On Models of Default Risk

We first discuss some mathematical tools used to compute the intensity of a single jump process, in its canonical filtration. In the second part, we try to clarify the meaning of default and the links between the default time, the asset's filtration, and the intensity of the default time. We finally discuss some examples.     

有违约风险贷款担保价值研究

在发达国家政府是贷款担保的主要担保人,对贷款担保定价研究的重要假设是担保人没有违约风险。在中国,绝大多数的贷款担保人有违约风险。本文研究了担保人有违约风险情况下提供担保和相互担保的财务特征和定价,对比分析了提供担保和相互担保行为对贷款担保人和银行价值的影响。研究表明,有违约风险担保的价值随着担保人公司价值和借款额的增大而增大,随着借款公司价值的增大而减少;银行的损失随着借款额的增大而增大,随着担保人公司价值和借款人公司价值的增大而减少。银行提供贷款时允许企业相互担保等于潜在为相互担保企业提供了免费的部分担保,随着借款人风险的增大,相互担保条件下的银行或有损失急剧增大,相互担保对于银行的价值有显著的负面影响。     

DEFAULT RISK INSURANCE AND INCOMPLETE MARKETS1

This paper uses the existence of secondary markets for debt instruments with default risk (e.g. corporate bonds) to define default insurance along the lines of financial economics. It examines whether, in the case of several risk-neutral measures, characteristics of default can be uniquely determined by the prices of contracts involving default-prone securities.     

信贷资产证券化的违约风险分析

识别和控制资产证券化过程中的风险是金融监管的客观需要。以信贷资产支持证券为例探讨资产证券化的特有风险—违约风险,并运用KMV模型测度个案违约风险,在此基础上提出一些控制违约风险的策略。     

VMI模式下信息共享对违约风险的防范和控制

供应商管理库存（Vender Managed Inventory,VMI）是21世纪前沿的供应链管理模式,VMI对供应链的新形式供应的形成和发展都产生了影响。但由于我国信息化起步晚,使得很多企业在实施VMI模式时仍存在不同程度的风险。为了实现对VMI违约风险防范和控制的有效性,供应链上的各个企业越来越注重供应链成员之间的协调关系,而这就需要以供应链上各个节点的成员企业进行高质量的信息传递和及时完整的信息共享为基础来建立和完善整个VMI系统。研究供应商实施VMI的过程中所面临的违约风险,重点分析VMI模式下信息共享对违约风险防范控制作用,可有效地实现信息共享以降低VMI模式下的违约风险。     

商业合同附随义务根本违约之判断标准

当事人在商业合同中构成附随义务根本违约的判断标准包括:当事人之间须存在有效的合同关系,当事人一方或双方实施了违反附随义务的行为以及违约后果严重致使非违约方合同目的落空。但是,不是只要一方当事人的违约致使他方合同目的落空就必然构成根本违约,基础目的、单方目的、直接目的、初始目的、单一目的的落空必然构成根本违约;而效果目的、嗣后目的的违反不能构成根本违约;间接目的、双方目的和混合目的的违反只有危及合同的根基时才能构成根本违约。     

INFINITE HORIZON INCOMPLETE MARKETS WITH A CONTINUUM OF STATES

In this paper we address existence of equilibria in an incomplete markets economy with countably many periods and a continuum of states at each node of the infinite tree. We consider two models: one where agents have to honor their commitments and another where default is allowed. In both models, marginal utility of income, at each node, is shown to be bounded, and we prove existence by taking finite-dimensional approximations and applying Fatou's lemma sequentially.     

违约精神损害赔偿比较研究

从比较视域本文考察英美法系、大陆法系主要国家及地区的违约精神损害赔偿制度,当今世界许多国家及地区均在不同程度上认可违约精神损害赔偿,尽管立法有宽严,但判例突破已成为一种不可扭转的强大趋势。英美法以不断出现的司法判例为动因,以"合同性质"、"合同目的"、"可预见性"及"明显后果"等为限制条件,把握违约精神损害赔偿的尺度,再到逐步扩大在司法实践中的运用,使之类型化,从而明确违约精神损害赔偿的适用范围。大陆法主要是通过扩大法条解释、变通救济理念予以救济,或通过增设法律条文进行规定,满足现实对违约精神损害赔偿的需求,这些均可作为我国构建违约精神损害赔偿制度的现实基础。     

