The Geography of Worker-Firm Sorting: Drivers of Rising Colocation
Nils Torben Hollandt, Steffen Müller
IWH Discussion Papers,
No. 22,
2025
Abstract
Spatial segregation of low- and high-wage workers is a persistent economic issue with broad social implications. Using social security data and an AKM wage decomposition, this paper examines spatial wage inequality in West Germany. Spatial inequality in log wages rose sharply between 1998 and 2008, mainly due to increased variance in worker pay premiums across regions (48%) and stronger positive spatial assortative matching of workers and establishments (40%), i.e. colocation. Changes in establishment wage premia are mostly unrelated to rising colocation whereas labor mobility even reduced it. Instead, growth in worker pay premiums among stayers was concentrated in regions where high-wage workers and high-wage establishments were overrepresented already in the 1990s and, thus, magnified pre-existing colocation leading to ‘colocation without relocation’. Germany’s rising trade surplus, especially with Eastern Europe, boosted stayers’ worker pay premiums in those ex-ante high-wage regions and fully explains rising colocation.
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The Price of Beauty: Biodiversity Effects on Residential Housing Markets
Michael Koetter, Birte Winter, Fabian Woebbeking
IWH Discussion Papers,
No. 21,
2025
Abstract
We study how and why local biodiversity affects residential property values. Leveraging remotely sensed greenness indicators and a novel dataset of granular property listings, we examine how changes in vegetation load on real estate prices. Hikes in greenness are associated with higher listing prices, fewer properties listed, and reduced liquidity in housing markets. These results suggest that price hikes in housing markets are driven by supply-side constraints instead of a “greenium” that buyers might be willing to pay due to innate preferences. Exogenous zoning shocks to foster biodiversity corroborate the presence of supply side constraints as price drivers in residential housing markets. Our findings emphasize the need to calibrate biodiversity and (social) housing policy objectives more explicitly.
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Real Estate Transaction Taxes and Credit Supply
Michael Koetter, Philipp Marek, Antonios Mavropoulos
Journal of Financial Stability,
September
2025
Abstract
We exploit staggered real estate transaction tax (RETT) hikes across German states to identify the effect of house price changes on mortgage credit supply. Based on approximately 33 million real estate online listings, we construct a quarterly hedonic house price index (HPI) between 2008:q1 and 2017:q4, which we instrument with state-specific RETT changes to isolate the effect on mortgage credit supply by all local German banks. First, a RETT hike by one percentage point reduces HPI by 1.2%. This effect is driven by listings in rural regions. Second, a 1% contraction of HPI induced by an increase in the RETT leads to a 1.4% decline in mortgage lending. This transmission of fiscal policy to mortgage credit supply is effective across almost the entire bank capitalization distribution.
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What’s the Melting Pot Worth? Multiculturalism and House Prices
Rachel Cho, Hisham Farag, Christoph Görtz, Danny McGowan, Huyen Nguyen, Max Schröder
IWH Discussion Papers,
No. 11,
2025
Abstract
Is there a multicultural neighborhood price premium? We exploit plausibly exogenous variation in British colonization patterns in Northern Ireland during the early 1600s which created neighborhoods of varying religious composition that persists until today. These religious groups are culturally distinct, but are observationally equivalent ethnically and socioeconomically. A standard deviation increase neighborhood-level multiculturalism raises house prices by 9.6%. Multiculturalism raises property prices by increasing asset liquidity and housing demand as a wider spectrum of society demand houses in these areas. The findings and mechanism contrast sharply with prior evidence showing negative relationships due to homophily, social networks, and identification challenges.
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Contractionary Macroprudential Policy, Collateral Valuation, and Risk-shifting in EU Banking
Michael Koetter, Felix Noth, Fabian Woebbeking
IWH Discussion Papers,
No. 4,
2025
Abstract
We study real estate lending responses to tighter macroprudential policy (MPP) in the form of lower required loan-to-value (LTV) ratios. Contract details of 2.4 million mortgage loans originated between 2008 and 2020 reveal significantly fewer new loan issuances in response to contractionary MPP, commensurate with an average reduction in aggregate lending of 21 percent. Loan-level analyses reveal, however, that banks comply with lower LTVs by systematically more benevolent valuations of residential real estate pledged as collateral instead of reducing loan size. Exploiting earthquakes as plausible exogenous shocks to property values corroborates these risk-shifting patterns by banks in the form of inflated property valuations after LTV shocks.
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Alumni
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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Archive
Media Response Archive 2021 2020 2019 2018 2017 2016 December 2021 IWH: Ausblick auf Wirtschaftsjahr 2022 in Sachsen mit Bezug auf IWH-Prognose zu Ostdeutschland: "Warum Sachsens…
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East Germany
The Nasty Gap 30 years after unification: Why East Germany is still 20% poorer than the West Dossier In a nutshell The East German economic convergence process is hardly…
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R&D Tax Credits and the Acquisition of Startups
William McShane, Merih Sevilir
IWH Discussion Papers,
No. 15,
2023
Abstract
We propose a novel mechanism through which established firms contribute to the startup ecosystem: the allocation of R&D tax credits to startups via the M&A channel. We show that when established firms become eligible for R&D tax credits, they increase their R&D and M&A activity. In particular, they acquire more venture capital (VC)-backed startups, but not non-VC-backed firms. Moreover, the impact of R&D tax credits on firms’ R&D is increasing with their acquisition of VC-backed startups. The results suggest that established firms respond to R&D tax credits by acquiring startups rather than solely focusing on increasing their R&D intensity in-house. We also highlight evidence that startups do not appear to benefit from R&D tax credits directly, perhaps because they typically lack the taxable income necessary to directly benefit from the tax credits. In this context, established firms can play an intermediary role by acquiring startups and reallocating R&D tax credits, effectively relaxing the financial constraints faced by startups.
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Social Capital and Regional Innovation: Evidence from Private Firms in the US
Iftekhar Hasan, Nada Kobeissi, Bo Wang, Haizhi Wang, Desheng Yin
Regional Studies,
No. 1,
2023
Abstract
In this study we investigate whether and to what extent social capital may affect regional innovation by focusing on private firms in the United States. We document that regional social capital is positively associated with the quantity, quality and novelty of county-level innovation by private firms. In addition, we find that the positive relation between social capital and regional innovation is more prominent in counties with a lower supply of financial capital. We also report that social capital is complementary to investments in research and development to produce inventive outcomes in local areas. Using a spatial Durbin model, we provide evidence that regional social capital has significant spillover effects in boosting the innovation activities of neighbouring counties.
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