This is a surprisingly candid article for the WSJ. The writer opines that
The global financial crisis is five years old. It isn’t over yet.
The reason we are observing negative interest rates is that the central banks are engaging in financial repression. These central banks are purposely keeping interest rates low in an attempt to stimulate the economy but also so that government can keep borrowing cheaply.
Interest rate manipulation is a zero-sum game, so that every cent the Federal government saves in interest costs is less money for those lending them the money.
The natural tendencies of the market can only be repressed for so long. Then, market forces will strike with a vengeance. If we had let market forces operate five years ago, we would have had a deeper recession but by now probably a stronger recovery.