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. |
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This chart shows Volatility for General Motors, defined to be the price range as a portion of the average price: So, to derive the Daily Volatility on 6/1/2009 of 115.6%, the price range for the day (0.74) was divided by the average price (0.64). Daily Volatility (the daily range as a portion of the daily average price) is plotted in green. Blue is Weekly Volatility, which is the weekly range as a portion of the weekly average price. It is important to avoid confusing this with the weekly average of the daily volatility, which is a completely different concept. The red plot shows the actual price. The remaining marks on the plot correspond to the Volatility measured across several time intervals. According to academic theory, Volatility is exactly equal to Risk. But investors often make a distinction between these two concepts. The different character of Volatility as seen in different time frames, lends some support to the investor's view. Average Daily Volatility over the history of GM has been 3% in contrast to the Average Quarterly Volatility of 26%. |
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You may be familiar with the "yield curve" which shows how interest bearing yields vary according to term. Each Volatility Curve is a snapshot in time. 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. |
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A frequency distribution of the green points on the first chart (the daily volatility) yields this histogram. |
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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 : |
| Wednesday, July 01, 2009: We have news on Public Service Enterprise Group Inc., ticker symbol PEG. Signs of an over-bought condition have become noticable. Also, there are breaking events concerning The Travelers Companies, Inc. and Kellogg Company. From the News Archive: (7/1/2009 ) Favorable events happened at Allegheny Energy, Inc., Bank of America Corporation, and American International Group, Inc.. Meanwhile, bad news came from Lexmark International, Inc.. |