模糊厌恶下股指期货风险对冲策略设计及实证分析

投资者对股指期货与现货有着不同的模糊厌恶,本文首先将此假设条件引入带交易成本的Garleanu and Pederson (2013)投资模型中,并以指数基金对冲策略为例,构建了一个股指期货动态对冲的理论模型。与非对冲策略相比,基于上述模型设计的对冲策略投资绩效更好,动态最优成交额占目标交易额的比例更小,目标成交额对收益率预测因子的敏感性更大。借助上述模型,本文选取2010年4月至2021年6月的中国ETF指数基金和股指期货数据,并以2015年9月股指期货管理措施实施为界进行区间划分,实证研究发现:(1)中国A股市场的ETF投资组合进行股指期货对冲显著提升了投资绩效,但股指期货管理会削弱该作用;(2)投资绩效改善主要来源于交易成本的下降与目标成交额因子敏感性的提升,该机制受到股指期货管理的约束;(3)与Garleanu and Pederson (2013)、Zhang et al. (2017)相比,本文对冲策略保留“抗跌”特点的同时增加了“易涨”特性。本文研究结果表明,在当前大力发展机构投资者的背景下应不断丰富股指期货、股指期权产品谱系,降低股指期货交易成本并完善持仓约束。     

试论新型农村资金合作体系的构建——基于演化博弈论的视角

本文深入分析了我国现有资金合作组织存在的问题,并运用演化博弈理论推导出资金合作制度运行的稳定条件,以此为线索,分别从合作机制创新、支持方式创新两方面重点论述了新型农村资金合作体系制度建设,指出新型农村资金合作组织可以通过拓展合作范围、建立联合社体系,形成规模效应;通过整合现有支农资源、创新支持方式,保障制度创新初级行动主体的净收益,限制搭便车行为。只有将这两者有机结合,才能保障新型农村资金合作体系的稳健运行。     

Optimal tax-timing and asset allocation when tax rebates on capital losses are limited

This article studies the portfolio problem with realization-based capital gain taxation when limited amounts of losses qualify for tax rebate payments, as is the case under current US tax law. When the tax rate applicable to realized losses exceeds that on realized capital gains, it can be optimal to realize capital gains immediately and pay capital gain taxes to regain the option to use potential future losses against a higher tax rate. This incentive adds an entirely new and as yet unstudied dimension to the portfolio problem. It causes risk averse investors to hold more equity and attain higher welfare levels than is the case when trading under a tax system that seeks to collect the same amount of taxes, but does not allow for tax rebate payments. This is because the benefit to these investors from having their losses subsidized is greater than the suffering from having profits taxed at a higher rate.     

Perfect hedging under endogenous permanent market impacts

We model a nonlinear price curve quoted in a market as the utility indifference curve of a representative liquidity supplier. As the utility function, we adopt a \(g\)-expectation. In contrast to the standard framework of financial engineering, a trader is no longer a price taker as any trade has a permanent market impact via an effect on the supplier’s inventory. The P&L of a trading strategy is written as a nonlinear stochastic integral. Under this market impact model, we introduce a completeness condition under which any derivative can be perfectly replicated by a dynamic trading strategy. In the special case of a Markovian setting, the corresponding pricing and hedging can be done by solving a semilinear PDE.     

New empirical evidence on the investment success of momentum strategies based on relative stock prices

This paper provides significant extensions and tests of momentum trading strategies based on relative prices that were first explored by George and Hwang (2004). We develop new momentum strategies based on the ratio of the current stock price to each of five different reference points in past prices: 52-week high, 52-week median, 52-week low, half-year high, and 2-year high. We measure their investment performance on the basis of the Fama and French 3-Factor and Momentum Model (Carhart four-factor model), and further employ the technique of nested trading strategies to measure incremental performance. The strategy based on the ratio of current stock price to its 52-week high price is the most profitable, and its performance is robust when tested over a wide range of financial and economic factors. Our results provide strong new evidence of the investment merits of a momentum trading strategy based on the 52-week high price ratio, and add new weight to challenges to the hypothesis that the stock market is efficient in the semi-strong sense.     

Pricing derivatives of American and game type in incomplete markets

In this paper the neutral valuation approach is applied to American and game options in incomplete markets. Neutral prices occur if investors are utility maximizers and if derivative supply and demand are balanced. Game contingent claims are derivative contracts that can be terminated by both counterparties at any time before expiration. They generalize American options where this right is limited to the buyer of the claim. It turns out that as in the complete case, the price process of American and game contingent claims corresponds to a Snell envelope or to the value of a Dynkin game, respectively.On the technical level, an important role is played by -sub- and -supermartingales. We characterize these processes in terms of semimartingale characteristics.Received: June 2003, Mathematics Subject Classification (2000):   91B24, 60G48, 91B16, 91A15, 60G40JEL Classification:   G13, D52, C73The authors want to thank PD Dr. Martin Beibel for the idea leading to the proof of Proposition A.4 and both anonymous referees for many valuable comments. The second author gratefully acknowledges financial support by the Deutsche Forschungsgemeinschaft through the Graduiertenkolleg Angewandte Algorithmische Mathematik at Munich University of Technology and by the Fonds zur Förderung der wissenschaftlichen Forschung at Vienna University of Technology.     

Information, trade, and derivative securities

Hellwig's (1980) model is used to analyze the value of improvingtrading opportunities by more frequent trading in the underlyingasset, or by trading in a derivative asset. With multiple tradingsessions, uninformed investors behave as rational trend followers,while more informed investors follow a contrarian strategy.As trading becomes continuous, Pareto efficiency is achieved.With trading in an appropriate derivative security, Pareto efficiencymay be achieved in only a single round of trading. All derivativeclaims are then priced on Black and Scholes (1973) principlesand, in the absence of further supply shocks, no trading willtake place in subsequent trading rounds.     

Asymptotics of ruin probabilities for controlled risk processes in the small claims case

We consider a risk process with the possibility of investment into a risky asset. The aim of the paper is to obtain the asymptotic behaviour of the ruin probability under the optimal investment strategy in the small claims case. In addition we prove convergence of the optimal investment level as the initial capital tends to infinity.     

Minimum return guarantees,investment caps,and investment flexibility

We study the merits of capped retirement products with guarantee for investors who have the flexibility to dynamically adjust their investment strategy. All contracts under consideration are fairly priced such that the net profit of the provider is zero. Without the rider, an expected utility maximizing CRRA investor does not want an investment cap. Here, she commits herself to a strategy a priori. With the flexibility rider, the optimization problem changes and the optimal strategy is a response to an exogenously set price. A fair pricing then anticipates the optimal response of the investor. We show that the maximum expected utility of the investor can, for anticipated fairly priced products, be obtained for a finite cap. Thus, a capped product design can give a Pareto improvement to the otherwise uncapped contract version.     

Smooth investment

In the classical portfolio optimization problem considered by Merton, the resulting constant proportion investment plan requires a diffusive trading strategy. This means that, within any arbitrarily small time interval, the investor must impractically both buy and sell stocks. We study the problems of a mean-square and a power utility investor for whom the trading strategy is constrained to be smooth, i.e. nondiffusive. This means that over sufficiently small time intervals, the investor is either a seller or a buyer of stocks. The mathematical framework is built around quadratic objectives such that trading activity is punished quadratically. Mean-square utility is quadratic, and power utility is covered by quadratic punishment of distance to Merton’s power utility portfolio. We present semi-explicit solutions and, in a series of numerical illustrations, show the impact of trading constraints on the portfolio decision over the investment horizon.