prices (see Shin 2009).1 Whatever the origins of the problem, one can give
a simple and persuasive account of the evolution of the crisis. Individual
banks extended credit to those wishing to buy homes with less and less
regard for the capacity of the borrowers to pay. If the unhappy borrower
did not fulfil his obligations the bank recovered the home, the price of
which was rising. Despite the cost of foreclosure, the underlying asset
guaranteed that the loss for the bank was not important. This led to a
rapid expansion in housing loans. The loans in question were distributed
among banks worldwide, through instruments which packaged loans of
varying quality together. This, we were told, was a good thing because it
diversified the risk. However, with a weakening of the US economy the
number of defaulters grew and, worse, prices in the housing market no
longer rose. At this point, banks started to examine their positions and to
evaluate the losses and potential losses due to the ‘subprime’ loans contained
in the instruments they were holding. The problem was not only
that some of the loans contained in the derivatives were ‘toxic’, that is,
they were either liable to default, or had already done so, but it was also
that the market’s evaluation of all these instruments declined. Thus, the
very presence of toxic assets, even when unidentified, dragged the price
of all the derivatives down. Many major banks found that their positions
were more than delicate and began to seek ways of redressing them.
However, the crucial problem was that banks did not know which of
their counterparts were in trouble and thus stopped lending to other
banks. The freezing of the interbank market brought the whole system
to a halt since banks are constantly in need of being able to finance various
transactions and habitually borrow from each other to do so.
Furthermore, as a result, not only banks but individuals and firms also
found themselves unable to borrow, just as Bernanke (1983) suggests was
the case after 1933