Timothy A. Clary | AFP | Getty Images
A concerned trader on the floor of the New York Stock Exchange.
"Of course we all know that past performance is no guarantee of future results, but history does have a way of at least warning us to the possibility of further declines," Sam Stovall, S&P's chief equity strategist, wrote in an analysis. "And 2010 may be no exception."
January 2010 saw the S&P 500 fall 3.7 percent while the index dropped 7.6 percent for the six-month period. The last time both figures were negative came in the market meltdown of 2008, when the S&P lost 38.5 percent for the year. Conversely, the two measures were slightly negative in 2005 but the index gained 3.0 percent for the year.
The best showing the market had when January and the first half were both negative came during the economic recovery of 1982, when the respective losses were 1.8 and 10.6 percent, but the market roared back in the second half to post a full-year gain of 14.8 percent.
With no such economic resurgence likely on the horizon, the odds are stacking against a full-year stock market gain.
"We're having a major tug of war between the earnings and the economic data, and the economy seems to be far more sluggish than the earnings," Art Cashin, director of floor operations at UBS, told CNBC (see video below). "That tells us the economy may be staggering some."
Indeed, if one were to look only at earnings the numbers so far have been stellar: Positive net surprises are at 76 percent, while positive revenue surprises are at 71 percent.
But with investors looking more towards outlook, the strong second-quarter numbers haven't been enough to boost the market.