The broad U.S. stock market (New York Stock Exchange Composite Index; top chart) has been making lower highs, but other equity markets have been in significant decline since mid-year, including EuroStoxx (FEZ; second chart from top); non-U.S. shares (EFA; third chart from top); and emerging markets (EEM; third chart from bottom).
At the same time, we've been seeing a precipitous decline in oil prices (USO; second chart from bottom) and dramatically declining yields at the long end (TLT; bottom chart). A common theme among these markets is deflation. My concern is that a capitulation leg down in oil from here would lead to a similar risk-off leg among stock markets, including the U.S., reflecting concerns regarding possible global recession. An update on the breadth and other indicators will expand upon this idea.
Further Reading: The Challenges of Disinflation