Sammy on the Failures of the Efficient Market Hypothesis

This one is by Sammy…

Here is some information on Behavioral Finance.

According to conventional financial theory, the world and its participants are, for the most part, rational “wealth maximizers”. However, there are many instances where emotion and psychology influence our decisions, causing us to behave in unpredictable or irrational ways.

Behavioral finance is a relatively new field that seeks to combine behavioral and cognitive psychological theory with conventional economics and finance to provide explanations for why people make irrational financial decisions

The Irvine Housing blogger nails it.

Efficient Markets vs. Behavioral Finance

The efficient markets theory is the idea that speculative asset prices always incorporate the best information about fundamental values and that prices change only because new information enters the market and investors act in an appropriate, rational manner with regards to this information. This idea dominated academic fields in the early 1970s. Efficient markets theory is an elegant attempt to tether asset prices to fundamentals through the common-sense notion that people would not behave in irrational ways with their money in financial markets.

Efficient markets theory explains the majority of market behavior, but it has one major flaw which renders it inoperable as a forecasting tool: it does not explain those instances when prices become very volatile and detach from their fundamental valuations…..when price change begins to feedback on itself, behavioral finance is the only theory that explains this phenomenon.

Behavioral Finance abandoned the quest of the efficient markets theory to find a rational, mathematical model to explain fluctuations in asset prices. Instead, behavioral finance looked to psychology to explain asset valuation and why prices rise and fall. The primary representation of market behavior postulated by behavioral finance is the price-to-price feedback model: prices go up because prices have been going up, and prices go down because prices have been going down. If investors are making money because asset prices increase, other investors take note of the profits being made, and they want to capture those profits as well. They buy the asset, and prices continue to rise. The higher prices rise and the longer it goes on, the more attention is brought to the positive price changes and the more investors want to get involved. These investors are not buying because they think the asset is fairly valued, they are buying because the value is going up. They assume other rational investors must be bidding prices higher, and in their minds they “borrow” the collective expertise of the market. In reality, they are just following the herd.

This one is by Sammy.