Every bubble has two components: an underlying trend that prevails in reality and a misconception relating to that trend. A boom–bust process is set in motion when a trend and a misconception positively reinforce each other. The process is liable to be tested by negative feedback along the way, giving rise to climaxes which may or may not turn out to be genuine. If a trend is strong enough to survive the test, both the trend and the misconception will be further reinforced. Eventually, market expectations become so far removed from reality that people are forced to recognize that a misconception is involved. A twilight period ensues during which doubts grow and more people lose faith, but the prevailing trend is sustained by inertia. As Chuck Prince, former head of Citigroup said during the twilight of the super bubble: ‘As long as the music is playing, you’ve got to get up and dance. We’re still dancing.’ Eventually, a point is reached when the trend is reversed, it then becomes self-reinforcing in the opposite direction. Boom–bust processes tend to be asymmetrical: booms are slow to develop and take a long time to become unsustainable, busts tend to be more abrupt, due to forced liquidation of unsustainable positions and the asymmetries introduced by leverage. — George Soros (source)

I think one of the most pervasive problems in the financial markets is investment with too short a time horizon. The fact that people look at quarterly returns of mutual funds is incredibly dysfunctional. I mean, there’s no way that you can expect somebody quarter in and quarter out or month in and month out to produce superior returns. There just aren’t pricing anomalies that are significant that are going to resolve themselves in a matter of months or weeks and so it’s a silly game to play. By extending your time horizon to three years, or four years, or five years, it opens up a whole host of investment opportunities that aren’t available to people that are playing this silly, short-term game. — David Swensen (source)

Price does matter. You increase your profit potential immensely if you buy low. If I buy at 32 and the stock goes to 75, I make a good profit. But if I buy at 20 and it goes to 75, I make a much higher return. Even a great company can be priced too high if there’s a lot of glamour attached to it. In that sense, temporary bad news about a good company may create a buying opportunity. It’s my job to find unusual companies and then judge whether the price they’re selling at is too high. — Philip Fisher (source)

The common thread that runs through all equity bull markets is confident expectations of higher earnings ahead. The common thread that ties the onset of all bear markets together is the loss of those confident expectations of higher earnings ahead. History shows that bull markets can go well beyond rational valuation levels as long as the outlook for future earnings is positive. — Peter Bernstein (source)