As e-business grows rapidly, interests in design principles for e-business web sites are increasing. A few studies have suggested design principles with concrete design features, but failed to link the features to the performance of an e-business site, such as attitudes of its customers or financial performance of the e-business company. This paper proposes a comprehensive framework that covers from concrete design features to financial performance for online stock trading, which is one of the most important domains of e-business. The proposed model for online stock trading sites consists of three design principles: functional convenience, representational delight, and structural firmness. Through empirical studies, this research found that the convenience, delight and firmness principles were closely related to the level of customer satisfaction, and, consequently, to the level of customer loyalty to the sites. We also identified important design features such as presentation of stock quotes in the homepage for each of the three design principles. Finally, the study results showed that customer loyalty would affect the financial performance of online stock trading companies. This paper concludes with the implications and limitations of the results.