170 likes | 432 Views
Common Risk Measures Descriptions and Comparisons. William C. Wojciechowski VIGRE Computational Finance Seminar Rice University October 15, 2003. Defining Risk. What is risk? How is risk measured? Types of risk – market, credit, liquidity, etc. Finance is one area of risk management
E N D
Common Risk MeasuresDescriptions and Comparisons William C. Wojciechowski VIGRE Computational Finance Seminar Rice University October 15, 2003
Defining Risk • What is risk? • How is risk measured? • Types of risk – market, credit, liquidity, etc. • Finance is one area of risk management • Against The Gods: The Remarkable Story of Risk - Peter L. Bernstein
Defining Risk • Risk - chance that an investment’s return will be less than expected. • Market Risk – loss in value due to decline in price • Event Risk – catastrophic actions cause decrease in value • Liquidity Risk – lose value by not being able to transact
Measuring Risk • X - a random variable representing the value of an investment at some future time t • Scalar, such as volatility of X? • Vector, such as a value and probability? • Consider the whole distribution of X?
Common Risk Measures • Dispersion Measures
Common Risk Measures • More dispersion does NOT equal more risk • Normal mixture model with possible large win • Normal model without possible large win
Common Risk Measures • More dispersion does NOT equal more risk
Common Risk Measures • More dispersion does not equal larger positive returns
Common Risk Measures • Dispersion below a target • Fishburn family
Common Risk Measures • VAR (Value at Risk) Measures
Common Risk Measures • Accumulate VAR (AVAR)
Common Risk Measures • Simulations • Generate random return streams X and Y • For each risk measure, calculate the risk of X and Y • Count the number of times the risk measure makes the correct decision
Simulations • Possibility of large gain
Simulations • Moderate chance of large loss
Simulations • Small chance of catastrophic loss
Conclusions • There are many possible measures of risk • Appears none of the common risk measures universally applies to all situations • Research opportunities are abundant
Reference • Guy Kaplanski and Yoram Kroll, “VAR risk measures vs traditional risk measures: an analysis and survey”, Journal of Risk, 4, Spring, 2002