This study investigates whether and how information asymmetry in the stock market affects the quantum of audit fees paid by auditees. It is based on a sample of 218 US publicly traded companies and adopts two well-established proxies for information asymmetry, namely bid-ask spread (BAS) and probability of informed trading (PIN). Empirical results provide evidence that, after controlling for all main audit fees determinants, information asymmetry is positively related to the quantum of audit fees paid. Overall, evidence supports the contention that less transparent companies convey higher audi...