Discussion Paper No. 255
November 9, 2021
Common Information-processing Irrationality as Trade Creator
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We show that a common (identical across investors) irrationality in information processing can be enough to create nontrivial trade, using one of standard partial-equilibrium environments. We can attribute this trade to their common irrationality because we strip the investors and their circumstances of all heterogeneities but purely age (in a sense experience), make investment horizon age-independent, and keep all information complete. The common irrationality in our model takes the form of a somewhat non-Bayesian information processing. The resulting trade between such essentially identical individuals with the very same irrationality in their information processing can also feature different kinds of mispricing.
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Discussion Paper No. 251
Public Good Overprovision by a Manipulative Provider
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We study contracting between a public good provider and users with private valuations of the good. We show that, once the provider extracts the users' private information, she benefits from manipulating the collective information received from all users when communicating with them. We derive conditions under which such manipulation determines the direction of distortions in public good provision. If the provider is non-manipulative, the public good is always underprovided, whereas overprovision occurs with a manipulative provider. With overprovision, not only high-valuation users, but also low-valuation users may obtain positive rents - users may prefer facing a manipulative provider.
Keywords:
information manipulation; public goods;
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Discussion Paper No. 242
Robust Contracting in General Contract Spaces
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We consider a general framework of optimal mechanism design under adverse selection and ambiguity about the type distribution of agents. We prove the existence of optimal mechanisms under minimal assumptions on the contract space and prove that centralized contracting implemented via mechanisms is equivalent to delegated contracting implemented via a contract menu under these assumptions. Our abstract existence results are applied to a series of applications that include models of optimal risk sharing and of optimal portfolio delegation.
Keywords:
robust contracts; nonmetrizable contract spaces; ambiguity; financial markets;
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Discussion Paper No. 230
Repeated Games with Endogenous Discounting
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In a symmetric repeated game with standard preferences, there are no gains from intertemporal trade. In fact, under a suitable normalization of utility, the payoff set in the repeated game is identical to that in the stage game. We show that this conclusion may no longer be true if preferences are recursive and stationary, but not time separable. If so, the players’ rates of time preference are no longer fixed, but may vary endogenously, depending on what transpires in the course of the game. This creates opportunities for intertemporal trade, giving rise to new and interesting dynamics. For example, the efficient and symmetric outcome of a repeated prisoner’s dilemma may be to take turns defecting, even though the efficient and symmetric outcome of the stage game is to cooperate. A folk theorem shows that such dynamics can be sustained in equilibrium if the players are sufficiently patient.
Keywords:
repeated games; efficiency; folk theorems; endogenous discounting;
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Discussion Paper No. 192
Procrastination and Learning about Self-Control
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We study a model of task completion with the opportunity to learn about own self-control problems over time. While the agent is initially uncertain about her future self-control, in each period she can choose to learn about it by paying a non-negative learning cost and spending one period. If the agent has time-consistent preferences, she always chooses to learn whenever the learning is beneficial. If the agent has time-inconsistent preferences, however, she may procrastinate such a learning opportunity. Further, if her time preferences exhibit inter-temporal conflicts between future selves (e.g., hyperbolic discounting), the procrastination of learning can occur even when the learning cost is zero. The procrastination also leads to a non-completion of the task. When the agent has multiple initially-uncertain attributes (e.g., own future self-control and own ability for the task), the agent’s endogenous learning decisions may be misdirected — she chooses to learn what she should not learn from her initial perspective, and she chooses not to learn what she should.
Keywords:
procrastination; self-control; naivete; hyperbolic discounting; misdirected learning;
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Discussion Paper No. 183
The More the Merrier? On the Optimality of Market Size Restrictions
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This paper provides a novel rationale for the regulation of market size when heterogeneous firms compete. A regulator seeks to maximize total welfare by choosing the number of firms allowed to enter the market, e.g. by issuing a certain number of licenses. Opening up the market for more firms has a two-fold effect: it increases competition and thus welfare, but at the same time, it also attracts more cost-intensive firms, driving down average production efficiency. The regulator hence faces a trade-off between raising beneficial competition and detrimental costs. If goods are sufficiently substitutable, the latter effect can outweigh the former. It is then optimal to restrict the market size, rationalizing a limit to competition. This result holds even in the absence of entry costs, search costs or increasing returns to scale, which previous literature required.
Keywords:
regulation; imperfect competition; oligopolies;
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Discussion Paper No. 175
November 8, 2021
Speculative Trade and Market Newcomers
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Arguing that in the real world relatively optimistic inexperienced investors are prey for relatively pessimistic veteran traders, we formalize this intuitive conjecture as a proven proposition in a simple model. This agreement to disagree leads to a perpetual bubble, in which more experienced, but less optimistic, investors keep selling overpriced assets to less experienced traders. As in a fraction of the uniform-experience literature, lack of short-selling makes room for the success of such bubble schemes. This previous literature did not allow for persistent effects of experience on beliefs and, instead, relied on more direct assumptions of belief heterogeneity. Although we map experience into beliefs in a specific way, the intuition behind the perpetual bubble involves the above-mentioned disagreement patterns, not belief formation itself.
Keywords:
speculative trade; price bubble; experience; optimism; belief heterogeneity; non-bayesian learning; short-telling;
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Discussion Paper No. 142
Equilibria Under Knightian Price Uncertainty
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We study economies in which agents face Knightian uncertainty about state prices. Knightian uncertainty leads naturally to nonlinear expectations. We introduce a corresponding equilibrium concept with sublinear prices and prove that equilibria exist under weak conditions. In general, such equilibria lead to Pareto inefficient allocations; the equilibria coincide with Arrow-Debreu equilibria only if the values of net trades are ambiguity-free in the mean. In economies without aggregate uncertainty, inefficiencies are generic. We introduce a constrained efficiency concept, uncertainty-neutral efficiency, equilibrium allocations under price uncertainty are efficient in this constrained sense. Arrow-Debreu equilibria turn out to be non-robust with respect to the introduction of Knightian uncertainty.
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Discussion Paper No. 129
Mean-Field Leader-Follower Games with Terminal State Constraint
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We analyze linear McKean-Vlasov forward-backward SDEs arising in leader-follower games with mean-field type control and terminal state constraints on the state process. We establish an existence and uniqueness of solutions result for such systems in time-weighted spaces as well as a convergence result of the solutions with respect to certain perturbations of the drivers of both the forward and the backward component. The general results are used to solve a novel single-player model of portfolio liquidation under market impact with expectations feedback as well as a novel Stackelberg game of optimal portfolio liquidation with asymmetrically informed players.
Keywords:
mean-field control; stackelberg game; mean-field game with a major player; portfolio liquidation;
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Discussion Paper No. 105
November 5, 2021
Aggregate Information and Organizational Structures
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We study an organization with a top management (principal) and multiple subunits (agents) with private information that determine the organization's aggregate efficiency. Under centralization, eliciting the agents' private information may induce the principal to manipulate aggregate information, which obstructs an effective use of information for the organization. Under delegation, the principal concedes more information rent, but is able to use the agents' information more effectively. The trade-off between the organizational structures depends on the likelihood that the agents are efficient. Centralization is optimal when such likelihood is low. Delegation, by contrast, is optimal when it is high.
Keywords:
D82; D86;
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