Stocks and bonds have been in relative lock-step for much of 2014 (stock prices and bond yields moving in same direction, aka 'stock lever').  The correlation had been on hold to a large degree over the past few sessions but made something of a comeback this morning when Treasuries came under selling pressure leading up to the 9:30am cash open for stocks.

Even then, we haven't seen enough to assume there's a causal relationship between the two in the short term.  Perhaps the biggest reason for this is that markets are still getting back into the swing of things after the lowest volume day of the year yesterday.  Big trades are still having an outsized impact on price/yield levels, and the whole affair is taking place in an inconsequentially narrow range very near the center of the longer-term range.

Further to the point of questionable correlations, bond markets have rallied since 11:40 while stocks have held steady.  MBS are actually back to 'unchanged' and 10yr yields are only half a bp (0.005%) away.