In 1984, he launched WSGP International, which concentrated on Investments in real estate and financial Service organizations in the western United States and on the Pacific Rim. In 1988, together with sons william E. Simon Jr. and J. Peter Simon, he founded william E. Simon & Sons, a global merchant bank with offices in New Jersey, Los Angeles, and Hong Kong. The firm is now extensively involved in providing venture capital. In 1990, he partnered with several Investors to form Catterton-Simon Partners, a private equity firm focused on beverages and other consumer products, which today is known as Catterton Partners.