The Stock Market Game[TM] is an educational program supported by the Securities Industry and Financial Markets Association (SIFMA) Foundation for Investor Education. The program is designed to teach students the importance of saving and investing by building their financial literacy skills. The primary focus of the study was to measure the impact of playing the Stock Market Game on student achievement in investor knowledge and mathematics. Since it is expected that a supplemental education program will improve students' understanding of program-related content, they expected that students who played The Stock Market Game would improve their knowledge of topics related to savings and investing. A review of program content, however, revealed the mathematical nature of The Stock Market Game, suggesting another possible expectation related to student performance. Namely, is the mathematical component of the program material strong enough to affect students' mathematics skills? The authors designed the study in order to answer two research questions about impact: (1) What is the impact of The Stock Market Game on student academic achievement in mathematics for students in Grades 4-10?; and (2) What is the impact of The Stock Market Game on student investor knowledge for students in Grades 4-10? The findings suggest that this supplemental program designed to teach students about an important topic, one that many states are beginning to consider a requirement--saving and investing, can help students to learn, not only about topics within financial literacy, but also core aspects of mathematics. (Contains 4 tables.)