ECB also banned 500 euro notes, which may also be another leading indicator. Sweden's housing market is in a downturn right now. If it starts looking like the early 90s, deeper negative rates might seem attractive (they are currently at -0.5% in SE).

Ah, I didn't know that there are already banks with negative interest rates. I'm surprised Swedes haven't started keeping sums of cash in their homes.

In the Netherlands, they had been going down until the +0.05% mark, where they have now stayed for some time.