Great piece from the guys at Bespoke on a strategy they call Close to Open. While owning the S&P500 or its proxy, the ETF $SPY, since its inception in 1992, investors would have seen a 193% return.
Not too shabby.
But instead of just buying and holding (or "buying and praying" as I like to call it), if investors had bought the $SPY at the end of each trading day and sold it when markets opened the next morning, investors would have seen their holdings rise by almost 400%!

This raises the question -- why even trade when the market is open?You say, no frickin' way. Well, Bespoke says, way. Like the fabled, flux capacitor, the implications of this are just mind-blowing. Source Who Needs the Trading Day (Bespoke Investment Group)