NASD sounds alarm on margin buying By Aaron Siegel April 11, 2007 NASD has issued a warning to investors about the dangers of margin buying, as the amount of debt U.S. investors took on rose to a record $321.2 billion in February. The figure topped the previous record of $299.9 billion in March 2000, at the peak of the last bull market, according to Reuters. Margin debt has more than doubled from $141.3 billion in January 2003, three months after the bear market bottomed out. The self-regulatory organizationâs latest investor alert comes as many American homeowners are unable to keep up with their mortgage payments. Delinquencies hit 4.95% in the fourth quarter, compared with 4.67% during the third quarter, according to the National Delinquency Survey released by Mortgage Bankers Association released last month. "We are concerned too many investors are unaware they could suffer substantial financial losses by using debt to purchase securities," said Mary L. Schapiro NASD chairman and chief executive, in a statement. "By updating our alert on this topic, we hope to remind investors not to underestimate the risks involved."