In this Research Insight, we examine Marginal Contribution to Risk and define two alternative versions of this measure: Marginal Contribution to Active Risk (MCAR), and Marginal Contribution to Tracking Error (MCTE). Since most industry practitioners regard “active risk” and “tracking error” as synonymous, this nomenclature has sometimes generated confusion. In this paper, we explain the similarities and differences between MCAR and MCTE and offer insights from our...