The chart below compares the S&P 500 since the beginning of 2009 to the weekly bullish sentiment reading from the American Association of Individual Investors (AAII). The two lowest readings in sentiment during this period came on 3/5/09 (18.92%) and 4/11/13 (19.31%). If you look closely at the chart, the level of the S&P 500 during these two weeks couldn't have been farther apart. In early March 2009, the S&P 500 was trading at multi-year bear market lows, while on 4/11/13, the S&P 500 closed at an all-time high. In other words, investors were as bearish at the depths of the financial crisis as they were when the market hit an all-time high, and that pretty much sums up the state of sentiment during this entire bull market.
Over the last two weeks, we have seen a modest rebound in bullish sentiment, which now stands at 28.29%. However, even after the rebound, bullish sentiment is currently lower than it has been in more than 85% of all prior weeks during this bull market, and it's well below the average of 37.8%.