Lehman Brothers (NYSE: LEH) was, until its Chapter 11 bankruptcy filing on September, 15, 2008, the fourth-largest securities firm in the U.S. and a leading provider of financial products that let companies package and re-sell risk. Lehman has a particularly strong history in fixed-income, which is a broad term for any investment that yields a regular (fixed) return. In recent years, the firm has recognized its heavy reliance on fixed income as a source of revenue and has moved to diversify into other areas of finance such as investment banking and investment and asset management.