“You know it's time to sell when shoeshine boys give you stock tips. This bull market is over.” That was the thinking of Joe Kennedy in late 1928, after getting a tip to buy Hindenburg during a shoeshine. Kennedy soon sold his entire stock portfolio and avoided one of the biggest stock market crashes in history. The Greater Fool Theory states that it is possible to make money by buying securities, whether or not they are overvalued, by selling them for a profit at a later date. This is because there will always be someone (i.e. a bigger or greater fool) who is willing to pay a higher price. But what happens when ... (full story)