HOUSE OF CARDS: Companies Build Bonds for European Central Bank to Buy.

The European Central Bank’s corporate-bond-buying program has stirred so much action in credit markets that some investment banks and companies are creating new debt especially for the central bank to buy.

In two instances, the ECB has bought bonds directly from European companies through so-called private placements, in which debt is sold to a tight circle of buyers without the formality of a wider auction.

It is a startling example of how banks and companies are quickly adapting to the extremes of monetary policy in what is an already unconventional age. In the past decade, wide-scale purchases of government bonds—a bid to lower the cost of borrowing in the economy and persuade investors to take more risk—have become commonplace. Central banks more recently have moved to negative interest rates, flipping on their head the ancient customs of money lending. Now, they are all but inviting private actors to concoct specific things for them to buy so they can continue pumping money into the financial system.

Something that can’t go on forever, won’t.