In Chinese culture, the Zodiac Year (“Benmingnian”) is widely regarded as inauspicious, reflecting a deep-rooted superstition that shapes risk perception and decision-making. Using data on 2,194 Chinese listed firms between 2003 and 2022, this study investigates whether chairpersons’ Zodiac Year superstition affects outward foreign direct investment (OFDI) strategies. We find that firms pursue more conservative OFDI strategies during the chairperson’s Zodiac Year—diversifying across more projects while reducing the size of individual investments—consistent with heightened risk aversion. The effect is amplified under greater operational uncertainty but weakens in firms with stronger formal institutional constraints, such as state ownership or political connections. It also weakens in regions more deeply shaped by Confucian traditions—a rational informal institution that curbs superstitious tendencies—and varies systematically with managerial characteristics such as gender and education. Overall, the findings reveal how culturally embedded, nonrational beliefs shape strategic decision-making in international business.