Transition Dynamics in Heterogeneous-agent Models and the Distributional Consequences of Taxation
Alexandra Gutsch, Christoph Schult
IWH Discussion Papers,
No. 7,
2026
Abstract
We study how idiosyncratic income risk shapes the aggregate and distributional effects of labor and capital income taxation in dynamic general equilibrium models. To this end, we compare a heterogeneous-agent (HA) model with uninsurable idiosyncratic labor productivity risk and a ten-representative-agent (TE) model in which households correspond to fixed wealth deciles without such risk. At the aggregate level, both models generate qualitatively similar responses; however, the HA model exhibits a smaller recessionary impact driven by precautionary savings behavior, which stabilizes investment. At the distributional level, the models differ sharply. In the HA framework, tax shocks trigger endogenous mobility across wealth deciles. These inter-decile transition dynamics tend to benefit lower deciles. In contrast, the TA model features fixed household positions. Our findings highlight that while simpler multi-representative-agent models can approximate aggregate dynamics well, they may miss important distributional adjustment channels. The relevance of these mechanisms ultimately depends on the empirical importance of mobility across the wealth distribution, pointing to a key trade-off between model simplicity and accuracy.
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Going Public and the Internal Organization of the Firm
Daniel Bias, Benjamin Lochner, Stefan Obernberger, Merih Sevilir
Journal of Finance,
Vol. 81 (1),
2026
Abstract
This paper examines how initial public offerings (IPOs) affect firms' internal organization. We find that IPO firms become more hierarchical and standardized organizations, characterized by additional layers, more managers, smaller control spans, and larger administrative functions. These changes occur mostly in preparation for the IPO and can be only partially explained by growth. IPO firms with greater human capital risk experience larger hierarchical changes. Hierarchical changes help firms standardize employee roles and formalize internal processes. Our results suggest that firms reorganize to reduce their dependence on key individuals' human capital when transitioning to public markets.
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Employment Responses to Increased Biodiversity Transition Risk
Duc Duy Nguyen, Huyen Nguyen, Trang Nguyen, Vathunyoo Sila
IWH Discussion Papers,
No. 20,
2025
Abstract
This paper examines how firms adjust the number and types of workers they hire in response to increased biodiversity transition risk. Using the adoption of the Key Biodiversity Areas Standard of 2016 as a source of variation that increases the risk of future land-use restrictions, we find that firms reduce job postings in affected areas and reallocate labor to less exposed regions. This effect is concentrated among firms that make negative impacts on biodiversity. Cuts are stronger among production roles, while hiring in green and adaptive occupations increases. The effect is not driven by changes in capital investment or workers’ labor supply decisions. Our findings contribute to the ongoing debate on the costs and benefits of biodiversity conservation policies and their implications for labor market outcomes.
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Road to Net Zero: Carbon Policy and Redistributional Dynamics in the Green Transition
Alessandro Sardone
IWH Discussion Papers,
No. 16,
2025
Abstract
This paper examines the macroeconomic and distributional effects of the European Union’s transition to Net Zero emissions through a gradually increasing carbon tax. I develop a New Keynesian Environmental DSGE model with two household types and distinct energy and non-energy sectors. Five alternative uses of carbon tax revenues are considered: equal transfers to households, targeted transfers to Hand-to-Mouth households, subsidies to green energy firms, and reductions in labor and capital income taxes. In the absence of technological progress, the carbon tax policy induces a persistent increase in energy prices and a reduction in GDP, investment, and consumption. Headline inflation falls below zero in the medium run, reflecting weaker aggregate demand. Distributional outcomes vary significantly depending on the implemented revenue recycling scheme: targeted transfers are the most progressive but entail larger macroeconomic costs, while subsidies and tax cuts mitigate output and investment losses but are less effective in narrowing the consumption gap. A limited foresight scenario, in which agents learn about policy targets sequentially, generates more volatile adjustment paths and temporary inflationary spikes around announcements, but long-run outcomes remain close to the baseline.
