Applications of state space models in finance
Applications of state space models in finance
Applications of state space models in finance
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118 6 Time-vary<strong>in</strong>g market beta risk <strong>of</strong> pan-European sectors<br />
probability density<br />
probability density<br />
probability density<br />
1.2<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
(a) OLS<br />
Median = 0.249<br />
F(0) = 30%<br />
−1.0 −0.5 0.0 0.5 1.0<br />
1.2<br />
(d) RW<br />
Median = 0.298<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
F(0) = 25%<br />
0.0<br />
−1.0 −0.5 0.0 0.5 1.0<br />
2.0<br />
1.5<br />
1.0<br />
0.5<br />
(g) GRW<br />
Median = 0.254<br />
F(0) = 14%<br />
0.0<br />
−1.0 −0.5 0.0 0.5 1.0<br />
probability density<br />
probability density<br />
probability density<br />
1.2<br />
(b) tG<br />
Median = 0.278<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
F(0) = 24%<br />
0.0<br />
−1.0 −0.5 0.0 0.5 1.0<br />
1.2<br />
(e) MR<br />
Median = 0.260<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
F(0) = 25%<br />
0.0<br />
−1.0 −0.5 0.0 0.5 1.0<br />
(h) MSM<br />
1.2 Median = 0.244<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
F(0) = 27%<br />
0.0<br />
−1.0 −0.5 0.0 0.5 1.0<br />
probability density<br />
probability density<br />
probability density<br />
1.2<br />
(c) SV<br />
Median = 0.289<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
F(0) = 28%<br />
0.0<br />
−1.0 −0.5 0.0 0.5 1.0<br />
1.2<br />
1.0<br />
0.8<br />
(f) MMR<br />
Median = 0.295<br />
F(0) = 23%<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
−1.0 −0.5 0.0 0.5 1.0<br />
(i) MS<br />
1.4<br />
1.2 Median = 0.250<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
F(0) = 29%<br />
0.0<br />
−1.0 −0.5 0.0 0.5 1.0<br />
Figure 6.13: Histograms <strong>of</strong> Spearman’s out-<strong>of</strong>-sample rank correlations (100 samples).<br />
correlations are smaller than zero. This means that the risk <strong>of</strong> generat<strong>in</strong>g a mislead<strong>in</strong>g<br />
signal is reduced.<br />
When evaluat<strong>in</strong>g a model, a common way to take the risk related to a forecast explicitly<br />
<strong>in</strong>to account is to calculate an <strong>in</strong>formation ratio (IR). Alexander (2001, p. 445)<br />
def<strong>in</strong>es an <strong>in</strong>formation ratio as “the mean prediction error divided by the standard deviation<br />
<strong>of</strong> the prediction error”. In the context <strong>of</strong> the cross-sectional analysis us<strong>in</strong>g rank<br />
correlations, an <strong>in</strong>formation ratio for a given model<strong>in</strong>g techniques n can be def<strong>in</strong>ed as<br />
IRn = E(ρS � n)<br />
, (6.44)<br />
V ar(ρS n)<br />
where ρS n = {ρS n,1, ρS n,2, . . . , ρS n,T }. The computed <strong>in</strong>formation ratios are reported <strong>in</strong><br />
Table 6.8. For the chosen out-<strong>of</strong>-sample period, the GRW model is confirmed to <strong>of</strong>fer<br />
the best risk-adjusted forecast<strong>in</strong>g performance, followed by the MMR and the RW model.<br />
To check which <strong>of</strong> these three <strong>models</strong> yields the best forecast<strong>in</strong>g performance over a more<br />
representative period <strong>of</strong> time, an out-<strong>of</strong>-sample period <strong>of</strong> ten years based on 520 samples<br />
Table 6.8: Information criteria <strong>of</strong> out-<strong>of</strong>-sample rank correlations.<br />
OLS tG SV RW MR MMR GRW MSM MS<br />
0.63 0.65 0.64 0.70 0.64 0.72 1.42 0.62 0.65