Over the last 30 years, an American has appeared on the cover of the annual Sports Illustrated Swimsuit Issue in 16 different years. The average performance of the S&P 500 during those 16 years is a gain of 10.6% with 13 positive years (81.3%). Of the fifteen years where no American appeared on the cover, the S&P 500 has averaged a gain of only 7.2% with 11 positive years (73%).
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Last year's market decline of 38.5% hurt the overall average return for years when an American appeared on the cover (somebody check Marissa Miller's passport), illustrating that like the Super Bowl indicator, there are always exceptions to the rule...While this year's [Israeli born] cover model indicates the less attractive scenario for the market, at this point most investors would probably be pretty happy with a gain of 7.2% in 2009.

Sports Illustrated Swimsuit Indicator [Think Big]