To test the house-money and break-even effects of Thaler and Johnson (1990), this paper samples Taiwanese banks to examine whether prior short-run investment performance affects subsequent investment behaviors. The finding is that the afore-mentioned effects are empirically supported: past investment gains manifestly correlate with subsequent risk-taking; prior losses elicit increased subsequent risk, because banks are likely over-optimistic and overconfident of the break-even opportunity, even if their losses are large. Moreover, investment risks rise as prior gains increase; larger the preceding losses beget higher subsequent risks, yet the sensitivity of risks to small prior losses is greater than when prior losses are large. The aforementioned biased behavior is more pronounced for privately-owned banks. Consequently, banks still possibly demonstrate behavioral biases, even though they possess investment proficiency.