Pecuniary Externalities Research Articles

Macroprudential policy with leakages

We explore how imperfect regulation enforcement affects the design of optimal macroprudential policy. We study an open economy workhorse model of macroprudential regulation motivated by pecuniary externalities. Our analytical characterization shows that imperfect enforcement generates two opposing effects. While tighter regulation leads to higher borrowing by unregulated agents, a “leakage effect”, mitigating the increase in fragility calls for “squeezing” regulated agents further. Quantitative simulations show that, overall, a macroprudential policy that accounts for the leakages remains successful at mitigating the vulnerability to financial crises.

Optimal Taxes under Private Information: The Role of Inflation

AbstractOnce explicit information available to the taxing authority and incentives associated with private information problems are explicitly taken into account, only a limited set of policy instruments are consistent with agents not engaging in side trades. Within this spirit, we study the role of taxes and inflation in minimizing the dead‐weight loss associated with the provision of good incentives and other market imperfections when fiat money is essential. When the government has a rich information set and can observe savings, effort, and consumption in frictionless markets, the constrained efficient allocation can be achieved with affine history‐dependent consumption taxes. Thus, monetary policy is redundant. In contrast, when the government observes sales, rather than actual consumption, a tax arbitrage exists. Uniform affine consumption taxes prevent side trades. We also find that a deviation from the Friedman rule is optimal as it helps induce truth‐telling and alleviate a pecuniary externality. However, optimal monetary and fiscal policies in this setting cannot implement the constrained efficient allocation.

Cournot Fire Sales

In standard Walrasian macro-finance models, pecuniary externalities due to fire sales lead to excessive borrowing and insufficient liquidity holdings. We investigate whether imperfect competition (Cournot) improves welfare through internalizing the externality and find that this is far from guaranteed. Cournot competition can overcorrect the inefficiently high borrowing in a standard model of levered real investment. By contrast, Cournot competition can exacerbate the inefficiently low liquidity in a standard model of financial portfolio choice. Implications for welfare and regulation are therefore sector specific, depending both on the nature of the shocks and the competitiveness of the industry. (JEL D43, D62, E44, G11, G21, G28, G30)

A theory of fiscal policy response to an epidemic.

Governments worldwide have issued massive amounts of debt to inject fiscal stimulus during the COVID‐19 pandemic. This paper analyzes fiscal responses to an epidemic, in which interactions at work increase the risk of disease and mortality. Fiscal policies, which are designed to borrow against the future and provide transfers to individuals suffering economic hardship, can facilitate consumption smoothing while reduce hours worked and hence mitigate infections. We examine the optimal fiscal policy and characterize the condition under which fiscal policy improves social welfare. We then extend the model analyzing the static and dynamic pecuniary externalities under scale economies—the decrease in labor supply during the epidemic lowers the contemporaneous average wage rate while enhances the post‐epidemic workforce health and productivity. We suggest that fiscal policy may not work effectively unless the government coordinates working time, and the optimal size of public debt is affected by production technology and disease severity and transmissibility.

Regulating Mortgage Leverage: Fire Sales, Foreclosure Spirals, and Pecuniary Externalities

This paper introduces a dynamic general equilibrium model to study how the distribution of leverage and foreclosure affect house prices. In the model, exogenous income shocks drive endogenous foreclosure and equilibrium house prices. The model shows how foreclosure sales, through their effect on housing supply, amplify and propagate house price drops. A calibration shows consumption and housing need to be sufficiently complementary to fit the data. Since leverage plays a key role in foreclosure, a regulator can reduce systemic risk by placing a cap on leverage. Counterfactual experiments show that in a world with less leverage, the same economic shock leads to less foreclosure and less severe, shorter busts in house prices.

Market Harms and Market Benefits

Market Harms and Market Benefits

Financing land acquisition for infrastructure projects

Land acquisition for infrastructure projects that require a large amount of funding can be financed with an equity-like protocol. The auction protocol does not require knowledge of the reservation value of the land acquired, nor does it require determination of the post-development value of the land in the surrounding area. Competition among private players transfers the value of pecuniary externalities, manifested in land price appreciation, to the government, which it can use to partially finance the project.

