住房价格、金融稳定与宏观审慎政策

本文通过建立包含异质性家庭、异质性厂商和金融机构的DSGE模型,分析对预期房价作出反应的货币政策和宏观审慎政策的传导机制和政策效果,研究不同政策的选择和协调问题。研究发现,首先,由于政策的作用范围不同,不同政策会对金融稳定和经济稳定产生不同影响。对预期房价作出反应的货币政策能够抑制住房需求和信贷供给,但也会抑制消费需求和产出;而对预期房价作出反应的逆周期LTV政策和逆周期资本充足率政策在应对房价波动导致的金融稳定问题时更加有的放矢。其次,外生冲击的来源会影响政策的选择和协调——当经济波动来源于需求冲击时,固定LTV政策搭配逆周期资本充足率的宏观审慎政策、不对预期房价作出反应的货币政策表现最优;当经济波动来源于供给冲击时,固定LTV政策搭配逆周期资本充足率的宏观审慎政策、对预期房价作出反应的货币政策表现最优。     

耐用品、投资专有冲击与货币政策福利

本文构建蕴含耐用品与非耐用品的两部门DSGE模型,研究投资专有冲击对货币政策及社会福利的影响。投资专有技术进步改进了投资转化为生产资本的效率,放大边际成本波动,增加了厂商调价动机和价格水平变动。即使耐用品价格完全灵活,最优货币政策也无法同时稳定价格和实际GDP。研究发现:(1)耐用品相对价格缺口波动率的上升虽然增加了实际GDP波动,但能够有效地降低投资专有技术对边际成本的冲击,减少价格变动的福利损失。所以两部门投资专有冲击时,央行倾向于稳定价格水平。与其相反,在单部门投资专有冲击和两部门生产技术冲击时,最优货币政策应降低耐用品相对价格缺口波动,稳定实际GDP。(2)对比三种泰勒规则:钉住非耐用品PPI、钉住加权平均PPI及钉住CPI,福利分析发现钉住非耐用品PPI最优,钉住CPI次之,钉住加权平均PPI的福利损失最大。就损失程度而言,投资专有冲击的福利损失是生产技术冲击的2倍,表明投资专有冲击加剧了最优货币政策在稳定价格与实际GDP间的权衡。     

Optimal monetary policy with durable consumption goods

We document that the durable goods sector is much more interest-sensitive than the nondurables sector, and then investigate the implications of these sectoral differences for monetary policy. We formulate a two-sector general equilibrium model that is calibrated both to match the sectoral responses to a monetary shock derived from our empirical VAR and to imply an empirically realistic degree of sectoral output volatility and comovement. While the social welfare function involves sector-specific output gaps and inflation rates, the performance of the optimal policy rule can be closely approximated by a simple rule that targets a weighted average of aggregate wage and price inflation. In contrast, a rule that stabilizes a more narrow measure of final goods price inflation performs poorly in terms of social welfare.     

Optimal fiscal and monetary policy with sticky prices

In this paper I consider the role of state-contingent inflation as a fiscal shock absorber in an economy with nominal rigidities. I study the Ramsey equilibrium in a monetary model with distortionary taxation, nominal non-state-contingent debt, and sticky prices. With sticky prices, the Ramsey planner must balance the shock absorbing benefits of state-contingent inflation against the associated resource misallocation costs. For government spending processes resembling post-war experience, introducing sticky prices generates striking departures in optimal policy from the case with flexible prices. For even small degrees of price rigidity, optimal policy displays very little volatility in inflation. Tax rates display greater volatility compared to the model with flexible prices. With sticky prices, tax rates and real government debt exhibit behavior similar to a random walk. For government spending processes resembling periods of intermittent war and peace, optimal policy displays extreme inflation volatility even when the degree of price rigidity is large. As the variability in government spending increases, smoothing tax distortions across states of nature becomes increasingly important, and the shock absorber role of inflation is accentuated.     

