(CNN Money) – Up is down, black is white.

Or at least that’s what it feels like in Europe, where at least one bank is paying some customers who borrow from it because interest rates have turned negative.

The European Central Bank has slashed official rates to record lows, and is pumping billions of euros into the economy to boost growth and inflation.

That has forced rates on some mortgage products far enough below zero to create a big headache for the banks: Do they now owe their borrowers?

“We are in uncharted waters,” said Luca Bertalot, secretary general of the European Mortgage Federation. “Monetary policy is changing the funding landscape in Europe completely.” Read the full story.

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