Rising skill premium and the dynamics of optimal capital and labor taxation

With capital‐skill complementarity, the secular decline in the price of capital equipment due to equipment‐specific technological progress (ESTP) keeps pushing up the demand for skilled relative to unskilled labor and raising the skill premium. This paper quantitatively characterizes the dynamics of optimal taxation in response. Two main results emerge, regardless of whether the Ramsey (1927) or the Mirrlees (1971) approach is adopted. First, a tax on capital equipment corrects the “pecuniary externalities” caused by ESTP. The correction prescribes a downward or an upward adjustment of tax rates over time, depending on whether ESTP takes place at an accelerated or a decelerated pace. Second, both Ramsey and Mirrlees approaches prescribe an increasing marginal tax rate on labor income over time. Interestingly, we find that the prescribed pattern of optimal taxation resembles the empirical decline in capital taxes and the increase in labor taxes observed in the United States. In particular, despite the significant rise in the skill premium, the welfare gains of tax reform toward optimal Ramsey taxes are modest and small.

Sudden Stops and Reserve Accumulation in the Presence of International Liquidity Risk

We propose a small open economy model where agents borrow internationally and invest in liquid foreign assets to insure against liquidity shocks, which temporarily shut out the economy of short-term credit markets. Due to the presence of a pecuniary externality individual agents borrow too much and hold too little liquid assets relative to a social planner. This ineffciency rationalizes macroprudential policy interventions in the form of reserve accumulation at the central bank coupled with a tax on foreign borrowing. Unless combined with other measures, a tax on foreign borrowing is detrimental to welfare; it reduces agents’ incentives to invest in liquid assets and thereby increases financial instability. Our model can quantitatively match the simultaneous depreciation of the exchange rate and contractions in output, gross trade flows, foreign liabilities and liquid reserves during Sudden Stop episodes.

Constrained Pseudo-Market Equilibrium

We propose a pseudo-market solution to resource allocation problems subject to constraints. Our treatment of constraints is general: including bihierarchical constraints due to considerations of diversity in school choice, or scheduling in course allocation; and other forms of constraints needed to model, for example, the market for roommates, combinatorial assignment problems, and knapsack constraints. Constraints give rise to pecuniary externalities, which are internalized via prices. Agents pay to the extent that their purchases affect the value the of relevant constraints at equilibrium prices. The result is a constrained-efficient market-equilibrium outcome. The outcome is fair to the extent that constraints treat agents symmetrically. (JEL D47, D61, D63, I11, I21)

Pecuniary externalities, bank overleverage, and macroeconomic fragility

AbstractPecuniary externalities in models with financial friction justify macroprudential policies for preventing excessive risk taking by economic agents. We extend the Diamond and Rajan model of banks with production factors and explore how a pecuniary externality affects a bank's leverage. We show that the laissez‐faire banks in our model take on excessive risks compared with the constrained social optimum. Our numerical simulations suggest that the crisis probability is 2–3 percentage points higher in the laissez‐faire economy than in the constrained social optimum.

Investment externalities in models of fire sales

Two alternative models of fire sales that yield the same aggregate predictions have different normative implications. If fire sales result from marginal misallocation, a pecuniary externality leads to ex-ante overinvestment. If they result from asymmetric information, the overinvestment result is reversed. However, there may be a tradeoff between present and future underinvestment. Ex-ante macroprudential policy may need to treat different types of investment differently, but ex-post intervention is useful in both cases.

Equilibrium foreign currency mortgages

This paper proposes a novel explanation for why foreign currency denominated loans to households have become so popular in some emerging economies. Our argument is based on what we call the debt limit channel, which arises when multi-period contracts are offered against collateral that is established on newly acquired assets. Whenever the difference between domestic and foreign interest rates is positive, this effect allows financially constrained agents to backload the real payments on their loans if they choose to borrow in foreign currency. We demonstrate in a structural macroeconomic framework that the debt limit channel is quantitatively important and can result in dollarization of debt despite realistic and correctly perceived exchange rate risk. Comparing this outcome to allocations under constrained-optimal policy reveals that much of the identified bias towards foreign currency is due to a pecuniary externality, i.e. borrowers' failure to internalize how their currency choice affects house prices.

Gain-Loss Utility and Inefficiency in the Aggregate Stock Market

The paper studies the constrained efficiency of the aggregate stock market in which the investor obtains gain-loss utility directly from fluctuations in asset returns, in addition to consumption. I reveal that the competitive equilibrium is inefficient without any frictions as long as the agent has such preferences. Because of pecuniary externalities, the agent chooses more capital stock compared with what the social planner with identical preferences does. The numerical analysis shows that the welfare loss of the inefficiency is nontrivial. The policy used to implement constrained optimal allocations specifies that the government should tax capital to raise gain-loss utility.

