Berlin rent index 2013: two rulings, two outcomes

Two recent rulings by the Berlin Regional Court on the 2013 rent index show how uncertain the legal situation around rent increases can be. The 2013 rent index has been controversial since its publication because it was not based on a direct data survey but extrapolated from older data using regression analysis.

First ruling: rent index as a valid estimate

In case 18 S 108/15, the court ruled in favour of the tenant. The 2013 rent index could be used as a "suitable basis for estimation" despite its methodological weaknesses. The judges argued pragmatically: the goal was to avoid unnecessary expert appraisal costs. Whether the index truly qualified as authoritative was left open.

Second ruling: expert appraisal beats the rent index

In case 18 S 183/15, a landlord prevailed who had supported his rent increase with an expert appraisal. The tenant's critical mistake: in her objection, she attacked both the appraisal and the rent index itself. By undermining the rent index, she weakened her own position. Instead of challenging both instruments, she should have defended the index and argued against the appraisal. The appraisal stood, and the tenant now pays a higher rent.

What property owners can take away

The contradictory rulings make one thing clear: for apartments in Berlin, the success of a rent increase depends not just on the numbers but also on legal strategy. Relying on the 2013 rent index risks having a court reject it. Commissioning an expensive appraisal offers no guarantee either. In boroughs with strong price dynamics in particular, this uncertainty complicates yield calculations.

More stability through the 2015 rent index

These rulings concern the old 2013 rent index. The new rent index published in May 2015 is based on a broad data survey again and is considered more scientifically sound. Legal certainty for future rent increases should improve. For cases still pending under the old index, individual legal review remains advisable.