Implications of habit formation for optimal monetary policy

We study the implications for optimal monetary policy of introducing habit formation in consumption into a general equilibrium model with sticky prices. Habit formation affects the model's endogenous dynamics through its effects on both aggregate demand and households’ supply of output. We show that the objective of monetary policy consistent with welfare maximization includes output stabilization, as well as inflation and output gap stabilization. We find that the variance of output increases under optimal policy, even though it acquires a higher implicit weight in the welfare function. We also find that a simple interest rate rule nearly achieves the welfare-optimal allocation, regardless of the degree of habit formation. In this rule, the optimal responses to inflation and the lagged interest rate are both declining in the size of the habit, although super-inertial policies remain optimal.     

Economic Parameters of Deforestation

In theory, economic instruments should overcome the market failuresthat lead to excessive deforestation. Secure property rightscould be established and enforced to eliminate the open accessproblem. In practice, the size of the welfare loss that arisesfrom market failures in the forest sector in the absence ofsuch first-best policies is determined by the incentives, prices,and policies faced by those who make decisions about land use.In many cases, the effects of policies on deforestation arenot straightforward. For example, there are conflicting viewson whether an increase in the price of logs leads to an increaseor a decrease in deforestation. The effect of a change in theprice of logs has particular relevance for the controversialdebate about the effect on deforestation of a ban on log exportsor other trade restrictions that lower the domestic price oflogs. This article provides an analytical framework for determiningthe effects of changes in economic policies and parameters ondeforestation. It models dynamic, profitmaximizing land-usechoices and obtains unambiguous comparative static results bydistinguishing between unmanaged and managed forests. The resultssuggest that measures to reduce the producer price of logs couldbe a second-best policy to reduce the pressures on the frontiersof unmanaged forests and to protect biodiversity.     

货币政策纳入资产价格目标后能更好地调控经济波动吗——基于金融结构视角的分析

本文通过构建包含金融结构的NK-DSGE模型,分析在不同的金融结构下,包含金融资产价格稳定目标的扩展型货币政策能否更加有效地熨平经济波动.研究表明:(1)相比传统货币政策,包含金融资产价格稳定目标的货币政策不仅能更好地熨平宏观经济波动、缩短波动持续期,还能提升社会福利;(2)在扩展型货币政策框架下,央行需结合不同类型冲击下金融结构与宏观调控变量波动的异质相关性,依据金融结构市场化进程,灵活调整其对各个变量的调控力度;(3)在扩展型货币政策框架下,当经济体系面临非持续性技术冲击、投资边际效率冲击或金融冲击时,金融结构市场化程度越高,社会福利增进效果越好.本文的研究为宏观经济调控政策特别是货币政策决策提供了有益启示,或可为新时期增强宏观经济调控效果、构建兼顾金融稳定和经济稳定的平衡发展路径提供新思路和新抓手.     

FX Intervention in the New Keynesian Model

We develop an open-economy New Keynesian Model with foreign exchange (FX) intervention in the presence of a financial accelerator and shocks to risk appetite in international capital markets. We obtain closed-form solutions for optimal monetary and FX intervention policies assuming the central bank cannot commit to future policies, and we compare the solution to that under policy commitment. We show how FX intervention can help reduce the volatility of the exchange rate, of inflation, and of the output gap, thus mitigating welfare losses associated with shocks in the international capital markets. We also show that, when the financial accelerator is strong, there is a risk of indeterminacy (self-fulfilling currency and inflation movements) although FX intervention can reduce this risk and thus reinforce the credibility of the inflation targeting regime. Model simulations match well the impact of a VIX shock obtained by local projections on a panel of inflation targeting emerging markets.     

