IDIOSYNCRATIC AND AGGREGATE RISKS,INEQUALITY AND GROWTH

The paper disaggregates productivity shocks at a firm level into idiosyncratic and aggregate risks, and studies their impacts on inequality, growth and welfare. It develops a growth model with human capital and incomplete insurance and credit markets that provides a closed‐form solution for income inequality dynamics. We find that uninsured idiosyncratic risks are the most important determinants of inequality, growth and welfare. They are the source of nondegenerate wealth distribution. A lower weight of these shocks leads to lower steady‐state inequality, higher growth and welfare. A redistribution of income that serves as social insurance against such risks increases welfare and decreases inequality. But, it also decreases growth by distorting individual consumption and saving decisions.     

When is market incompleteness irrelevant for the price of aggregate risk (and when is it not)?

In a standard incomplete markets model with a continuum of households that have constant relative risk aversion (CRRA) preferences, the absence of insurance markets for idiosyncratic labor income risk has no effect on the premium for aggregate risk if the distribution of idiosyncratic risk is independent of aggregate shocks and aggregate consumption growth is independent over time. In equilibrium, households only use the stock market to smooth consumption; the bond market is inoperative. Furthermore, the cross-sectional distributions of wealth and consumption are not affected by aggregate shocks. These results hold regardless of the persistence of idiosyncratic shocks, even when households face tight solvency constraints. A weaker irrelevance result survives when we allow for predictability in aggregate consumption growth.     

The long run relationship between private consumption and wealth: common and idiosyncratic effects

We investigate the long run relationship between private consumption, disposable income and wealth approximated by equity and house price indices for a panel of 15 industrialized countries. Consumption, income and wealth are cointegrated in their common components. The impact of house prices exceeds the effect arising from equity wealth. The long run vector is broadly in line with the life cycle permanent income hypothesis, if house prices are allowed to enter the relationship. At the idiosyncratic level, a long run equilibrium is detected between consumption and income, i.e. the wealth variable can be excluded. The income elasticity in the idiosyncratic relationship is significantly less than unity. Hence, the presence of wealth effects in consumption equations arises from the international integration of asset markets and points to the relevance of risk sharing activities of agents. Without sufficient opportunities, an increase in national saving rates would be expected, leading to a lower path of private consumption expenditures.     

Recursive equilibrium in endogenous growth models with incomplete markets

This paper analyzes the existence of recursive equilibria in a class of convex growth models with incomplete markets. Households have identical CRRA-preferences, production displays constant returns to scale with respect to physical and human capital, and all markets are competitive. There are aggregate productivity shocks that affect aggregate returns to physical and human capital investment (stock returns and wages), and there are idiosyncratic shocks to human capital (idiosyncratic depreciation shocks) that only affect individual human capital returns. Aggregate and idiosyncratic shocks follow a joint Markov process. Conditional on the aggregate state, idiosyncratic shocks are independently distributed over time and identically distributed across households. Finally, households have the opportunity to trade assets in zero net supply with payoffs that depend on the aggregate shock, but markets are incomplete in the sense that there are no assets with payoffs depending on idiosyncratic shocks. It is shown that there exists a recursive equilibrium for which equilibrium prices (returns) only depend on the exogenous aggregate shock variable (the wealth distribution is not a relevant state variable). Moreover, the allocation associated with this recursive equilibrium is identical to the equilibrium allocation of an economy in which households live in autarky and face both aggregate and idiosyncratic risk.I would like to thank for helpful comments Peter Howitt, Bob Lucas, Michael Magill, Tomo Nakajima, Herakles Polemarchakis, Martine Quinzii, Kevin Reffett, an anonymous referee, and seminar participants at various universities and conferences.     

Precautionary savings or working longer hours?

This paper quantifies the macroeconomic implications of the lack of insurance against idiosyncratic labor market risk. I show that in a model economy calibrated to observed individual level data, households make ample use of work effort as a consumption smoothing mechanism. As a consequence, aggregate consumption is 0.6% lower, work effort is 18% higher and labor productivity is 12% lower than they would be in a complete markets setting. Not surprisingly, the welfare benefits of moving towards complete markets are very large. Accounting for the whole transition to the new complete markets steady state I find the welfare costs of market incompleteness above 16% of individual lifetime consumption.     

Multi-dimensional risk and the cost of business cycles

This paper analyzes the welfare costs of business cycles when workers face uninsurable idiosyncratic labor income risk. In accordance with the previous literature, this paper decomposes labor income risk into an aggregate and an idiosyncratic component, but in contrast to the previous literature, this paper allows for multiple sources of idiosyncratic labor income risk. Using the multi-dimensional approach to idiosyncratic risk, this paper provides a general characterization of the welfare cost of business cycles when preferences and the (marginal) process of individual labor income in the economy with business cycles are given. The general analysis shows that the introduction of multiple sources of idiosyncratic risk never decreases the cost of business cycles, and strictly increases it if there are cyclical fluctuations across the different sources of risk. This paper also provides a quantitative analysis based on a version of the model that is calibrated to match US labor market data. The quantitative analysis suggests that realistic variations across two particular dimensions of idiosyncratic labor income risk increase the welfare cost of business cycles by a substantial amount.     

