Are there any safe investments left?

Credit Suisse calculates the supply of assets that markets deem safe has fallen to $12 trillion from $22 trillion in the past four years. Emerging-market foreign-exchange reserves, the primary source of demand, have risen to nearly $7 trillion from $4 trillion in the same period.

So what?

“In the financial system,” says Mohamed El-Erian, co-chief investment officer of bond-market heavy Pimco, “you cannot replace something with nothing.” For now, this benefits governments in the U.S. and (to the consternation of France) the U.K., which can borrow cheaply because they are drawing so much frightened money. Bill Gross, the other half of the Pimco team, describes the U.S. Treasury as “the cleanest shirt in the dirty-laundry pile.”

Longer term? That’s hard to know…

For now, global angst is driving people to buy U.S. Treasurys, but that may not last once the crisis abates, as it surely will. “We have time,” Mr. El-Erian says. “We don’t have infinite time.”