SEARCH
Search Details
ZIERHUT MichaelGraduate School of EconomicsAssociate Professor
Research activity information
■ Paper- Abstract In production economies with incomplete markets, shareholders disagree about the objective of the firm. We show that a weak financial intermediary, who is unable to complete markets, can offer just enough spanning to resolve this disagreement. The intermediary is limited to offering one customized contract per consumer. Knowledge of demand functions is sufficient for offering the right contracts. Once agreement among shareholders is reached, productive efficiency is restored, which in turn permits a Pareto efficient market outcome. This result shows that the first welfare theorem does not depend on complete spanning, but merely on institutions that provide the right span. However, this cannot be said about the second welfare theorem: For some wealth distributions, equilibria with transfers fail to exist due to nonconvexities caused by market incompleteness.Springer Science and Business Media LLC, Jul. 2020, Economic Theory, 73(2-3) (2-3), 457 - 486[Refereed]Scientific journal
- Abstract In oligopoly models with differentiated products, producers face a market demand function that reflects the preferences of consumers. However, typical assumptions on preferences place only weak restrictions on the shape of aggregate demand. This may result in profit functions that are not strictly quasiconcave, in best-reply correspondences that are not differentiable, and in equilibria that are not robust to perturbations. This paper establishes differentiability and robustness as a generic property: for an open, dense set of economies, best replies are differentiable in a neighborhood of equilibria, which is a precondition for comparative statics. All these economies have a finite number of equilibria in pure strategies.Springer Science and Business Media LLC, Mar. 2020, Economic Theory, 71(1) (1), 341 - 374[Refereed]Scientific journal
- Abstract This paper studies a sole proprietorship economy with imperfect competition in a transferable utility setting. While consumers behave as price takers, producers issue real assets strategically to maximize their own utility. Even when complete markets are technologically feasible, equilibria with incomplete markets are robust, and they appear in large numbers: There is a continuum of equilibria with different asset spans that can be welfare-ranked. This real indeterminacy does not vanish as the number of producers goes to infinity. Therefore, the self-interest of producers restricts economic outcomes but does not determine them.Springer Science and Business Media LLC, Jan. 2020, Economic Theory, 71(1) (1), 81 - 114[Refereed]Scientific journal
- Elsevier BV, Aug. 2019, Journal of Mathematical Economics, 83, 127 - 136[Refereed]Scientific journal
- Springer Science and Business Media LLC, Mar. 2016, Economic Theory, 64(1) (1), 23 - 45[Refereed]Scientific journal
- Springer Science and Business Media LLC, Sep. 2015, Economic Theory, 62(3) (3), 495 - 516[Refereed]Scientific journal
- Springer Science and Business Media LLC, Jan. 2014, Economic Theory Bulletin, 2(1) (1), 111 - 113[Refereed]Scientific journal
- KIER Workshop on Microeconomics and Game Theory, Kyoto University, Feb. 2026Solving the Roommate Problem with Rock-Paper-Scissors[Invited]
- Strategic Interactions and General Equilibrium XIV, Jan. 2026Solving the Roommate Problem with Rock-Paper-Scissors
- Vienna Graduate School of Finance 20th Anniversary Conference, Aug. 2025The Arbitrage Pricing Theory in Incomplete Markets[Invited]
- 24th SAET Conference, Jul. 2025Solving the Roommate Problem with Rock-Paper-Scissors
- IX Hurwicz Workshop on Mechanism Design Theory, Dec. 2024Solving the Roommate Problem with Rock-Paper-Scissors
- 10th Hitotsubashi Summer Institute: Microeconomic Theory, Jul. 2024Solving the Roommate Problem with Rock-Paper-Scissors[Invited]
- GSE Research Seminar, Nagoya University, May 2024Competition in Securitization[Invited]
- Economics Seminar, Kwansei Gakuin University, Apr. 2024Competition in Securitization[Invited]
- Waseda Organizational and Financial Economics Seminar, Waseda University, Jan. 2024The Arbitrage Pricing Theory in Incomplete Markets[Invited]
- Rokkodai Theory Seminar, Kobe University, Nov. 2023Competition in Securitization[Invited]
- KIER Workshop on Microeconomics and Game Theory, Kyoto University, Sep. 2023Competition in Securitization[Invited]
- 22nd SAET Conference, Jul. 2023Competition in Securitization
- XXXI European Workshop on Economic Theory, Jul. 2023From Hicksian Demand to Walrasian Equilibrium: An Elementary Existence Proof
- Microeconomics Workshop, Keio University, Jun. 2023Competition in Securitization[Invited]
- Workshop on Strategic Interactions and General Equilibrium XI, Jan. 2023Competition in Securitization
- Probability and Mathematical Finance Seminar, Ritsumeikan University, Nov. 2022The Arbitrage Pricing Theory in Incomplete Markets[Invited]
- 21st SAET Conference, Jul. 2022The Arbitrage Pricing Theory in Incomplete Markets
- XXX European Workshop on Economic Theory, Jul. 2022Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty
- Microeconomics Workshop, University of Tokyo, Jul. 2022Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty[Invited]
- RIEB International Symposium on Incomplete Markets, Kobe University, Jun. 2022The Arbitrage Pricing Theory in Incomplete Markets[Invited]
- KIER Workshop on Microeconomics and Game Theory, Kyoto University, Jun. 2022From Hicksian Demand to Walrasian Equilibrium: An Elementary Existence Proof[Invited]
- Economic Theory Workshop, Hitotsubashi University, Feb. 2022Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty[Invited]
- Center for Economic Research Seminar, Instituto Tecnologico Autonomo de Mexico, Aug. 2021Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty[Invited]
- 20th SAET Conference, Jun. 2021Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty
- XXIX European Workshop on Economic Theory, Jun. 2021The Arbitrage Pricing Theory in Incomplete Markets
- KIER Workshop on Microeconomics and Game Theory, Kyoto University, Mar. 2021Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty[Invited]
- Economic Theory Seminar, Royal Holloway, University of London, Feb. 2021Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty[Invited]
- Workshop on Time, Uncertainty and Strategies VI, Dec. 2019Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty[Invited]
- C-SEB Seminar, University of Cologne, Dec. 2019Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty[Invited]
- 19th SAET Conference, Jun. 2019Fairness and Perfect Competition: A Contradiction?
