The bank is an example of an institution whose activity has always been the subject of particularly broad interest that in turn required a comprehensive assessment. During the transition to a knowledge-based economy, this assessment must include new areas, including new forms of capital. Human capital, structural capital and customer capital are the three new forms of capital, which constitute the so-called intellectual capital. Customer capital is undoubtedly the one that is the least known. The need to assess customer capital is no longer questioned, however, issues remain as to its definition, specifying the management phases for such capital, the principles and scope of its assessment, its place within a comprehensive assessment of a bank's activities and the selection of measurement instruments. The article proposes the possible solutions regarding selected aspects of customer capital assessment.