Wang Yung-tsai was the younger brother of Wang Yung-ching, founder of Formosa Plastics Group. He was born in Chyokutan, Shinden Town, Bunsan District, Taihoku Prefecture, Japanese Taiwan.

Wang Yung-ching, also called YC Wang, was a Taiwanese businessman. He was best known for being at the chairman of Formosa Plastics Corporation, one of Taiwan's foremost plastic manufacturing establishments until is retirement in June 2006, where he stepped down at the age of 89.