The VARMAX procedure currently does not support missing values. PROC VARMAX uses the first contiguous group of observations that have no missing values for any of the MODEL statement variables. Observations at the beginning of the data set that have missing values for any MODEL statement variables are not used or included in the output data set. At the end of the data set, observations can have dependent (endogenous) variables with missing values and independent (exogenous) variables with nonmissing values.