Chapter II: Understanding Price Volatility behaviour is essential to assessing the risk associated with positions across different time spans. |
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This chart shows Volatility for Southwest Bell Communications, defined to be the price range as a portion of the average price: For instance, on 11/30/2005 the average price was 25.07 with a range of 0.55, indicating a Daily Volatility of 2.1%. 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. 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. Volatility, as measured through various intervals, ( Daily, Weekly, Monthly and Quarterly) is plotted according to color. 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. During 21 years, the Average Quarterly Volatility of SBC stock price has been 19% while the Average Daily Volatility has been 2%. |
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If you have ever seen a "yield curve" you should be able to understand the concept behind this "yield curve". Each Volatility Curve is a snapshot in time. From left to right, each position plots the Volatility associated with increasing intervals of time. The relationship between the length of time, and the expected change in price, is not linear, as is demonstrated by this chart. |
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This histogram is a frequency distribution of Daily Volatility, corresponding to the green points on the first chart on this page. |
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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 SBC : |
| In the news, Friday, February 18, 2011: An unfavorable condition has developed with Aetna Inc., ticker symbol AET. Also, there are breaking events concerning Dollar Tree, Inc. (DLTR) and First Niagara Financial Group Inc. (FNFG) |