Like Clark Kent, this firm holds some super powers. Clark Enterprises, Inc. (CEI) is a holding company with diverse investments in real estate, construction, financial markets, and venture capital. Its flagship subsidiary Clark Construction Group is one of the largest private general contractors in the US, providing construction management, design/build, and consulting services. Other CEI units develop, manage, and lease residential and office real estate. Private equity and venture capital arm CNF Investments manages $350 million in capital and invests in the technology, healthcare, oil and gas, social media, and education sectors. Founded in 1972, Chairman and CEO James Clark still owns CEI.