Increasing returns to savings and wealth inequality

In this paper I present an explanation to the fact that in the data wealth is substantially more concentrated than income. Starting from the observation that the composition of households' portfolios changes towards a larger share of high-yield assets as the level of net worth increases, I first use data on historical asset returns and portfolio composition by wealth level to construct an empirical return function. I then augment an Overlapping Generation version of the standard neoclassical growth model with idiosyncratic labor income risk and missing insurance markets to allow for returns on savings to be increasing in the level of accumulated assets. The quantitative properties of the model are examined and show that an empirically plausible difference between the return faced by poor and wealthy agents is able to generate a substantial increase in wealth inequality compared to the basic model, enough to match the Gini index and all but the top 1 percentile of the US distribution of wealth.     

Social security,saving, and macroeconomics

Arguing within the framework of a life-cycle hypothesis of consumption of the individual household, Martin Feldstein has claimed that a pay-as-you-go, unfunded social-security system implies a private-sector perception of wealth which both depresses private saving and raises aggregate consumption. But the effects in a macro-economic context are not the same. With less than full employment, perceived increments to private wealth in social security or any other government obligations should increase current and planned future consumption and saving, raising employment and output. With full employment, as long as monetary policy is appropriately accommodating, such increments to wealth should raise prices but leave all real variables, including capital accumulation, unaffected. Increases in social-security wealth would merely substitute for real private wealth in the form of explicit government bonds. Econometric estimates from corrected U.S. data on social security, public debt, income, and employment are consistent with these hypotheses.     

Incomplete markets,liquidation risk,and the term structure of interest rates

We analyse the term structure of interest rates in a general equilibrium model with incomplete markets, borrowing constraint, and positive net supply of government bonds. Uninsured idiosyncratic shocks generate bond trades, while aggregate shocks cause fluctuations in the trading price of bonds. Long bonds command a “liquidation risk premium” over short bonds, because they may have to be liquidated before maturity – following a bad idiosyncratic shock – precisely when their resale value is low – due to the simultaneous occurrence of a bad aggregate shock. Our framework endogenously generates limited cross-sectional wealth heterogeneity among the agents (despite the presence of uninsured idiosyncratic shocks), which allows us to characterise analytically the shape of the entire yield curve, including the yields on bonds of arbitrarily long maturities. Agents? desire to hedge the idiosyncratic risk together with their fear of having to liquidate long bonds at unfavourable terms implies that a greater bond supply raises the level of the yield curve, while an increase in the relative supply of long bonds raises its slope.     

Banking Market Structure and Macroeconomic Stability: Are Low‐Income Countries Special?

Does the structure of banking markets affect macroeconomic volatility and, if yes, is this link different in low‐income countries? In this paper, we explore the channels through which the structure of banking markets affects macroeconomic volatility. Our research has three main findings. First, we study whether idiosyncratic volatility at the bank level can impact aggregate volatility. We find weak evidence for a link between granular banking sector volatility and macroeconomic fluctuations. Second, a higher share of domestic credit to GDP coincides with higher volatility in the short run. Third, a higher level of cross‐border asset holdings increases volatility in low‐income countries.     

Optimal asset taxes in financial markets with aggregate uncertainty

This paper studies Pareto-optimal risk-sharing arrangements in a private information economy with aggregate uncertainty and ex ante heterogeneous agents. I show how to implement Pareto optima as equilibria when agents can trade claims to consumption contingent on aggregate shocks in financial markets. The first result is that if aggregate and idiosyncratic shocks are independent, the implementation of optimal allocations does not require any interventions in financial markets. This result can be extended to dynamic settings in the sense that, in this case, only savings need to be distorted, but not trades in financial markets. Second, I characterize optimal trading distortions in financial markets when aggregate and idiosyncratic shocks are not independent. In this case, optimal asset taxes must be higher for those securities that pay out in aggregate states in which consumption is more volatile. For instance, this can provide an efficiency justification for the frequently observed differential tax treatment of different asset classes, such as debt and equity claims.     

Wealth and the capitalist spirit

The wealth distribution in the U.S. is more unequal than either the income or earnings distribution, a fact current models of saving behavior have difficulty explaining. Using Max Weber’s [Weber, M. (1905). The Protestant Ethic and the Spirit of Capitalism. Charles Scribners’ and Sons (1958 translated edition)] idea that individuals may have a ‘capitalist spirit’, I construct and simulate a model where individuals accumulate wealth for its own sake rather than as deferred consumption. Including capitalist spirit preferences in a simple life cycle model, with no other modifications, generates a skewness of wealth consistent with that observed in the U.S. economy. Furthermore, capitalist spirit preferences provide a way to generate decreasing risk aversion with increases in wealth without resorting to idiosyncratic rates of time preference.     

