As if the past week weren't fun enough, we've now got fourth-quarter earnings to look forward to.Five companies in the S&P 500 (SPX) will report earnings this week, highlighted by Alcoa ( AA) on Tuesday, but then all hell will break lose the week starting Jan. 14 as one penitent after another steps up into Wall Street's public confession booth. At the moment, according to Thomson Financial, the estimated aggregate growth rate for the S&P 500 companies in the fourth quarter of last year is at a stunning -9.5%. If there's one reason why the market has tanked recently, it is this: On Oct. 1, the estimated growth rate for the fourth quarter was fantasized at +11.5%. Unless a miracle happens -- and to be honest, I'd be short the Miracle Index, if there were one -- these will be the first back-to-back quarters of negative earnings growth for the S&P since the fourth quarter of 2001 and the first quarter of 2002. Of course, most of the downward pressure on earnings has come from financial stocks. Thomson reports that estimates for diversified financial companies suggest their earnings will be down by $14.3 billion, investment banks and brokerages will lose $12.9 billion and mortgage lenders will be down $6.3 billion.