Internal rationality, imperfect market knowledge and asset prices

Adam, Klaus and Marcet, Albert (2011) Internal rationality, imperfect market knowledge and asset prices. CEP Discussion Papers (CEPDP1068). London School of Economics and Political Science. Centre for Economic Performance, London, UK.

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Abstract

We present a decision theoretic framework in which agents are learning about market behavior and that provides microfoundations for models of adaptive learning. Agents are ‘internally rational’, i.e., maximize discounted expected utility under uncertainty given dynamically consistent subjective beliefs about the future, but agents may not be ‘externally rational’, i.e., may not know the true stochastic process for payoff relevant variables beyond their control. This includes future market outcomes and fundamentals. We apply this approach to a simple asset pricing model and show that the equilibrium stock price is then determined by investors’ expectations of the price and dividend in the next period, rather than by expectations of the discounted sum of dividends. As a result, learning about price behavior affects market outcomes, while learning about the discounted sum of dividends is irrelevant for equilibrium prices. Stock prices equal the discounted sum of dividends only after making very strong assumptions about agents’ market knowledge.

Item Type:	Monograph (Discussion Paper)
Official URL:	https://cep.lse.ac.uk/_new/publications/discussion...
Additional Information:	© 2011 The Author(s)
Divisions:	Centre for Economic Performance
Subjects:	H Social Sciences > HC Economic History and Conditions H Social Sciences > HG Finance
JEL classification:	G - Financial Economics > G1 - General Financial Markets > G12 - Asset Pricing; Trading volume; Bond Interest Rates G - Financial Economics > G1 - General Financial Markets > G14 - Information and Market Efficiency; Event Studies D - Microeconomics > D8 - Information, Knowledge, and Uncertainty > D83 - Search; Learning; Information and Knowledge; Communication; Belief D - Microeconomics > D8 - Information, Knowledge, and Uncertainty > D84 - Expectations; Speculations
Date Deposited:	22 Feb 2024 15:06
Last Modified:	22 Feb 2024 15:06
URI:	http://eprints.lse.ac.uk/id/eprint/121722

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