1-step ahead volatility forecast,可以手算
假设有 1000 observations
garch(1,1)-n 配适模型是:
r(t)=0.007446+res(t)
sig2(t)=0.0000834 + 0.1147*res(t-1)^2 + 0.8511*sig2(t-1)
sig2(1000) = 0.001714
res(1000) = 0.104154
1-step ahead forecast is
sig2(1000)(1) = 0.0000834 + 0.1147*res(1000)^2 + 0.8511*sig2(1000)
1-day horizon 5% VaR for long position is
VaR = Amount of position*(0.007446-1.65*sqrt(sig2(1000)(1)))
(the negative sign signifies a loss)
[此贴子已经被作者于2007-5-18 7:49:06编辑过]