Linear Factor Models in Finance

Three tests are implemented. The multivariate F test and the average F test are based on the linear regression framework: each of the n asset returns is specified as a linear function of the k factor returns. In the stochastic discount factor framework, the stochastic discount factor is assumed to be a linear function of the k factor returns and the parameters are estimated via the n moment conditions using the GMM with the weighting matrix advocated by Hansen and Jagannathan (1997).
Both the multivariate F test and the average F test start with the following multivariate linear regression:
| (6.12) | |
where ? i is a 1 k vector of factor loadings of asset i and f t is a k 1 vector of the k factor returns at time t. If the expected return of asset i is linear in betas, i.e. a linear combination of the k factors is on the efficient frontier, then
| (6.13) | |
Equation (6.12) and equation (6.13) imply that ?, the n 1 vector of n asset pricing errors, is jointly equal to zero.
Assuming that the random error,
, is normally distributed, together with assumptions stated in the first section, the multivariate F test is given by
| (6.14) | |
where

where
is a vector of n 1 asset excess returns at time t, f t is a vector of