The voluntary management forecast report (MFR) is arguably one of the most important sources of forward-looking information for outside investors, suppliers, analysts, and other stakeholders. In this study, we investigate the effects of firm-specific textual content in the MFRs of an important third-party, the customer (i.e., customer-specific textual content), on the forward-looking information environment of a firm. We find the following. First, the extent of forward-looking customer-specific textual content in a customer’s MFRs is negatively and significantly related to the forward-looking information asymmetry of the (supplier) firm. Second, investors assess and verify the credibility of the customer-specific textual content both between textual and numerical information modes and within the textual mode. Third, the customer-specific textual content in a customer MFRs is read by analysts following and institutional investors of the (supplier) firm. Our findings reveal the relevance and importance of customer-specific forward-looking textual information to a firm’s forward-looking information environment.