Part 8 Flashcards
Volatility clustering
Large changes tend to follow large changes; small changes tend
to follow small changes
Fat tails
Fat tails
▶ Excess kurtosis: more extremes than predicted by a normal
distribution
Leverage effects
Assymetric effects: volatility tends to go up more after
negative returns
Calculating ARCH-LM test
T (obvs) x R^2 - X^2 (q - restrictions)
So if the test statistic is greater than the critical value here (ARCH-LM)
We reject the null that there are no arch effects and we insists that in fact there is
Problems with ARCH-LM
Not obvious how to choose right q
Required q might be very large
Unconditional variance formula (GARCH)
α0 /
1 − (α1 + β)
For a to be well behaved, variance estimates are …
The variance estimates are always positive
▶ The variance estimates are stationary
For E-GARCH, if If γ < 0 is there evidence of leverage
No
For GJR Garch, If γ > 0 is there evidence of leverage?
No
For GARCH-M (Garch in mean), what do you allow to enter equation and why?
Higher risk → higher return, so might make sense to include
estimate of volatility into mean equation
Day and Lewis (1992) considered whether Implied Volatility or
GARCH do a better job at forecasting volatility. What did they conclude (2)
In sample: Both IV and GARCH / EGARCH contain unique
information.
▶ Out of sample: Neither really accurately predicts volatility