Caution should be exercised when using the FIML estimator, an H.var equation for modeling the variance, and RESTRICT or BOUNDS statements. If the restriction or boundary constraint is "active", then the standard errors associated with the model parameter estimates are not correct.

Equality restrictions expressed with a RESTRICT statement are always considered to be active, and therefore, result in incorrect standard errors. Boundary constraints expressed with a BOUNDS statement are considered to be active only if a parameter estimate is fixed at one of the boundary points provided in a BOUNDS statement. When a boundary constraint is active, a row appears at the bottom of the Parameter Estimates table with a parameter name of the form, "Bound n".

This set of options and statements is commonly used when estimating ARCH or GARCH models with the MODEL procedure. No circumventions are available within the MODEL procedure. However, you may want to consider the AUTOREG procedure as a possible alternative. If the model cannot be fit in PROC AUTOREG, then the NLP procedure in the SAS/OR product may be an alternative if you can specify the likelihood function for your desired model.