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Climate Risks and Debt Structure
Bill Francis, Iftekhar Hasan, Chunxia Jiang, Zenu Sharma, Yun Zhu
British Accounting Review,
Vol. 57 (5),
2025
Abstract
This paper examines the impact of climate risks on the debt structure of a sample of U.S. firms from 2002 through 2020. Climate risks—mainly physical, regulatory, and transition risks—are associated with a concentrated debt structure for the affected firms. However, when climate risks propagate through the channels of expected bankruptcy costs and sustainability, they are associated with a more diversified debt structure. Additionally, climate risks asymmetrically impact the relationship between access to finance and debt structure. Results from a quasi-natural experiment reaffirm the impact of climate risks on debt structure.
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Within-Country Inequality and the Shaping of a Just Global Climate Policy
Marie Young-Brun, Francis Dennig, Frank Errickson, Simon Feindt, Aurélie Méjean, Stéphane Zuber
Proceedings of the National Academy of Sciences of the United States of America (PNAS),
Vol. 122 (39),
2025
Abstract
Climate policy design must balance emissions mitigation with concerns for fairness, particularly as climate change disproportionately affects the poorest households within and across countries. Integrated Assessment Models used for global climate policy evaluation have so far typically not considered inequality effects within countries. To fill this gap, we develop a global Integrated Assessment Model representing national economies and subnational income, mitigation cost, and climate damage distribution and assess a range of climate policy schemes with varying levels of effort sharing across countries and households. The schemes are consistent with limiting temperature increases to 2 °C and account for the possibility to use carbon tax revenues to address distributional effects within and between countries. We find that carbon taxation with redistribution improves global welfare and reduces inequality, with the most substantial gains achieved under uniform taxation paired with global per capita transfers. A Loss and Damage mechanism offers significant welfare improvements in vulnerable countries while requiring only a modest share of global carbon revenues in the medium term. The poorest households within all countries may benefit from the transfer scheme, in particular when some redistribution is made at the country level. Our findings underscore the potential for climate policy to advance both environmental and social goals, provided revenue recycling mechanisms are effectively implemented. In particular, they demonstrate the feasibility of a welfare improving global climate policy involving limited international redistribution.
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Climate Change Economics in Vietnam: Redefining Economic Impact
Christian Otto, Christoph Schult, Thomas Vogt
IWH Discussion Papers,
No. 15,
2025
Abstract
Vietnam, a lower-middle-income economy, faces severe climate risks from heat waves, sea-level rise, and tropical cyclones, which are expected to intensify under ongoing global warming. Using a dynamic general equilibrium model, we analyze economic transition dynamics from 2015 to 2100, incorporating heat-induced labor productivity losses, agricultural land loss, and cyclone-related property damage. We compare a Paris-compatible scenario limiting warming to below 2 °C with a high-emission scenario reaching 4–5 °C. While output and investment impacts remain highly uncertain and statistically indistinguishable across scenarios until 2100, consumption losses are significantly larger under high emissions, mainly driven by heat-related productivity declines, with cyclones contributing most to uncertainty. These findings underscore the importance of considering multiple impact channels beyond output damages in climate-development research.
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Carbon Transition Risk and Corporate Loan Securitization
Isabella Müller, Huyen Nguyen, Trang Nguyen
Journal of Financial Intermediation,
Vol. 63 (July),
2025
Abstract
We examine how banks manage carbon transition risk by selling loans given to polluting borrowers to less regulated shadow banks in securitization markets. Exploiting the election of Donald Trump as an exogenous shock that reduces carbon transition risk, we find that banks engage in regulatory arbitrage and use brown loan securitization to manage their exposure to carbon transition risk. Banks are more likely to securitize brown loans when carbon transition risk is high but keep these loans on their balance sheets when the risk is reduced. In addition, securitization enables banks to offer lower interest rates to polluting borrowers but does not affect the supply of green loans. Our findings are more pronounced among banks with low levels of capitalization, domestic banks, and banks that do not display green lending preferences. We discuss how securitization can weaken the effectiveness of bank climate policies.
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IWH Alumni The IWH maintains contact with its former employees worldwide. We involve our alumni in our work and keep them informed, for example, with a newsletter. We also plan…
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Research Clusters
Three Research Clusters Each IWH research group is assigned to a topic-oriented research cluster. The clusters are not separate organisational units, but rather bundle the…
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