This study investigates the effect of extreme uncertainty on disclosure behaviour by analyzing the quality and quantity of forward‐looking disclosures during the global financial crisis and pre‐crisis periods, controlling for other determinants of disclosure behaviour. Prior research has struggled to distinguish between the quality and quantity dimensions of forward‐looking disclosures. Also, the impact of the recent financial crisis on these forward‐looking disclosure attributes has not yet been examined systematically. We address this gap by exploiting the unique setting of German publicly traded firms. These firms must provide forward‐looking information within their audited financial statements, although relevant regulation is sufficiently vague to allow great variation in the quality, scope and quantity of forward‐looking disclosures actually observed. Using hand‐collected data from 2005 to 2009, we provide evidence of a significantly negative association between crisis and disclosure quality. This finding is robust to several different disclosure quality proxies and regression specifications. In contrast, we find no negative significant relation between crisis and disclosure quantity; rather, there is evidence that reported volume increases during the crisis. Our results are consistent with extreme uncertainty, as occurring during times of crisis, negatively affecting the quality of voluntary disclosures, while firms maintain or increase disclosure quantity, ultimately diluting the information density of forward‐looking disclosures.