In this video, Matt Koppenheffer describes the one key opportunity for AIG (AIG 1.15%) investors. Matt believes the company's valuation makes it an attractive investment. AIG currently trades at a 40% discount to its tangible book value, far less than what it traded for before the financial crisis. Matt suspects lingering memories of that financial crisis lead investors to avoid the stock. There are also concerns that AIG's core businesses aren't that good relative to the past. Matt believes AIG's property and life insurance businesses are solid and, especially if interest rates increase, will contribute to the financial success of the company.