The S&P 500 has been up in each of the last four days, and it closed on Wednesday at a new all-time high. Investors must be getting more bullish right? Wrong. In the latest weekly survey from the American Association of Individual Investors (AAII), bullish sentiment declined from 44.69% down to 35.17%. That represents the largest weekly drop since the first week of January, and brings the percentage of bullish individual investors back below its bull market average of 38.4%. If individual investors aren't buying who is?