T sai Hong-tu is a Taiwanese billionaire and the chairman of Cathay Financial Holdings, one of Taiwan's largest and most powerful financial services conglomerates. He is a member of the influential Tsai family, one of the wealthiest dynasties in the country. He is the eldest son of the late Tsai Wan-lin, the patriarch who built the family's initial empire in insurance and real estate. After his father's death, the family's vast assets were divided among his sons.

Tsai Hong-tu, along with his brothers Cheng-ta and Cheng-Chiu, took control of the Cathay Financial side of the family's business. As chairman of the main holding company, he is the public face and principal leader of the group. He has overseen the growth and modernization of the family's massive business, which has a dominant presence in life insurance (through Cathay Life Insurance, Taiwan's largest), banking (Cathay United Bank), and asset management. He is considered one of the most powerful figures in Taiwanese finance.