Default and aggregate income

This paper studies how default varies with aggregate income. We analyze a model in which optimal contracts enable risk sharing of privately observed, idiosyncratic income by allowing for default. Default provisions allow agents with low idiosyncratic income realizations to repay less and thus provide insurance. Default penalties ensure that only these agents default. We show that default can occur under the optimal contract and that default provisions vary with aggregate income. We provide conditions such that both the amount of default and default penalties vary countercyclically with aggregate income and show that the default rate can be discontinuous.     

Monetary and fiscal policies in a heterogeneous‐agent economy

We study the effects of long‐run inflation and income taxation in an economy where households face uninsurable idiosyncratic risks. We construct a tractable competitive‐search framework that generates dispersion of prices, income and wealth. We analytically characterize the stationary equilibrium and the policy effects on individual choices. Quantitative analysis finds that monetary and fiscal policies have distinct effects on macro aggregates, such as output, savings and wealth, income and consumption inequalities. There is a hump‐shaped relationship between welfare and the respective policies. Overall, welfare is maximized by a deviation from the Friedman rule, paired with distortionary income taxation.     

Estimating the marginal propensity to consume using the distributions of income,consumption, and wealth

Studies of economic inequality almost always separately examine income, consumption, and wealth inequality, and hence, miss the important synergy amongst the three measures explicit in the life-cycle budget constraint. These joint distributions, however, are important in evaluating macroeconomic impacts of changes in income because the response may differ across the wealth distribution. This heterogeneity in the response to income changes can have significant impact on the effectiveness of government fiscal policy. Using the Panel Study of Income Dynamics from 1999–2013, we examine how the marginal propensity to consume (MPC) differs across the wealth distribution. We find that the MPC is lower at higher wealth quintiles, indicating that low wealth households cannot smooth consumption as much as other households. This implies that increasing wealth inequality likely reduces aggregate consumption, which, in turn, could limit economic growth.     

The Earned Income Tax Credit: Targeting the poor but crowding out wealth

This paper quantifies the individual, aggregate and welfare effects of the US Earned Income Tax Credit (EITC). In particular, we analyze the labour supply and saving responses to changes in tax credit generosity and their implications for prices and welfare. Our results show that the EITC is a subsidy on labour income and a tax on savings. An increase in EITC generosity raises labour force participation, reduces savings for many and provides insurance to working poor households. The EITC reduces earnings inequality but increases the skill premium and wealth inequality. A 10% increase in tax credit generosity increases welfare by 0.31% and benefits the majority of the population.     

Savings and pensions in The Netherlands

We describe the distribution of private wealth of Dutch households over the life cycle and relate this to the size of individual entitlements to pay-as-you-go social security benefits and funded pension benefits. We also investigate saving motives and find that saving for old age plays only a minor role. Precautionary motives play some role, but in view of the very extensive social safety net it does not seem likely that precaution is an important factor in saving decisions. Altogether, the data are consistent with the view that an extensive social safety net and generous old age income provisions reduce the need to accumulate private wealth.     

Credit constraints,growth and inequality dynamics

This paper examines how credit constraints affect the dynamics of wealth and thereby the dynamics of capital and output growth. We develop standard Ak growth models that display transitional dynamics, contrary to general belief, once the complete credit markets assumption is relaxed. The mechanism is that credit constraints make individual productivity differences persist, which in turn leads to the persistence of income inequality. The dynamics of inequality is jointly determined with the dynamics of aggregate capital. The economy thus passes through a transitional period of inequality, individual and aggregate capital dynamics before it converges to a long-run balanced growth path. The application of the model to the analysis of intergenerational mobility and inequality dynamics suggests substantial economic and policy significance. In particular, introducing credit constraints to the Barro Ak model, public investment could have an indirect impact on growth via its effect on inequality and mobility.     

Heterogeneous Risk Preferences and the Welfare Cost of Business Cycles

I study the welfare cost of business cycles in a complete-markets economy where some people are more risk averse than others. Relatively more risk-averse people buy insurance against aggregate risk, and relatively less risk-averse people sell insurance. These trades reduce the welfare cost of business cycles for everyone. Indeed, the least risk-averse people benefit from business cycles. Moreover, even infinitely risk-averse people suffer only finite and, in my empirical estimates, very small welfare losses. In other words, when there are complete insurance markets, aggregate fluctuations in consumption are essentially irrelevant not just for the average person - the surprising finding of Lucas (1987) - but for everyone in the economy, no matter how risk averse they are. If business cycles matter, it is because they affect productivity or interact with uninsured idiosyncratic risk, not because aggregate risk per se reduces welfare.     

The 2007–2009 financial crisis: changing market dynamics and the impact of credit supply and aggregate demand sensitivity

This article singles out the determinants of changes in US firms’ systematic risk and idiosyncratic return induced by the 2007–2009 financial crisis. After establishing that systematic risk changes during the crisis, the results show that higher operational and financial leverage coincide with an increase in systematic risk, while high cash availability is associated with a decrease in systematic risk. The crisis-induced idiosyncratic return worsens with increasing financial leverage, higher sensitivity to aggregate demand shocks and banking sector problems, and lower operational leverage. Additional results show that the aforementioned variables have economically large effects on firm performance during the crisis.