The first thing you hear at a job in equities related market is the important concept of 'liquidity'. There as many culprits for the excess of liquidity or for the lack of it. The usual suspects: the arabs-they dont damn know what to do with their oil money, so they pay money managers huge money just to have some fun moving the markets. Ah the man soros, every time an emerging economy does something funny it would be Soros. Oh c'mon, he is an exploiter, he would be behind this syndrome.. The Japs, if they are collectively not screwing Detroit they are busy thinking up of innovative ways to make people jump into carry trades. The Chinese, oh boy oh boy, they are always in the 'be a man, do the right thing' syndrome and if you dont do what think is right they will soon pump in billions of dollars of reserves that they hold. Add to that the stupid companies that are scared shit of the private equity boys and are putting more cash back into investors and you have money money and moore money everywhere. It does not help that gold and land are going nowhere (in terms of other assets).
So what we have is a heady cocktail of money that is moving around which is increasing asset prices in every damn class you could think. Oh its so different from the earlier crashes. Ya right-what is so different is that the asset classes are so badly linked that diversification is impossible. So any trigger will lead to an orgy not a individual screw up. As usual lots of people make money when the market crashes, but this time it could leave a lot more peoople naked. Meanwhile analysts will always simply say: I told you so, its all a matter of the damn liquidity.