Very rarely can a single stock make you a millionaire. Icahn Enterprises (IEP 1.52%) is no exception. Investing in this stock should be part of a diversified approach focused on long-term results. But that doesn't mean shares can't provide meaningful upside to your investment portfolio, especially at today's depressed prices. In the past year, Icahn Enterprises stock has lost roughly two-thirds of its value. Many investors are taking a closer look, given the company is controlled by a well-respected investo ...