In the event of auditor switches, firms are only required to disclose the fees paid to successor auditors. They are not required to disclose the fees paid to predecessor auditors. This study examines the factors that motivate firms to voluntarily disclose predecessor auditor fees. We predict and find that firms that switch their auditors later in the year, receive initial-year fee discounts, or make downgrade auditor switches are more likely to disclose the fees paid to predecessor auditors. These results suggest that predecessor auditor fee disclosures are made to mitigate negative perceptions associated with auditor switches, such as potential opinion shopping or lower audit quality. Further analyses show that firms disclosing predecessor auditor fees are less likely to restate earnings and less likely to change auditors again shortly after the auditor switch, suggesting that predecessor auditor fee disclosures are not indicative of lower audit quality or opinion shopping.