[staticman2]

My guess is:

1) Bonds and bank accounts are paying less than inflation, so to not lose money you need to invest in stock. That doesn't mean inflation is high rather bank accounts stink.

2) People figured out based on recent fed action that the U.S. has a policy of privatizing the gains and socializing the losses. Therefore stocks appear to not be risky, so people bought them up. The only reason you'd put money in a bank account rather than stock is stock can go down, but if you think the government will intervene to prevent stock going down, you might hold a greater amount of assets in stock, bidding up the price.