There were 188 federal securities class action lawsuits filed against companies last year, up slightly from the 176 suits filed in 2010, according to a report from the Stanford Law School Securities Class Action Clearinghouse and Cornerstone Research.

Thirty-three of last year's lawsuits, or 18%, involve accusations of fraud against Chinese companies that listed on U.S. exchanges via a reverse merger. That's up from nine lawsuits in 2010 related to Chinese reverse-merger companies. But the report points out that 24 of the 2011 cases were filed in the first half of the year and just nine in the second half, suggesting that the litigation is subsiding.

The lawsuits against the Chinese companies are distinct from other class action filings, with 65% of the reserve-merger suits alleging violations of generally accepted accounting principles, vs. just 32% of other suits. On the other hand, none of the reverse-merger filings involve charges of insider trading, while 21% of other class action filings do.