U.S. money supply has declined by 2% or more only four times since 1870 other than the current contraction. In each of those previous cases, a major U.S. economic downturn followed.

Two historic moves in M2 money supply over the past two years might signal a big move to come for stocks. S&P 500 +---% | Stock Advisor +---% Join The Motley ... Image source: Getty Images.

But the money supply is finally growing again, and its growth is accelerating. In April and May, the M2 money supply grew 0.6% year over year. That climbed to 1% in June and 1.3% in July.

Image source: Getty Images. U.S. money supply growth is accelerating. One factor that's given the biggest companies in the stock market an unfair advantage in recent years has been the tightening ...