Class action security lawsuits are on the rise, with a large spike in federal litigation alleging disclosure violations in merger and acquisition transactions, according to a study by the Stanford Law School Securities Class Action Clearinghouse and Cornerstone Research.

The study revealed the number of lawsuits related to M&A transactions increased 471 percent.

The study also found that of all class action security suits in 2010, 15.4 percent of Standard & Poor's 500 healthcare companies were named defendants in a class action.