Abstract: Greed is a significant motivator for economic behaviour, influencing various financial decisions. This study investigates the impact of investors' level of greed on the disposition effect – a phenomenon where investors are reluctant to realise losses but sell winning stocks prematurely. We find that investors with higher levels of greed exhibit a significantly stronger disposition effect than less greedy investors, though this relationship reveals an intriguing complexity. While greedy investors show an increased tendency to realise gains quickly, which substantially lowers their investment performance, they paradoxically demonstrate more rational behaviour in loss realization. This unexpected finding suggests that greedy investors, in their pursuit of new opportunities, are better able to overcome psychological barriers to realising losses rather than dwelling on them. Our analysis is robust across different measures of the disposition effect and consider various personality characteristic of participants. We also demonstrate that if participants had delayed the realisation of gains by four periods, they could have increased their portfolio performance by 7.46%. These findings contribute to the limited literature on the effects of greed on individual financial behaviour and provide a more nuanced understanding of how greed influences trading decisions. Our study therefore offers practical implications for investors and financial advisors aiming to improve investment outcomes by considering both the benefits and drawbacks of greed-driven trading behaviour.