Lecture Two (1 - 50) Flashcards
what did Keynes think about economic models?
argued that the assumptions they had were not backed by sound reasoning and said “it’s better to be roughly right than precisely wrong”
what happens when the efficient market hypothesis fails? (in the context of schumpeter’s flow)
when investors don’t trust the entrepreneurs or feel they’re not getting fair value for the price they’re paying then the circular flow doesn’t work
… this makes stock market inefficiency socially costly
has technical analysis ever been proven
yes, but with weak evidence (50.5% of the time it was successful)
what happened in circa 1975 that greatly affected how academics and practitioners view the financial markets and EMH?
Fama published work on the EMH and Burton Malkiel published Random Walk down Wall St. which made people start taking the EMH more seriously
what are the 2 main propositions with the pricing of securities through the EMH according to Fama
- securities are priced based on past information
- only new information can change a security’s price
have statistical test on whether or not hedge funds beat the market ever been right? … and what’s the caveat
no, hedge funds and all other “fundamentally selected” portfolios have not proven to beat randomly selected portfolios over time.
… the caveat is that these stats tests are too noisy to prove that mkts are efficient
weak form
semi strong form
strong form
… EMH
weak: past and present stock returns do NOT predict future returns
semi strong: stock returns can’t be predicted with public info
strong: future stock returns cannot be predicted
what is the lucas critique in finance (how does it apply to the mkts)?
lucas critique: models in social sciences don’t work when ppl know about the models, so ppl should bake that into their models (rational expectations)
- when applying this to finance, models designed to capitalize on people’s mistakes in the mkt eventually won’t work b/c they’ll learn about the model being used (alpha gets evaporated)
does the lucas critique in finance imply EMH
Yes
Because it argues that eventually all alpha from quantitative models and trading strategies will be eroded to the point where there is no extra return to be captured
law of large numbers
the mean of every independent estimate is always more accurate than the closest estimate
using Shiller’s empirical evidence of stock market efficiency, are securities actually priced based on the PV of future dividends?
No because the variance in S&P returns is too high to be explained by the variance in future dividends
- this means that there are other factors at play, like psychology
what is the idea of bounded rationality
rational people base their actions on approx. solutions / heuritistics if the cost of getting an exact solution is GREATER than the cost of occasional mistakes from using heuristics
what are transcomputational problems
problems that can be solved but takes too much time and resources for it to be worth solving
how does bounded rationality relate to the cost of information for arbitrageurs
the incremental value of information diminishes as you go up the curve and becomes ‘too costly’ for arbitrageurs to pursue
… this means that semi strong EMH doesn’t apply since not ALL public information is reflected in stock prices
at what point to arbitrageurs stop pursuing addtl. information for trading decisions?
beyond MC(I) = MR(I)
(i.e. marginal cost of more information can’t be lower than the marginal revenue generated from it)
what is the zen equilibrium?
if the mkt is too efficient, arb traders can’t earn enough to cover information cost and noise traders affect prices more (less efficient mkt)
if the mkt is too inefficient, then arb traders are more active and noise traders affect prices less (more efficient mkt)
… then the mkt comes to rest at an efficient level of inefficiency where MC(I) = MR(I)
what happened with the collapse of LTCM and what did it imply about arbitrage
LTCM saw a mispricing between US dollar denominated Russian bonds and ruble denominated Russian bonds, so they sold US den. bonds short and bought ruble den. bonds
… the Russian Gov. defaulted on its ruble den. bonds but not its US den. bonds which went against their trade
… when they were required to sell out of their position they didn’t have enough $ to pay back investors and Merton + Scholes had a slurry of lawsuits
what is the evidence that arbitrage is incomplete
people attach different values to different goods (i.e. stocks)
if the mkt were totally efficient, then a one cent rise/fall in a stock would cause infinite sell/buy demand (keeping the price of the security in check)
but this doesn’t hold because people have different values assigned to different stocks