Smooth and Persistent Forecasts of German GDP: Balancing Accuracy and Stability
Katja Heinisch, Simon van Norden, Marc Wildi
IWH Discussion Papers,
Nr. 1,
2026
Abstract
Forecasts that minimize mean squared forecast error (MSE) often exhibit excessive volatility, limiting their practical applicability. We address this accuracy-smoothness trade-off by introducing a Multivariate Smooth Sign Accuracy (M-SSA) framework, which extracts smoothed components from leading indicators to enhance the signal-to-noise ratio and control the forecast volatility and timing. Applied to quarterly German GDP growth, our method yields smoothed forecasts that can improve forecasting accuracy, particularly over medium-term horizons. We find that while smoother forecasts tend to lag slightly around turning points, this can be offset by adjusting the forecast horizon. These findings highlight the practicality of the M-SSA framework for both forecasters and policymakers, especially in settings where forecast revisions or policy adjustments are costly.
Artikel Lesen
11.12.2025 • 34/2025
Konjunktur aktuell: Leichte Belebung kommt, Strukturprobleme bleiben
Zum Jahresende 2025 ist weiterhin unklar, ob sich die deutsche Wirtschaft auf Erholungskurs befindet, zumal die Exportschwäche auch im Herbst andauert. Dennoch ist für das Jahr 2026 aufgrund von finanzpolitischen Impulsen und gestiegenen Realeinkommen eine leichte Belebung zu erwarten. Nach der Winterprognose des Leibniz-Instituts für Wirtschaftsforschung Halle (IWH) dürfte die Produktion dann um 1,0% zunehmen, nach 0,2% im Jahr 2025. Im September waren die IWH-Konjunkturforscher von einem Zuwachs von 0,8% für 2026 und 0,2% für das laufende Jahr ausgegangen. In Ostdeutschland wird die Expansionsrate im Jahr 2026 nach der vorliegenden Prognose demographisch bedingt wohl etwas niedriger ausfallen.
Oliver Holtemöller
Lesen
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.
Artikel Lesen
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 risk, we find that banks’ securitization decisions are sensitive to borrowers’ carbon footprints. Banks are more likely to securitize brown loans when carbon risk is high but swiftly change to keep these loans on their balance sheets when carbon risk is reduced after Trump’s election. Importantly, 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 domestic banks and banks that do not display green lending preferences. We discuss how securitization can weaken the effectiveness of bank climate policies through reducing banks’ incentives to price carbon risk.
Artikel Lesen
Application Barriers and the Socioeconomic Gap in Child Care Enrollment
Henning Hermes, Philipp Lergetporer, Frauke Peter, Simon Wiederhold
Journal of the European Economic Association,
Vol. 23 (3),
2025
Abstract
Why are children with lower socioeconomic status (SES) substantially less likely to be enrolled in child care? We study whether barriers in the application process work against lower-SES children — the group known to benefit strongest from child care enrollment. In an RCT in Germany with highly subsidized child care (N = 607), we offer treated families information and personal assistance for applications. We find substantial, equity-enhancing effects of the treatment, closing half of the large SES gap in child care enrollment. Increased enrollment for lower-SES families is likely driven by altered application knowledge and behavior. We discuss scalability of our intervention and derive policy implications for the design of universal child care programs.
Artikel Lesen
Social Connections and Information Leakage: Evidence from Target Stock Price Run-up in Takeovers
Iftekhar Hasan, Lin Tong, An Yan
Journal of Financial Research,
Vol. 48 (2),
2025
Abstract
Does information leakage in a target's social networks increase its stock price prior to a merger announcement? Evidence reveals that a target with more social connections indeed experiences a higher pre-announcement price run-up. This effect does not exist during or after the merger announcement, or in windows ending two months before the announcement. It is more pronounced among targets with severe asymmetric information, and weaker when the information about the upcoming merger is publicly available prior to the announcement. It is also weaker in expedited deals such as tender offers.
Artikel Lesen
Medienecho
Medienecho Februar 2026 Oliver Holtemöller: Talsohle scheint erreicht in: Wirtschaftswoche, 13.02.2026 IWH: »Rosenkrieg« ums Arbeitszeugnis (Bericht mit Bezug auf…
Zur Seite
Forschungscluster
Drei Forschungscluster Jede IWH-Forschungsgruppe ist einem themenorientieren Forschungscluster zugeordnet. Die Cluster stellen keine eigenen Organisationseinheiten dar, sondern…
Zur Seite
IWH-DPE in a Nutshell
IWH-DPE in a Nutshell Job Market Candidates Candidates from all four IWH departments will enter the academic job market in 2025/2026. Visit our job market page and learn more…
Zur Seite
Courses
Courses Courses are organised in coordination with partner institutions within the Central-German Doctoral Program Economics (CGDE) network. IWH organises First-Year Courses in…
Zur Seite