The major indexes often move in tandem with one another. Today the SPY
along with several other indexes broke below the 50dma on heavy volume
. The NASDAQ ( QQQ
displayed here) has been the strongest of the indexes for the bulk of this uptrend. Today it sliced below its 21ema for the first time in about a month. It looks poised to test the 50dma within the next day or two. That will likely send the other indexes lower along with it.