This paper explores the financial implications of new product preannouncements for firms, particularly within the software and hardware industries. It leverages agency and signaling theories, along with rational learning theory, to examine how these announcements influence shareholder value. The research finds that while short-term abnormal returns are only positive when the preannouncement provides specific information about the product, long-term abnormal returns are significantly positive, especially when firms provide ongoing updates and possess high reliability in delivering on past preannouncements. The study employs the calendar-time portfolio methodology to analyze these long-term effects, offering practical guidelines for managers on managing communications to maximize financial value from preannouncing products.