The S&P 500 Index and CBOE Volatility Index have historically moved in opposite directions about 80 percent of the time, but that’s changed recently...

As Bloomberg reports, both gauges are heading for declines this month, after the two rose in tandem in February.

That’s weakened their inverse correlation, sending it to levels not seen since April 2005...

After March/April 2005, the S&P 500 dropped around 8% (breaking down as the correlation reverted to norm)

In May 2012, the S&P 500 dropped 11% after VIX and Stocks' decoupled and correlation surged.

The smaller spikes in VIX-Stock correlation also saw notable equity market drawdowns (Feb/March 07 down 6.6%, Oct 09 down 6.5%, Dec 2012 down 3.5%)

So what will happen this time?