What's Driving Stocks Higher? Sheer Disbelief

As a fan of investor psychology, I find sentiment intriguing. Measuring it is a challenge. We can’t trust what people say because they become bullish after they buy and bearish after they sell, convincing themselves that past trades were the correct way to go. Humans are notorious liars — especially to themselves. When they are not lying, they often can be found busy making excuses and other rationalizations for their actions.