We studied the key success factors for 48 financial products introduced in the United States from 1984 to 1987. The results of correlation and partial correlation analyses were largely consistent with prior research, indicating that "personal selling factors," "market growth rate," and "market size" had the most significant influence on product success. Additionally, "marketing support," "product superiority," and "customer understanding and interest" were also found to have an impact. However, the analysis using mediating variables revealed many interesting findings that had been overlooked in prior research. "Technology-needs fit," "customer understanding-needs fit," "market competition and cost," "customization and cost," and "novelty and cost" exhibited considerable mediating effects among themselves. Moreover, "product superiority and personal selling," "technology and needs fit," and "needs fit and customer understanding" interacted to produce synergy effects. Therefore, these factors should be carefully considered during new product development. The research findings are believed to be applicable to the Korean financial market as well. However, it would be advisable to replicate the study using new product data from the Korean financial market.