Everyone expects September to hold true to form as the cruelest of all months for investors. But will this become a self-fulfilling prophecy this year?

• By 11.2 percent in 2002.

• Some 9.2 percent in 2008.

• Nearly 8.2 percent in 2001.

So, how is this September looking by comparison? In 2009, we appear to most resemble September 2003. In that year, we had a mild loss of 1.2 percent and some of the same technical indicators were in place during the month.

How strong are the technicals now? Currently, the S&P's 50-day moving average is 10 percent above the 200-day moving average. This is a rare occurrence; it has only happened 18 times since 1955. During those periods, about 75 percent of the time the market has continued to rise over the next 3-, 6- and 12-month periods.

And those expansions haven't been tame. In fact, they've shown a tendency to move significantly higher -- on average landing around 12 percent higher after 12 months.

As in 2003, the current September is setting up as a period of very shallow corrections. After nervously awaiting Iraq War ll early in 2003, stocks bottomed that March. In fact, the pattern closely parallels the March 2009 trough.

Fundamentally, of course, the economic conditions are much different this time. But there are similarities as well. In 2009, recovery arrived in the third quarter -- roughly the same time when markets started looking up six years ago as war worries faded.

Some other intriguing similarities show up when comparing ugly Septembers. In terms of sectors, in 2001 it was leisure down around 34 percent; in 2002, it was semiconductors caving by 22 percent; and in 2008, steel fell around 32 percent.

Intuitively, this would make sense, as these are all highly sensitive to the economy, which in each of those Septembers was still in a tailspin. Now, as the recovery unfolds, we're seeing technology, (including biotech), electronics and the Internet as areas of strength.

Just look at the First Trust Biotech Fund (NYSEArca: FBT) and the Vanguard Information Technology ETF (NYSEArca: VGT).

But some clouds remain on the horizon. If they turn to rain, it's likely that'll happen closer to the third-quarter earnings reporting season. It would seem prudent at this point, with the extended run-up, to brace for at least a temporary downdraft. Just consider what happened in early July as investors took an apprehensive view of second-quarter earnings -- stocks dipped a quick 8 percent.

Only after the majority of companies exceeded estimates did the market make fresh 2009 highs.

With the next round of earnings coming early next month, it's also going to be important that 2008's third-quarter earnings reflected heavy write-downs and extreme caution about prospects going forward.

So, now, we're entering a period when a lot of companies will be able to step, rather than jump, over the incredibly low bar that has been set.

In other words, while it seems we'll start earnings season with a move down -- possibly very swift and volatile -- relatively easy comparisons to year-over-year earnings numbers in the third quarter of 2009 could very well be the basis of an equally swift reversal to the upside later in the November reporting period.

Bruce Zaro is chief technical strategist at Delta Global Advisors. He welcomes comments and suggestions for future IU.com blogs at: bzaro@deltaga.com.