The market reaction to auditor resignations

Under UK company law, external auditors who resign must warn shareholders and creditors of any matter that ought to be brought to their attention. Auditor resignations and the subsequent change in auditor are informative corporate events. Resignation from office is likely to be a costly signal for the audit firm, particularly when the client is a quoted company. Our analysis of daily data suggests that there is a negative reaction to the auditor resignation on the date of the resignation letter, even though very few auditors indicate there were problems of which the shareholders and creditors should be made aware. This provides backing for the statutory rules on disclosure of the auditor resignation. We also find that the extent of the market reaction on the day of the resignation is related to the size of the resigning audit firm.