Good pick up.....there could be a capital drain/flight on the German banks affecting there liquidity (ability to operate) with the negative interest rates.
For example negative rates offer no yields so Germans are increasingly holding there money literally in safes or investing in gold.
Are Negative Rates Backfiring? Here’s Some Early Evidence
Economists worry that people and businesses are saving more, instead of spending
In December, Ms. Hofmann, the Korschenbroich fruit vendor, used her Christmas bonus
to buy two 10-gram bars of gold. She has since bought more and has put it, and every
euro she can set aside, into a safe at home, saying she doesn’t trust banks. “Every time I
check my savings account, it makes me want to cry,” she says.