ABSTRACT We investigate the effect of CFO narcissism, as measured by signature size, on financial reporting quality. Experimentally, we validate that narcissism predicts misreporting behavior, and that signature size predicts misreporting through its association with narcissism. Empirically, we examine notarized CFO signatures and find CFO narcissism is associated with more earnings management, less timely loss recognition, weaker internal control quality, and a higher probability of restatements. The results are consistent for within‐firm comparisons focusing on CFO changes and are robust to controlling for CFO overconfidence and CEO narcissism. The results highlight the importance of CFO characteristics in the domain of financial reporting decisions.