Table 2 shows that in the Alternative Reference Model the prior weights match the equilibrium
weights as uncertainty in the estimated covariance is not a factor. It also shows that the posterior
unconstrained weight of an asset included in no views does not change from the equilibrium
weight. Further it shows no impact from the absolute view on Germany, the expected return is
already taken into account by the results from scenario 1.
With both reference models the unconstrained weights for an asset with no views, e.g. Japan, do
not change. This matches our assertion earlier that this is a general property of the BlackLitterman
model.
In this case the Alternative Reference Model leads to larger movements from the equilibrium.
This is because of the use of point estimates and the lack of the impact from the uncertainty in
the estimates. We can also see the impact of the updated posterior covariance is a second order
effect, as we can see from the last column from Table 1 it is less than 10% of the total change
from the prior unconstrained weight.
Table 2 – Alternative Reference Model Results