The number of federal securities fraud class actions increased to 188 in 2011, a 6.8% increase compared with the previous year, with a significant percentage of those stemming from merger and acquisition activity, according to the Stanford Law School's Securities Class Action Clearinghouse in a report issued Thursday.

M&A activity accounted for 43 of the 188 filings, or 22.9% of the total, according to the Palo Alto, Calif.-based clearinghouse, which prepares its report in cooperation with Boston-based Cornerstone Research.

Noting these large numbers, some executive management liability experts have said they expect plaintiffs to continue moving these cases out of state courts in hopes of larger recoveries.

Meanwhile, although litigation against Chinese issuers listed on U.S. exchanges through reverse mergers accounted for 33 class actions last year, 24 of these were filed in the first half of the year and only nine in the second half, according to the report.

“As the peak of the financial crisis recedes, filings related to the crisis also continue to decline,” according to the report. There were only three such filings in 2011, compared with 13 in 2010 and 53 in 2009.

The report states the number of class actions filed overall was 3.1% below the annual average of 194 filings observed between 1997 and 2010.

Commenting on the report, clearinghouse Director Joseph Grundfest said in a statement: “This corner of the litigation market continues to run at a pace well below historic norms. The rapid run-up and subsequent decline of litigation against Chinese insurers that entered the U.S. market through reverse mergers suggest that this form of litigation may be close to having run its course. The decline in financial crisis claims further depressed the overall statistics.

“It’s only the growth of merger-related litigation, which has historically been brought in state courts, that inflates the aggregate statistics so that they even approach historic norms. Taken together, these data suggest there are far fewer claims of traditional securities fraud by U.S. issuers than has been the case since the mid-1990s.”

The report is available at http://securities.stanford.edu.