ASSET PRICING Flashcards
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
Why do consumers turn to fellow customers when choosing among products instead of relying on expert advice?
Because of:
1. The emergence of social media platforms;
- The increase in creation, popularity & consumption of user-generated content.
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
What are the 2 Research Questions of this paper?
- Do peer opinions include value-relevant news or do they merely constitute “random chatter” (i.e. the task should be left to professional analysts)?
- Are some users attempting to intentionally spread false “information” and mislead fellow market participants?
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
What are the goals of this study?
- To assess the performance of investors-turned-advisors
2. To test whether investors can turn to their peers for genuine, useful investment advice.
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
What is the main source of the data in this study, and how is it measured?
“Seeking Alpha (SA)” - one of the biggest investment-related social media websites in the US.
The data is measured in the frequency of negative words used in an article.
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
What are the two channels in SA for investors to voice their opinion?
- Through opinion articles which are reviewed by a panel and are subject to editorial changes;
- Through commentaries written in response to the opinion articles.
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
What are the key variables used to make a regression in this study?
X1 & X2:
1. NegSAi,t – an average fraction of NEGATIVE WORDS across all single-ticker ARTICLES published on SA about company i on day t
- NegSA-Commenti,t – an average fraction of NEGATIVE WORDS across all SA COMMENTS posted in an article about company i on day t
Y:
3. ARet - abnormal returns - “the difference between RAW RETURNS minus RETURNS on a value-weighted portfolio OF FIRMS WITH SIMILAR SIZE, book-to-market ratio, and past returns”.
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
What is the main finding of this study?
“The fraction of negative words in SA articles and the fraction of negative words in SA comments both negatively predict stock returns over the ensuing three months”.
As per our dear Kostja:
If negative words in articles/comments are up by 1%,
the future abnormal returns are lower by 0.332%/0.194%.
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
What are the possible reasons (channels) behind the main finding of the study?
Possible reasons behind findings:
- Predictability Channel: SA articles & commentaries contain pieces of value-relevant information which are not fully factored into the stock price as of the article publication date. As investors learn from the SA view, prices gradually adjust.
- -If this reason is true:
- —SA views indeed predict future stock market performance;
- —Social media outlets are a useful source of value-relevant advice - Clout Channel: SA views reflect false information and cause investors to trade in the direction of the underlying articles and comments and move prices accordingly” (i.e. exploiting naïve investors)
- -This reason is less likely to be true due to:
- —SA followers’ insufficient capital to cause real & sufficient market movements.
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
What is an Earnings Surprise?
The difference between:
–the REPORTED earnings-per-share (EPS) AND;
–the average of financial ANALYSTS’ EPS FORECASTS issued within 30 days prior to the earnings announcement.
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
How do the authors prove if the information in SA is value-relevant (Predictability Channel) or false (Clout Channel)?
They regress the number of negative words in articles/comments (the same X1 & X2 as before) on subsequent earnings surprises (new Y).
If they find that negative words predict earnings surprises: the information in SA is value-relevant and is not fully factored into the stock price as of the article publication date.
If they find that negative words do NOT predict earnings surprises: the information in SA is false as users cannot affect the company’s earnings (no relationship between X1, X2 & Y).
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
Do the authors find that the SA articles & commentaries contain pieces of value-relevant or false information?
They find that:
“The fraction of negative words in SA articles & comments strongly predict earnings surprises,” which suggests that the opinions expressed in SA articles & comments.
indeed provide value-relevant information.
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
Why should a SA user share their insights of value-relevant information publicly?
- Popularity: (users want attention & recognition they receive from posting opinions that subsequently are
confirmed by the stock market. Sometimes, SA articles
are referred to and discussed in Forbes, WSJ, etc. - many users strive to become online celebrities)
- Monetary Compensation: (each SA contributor earns $10 per 1,000-page views & potentially more depending on the article quality)
- -is TESTED on this paper - Immediate Feedback: (users correct bad
articles, which, on the assumption that the crowd is educated, increases the informativeness of social media)
–is TESTED on this paper - Convergence to Fundamental Value: (if SA users have some price impact they can expect the direction of market prices to go to what authors perceive to be the
fair fundamental value)
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
The authors test whether Monetary Compensation and Immediate Feedback drives users to post more value-relevant information on the paper. What do they conclude?
