Along this dissertation I propose to walk the reader through several macroeconomic implications of information asymmetries, with a special focus on financial issues. This exercise is mainly theoretical: I develop stylized models that aim at capturing macroeconomic phenomena such as self-fulfilling liquidity dry-ups, the rise and the fall of securitization markets, and the creation of systemic risk. The dissertation consists of three chapters. The first one proposes an explanation to self-fulfilling liquidity dry-ups. The second chapters proposes a formalization of the concept of market discipline and an application to securitization markets as risk-sharing mechanisms. The third one offers a complementary analysis to the second as the rise of securitization is presented as banker optimal response to strict capital constraints. Two concepts that do not have unique acceptations in economics play a central role in these models: liquidity and market discipline. The liquidity of an asset refers to the ability for his owner to transform it into current consumption goods. Secondary markets for long-term assets play thus an important role with that respect. However, such markets might be illiquid due to adverse selection. In the first chapter, I show that: (1) when agents expect a liquidity dry-up on such markets, they optimally choose to self-insure through the hoarding of non-productive but liquid assets; (2) this hoarding behavior worsens adverse selection and dries up market liquidity; (3) such liquidity dry-ups are Pareto inefficient equilibria; (4) the government can rule them out. Additionally, I show that idiosyncratic liquidity shocks à la Diamond and Dybvig have stabilizing effects, which is at odds with the banking literature. The main contribution of the chapter is to show that market breakdowns due to adverse selection are highly endogenous to past balance-sheet decisions. I consider that agents are under market discipline when their current behavior is influenced by future market outcomes. A key ingredient for market discipline to be at play is that the market outcome depends on information that is observable but not verifiable (that is, information that cannot be proved in court, and consequently, upon which enforceable contracts cannot be based). In the second chapter, after introducing this novel formalization of market discipline, I ask whether securitization really contributes to better risk-sharing: I compare it with other mechanisms that differ on the timing of risk-transfer. I find that for securitization to be an efficient risk-sharing mechanism, it requires market discipline to be strong and adverse selection not to be severe. This seems to seriously restrict the set of assets that should be securitized for risk-sharing motive. Additionally, I show how ex-ante leverage may mitigate interim adverse selection in securitization markets and therefore enhance ex-post risk-sharing. This is interesting because high leverage is usually associated with “excessive” risktaking. In the third chapter, I consider risk-neutral bankers facing strict capital constraints; their capital is indeed required to cover the worst-case-scenario losses. In such a set-up, I find that: 1) banker optimal autarky response is to diversify lower-tail risk and maximize leverage; 2) securitization helps to free up capital and to increase leverage, but distorts incentives to screen loan applicants properly; 3) market discipline mitigates this problem, but if it is overestimated by the supervisor, it leads to excess leverage, which creates systemic risk. Finally, I consider opaque securitization and I show that the supervisor: 4) faces uncertainty about the trade-off between the size of the economy and the probability and the severity of a systemic crisis; 5) can generally not set capital constraints at the socially efficient level.

Along this dissertation I propose to walk the reader through several macroeconomic<p>implications of information asymmetries, with a special focus on financial<p>issues. This exercise is mainly theoretical: I develop stylized models that aim<p>at capturing macroeconomic phenomena such as self-fulfilling liquidity dry-ups,<p>the rise and the fall of securitization markets, and the creation of systemic risk.<p>The dissertation consists of three chapters. The first one proposes an explanation<p>to self-fulfilling liquidity dry-ups. The second chapters proposes a formalization<p>of the concept of market discipline and an application to securitization<p>markets as risk-sharing mechanisms. The third one offers a complementary<p>analysis to the second as the rise of securitization is presented as banker optimal<p>response to strict capital constraints.<p>Two concepts that do not have unique acceptations in economics play a central<p>role in these models: liquidity and market discipline.<p>The liquidity of an asset refers to the ability for his owner to transform it into<p>current consumption goods. Secondary markets for long-term assets play thus<p>an important role with that respect. However, such markets might be illiquid due<p>to adverse selection.<p>In the first chapter, I show that: (1) when agents expect a liquidity dry-up<p>on such markets, they optimally choose to self-insure through the hoarding of<p>non-productive but liquid assets; (2) this hoarding behavior worsens adverse selection and dries up market liquidity; (3) such liquidity dry-ups are Pareto inefficient<p>equilibria; (4) the government can rule them out. Additionally, I show<p>that idiosyncratic liquidity shocks à la Diamond and Dybvig have stabilizing effects,<p>which is at odds with the banking literature. The main contribution of the<p>chapter is to show that market breakdowns due to adverse selection are highly<p>endogenous to past balance-sheet decisions.<p>I consider that agents are under market discipline when their current behavior<p>is influenced by future market outcomes. A key ingredient for market discipline<p>to be at play is that the market outcome depends on information that is observable<p>but not verifiable (that is, information that cannot be proved in court, and<p>consequently, upon which enforceable contracts cannot be based).<p>In the second chapter, after introducing this novel formalization of market<p>discipline, I ask whether securitization really contributes to better risk-sharing:<p>I compare it with other mechanisms that differ on the timing of risk-transfer. I<p>find that for securitization to be an efficient risk-sharing mechanism, it requires<p>market discipline to be strong and adverse selection not to be severe. This seems<p>to seriously restrict the set of assets that should be securitized for risk-sharing<p>motive.<p>Additionally, I show how ex-ante leverage may mitigate interim adverse selection<p>in securitization markets and therefore enhance ex-post risk-sharing. This<p>is interesting because high leverage is usually associated with “excessive” risktaking.<p>In the third chapter, I consider risk-neutral bankers facing strict capital constraints;<p>their capital is indeed required to cover the worst-case-scenario losses.<p>In such a set-up, I find that: 1) banker optimal autarky response is to diversify<p>lower-tail risk and maximize leverage; 2) securitization helps to free up capital<p>and to increase leverage, but distorts incentives to screen loan applicants properly; 3) market discipline mitigates this problem, but if it is overestimated by<p>the supervisor, it leads to excess leverage, which creates systemic risk. Finally,<p>I consider opaque securitization and I show that the supervisor: 4) faces uncertainty<p>about the trade-off between the size of the economy and the probability<p>and the severity of a systemic crisis; 5) can generally not set capital constraints<p>at the socially efficient level. / Doctorat en Sciences économiques et de gestion / info:eu-repo/semantics/nonPublished