[bryanlarsen]

M2 growth relative to the growth of size of the economy is basically the same as inflation, in the Milton Friedman Chicago school.

So if M2 growth and the S&P 500 are similar, that means that the S&P 500 is fairly well correlated with the size of the economy. Quelle surprise!

[rafaelero]

Hmm. Looks like M2 growth can be seen as GDP growth + excessive money supply (inflation) then. That is, whenever M2 decouples from GDP, then it most likely will convert to inflation.