COVID-19 pandemic,oil prices,stock market,geopolitical risk and policy uncertainty nexus in the US economy: Fresh evidence from the wavelet-based approach

In this paper, we analyze the connectedness between the recent spread of COVID-19, oil price volatility shock, the stock market, geopolitical risk and economic policy uncertainty in the US within a time-frequency framework. The coherence wavelet method and the wavelet-based Granger causality tests applied to US recent daily data unveil the unprecedented impact of COVID-19 and oil price shocks on the geopolitical risk levels, economic policy uncertainty and stock market volatility over the low frequency bands. The effect of the COVID-19 on the geopolitical risk substantially higher than on the US economic uncertainty. The COVID-19 risk is perceived differently over the short and the long-run and may be firstly viewed as an economic crisis. Our study offers several urgent prominent implications and endorsements for policymakers and asset managers.     

Bank Capital Standards for Market Risk: A Welfare Analysis

We propose a simple model that is suitable for evaluating alternativebank capital regulatory proposals for market risk. Our modelformalizes the conflict between bank objectives and regulatorygoals. Banks' decisions represent a tension between their desireto exploit the deposit-insurance put option and their desireto preserve franchise value. Regulators seek to balance thesocial value of deposits in mediating transactions against thedeadweight costs of failure resolution. Our social welfare criterionis standard: a weighted average agents' utilities. We demonstrate that banks do not incrementally alter their portfoliorisk as the economic environment changes. Rather, banks eitherchoose the minimal feasible risk or the maximal feasible risk.This pattern, in turn, drives regulatory decisions: The firstgoal of the regulator is to induce banks to choose the minimalrisk level. For all nontrivial cases, unregulated banks failto choose the first-best allocations. Traditional ex-ante capitalrequirements can induce banks to choose the socially-optimallevel of portfolio risk, but the required capital is often inefficientlyhigh. In contrast, variants of the Federal Reserve Board's precommitmentproposal imply far smaller efficiency losses, and achieve allocationsat or nearthe first-best for most reasonable model specifications.The ex-post penalties required for the optimal implementationof precommitment are not excessively large. The welfare gainsfrom precommitment are even higher when the precommitment penaltyfunction is precluded from sending banks into default. We concludethat state-contingent regulatory mechanisms, of which the precommitmentapproach is an example, offer the possibility of substantialgains in regulatory efficiency, relative to traditional statenon-contingent regulation.     

Housing-market heterogeneity in a monetary union

This paper studies the implications of cross-country housing-market heterogeneity in a monetary union for both shock transmission and welfare. I develop a two-country new Keynesian general equilibrium model with housing and collateral constraints to explore this issue. The conventional wisdom is that welfare would be higher in a monetary union if mortgage markets were homogeneous. This paper shows instead that welfare is higher only when homogenization does not result in higher aggregate volatility (because of financial accelerator effects) or does not redistribute too much wealth from borrowers to savers.     

Financial contagion and the role of the central bank

We investigate the role of a central bank (CB) in preventing and avoiding financial contagion. The CB, by imposing reserve requirements on the banking system, trades off the cost of reducing the resources available for long-term investment with the benefit of raising liquidity to face an adverse shock that could cause contagious crises. We argue that contagion is not due to the structure of the interbank deposit market, but to the impossibility to sign contracts contingent on unforeseen contingencies. As long as incomplete contracts are present, the CB may have a useful role in curbing contagion. Moreover, the CB allows the banking system to reach first-best allocation in all the states of the world when the notion of incentive-efficiency is considered. If the analysis is restricted to constrained-efficiency, the CB still avoids contagion without, however, reaching first-best consumption allocation. The model provides a rationale for reserve requirements without the presence of fiat money or asymmetric information.     

