r. What is the Efficient Markets Hypothesis (EMH) and what are its three forms?
What evidence supports the EMH? What evidence casts doubt on the EMH?
Answer: The EMH is the hypothesis that securities are normally in equilibrium, and are
“priced fairly,” making it impossible to “beat the market.”
Weak-form efficiency says that investors cannot profit from looking at past
analysts can still obtain and process new information fast enough to gain a small
advantage.
Strong-form efficiency says that all information, even inside information, is
embedded in stock prices. This form does not hold—insiders know more, and could
take advantage of that information to make abnormal profits in the markets. Trading
vast majority of portfolio managers do not consistently have returns in excess of
CAPM predictions. There are two possible exceptions that earn excess returns: (1)
small companies and (2) companies with high book-to-market ratios.
In addition, there are times when a market becomes overvalued. This is often
called a bubble. Bubbles are hard to burst because trading strategies expose traders to