The ratio of the market value of equities outstanding to nominal GDP aka "The Warren Buffet Indicator" is at the highest level in about 13 years. This ratio became associated with Warren Buffet after he remarked in a 2001 Fortune Magazine article that this "is probably the best single measure of where valuations stand at any given moment". The numerator comes from the Flow of Funds so we will have to wait until March 6th to confirm that this relationship has moved to an even higher extreme in 4Q13. But regardless, you can add this to the list of valuation measures that show stock valuations are at lofty levels.