PT - JOURNAL ARTICLE AU - Arnaldo Oliveira TI - A Discussion of Investing Theories AID - 10.3905/jwm.2003.320460 DP - 2003 Jan 31 TA - The Journal of Wealth Management PG - 15--22 VI - 5 IP - 4 4099 - https://pm-research.com/content/5/4/15.short 4100 - https://pm-research.com/content/5/4/15.full AB - This article examines four leading investing theories: 1) the firm-foundation theory of S. Eliot Guild, 2) the theory of investment value of John B. Williams, 3) the John M. Keynes castle-in-the-air theory, and 4) the theory of games and economic behavior of John Von Neumann and Oskar Morgenstern. It discusses the use of fundamental and technical analysis by each theory, as well as the asset valuations models derived from the four of them. This article thus synthesizes, compares, and contrasts the four theories and proposes a holistic approach for future financial research.