Remember the vicious cycle that threatened the entire European banking sector in 2012?

It went something like this: over indebted sovereigns depended on domestic banks to buy their debt, but when yields on that debt spiked, the banks took a hit, inhibiting their ability to fund the sovereign, whose yields would then rise some more, further curtailing banks' ability to help out, and so on and so forth.

Well don't look now, but central bankers' headlong plunge into NIRP-dom has created another “doom loop” whereby negative rates weaken banks whose profits are already crimped by the new regulatory regime, sharply lower revenue from trading, and billions in fines. Weak banks then pull back on lending, thus weakening the economy further and compelling policy makers to take rates even lower in a self-perpetuating death spiral. Meanwhile, bank stocks plunge raising questions about the entire sector's viability and that, in turn, raises the specter of yet another financial market meltdown.

Below, find the diagram that illustrates this dynamic followed by a bit of color from WSJ:

From WSJ: