U.S. stocks just continue to cruise right along, although investors seem to be displaying a healthy level of caution, looking over their shoulders as they whistle past the graveyard and bet on ongoing improvement in corporate earnings and economic growth. Despite extremely overbought technical conditions and regional hot spots that may ultimately threaten global economic recovery, investors seem undeterred.

After its long-awaiting breakout of the 1900 level the other week, the S&P 500 gained another +1.3% last week alone, but this double-low progression as I call it -- i.e., on extremely low volume and with persistently low volatility -- is worrisome.

Stocks ended last week on a high note, closing a smidge above strong resistance at 1900 for the S&P 500, which set a new closing high for the large-cap index, albeit on low pre-holiday volume. With the Memorial Day holiday giving us a short week of trading, all eyes are on voting in Ukraine, where a decisive win for billionaire business tycoon Petro Poroshenko seems assured.