Behavioral intention is central to investment-related decision making, but belief-based predictors and motivational need satisfaction should not be conflated. This quantitative cross-sectional study examined 512 undergraduate students in Jiangxi Province, China, drawing on the Theory of Planned Behavior (TPB) and Self-Determination Theory (SDT). Multiple regression tested attitudes, subjective norms, and perceived behavioral control as predictors of intention to apply investment strategies; descriptive statistics and correlations separately characterised autonomy, competence, and relatedness. The TPB model explained 55.2% of the variance in intention. All three TPB predictors were statistically significant, with perceived behavioral control having the largest unstandardized coefficient (B = 0.36, p