This study examines the relationship between a firm ’s internal monitoring
mechanism and its impact on the audit fee. The first hypothesis investigates whether firms with independent corporate boards (chief executive of officer and chairman being separate individuals) provide a more effective internal monitoring mechanism and are thus associated with lower control risk, resulting in lower audit effort and fees as compared to nonindependent, CEO-dominated boards. The second hypothesis examines whether the effectiveness of the internal monitoring mechanism provided by independent corporate boards is independent of the firms ’ growth opportunities. High growth firms are by nature more difficult to monitor due to the existence of discretionary investments and measurement problems associated with future assets. Thus, the negative association between independent corporate boards and audit fees is expected to be affected by firm’s growth. Results using 650 observations from Hong Kong companies provide support for both hypotheses.