This thesis contains three independent essays exploring macroeconomic dynamics through the lens of quantitative models, focusing on housing, demographics, macroprudential, monetary and fiscal policy. Chapter 1 examines the impact of demographic change on house prices and the real rate, utilizing a general equilibrium model with housing and mortgage choices over the life cycle. Aging populations are a prominent trend in most advanced economies, with significant implications for asset prices, particularly housing, a primary asset for many households. Calibrated to German microdata, the model reveals that past demographic factors have contributed to a long-term rise in house prices. Notably, indirect general equilibrium effects, such as declining real rates, have played a substantial role. Based on projected demographic trends, the model suggests that over the remainder of the 21st century, population decline and continued aging will exert downward pressure on real house prices, while a shift in the wealth composition from capital to housing wealth may mitigate the decline in the real rate. Chapter 2, joint work with Pablo Herrero and Caterina Mendicino, explores the aggregate and distributional effects of loan-to-value (LTV) tightening shocks, and their interaction with monetary policy, using a Heterogeneous-Agent New Keynesian (HANK) model. Stricter LTV limits affect the economy through aggregate demand effects, triggering a decline in aggregate consumption, house prices, and inflation. Our results suggest that general equilibrium channels amplify the impact of LTV tightening, disproportionately affecting highly leveraged borrowers. Stronger monetary policy accommodation mitigates these effects, limiting the aggregate costs of stricter LTV regulations and their unequal burden across households. These findings highlight the importance of coordinated macroprudential and monetary policies. Chapter 3, joint work with Francesca Vinci, explores the role of a central fiscal capacity (CFC) in a two-region DSGE model of a currency union with public investment. Against the backdrop of an incomplete European fiscal governance framework, we propose a framework to assess a CFC in the euro area, aimed at stabilizing the business cycle, promoting sovereign debt sustainability, and reducing procyclicality in public investment. Our two-region DSGE model with a permanent CFC allocates resources based on the relative output gap while earmarking funds for public investment and imposing fiscal adjustment requirements for the high-debt region. The CFC enhances business cycle stabilization for both regions and significantly reduces the welfare cost of fluctuations.

-- 1 Demographic Change, House Prices, and the Real Rate -- 2 The Aggregate Demand Channel of Loan-to-Value Shocks -- 3 Marrying Fiscal Rules & Investment: a Central Fiscal Capacity for Europe -- References -- Appendix A Demographic Change, House Prices, and the Real Rate -- Appendix B The Aggregate Demand Channel of Loan-to-Value Shocks -- Appendix C Marrying Fiscal Rules & Investment: a Central Fiscal Capacity for Europe

Examining Board: Prof. Russell Cooper (European University Institute, Supervisor); Prof. Alexander Monge-Naranjo (European University Institute, Co-supervisor); Prof. Michalis Haliassos (Goethe University Frankfurt); Prof. Dirk Krueger (University of Pennsylvania)

Defence date: 19 June 2025