Investing.com - Laurence D. Fink has long been a leader on Wall Street. Lately, he's also been speaking out on behalf of Main Street. The chairman and CEO of BlackRock says CEOs need to make sure their companies make "a positive contribution to society." In the wake of the fatal Parkland school shooting, BlackRock decided to remove companies that manufacturer and sell firearms from its investment funds.Such a foray into the social-political arena may not be much of a stretch for a Wall Street titan like Fink, who is a lifelong member of the Democratic Party. He grew up in a decidedly middle-class family in Van Nuys, California, where he earned a BA in political science from UCLA in 1974.After receiving an MBA in real estate from UCLA in 1976, Fink made the leap to Wall Street. During his 12 years at First Boston he ran the bond and real estate departments and was instrumental in creating the mortgage-backed security market.Fink and seven other partners founded BlackRock in 1988. As CEO, he led the firm's merger with Merrill Lynch Investment Managers and acquisition of Barclays (LON:BARC) Global Investors. Now the industry's largest money management firm, BlackRock controls $6.228 trillion in assets.Outside of work, Fink is involved with a diverse group of organizations, serving as a trustee or board member of New York University, the NYU Langone Medical Center, the Museum of Modern Art, the Council on Foreign Relations and the Nature Conservancy. Fink is said to worth more than $1 billion.