In contrast to previous literature, our study not only examines the communicative value of Key Audit Matters (KAMs) through the capital market reaction to KAMs but also analyses the content and reporting format of KAMs, which vary based on the intrinsic risk of business activity. Using a sample of Chinese firms from 2017 to 2020, we find that more M&A-related KAMs are reported and they are disclosed through less boilerplate language when M&As are accompanied with the Performance Commitment contracts (PCs), an indicator as high possibility of overpayment during M&As thus inducing the high risk of the goodwill impairment and high litigation risk. Additionally, we find that the negative impact of PCs on boilerplate language is amplified when the benchmark in PCs is precisely achieved or when the firm has been sued in recent years. In other words, the disclosure of M&A-related KAMs is more tailored to the client firm when auditors observe a high risk for accountability. Consequently, capital market participants, as well as other recipients of auditing reports, such as regulators and analysts, perceive non-boilerplate M&A-related KAMs as informative for their decision-making process.