In this paper, we introduce a new traveling wave with a buffer zone,
which is approached by an asymmetric credit migration model with fixed
migration boundary. The asymptotic behavior of the solution of the model
is discussed. By constructing two sets of sub and super solutions
sequences, it is proved that the solution of the credit rating migration
model approaches the new traveling wave with buffer zone as time goes to
infinite in a direction. Additionally, some numerical results are
presented.