@K26k
I don't know for sure, but I would imagine it's something like this:

People sell their shares to brokerages, because they want rid of (effectively) worthless shares.

This means, more shares are on the market, which nobody wants. This will depress the share value even further (simple economic rules: the more there is of something on the market, the cheaper it becomes, because there is a plentiful supply).

Likewise, when confidence is restored (e.g. a government buying up worthless shares (a.k.a nationalisation) or buying bad debt up) then share prices will go up and people will start buying again, hence, stimulating the economy. So, people will start buying shares up because they want to buy it when it's low and make a profit.

That's a rough idea of how I imagine it to happen.....
(The Stig, Thu 16 Oct 2008, 10:59, Reply)