Persistent Leverage in Portfolio Sorts: An Artifact of Measurement Error? Staff Working Paper 2014-55 Michael Mueller Studies such as Lemmon, Roberts and Zender (2008) demonstrate how stable firms’ capital structures are over time, and raise the question of whether new theories of capital structure are needed to explain these phenomena. Content Type(s): Staff research, Staff working papers Topic(s): Econometric and statistical methods, Financial markets JEL Code(s): C, C1, C18, G, G3, G32