- Monetary Compensation Findings
- -“The number of page views AND the number of times an article is read-to-end are increasing with the author’s historical level of consistency.“
- -SA followers can “differentiate between authors that offer historically good VS bad advice;
- -SA followers give more “popularity” to the good than the bad advice given. - Immediate Feedback:
- -The authors test “to what degree SA commentaries are of a different tone than the underlying SA article”
- -They find that “followers disagree with authors more when the authors’ articles have been inconsistent.”
- -They find that if “the authors’ articles are inconsistent, it is the tone of COMMENTS that more reliably predicts subsequent stock market performance.”
“Wisdom of Crowds: The Value of Stock Opinions Transmitted Through Social Media” (Chen, H., De, P., Hu, Y. J., Huang, B., (2014))
What are the key takeaways from the article?
- -Peer-based advice is Useful & Value-Relevant
- -Social media outlets enable direct & immediate interaction among users which, combined with intelligence of a “crowd,” are one of the primary reasons social media platforms are able to produce value-relevant content.
“…and the Cross-Section of Expected Returns”
(Harvey, C. R., Liu, Y., Zhu, H. (2016))
Why should we have tougher criteria today for discovering a factor that supposedly explains expected returns?
Context:
There have been hundreds of papers trying to explain the cross-section (factors) of expected returns since one of the first CAPM tests forty years ago. Given this extensive data mining, the usual t-statistics cut-off is insufficient for establishing significance. Moreover, most of the sample factors have been proposed over the last ten years.
Why should we have tougher criteria?
–The rate of discovering a true factor has likely decreased.
–There is a limited amount of data
–The cost of data mining (examining databases to gain new information) has dramatically decreased (aka it is easy to get data)
“…and the Cross-Section of Expected Returns”
(Harvey, C. R., Liu, Y., Zhu, H. (2016))
What are Type I & Type II Errors in Statistics?
Type I and Type II errors
• Type I error:
- -a false positive;
- -the error of rejecting a null hypothesis when it is actually true;
- -plainly speaking, we are observing a difference when in truth there is none.
• Type II error:
- a false negative;
–the error of not rejecting a null hypothesis when the alternative hypothesis is true.
–plainly speaking, it occurs when we are failing to
observe a difference when in truth there is one.
“…and the Cross-Section of Expected Returns”
(Harvey, C. R., Liu, Y., Zhu, H. (2016))
What is Multiple Testing in Statistics?
Multiple Testing:
–the potential increase in Type I error that occurs
when statistical tests are used repeatedly.
What does that mean?
Suppose we consider the efficacy of a drug in terms of the reduction of any one of a number of disease symptoms. As more (=multiple) symptoms are considered on the same sample, it becomes increasingly likely that the drug will appear to be an improvement (=more false positives) over existing drugs in terms of at least one symptom.
“…and the Cross-Section of Expected Returns”
(Harvey, C. R., Liu, Y., Zhu, H. (2016))
What is a Bonferroni Correction?
Bonferroni Correction:
Shows how much the size of the allowable error (usually 0.05/0.10) should be reduced to reject null hypothesis (depending on the number of tests done).
“…and the Cross-Section of Expected Returns”
(Harvey, C. R., Liu, Y., Zhu, H. (2016))
What do the researchers do in their experiment?
- They use Multiple Testing Framework for the 316 supposedly “discovered” factors to determine whether they are still applicable if put under a more “strict” cut-off.
- They use Bonferroni, Holm & BHY corrections to determine what the “cut-off” for rejecting null hypothesis should have been for the factors.
- They compute adjusted t-statistics using the three adjustments and plot the sample factors against the new significance levels.