Using Korean listed firms subject to the auditor “designation rule”, this paper shows that (1) firms that switch auditors exhibit lower stock liquidity than firms that do not switch auditors, and (2) the negative liquidity effect of auditor switches is concentrated in firms that switch to low-quality auditors. Meanwhile, firms that switch auditors under the auditor designation system do not exhibit lower stock liquidity, consistent with audit designation mitigating the concerns about audit quality deterioration around auditor changes. Furthermore, we find that foreign ownership has a mitigating impact on the negative relation between auditor switches and stock liquidity, suggesting that investors are less concerned about auditor switches when an alternative monitoring mechanism exists.