- Economic Theory Seminar, Australian National University, Feb. 2019Fairness and Perfect Competition: A Contradiction?[Invited]
- VII Hurwicz Workshop on Mechanism Design Theory, Dec. 2018The Arbitrage Pricing Theory in Incomplete Markets
- XXVII European Workshop on General Equilibrium Theory, Jun. 2018Nonexistence of Constrained Efficient Production Plans
- 2018 North American Meeting of the Econometric Society, Jun. 2018Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty
- Workshop on Mathematics of Behavioral Economics and Knightian Uncertainty in Financial Markets, May 2018Dynamic Inconsistency and Inefficiency of Equilibrium under Knightian Uncertainty[Invited]
- Seminar at the Department of Business and Economics, University of Southern Denmark, May 2018The Arbitrage Pricing Theory in Incomplete Markets[Invited]
- Economic Seminar, University of Samalanca, Feb. 2018Nonexistence of Constrained Efficient Production Plans[Invited]
- 17th SAET Conference, Jun. 2017Indeterminacy of Cournot-Walras Equilibrium with Incomplete Markets
- XXVI European Workshop on General Equilibrium Theory, Jun. 2017Indeterminacy of Cournot-Walras Equilibrium with Incomplete Markets
- Mathematical Economics Seminar, Poznan University of Economics and Business, Jun. 2017Generic Regularity of Differentiated Product Oligopolies[Invited]
- VI Hurwicz Workshop on Mechanism Design Theory, Dec. 2016Indeterminacy of Cournot-Walras Equilibrium with Incomplete Markets
- UECE Lisbon Meetings in Game Theory and Applications, Nov. 2016Competition in Securitization
- XXV European Workshop on General Equilibrium Theory, Jun. 2016Competition in Securitization
- Math Econ Seminar, University of Minnesota, Mar. 2016Competition in Securitization[Invited]
- Brown Bag Lunch Seminar, University of Innsbruck, Jun. 2015Constrained Efficiency versus Unanimity in Incomplete Markets[Invited]
- XXII European Workshop on General Equilibrium Theory, Jun. 2013Partially Revealing Rational Expectations Equilibrium with Real Assets and Binding Constraints
■ Research Themes
- 日本学術振興会, 科学研究費助成事業, 研究活動スタート支援, 神戸大学, Jul. 2024 - Mar. 2026, Principal investigatorStable Matching without Preference Restrictions
- German Research Foundation (DFG), Kyoto University, Oct. 2020 - Sep. 2022, Principal investigatorEndogenous Market Incompleteness in Discontinuous Games
- German Research Foundation (DFG), Humboldt University, Oct. 2017 - Sep. 2020, Principal investigatorStrategic Behavior of Firms in Incomplete Markets
- German Research Foundation (DFG), Humboldt University, Jun. 2019, Principal investigatorXXVIII European Workshop on Economic Theory
- XXXIII European Workshop on Economic TheoryXXXIII European Workshop on Economic Theory2026
- 24th SAET Conference24th SAET Conference2025
- 22nd SAET Conference22nd SAET Conference2023Academic society etc
- XXXI European Workshop on Economic TheoryXXXI European Workshop on Economic Theory2023Academic society etc
- 21st SAET Conference21st SAET Conference2022Academic society etc
- XXX European Workshop on Economic TheoryXXX European Workshop on Economic Theory2022Academic society etc
- 20th SAET Conference20th SAET Conference2021Academic society etc
- 19th SAET Conference19th SAET Conference2019Academic society etc
- XXVIII European Workshop on Economic TheoryXXVIII European Workshop on Economic Theory2019Academic society etc
- WU Gutmann Center Symposium 2017: Financial Advice and Asset ManagementWU Gutmann Center Symposium 2017: Financial Advice and Asset Management2017Competition etc