Chapter II: This survey looks at historical volatility of General Motors prices. The risks associated with long and short term positions can be evaluated according to projected shapes of the Volatility Curve. |
| Prev. Co. | Next Co. | |
|
| ||
|
Volatility is defined as the price range for a period, divided by the average price for the period: For instance, on 6/1/2009 the average price was 0.64 with a range of 0.74, indicating a Daily Volatility of 115.6%. The Daily Volatility is obtained by dividing the daily range by the daily average. A longer Volatility period such as Weekly Volatility is obtained by dividing the weekly price range by the weekly mean price. This is a different concept from the weekly average of daily volatility. The red plot shows the actual price. The remaining marks on the plot correspond to the Volatility measured across several time intervals. Investors often make a distinction between the concept of Volatility, and the concept of Risk. Academics define them to be exactly equivalent, but as can be seen here, there is good reason to distinguish between the levels of volatility or risk experienced across different time frames. During 29 years, the Average Quarterly Volatility of GM stock price has been 26% while the Average Daily Volatility has been 3%. |
| Prev. Co. | Next Co. | |
| ||
|
You may be familiar with the "yield curve" which shows how interest bearing yields vary according to term. These Volatility Curves each apply to a discrete time interval. As the timespan across which Volatility is measured increases, the Volatility is expected to increase. However, as seen in this plot of the GM Volatility Curve, the increase is not constant. |
| Prev. Co. | Next Co. | |
| ||
|
This histogram is a frequency distribution of Daily Volatility, corresponding to the green points on the first chart on this page. |
| Prev. Co. | Next Co. | |
| ||
|
In a similar vein, the Frequency Distribution of the Quarterly Volatility is plotted here. This is the distribution of the values plotted in purple on the top chart from this page. |
Refined Volatility Risk Analysis for GM : |
| Monday, February 08, 2010: We have news on American International Group, Inc., ticker symbol AIG. Some signs of an over-sold condition have become evident. Also, there are breaking events concerning Nicor Inc. and Archer-Daniels-Midland. From the News Archive: (2/5/2010 ) Favorable events happened at Regions Financial Corporation, Marathon Oil Corporation, and Pactiv Corporation. Meanwhile, bad news came from Genzyme Corporation. |