What we worry about is a huge, sudden demand for liquidity that would create, as we term it, dislocations in core funding markets. When that happens, the core funding markets that make sure there is liquidity and funding for all kinds of things in our economy—everything from governments funding themselves for rolling over debt to corporations rolling over their debt to making sure there's stability in markets like mortgages, consumer loans and commercial loans.... When you have a very sudden spike in demand for liquidity, what happens is that you can get margin calls on investors and, in order to meet those margin calls, investors can start selling assets. There can be more assets available for sale than there are buyers in that type of stressed environment, and you can get very large moves in prices that disrupt markets.
That's the scenario we picture when we think of more than one thing going wrong at one time. Some of these things can interact with and feed each other, and you can get a bit of a confidence spiral.