总量型和结构型货币政策工具的选择与搭配——基于结构性去杠杆视角下的分析

本文基于我国34类工业行业的年度数据,识别信贷配置偏向特征对结构性杠杆的影响,以及货币政策应对效应的特征事实:信贷偏向的存在导致不同产权性质企业杠杆变化呈现异质性,这种异质性所产生的结构性杠杆现象因经济周期不同阶段而异,传统总量型货币政策工具难以有效解决结构性杠杆问题。为更深入理解这一现象以及结构性去杠杆下货币政策最优选择问题,本文通过构建一个同时包含信贷配置偏向特征、企业杠杆结构变化特征、总量型与结构型货币政策工具影响特征的DSGE模型进行分析,研究结果表明:总量型货币政策数量工具的宽松操作可以有效应对技术冲击下结构性杠杆问题;总量型工具紧缩资金供给,结合结构型工具定向紧缩,是应对成本推动冲击下结构性高杠杆问题的较好选择;当经济面临风险冲击下结构性杠杆和经济下行并存问题时,需要结构型货币政策数量工具和价格工具同时操作,紧缩国企贷款,同时降低民企融资成本。     

The 4% strategy revisited: a pre-commitment mean-variance optimal approach to wealth management

In contrast to single-period mean-variance (MV) portfolio allocation, multi-period MV optimal portfolio allocation can be modified slightly to be effectively a down-side risk measure. With this in mind, we consider multi-period MV optimal portfolio allocation in the presence of periodic withdrawals. The investment portfolio can be allocated between a risk-free investment and a risky asset, the price of which is assumed to follow a jump diffusion process. We consider two wealth management applications: optimal de-accumulation rates for a defined contribution pension plan and sustainable withdrawal rates for an endowment. Several numerical illustrations are provided, with some interesting implications. In the pension de-accumulation context, Bengen (1994)’s [J. Financial Planning, 1994, 7, 171–180], historical analysis indicated that a retiree could safely withdraw 4% of her initial retirement savings annually (in real terms), provided that her portfolio maintained an even balance between diversified equities and U.S. Treasury bonds. Our analysis does support 4% as a sustainable withdrawal rate in the pension de-accumulation context (and a somewhat lower rate for an endowment), but only if the investor follows an MV optimal portfolio allocation, not a fixed proportion strategy. Compared with a constant proportion strategy, the MV optimal policy achieves the same expected wealth at the end of the investment horizon, while significantly reducing the standard deviation of wealth and the probability of shortfall. We also explore the effects of suppressing jumps so as to have a pure diffusion process, but assuming a correspondingly larger volatility for the latter process. Surprisingly, it turns out that the MV optimal strategy is more effective when there are large downward jumps compared to having a high volatility diffusion process. Finally, tests based on historical data demonstrate that the MV optimal policy is quite robust to uncertainty about parameter estimates.     

Systemic risk: A new trade-off for monetary policy?

We introduce time-varying systemic risk (à la He and Krishnamurthy, 2014) in an otherwise standard New-Keynesian model to study whether simple leaning-against-the-wind interest rate rules can reduce systemic risk and improve welfare. We find that while financial sector leverage contains additional information about the state of the economy that is not captured in inflation and output leaning against financial variables can only marginally improve welfare because rules are detrimental in the presence of falling asset prices. An optimal macroprudential policy, similar to a counter cyclical capital requirement, can eliminate systemic risk raising welfare by about 1.5%. Also, a surprise monetary policy tightening does not necessarily reduce systemic risk, especially during bad times. Finally, a volatility paradox a la Brunnermeier and Sannikov (2014) arises when monetary policy tries to excessively stabilize output.     

