The momentum effect of assets of various classes has been known and presented in the literature for a long time. However, there is no work confirming the existence of a similar effect on intellectual assets. The reason for this lies in a different mechanism for the trade turnover of such assets. In this paper, the comparable effect of copyright assets traded on modern digital microstock platforms is proved. The paper proposes first a structural model of the portfolio of digital assets of copyright that explains the momentum effect of assets of this class. The revealed effect is then introduced in the hybrid Bayesian network model of digital images portfolio, developed by the authors to study financial risk.