HOUSING FINANCE AND MONETARY POLICY

We document three facts concerning how the structure of housing finance affects the monetary transmission mechanism: first, the characteristics of residential mortgage markets differ markedly across industrialized countries; second, the impact of monetary policy shocks to residential investment and house prices is significantly stronger in those countries with larger flexibility/development of mortgage markets; third, the transmission to consumption is stronger only in those countries where mortgage equity release is common and mortgage contracts are predominantly of the variable‐rate type. We then build a two‐sector DSGE model with financial constraints to rationalize those facts.     

定价核之谜与概率权重函数

采用期权及标的资产价格数据, 基于离散时间EGARCH模型和连续时间GARCH扩散模型分别估计了客观与风险中性密度, 进而推导了经验定价核. 在此基础上, 基于等级依赖期望效用模型, 在标准的效应函数形式下构建了相应的概率权重函数. 采用香港恒生指数及其指数权证价格数据进行实证研究, 结果表明: (1) 经验定价核不是单调递减的, 而是展现出驼峰(非单调性), 即“定价核之谜”;(2) 经验概率权重函数展现S型, 表明市场投资者低估尾部概率事件, 高估中、高概率事件;(3) “定价核之谜”可以由具有标准效用函数与S型概率权重函数的等级依赖期望效用模型解释。     

资产泡沫、技术创新与经济增长

本文从理论和实证两个角度研究了资产泡沫发生、技术创新与经济增长之间的相关性。理论方面,本文构建了符合我国经济典型事实的熊彼特经济增长模型。模型中,企业家在为研发筹集资金时面临融资约束。由于融资约束的存在导致资本市场的资金供过于求,发生资产泡沫可促进企业平均的研发投入增加,研发成功的概率相应上升。实证方面,本文采用FF-TVP-SV-VAR和TVAR模型以及我国2000-2016年的月度数据分别对理论分析得出的结论进行检验。实证结果表明,资产泡沫发生可以促进技术创新,但该效应依赖于融资约束。此外,本文识别了融资约束的两个门限值。低于下限值时,资产泡沫可通过技术创新效应促进经济增长;高于下限值时,资产泡沫的技术创新效应较弱,因而对经济增长产生负向作用。     

基于投资者异质信念的均衡资产定价模型研究

在行为金融框架下,采用投资者在价格期望方面存在的意见分歧来表征投资者异质信念,构建投资者异质信念下的均衡资产定价模型,从理论上证明投资者异质信念是影响资产价格的重要因素,投资者信念差异程度与均衡价格同向变动,并以封闭式基金折价为例说明该模型对金融市场价格异象的解释力.为检验理论模型的结论,选取中国股票市场数据构建计量经济模型,对投资者异质信念程度及其波动性对资产价格的影响进行实证分析,实证结果支持理论模型的结论.实证结果还发现,投资者异质信念的条件波动性变量系数显著,对股市收益率有显著的影响,说明投资者异质信念的波动对股市价格指数有显著的溢出效应,信息的传递效率会影响投资者的意见分歧程度,因此有效的信息披露机制能够更好地减少异质信念带来的股价高估问题.     

Savage in the Market

We develop a behavioral axiomatic characterization of subjective expected utility (SEU) under risk aversion. Given is an individual agent's behavior in the market: assume a finite collection of asset purchases with corresponding prices. We show that such behavior satisfies a “revealed preference axiom” if and only if there exists a SEU model (a subjective probability over states and a concave utility function over money) that accounts for the given asset purchases.     

CAPITAL INFLOWS,FINANCIAL STRUCTURE AND HOUSING BOOMS

We use a panel VAR to study the effect of shocks to capital inflows, which are identified using sign restrictions, on the housing market in OECD countries. To explore how effects of these shocks change with the structure of the mortgage market and the degree of mortgage securitization, we allow the VAR coefficients to vary with mortgage‐market characteristics. Our results indicate that capital‐inflow shocks have a significant and positive effect on real house prices, real credit available to the private sector, and real residential investment. The responses of these variables are stronger in countries with more developed mortgage markets and in countries where securitization is allowed.     

Illiquide Assets in der Portfoliooptimierung

When optimizing a portfolio, which comprises liquid as well as illiquid assets, under the constraint of a liquidity requirement, one has to take into account the particular characteristics of illiquid assets. Illiquid assets in this context have the constituting property that they can only be sold as a whole and – if sold on a short term basis – selling leads to losses. Performing the analysis of a single period model in a mean downside risk framework with one liquid and one illiquid asset, significant differences are proven in comparison to the results of an optimization concerning solely liquid assets. For example, although the return on assets is safe in the first scenario, the portfolio value is already risky due to the uncertain liquidity requirement and situations arise where the allocation to both the liquid and the illiquid asset is optimal. Furthermore, when asset returns are uncertain, the expected portfolio value depends on the assets’ variances and can even be increased by positive correlations.     

