Glossary
Mietspiegel
Official Rent Index. The municipal reference table of local comparative rents (ortsübliche Vergleichsmiete) by location, size, age and quality. It anchors rent increases and the Mietpreisbremse.
Cities over 100,000 residents must maintain one; 'qualified' Mietspiegel (statistically derived, § 558d BGB) carry legal presumption. Existing-tenancy increases must be justified against it and respect the Kappungsgrenze.
Investor lens: the gap between Mietspiegel level and market asking rents shows the reversion potential in a city — large gaps (e.g. Bochum 6.90 vs 8.28 €/m², Augsburg 9.80 vs ~15 €/m² asking, 2025/26) mean regulated in-place rents have room to grow, or that regulation binds hard on re-letting where the Mietpreisbremse applies.