It's certainly overbought, but I don't think price to sales is a good metric. I don't know what the P/E or PEG is, but that's more appropriate because technology has caused productivity to decouple from wages. In other words, lower variable cost technology companies with higher margins are leading the markets higher. The problem is going to come when the supply of credit starts to dry up causing growth/carry trade/debt service issues and the asset allocation imbalance(too high concentration in riskier assets) amplifies it.