Several recent papers introduce different mechanisms to explain why asset bubbles are observed in periods of larger growth. These papers share common assumptions, heterogeneity among traders and credit market imperfection, but differ in the role of the bubble, used to provide liquidities or as collateral in a borrowing constraint. In this paper, we introduce heterogeneous traders by considering an overlapping generations model with households living three periods. Young households cannot invest in capital, while adults have access to investment and face a borrowing constraint. Introducing bubbles in a quite general way, encompassing the different roles they have in the existing literature, we show that the bubble may enhance growth when the borrowing constraint is binding. More significantly, our results do not depend on the-liquidity or collateralrole attributed to the bubble. We finally extend our analysis to a stochastic bubble, which may burst with a positive probability. Because credit and bubble are no more perfectly substitutable assets, the liquidity and collateral roles of the bubble are not equivalent. Growth is larger when bubbles play the liquidity role, because the burst of a bubble used for liquidity is less damaging to agents who invest in capital.

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We are interested in the occurrence of expectation-driven fluctuations of a rational bubble and the (de-)stabilizing role of monetary policy. Our explanation of fluctuations is based on credit market imperfections. For this purpose, we consider an overlapping generations exchange economy where households realize a portfolio choice between money and bubble. Money is held because of a partial cash-in-advance constraint affected by the bubble. Bubble acts as a store of value, but also as a collateral. Indeed, a higher value of the bubble implies a higher amount of collateral, which, in turn, reduces the need of cash, and thus increases consumption purchased on credit. Under these credit market features, expectation-driven fluctuations and the multiplicity of steady-states occur, in particular for arbitrarily small market distortions. Investing the stabilizing role of monetary policy, we show that when the monetary policy rule depends on expected inflation only, a more active rule stabilizes only if collateral has a large effect on consumption financed on credit. Finally, we enrich this rule by including asset prices. A policy which depends on asset prices can stabilize whatever the effect of collateral and can also rule out the multiplicity of steady states. More generally, this paper emphasizes the * We would like to thank

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In this paper, we are interested in the interplay between real estate bubble, aggregate capital accumulation and taxation in an overlapping generations economy with altruistic households. We consider a three-period overlapping generations model with three key elements: altruism, portfolio choice, and financial market imperfections. Households realise different investment decisions in terms of asset at different periods of life, face a binding borrowing constraint and leave bequests to their children. We show that altruism plays a key role on the existence of a productive real estate bubble, i.e. a bubble in real estate raising physical capital stock and aggregate output. The key mechanism relies on the fact that a real estate bubble raises income of retired households. Because of higher bequests, there children are able to invest more in productive capital. Introducing fiscal policy, we show that raising real estate taxation dampens capital accumulation. JEL classification: E22; E44; G11.

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In this paper, I study how heterogeneity amongst agents affects the occurrence of expectation-driven asset price fluctuations in a pure exchange economy à la Lucas, with infinitely lived households, under the hypothesis of spirit of capitalism (SOC). I consider heterogeneous households in terms of preferences, endowments, and initial wealth, and capture the SOC through preferences for wealth. Preferences for wealth are the key element of this paper in a twofold aspect. First, they explain the occurrence of asset price fluctuations driven by self-fulfilling changes in expectations. Second, heterogeneity in endowments affects asset price level and dynamics only if preferences are heterogeneous. For instance, if agents with the strongest SOC are also the rich in terms of endowments, heterogeneity in endowments heightens the asset price level in the long run and destabilizes by enlarging the range of parameter values for which expectation-driven asset price fluctuations occur.

Entrepreneurship, growth and total factor productivity are larger when there is a …nancial bubble. We explain these facts using a growth model with …nancial bubbles in which individuals face heterogeneous wages and returns on productive investment. The heterogeneity in the return of investment separates individuals between savers and entrepreneurs. Savers buy …nancial assets, which are deposits or a …nancial bubble. Entrepreneurs incur in a start-up cost and borrow to invest in productive capital. The bubble provides liquidities to credit-constrained entrepreneurs. These liquidities increase investment and entrepreneurship when the startup cost is large enough, which explains that growth and entrepreneurship can be larger with bubbles. Finally, productivity can be larger when the bubble further increases the investment of more productive entrepreneurs. This can occur when the return of investment is correlated with wages.