More on the second situationn;

The cash injections by US, UK and lately Qatar governemnt are designed to ward off the situation where Banks are forced to call in the loans or ask the loanees to regularise it by paying the difference between the property value and the loan.

However, this is a short term cushion. In mid to long terms, the banks will call in the loans and the property market will be re-evaluated.

Once this happens, other banks will follow suite.

Once it starts, nobody knows where the property value devaluation will stop in North America. This is what the government are trying to ward off by cash infusion.

As for Qatar, the economy is not that well documented. So any prediction is useless. Qatar Government is also cash rich from Gas Sales. So they may just underwrite the whole thing and support the market. Who knows.