违约风险下的信贷决策模型与机制

研究了违约风险下的信贷决策模型与机制,通过以银行个体合理性和激励相容性作为约束条件,建立了在考虑违约风险和项目成功概率条件下的信贷决策模型,分别给出了基于抵质押贷款和信用贷款策略下的信贷决策机制,探讨了信贷配给机制与无配给机制的设计方法,给出了在信贷出现配给时银行发放信用贷款和有抵质押贷款的条件.最后运用实例详细分析并讨论了不同违约概率条件下企业项目成功概率对银行期望收益的影响,得到了银行相应的贷款临界值和在不同项目成功概率条件下银行最大可接受的违约概率.     

A Robust Model of Bubbles With Multidimensional Uncertainty

Observers often interpret boom–bust episodes in asset markets as speculative frenzies where asymmetrically informed investors buy overvalued assets hoping to sell to a greater fool before the crash. Despite its intuitive appeal, however, this notion of speculative bubbles has proven difficult to reconcile with economic theory. Existing models have been criticized on the basis that they assume irrationality, that prices are somewhat unresponsive to sales, or that they depend on fragile, knife‐edge restrictions. To address these issues, I construct a rational version of Abreu and Brunnermeier (2003), where agents invest growing endowments into an asset, fueling appreciation and eventual overvaluation. Riding bubbles is optimal as long as the growth rate of the bubble and the probability of selling before the crash are high enough. This probability increases with the amount of noise in the economy, as random short‐term fluctuations make it difficult for agents to infer information from prices.     

Coordinating contracts for a financially constrained supply chain

We consider a financially constrained supply chain in which a supplier (leader) sells products to a retailer (follower) who has no access to bank financing due to her low credit rating. However, the supplier can borrow from a bank and offer trade credit to the retailer to alleviate her financial constraint. Failure to pay off a bank loan or trade credit incurs a variable default cost. We analyze the centralized version of the supply chain to obtain new coordination requirements. We then examine whether revenue-sharing, buyback, and all-unit quantity discount contracts can coordinate our supply chain. We show that the all-unit quantity discount contract fails to coordinate. However, the revenue-sharing and buyback contracts can coordinate the supply chain, but only when the supply chain has a sufficient total working capital. Moreover, they cannot allocate profit flexibly unless the supplier has a large enough working capital. Finally, we design a generalized revenue-sharing contract that coordinates the supply chain with flexible profit allocation, and also show by numerical examples its superiority over the revenue-sharing and buyback contracts.     

Over‐the‐Counter Markets

We study how intermediation and asset prices in over‐the‐counter markets are affected by illiquidity associated with search and bargaining. We compute explicitly the prices at which investors trade with each other, as well as marketmakers' bid and ask prices, in a dynamic model with strategic agents. Bid–ask spreads are lower if investors can more easily find other investors or have easier access to multiple marketmakers. With a monopolistic marketmaker, bid–ask spreads are higher if investors have easier access to the marketmaker. We characterize endogenous search and welfare, and discuss empirical implications.     

Predicting Cancer‐Prevention Behavior: Disentangling the Effects of Risk Aversion and Risk Perceptions

Experimental and survey research spanning the last two decades concludes that people who are more risk tolerant are more likely to engage in risky health activities such as smoking and heavy alcohol consumption, and are more likely to be obese. Subjective perceptions of the risk associated with different activities have also been found to be associated with health behaviors. While there are numerous studies that link risk perceptions with risky behavior, it is notable that none of these controls for risk aversion. Similarly, studies that control for risk aversion fail to control for risk misperceptions. We use a survey of 474 men and women to investigate the influence of risk aversion, risk misperceptions, and cognitive ability on the choice to engage in behaviors that either increase or mitigate cancer risk. We measure optimism in two dimensions: baseline optimists are those who inaccurately believe their cancer risk to be below its expert‐assessed level, while control optimists are those who believe they can reduce their risk of cancer (by changing their lifestyle choices) to a greater extent than is actually the case. Our results indicate that baseline optimism is significantly and negatively correlated with subjects′ tendencies to engage in cancer‐risk‐reducing behaviors, and positively correlated with risky behaviors. Subjects’ control misperceptions also appear to play a role in their tendency to engage in risky and prevention behaviors. When controlling for both of these types of risk misperception, risk aversion plays a much smaller role in determining health behaviors than found in past studies.     