Home bias,exchange rate disconnect,and optimal exchange rate policy

This paper examines how much the central bank should adjust the interest rate in response to real exchange rate fluctuations. The paper first demonstrates, in a two-country Dynamic Stochastic General Equilibrium (DSGE) model, that home bias in consumption is important to replicate the exchange rate volatility and exchange rate disconnect documented in the data. When home bias is high, the shock to Uncovered Interest rate Parity (UIP) can substantially drive up exchange rate volatility while leaving the volatility of real macroeconomic variables, such as GDP, almost untouched. The model predicts that the volatility of the real exchange rate relative to that of GDP increases with the extent of home bias. This relation is supported by the data. A second-order accurate solution method is employed to find the optimal operational monetary policy rule. Our model suggests that the monetary authority should not seek to vigorously stabilize exchange rate fluctuations. In particular, when the central bank does not take a strong stance against the inflation rate, exchange rate stabilization may induce substantial welfare loss. The model does not detect welfare gain from international monetary cooperation, which extends Obstfeld and Rogoff's [Obstfeld, M., Rogoff, K.,2002. Global implications of self-oriented national monetary rules, Quarterly Journal of Economics May, 503–535] findings to a DSGE model.     

Bank Capital Standards for Market Risk: A Welfare Analysis

We propose a simple model that is suitable for evaluating alternative bank capital regulatory proposals for market risk. Our model formalizes the conflict between bank objectives and regulatory goals. Banks' decisions represent a tension between their desire to exploit the deposit-insurance put option and their desire to preserve franchise value. Regulators seek to balance the social value of deposits in mediating transactions against the deadweight costs of failure resolution. Our social welfare criterion is standard: a weighted average agents' utilities.We demonstrate that banks do not incrementally alter their portfolio risk as the economic environment changes. Rather, banks either choose the minimal feasible risk or the maximal feasible risk. This pattern, in turn, drives regulatory decisions: The first goal of the regulator is to induce banks to choose the minimal risk level. For all nontrivial cases, unregulated banks fail to choose the first-best allocations. Traditional ex-ante capital requirements can induce banks to choose the socially-optimal level of portfolio risk, but the required capital is often inefficiently high. In contrast, variants of the Federal Reserve Board's precommitment proposal imply far smaller efficiency losses, and achieve allocations at or near the first-best for most reasonable model specifications. The ex-post penalties required for the optimal implementation of precommitment are not excessively large. The welfare gains from precommitment are even higher when the precommitment penalty function is precluded from sending banks into default. We conclude that state-contingent regulatory mechanisms, of which the precommitment approach is an example, offer the possibility of substantial gains in regulatory efficiency, relative to traditional state non-contingent regulation.     

Should a monetary policymaker look at money?

This paper examines whether monetary indicators are useful in implementing optimal discretionary monetary policy when the policymaker has incomplete information about the environment. We find that money does not contain useful information for the policymaker, if we calibrate the model to the U.S. economy. If money demand were to be appreciably less variable, observations on money could be useful in response to productivity shocks but would be harmful in response to money-demand shocks. We provide an incomplete information example where equilibrium welfare declines when the money-demand volatility decreases.     

The impact of global economic policy uncertainty on portfolio optimization: A Black–Litterman approach

This paper investigates the asymmetric impact of global economic policy uncertainty (GEPU) on global asset allocation. We employ the Double Asymmetric GARCH-MIDAS (DAGM) model to examine the asymmetric effect of GEPU shocks on long-term volatilities of global equities, bonds, commodities, clean energy and Bitcoin. The GEPU-based volatility is used as a proxy for the uncertainty of the investor’s views in the Black-Litterman (BL) framework. Empirical results show that the BL model with GEPU-based views yields higher out-of-sample risk-adjusted returns than other traditional benchmarks in most cases. The findings suggest that investors should consider the influence of GEPU when making portfolio decisions.     

Trade Reform in the Partially Liberalized Economy of Turkey

Recent reforms in trade policy in Turkey have produced a foreigntrade regime that exhibits very little antiexport bias on average.A quantitative, multisectoral general equilibrium model of theTurkish economy shows that piecemeal trade policy reform, basedon first-best rationales that are appropriate for highly distortedeconomies, would not now be appropriate. Further tariff reductionsmust be coordinated with export subsidy reductions to attainsignificant welfare benefits. The dispersion of distortions,especially export subsidies, is more important than their level.A policy of harmonizing tariffs to the common external tariffof the European Community has virtually no effect on welfare.