Wall Street seems to have cleaned up its act. Or maybe it's just that people aren't losing buckets of money in the stock market anymore. The number of securities fraud class-action suits filed in 2006 plummeted to an all-time low in 2006. Stanford Law School and Cornerstone Research report class-action suits decreased by 38 percent, to 110 filings in 2006, versus the previous year. That's nearly 43 percent lower than the 10-year historical average of 193.