Related to this explaination
are those who point to debt deflation causing those who borrow to the owe even more in real terms.
Second,
there are structural theories,
most importantly Keynesian,
but also including those who point to the breakdown of international trade,
and institutional economists who point to underconsumption and overinvestment,
namely, economic bubble,
malfeasance by bankers and industrialists,
or incompetence by government officials.
The consensus viewpoint
is that there was a large scale loss of confidence
that led to a sudden reduction in consumption and investment spending.
Once panic and deflation set in,
many people believed
they could make more money
by keeping clear of the markets
as prices dropped lower
and a given amount of money bought even more goods,
exacerbating the drop in demand.