The literature on corporate elites has paid significant attention to the leadership structure at the very top of organizations (for example, the consolidation vs. separation of the chief executive officer (CEO) and board chair positions-for a review, see Daily and Dalton, 1997). This is because corporate elites in different governance positions may have different interests, which means that the leadership structure at the top can influence organizational outcomes (Jensen and Zajac, 2004). Recently, there is an emerging research stream that specifically focuses on an important structure at the top: the presence of a chief operating officer (COO)/president who is separate from a CEO, and examines the performance consequences (accounting performance and stock market reactions) of this structure and the tenure outcomes of the Keywords: presence of a separate COO/president; CEO dismissal; strategic change *Correspondence to: Yan Zhang, Jesse H. Jones Graduate School of Management, Rice University, 6100 Main Street, Houston, TX 77005, U.S.A. E-mail: yanzh@rice.edu COO/president (e.g., Cannella and Shen, 2001;Davidson, Nemec, and Worrell, 2001;Hambrick and Cannella, 2004;Heenan and Bennis, 1999;Levinson, 1993;Shen and Cannella, 2003).There can be two separate roles of a COO/president: one representing an heir apparent in training for the CEO position and the other representing a co-leader delegated with internal operating authority. From a co-leader perspective, Hambrick and Cannella (2004: 959) argued that 'the decision to have a COO represents a major structural choice: it explicitly divides between two people a set of toplevel roles that are typically fulfilled by one person; it draws a structural distinction between strategy formulation and implementation; it adds an organizational layer; and it adds a highly-paid executive position to the organization's costs.' From a succession (heir apparent) perspective, Vancil (1987) found that many firms identified an heir apparent in the COO and/or president position in advance of the actual succession event and used this position to groom the next CEO. Findings of