A Model of Endogenous Financial Inclusion: Implications for Inequality and Monetary Policy

AbstractWe propose a monetary model with endogenous credit market participation to study the impact of financial inclusion on inequality and welfare. We find that consumption inequality results from differences in agents' decision to access financial services. This heterogeneity generates a pecuniary externality, potentially resulting in some agents overconsuming. Moreover, monetary policy has distributional consequences. To quantify these effects, we calibrate our model to India, accounting for a third of observed consumption inequality. Finally, we analyze various policies aimed at increasing financial inclusion and find that a direct transfer to bank account holders yields the highest welfare and lowest consumption inequality.

A Theory of Foreign Exchange Interventions

Abstract We study a real small open economy with two key ingredients (1) partial segmentation of home and foreign bond markets and (2) a pecuniary externality that makes the real exchange rate excessively volatile in response to capital flows. Partial segmentation implies that, by intervening in the bond markets, the central bank can affect the exchange rate and the spread between home- and foreign-bond yields. Such interventions allow the central bank to address the pecuniary externality, but they are also costly, as foreigners make carry trade profits. We analytically characterize the optimal intervention policy that solves this trade-off: (1) the optimal policy leans against the wind, stabilizing the exchange rate; (2) it involves smooth spreads but allows exchange rates to jump; (3) it partly relies on “forward guidance,” with non-zero interventions even after the shock has subsided; (4) it requires credibility, in that central banks do not intervene without commitment. Finally, we shed light on the global consequences of widespread interventions, using a multi-country extension of our model. We find that, left to themselves, countries over-accumulate reserves, reducing welfare and leading to inefficiently low world interest rates.

A Market-Based Solution for Fire Sales and Other Pecuniary Externalities

In economies with a continuum of agents of different types, pecuniary externalities are removed with market exchanges. Agents choose from among various possible prices they want to prevail in the future and buy or sell rights in these market exchanges for future trade. Each agent can choose the exchange it wants without regard to what any other agent is doing. But crucially, the right to trade in each and every exchange is priced. The fee structure has a per-unit price and quantity decomposition: a price, as determined by the exchange chosen, times the quantity of rights acquired.

Capital Controls: Theory and Evidence

This paper synthesizes recent advances in the theoretical and empirical literature on capital controls. We start by observing that international capital flows have both benefits and costs, but some of these are not internalized by individual actors and thus constitute externalities. The theoretical literature has identified pecuniary externalities and aggregate demand externalities that respectively contribute to financial instability and recessions. These externalities provide a natural rationale for countercyclical capital controls that lean against boom and bust cycles in international capital flows. The empirical literature has developed several measures of capital controls to capture different aspects of capital account openness. We evaluate the strengths and weaknesses of different measures and provide an overview of the empirical findings on the effectiveness of capital controls in addressing the externalities identified by the theory literature, that is, in reducing financial fragility and enhancing macroeconomic stability. We also discuss strategies to deal with the endogeneity of capital controls in such statistical exercises. We conclude by providing an overview of the historical and current debates on the role of capital controls in macroeconomic management and their relationship to the academic literature. (JEL D62, F32, F33, F38, F44)

Optimal Taxation with Private Insurance

Abstract We derive a fully non-linear optimal income tax schedule in the presence of private insurance. We fill the gap in the literature by studying the optimal tax formula with a comprehensive structure of the private markets—including incomplete markets models—both theoretically and quantitatively. As in the standard taxation literature without private insurance, the optimal tax formula can still be expressed in terms of standard sufficient statistics. With private insurance, however, the formula involves additional terms that reflect how the private market interacts with public insurance. For example, the optimal tax formula should also consider asset distribution and pecuniary externalities as well as the welfare effects of borrowing constraints.

When Do Currency Unions Benefit from Default?

Since the Eurozone Crisis of 2010-12, a critical debate on the viability of a currency union has focused on the role of a fiscal union in adjusting for country heterogeneity. However, a fully-fledged fiscal union may not be politically feasible. This paper develops a two-country general equilibrium model to examine the benefits of the bankruptcy code of a capital markets union - in the absence of a fiscal union - as an alternative mechanism to improve the financial stability and welfare of a currency union. When domestic credit risks are present, I show that a lenient bankruptcy code in the cross-border capital markets union removes the pecuniary externality of banking insolvency, so it leads to a Pareto improvement within the currency union. Moreover, the absence of floating nominal exchange rates removes a mechanism to neutralise domestic credit risks; I show that softening the bankruptcy code can recoup the lost benefits of floating nominal exchange rates. The model provides the financial stability and welfare implications of bankruptcy within a capital markets union in the Eurozone.