For 45 years - until Alan Greenspan in 1994 - the average wealth-to-income of American households had held steady around 4.9x - but as of Q4 2016, for the first time in US history, household wealth has reached a point where it is 6.5 times large than inflation-adjusted household disposable income in America.
As Bloomberg reports, the surge - driven by higher stock prices and property values, according to The Fed - pushed this measure of relative exuberance (think of it as the country's price-to-earnings ratio) above the housing boom peak of mid-2000s and well above the dot-com bubble driven highs of the last 1990s.
As Alliance Bernstein economist Joe Carson wrote in a note: "Economic and financial history do not always repeat, but sometimes they do."
So the question is - what happens next?