Leverage and Default in Binomial Economies: A Complete Characterization

Our paper provides a complete characterization of leverage and default in binomial economies with financial assets serving as collateral. Our Binomial No‐Default Theorem states that any equilibrium is equivalent (in real allocations and prices) to another equilibrium in which there is no default. Thus actual default is irrelevant, though the potential for default drives the equilibrium and limits borrowing. This result is valid with arbitrary preferences and endowments, contingent or noncontingent promises, many assets and consumption goods, production, and multiple periods. We also show that only no‐default equilibria would be selected if there were the slightest cost of using collateral or handling default. Our Binomial Leverage Theorem shows that equilibrium Loan to Value (LTV) for noncontingent debt contracts is the ratio of the worst‐case return of the asset to the riskless gross rate of interest. In binomial economies, leverage is determined by down risk and not by volatility.     

Bargaining without a Common Prior—An Immediate Agreement Theorem

In sequential bargaining models without outside options, each player's bargaining power is ultimately determined by which player will make an offer and when. This paper analyzes a sequential bargaining model in which players may hold different beliefs about which player will make an offer and when. Excessive optimism about making offers in the future can cause delays in agreement. The main result states that, despite this, if players will remain sufficiently optimistic for a sufficiently long future, then in equilibrium they will agree immediately. This result is also extended to other canonical models of optimism.     

Liquidity Constrained Markets Versus Debt Constrained Markets

This paper compares two different models in a common environment. The first model has liquidity constraints in that consumers save a single asset that they cannot sell short. The second model has debt constraints in that consumers cannot borrow so much that they would want to default, but is otherwise a standard complete markets model. Both models share the features that individuals are unable to completely insure against idiosyncratic shocks and that interest rates are lower than subjective discount rates. In a stochastic environment, the two models have quite different dynamic properties, with the debt constrained model exhibiting simple stochastic steady states, while the liquidity constrained model has greater persistence of shocks.     

限制最大损失时的证券投资组合模型及有效边界解析表达式

在有限自然状态的市场环境下,本文利用传统的均值-方差模型研究了限制最大损失时的证券投资组合问题,首先指出了含有无风险资产与不含有无风险资产两种情形在限制最大损失时模型的求解本质上是一样的,然后作为典型代表研究了n种风险资产在限制最大损失时的前沿边界及有效边界存在的充要条件及其本质特征,并根据这些结论给出了确定前沿边界及有效边界解析表达式的具体方法和步骤,最后作为结论的直接应用和说明,给出了一个具体的算例分析。     

The Identification of Beliefs From Asset Demand

The demand for assets as prices and initial wealth vary identifies beliefs and attitudes towards risk. We derive conditions that guarantee identification with no knowledge either of the cardinal utility index (attitudes towards risk) or of the distribution of future endowments or payoffs of assets; the argument applies even if the asset market is incomplete and demand is observed only locally.     

均值-方差模型具有一般不确定性下的最优资产组合选择

引入以记忆系数和无差异系数表征的随机变量测度均值-方差模型的一般不确定性特征,反映投资者的模型信任程度,研究均值-方差模型具有一般不确定性下的最优资产组合选择问题。基于资本市场线理论,构建最优资产组合选择是模型信任程度和基于均值-方差模型的传统资产组合选择的线性函数;基于记忆系数和无差异系数的不同组合,运用基于事例推理的方法求解二次效用投资者的最优模型信任程度,获得均值-方差模型具有一般不确定性下的最优资产组合,并以上证综指1997年1月-2014年8月的月度收益数据形成两个研究样本予以实证比较研究。结果表明,较大风险规避投资者,在较大记忆系数和较小无差异系数下,其模型信任程度调整较快、资产组合调整幅度大,表现出可获得性和代表性行为偏差,通常采取积极资产组合策略;反之,其模型信任程度调整渐进、资产组合调整幅度小,表现出锚定性和保守性行为偏差,通常采取消极资产组合策略;模型一般不确定性对最优资产组合选择的影响强于股票市场记忆性的影响。研究体现了投资者的有限理性,将传统的资产组合选择问题延伸至行为金融学领域。     

流动性资产定价理论与实证研究

由于交易成本、市场摩擦等因素的影响,资产价格偏离标准资产定价理论的预期,产生了流动性溢价。非流动性产生的来源、机理、性质引起学术界持续的兴趣,尤其是非流动性对最优消费和投资策略,资产价格和收益,以及风险溢价的影响成为资产定价领域里最具有挑战性的课题之一。本文从理论和实证两个方面对探讨流动性与资产价格之间关系的文献进行了简要回顾。     

抵押贷款证券的效用无差别定价

当前抵押贷款证券化产品定价方法主要是现金流贴现取平均的方式,其本质是一种风险中性定价,忽视了不同投资者的风险态度在资产定价中的决定作用。本文运用Hodges and Neuberger(1989)提出的效用无差别定价原理,提出抵押贷款证券化衍生产品定价的一种新的方法。假设投资者具有对数消费效用,本文得到了易于实现的抵押贷款证券化产品定价计算公式,给出了Monte Carlo数值计算方法和应用举例,并进行了比较静态分析。