This paper studies a financial market transaction model and convergence of Markovian price processes generated by an a-double auction in Xu et al. (Expert Syst Appl 41(16):7032-7045, 2014) and extends their results for a fixed a in [0, 1] to the case where a is governed by a time non-homogeneous Markov chain over a set of finite states defined by R fa 1 ; a 2 ; . . .; a r g, 0 a 1 \a 2 \ Á Á Á \a r 1. A convergence result similar to that in Xu et al. ( 2014) holds, with the fixed a replaced with the average a à ¼ 1 r P r h¼1 a h . We also identify the conditions under which a price process generated by such a Markovian a-double auction converges in probability to a Walrasian equilibrium of the underlying financial market transaction model. A number of simulations are conducted and these simulations are consistent with the theoretical results of the paper.