论农村保险市场的开拓

我国农村是一个潜力巨大的保险市场,然而,诸多原因影响农村保险市场发展,只有通过深入分析,才能找出影响农村保险市场发展原因的症结之所在,进而找到开拓农村保险市场的相应对策。     

Pricing of New Securities in an Incomplete Market: the Catch 22 of No-Arbitrage Pricing

There are two distinctly different approaches to the valuation of a new security in an incomplete market. The first approach takes the prices of the existing securities as fixed and uses no-arbitrage arguments to derive the set of equivalent martingale measures that are consistent with the initial prices of the traded securities. The price of the new security is then obtained by appealing to certain criteria or on the basis of some preference assumption. The second method prices the new security within a general equilibrium framework. This paper clarifies the distinction between the two approaches and provides a simple proof that the introduction of the new security will typically change the prices of all the existing securities. We are left with the paradox that a genuinely new derivative security is not redundant, but the dominant pricing paradigm in derivative security pricing is the no-arbitrage approach, which requires the redundancy of the security. Given the widespread practice of using the no-arbitrage approach to price (or bound the price of) a new security, we also comment on some justifications for this approach.     

Consumption and Portfolio Policies With Incomplete Markets and Short-Sale Constraints: the Finite-Dimensional Case1

We use a martingale approach to study optimal intertemporal consumption and portfolio policies in a general discrete-time, discrete-state-space securities market with dynamically incomplete markets and short-sale constraints. We characterize the set of feasible consumption bundles as the budget-feasible set defined by constraints formed using the extreme points of the closure of the set of Arrow-Debreu state prices consistent with no arbitrage, and then establish a relationship between the original problem and a dual minimization problem.     

Bounds on European Option Prices under Stochastic Volatility

In this paper we consider the range of prices consistent with no arbitrage for European options in a general stochastic volatility model. We give conditions under which the infimum and the supremum of the possible option prices are equal to the intrinsic value of the option and to the current price of the stock, respectively, and show that these conditions are satisfied in most of the stochastic volatility models from the financial literature. We also discuss properties of Black–Scholes hedging strategies in stochastic volatility models where the volatility is bounded.     

ON UTILITY-BASED PRICING OF CONTINGENT CLAIMS IN INCOMPLETE MARKETS

We study the uniqueness of the marginal utility-based price of contingent claims in a semimartingale model of an incomplete financial market. In particular, we obtain that a necessary and sufficient condition for all bounded contingent claims to admit a unique marginal utility-based price is that the solution to the dual problem defines an equivalent local martingale measure.     

CONSUMPTION AND PORTFOLIO POLICIES WITH INCOMPLETE MARKETS AND SHORT-SALE CONSTRAINTS IN THE FINITE-DIMENSIONAL CASE: SOME REMARKS

This paper extends He and Pearson's (1991) martingale approach to the study of optimal intertemporal consumption and portfolio policies with incomplete markets and short-sale constraints to a framework in which no assumptions are made on the price process for the securities. We show how both their characterization of the budget-feasible set and duality result can be extended to account for an unbounded set II of Arrow-Debreu state prices compatible with the arbitrage-free assumption. We also supply a (fairly general) sufficient condition for II to be bounded, as required in their setting.     

Value Preserving Strategies and a General Framework for Local Approaches to Optimal Portfolios

We present some new general results on the existence and form of value preserving portfolio strategies in a general semimartingale setting. The concept of value preservation is derived via a mean-variance argument. It is also embedded into a framework for local approaches to the problem of portfolio optimization.     

Ergodicity, State Prices, and Long Bond Returns

We present an analysis of price systems in securities markets with infinitely many time periods and infinitely many uncertain states of the world. A key result is that a Markov price system (MPS) has a unique representation in terms of the returns on a known set of bonds. The result implies that securities prices are the discounted value of dividends, where discount factors are the reciprocal of the returns on a long-horizon discount bond.     

On the Pricing of Contingent Claims with Frictions

This paper studies the problem of pricing contingent claims in a market which has frictions in the form of costs, such as penalty functions corresponding to constraints. An arbitrage-free interval is identified, and a fair price based upon utility functions is proposed. It provides a framework to study incomplete markets that is simplier than the one related to constraints on portfolios introduced by Karatzas and Kou.