When a public company announces that it is being acquired, no one is surprised anymore when suits are filed against that company's directors. Whether the price is good or great doesn't seem to matter. In 2013, 97.5 percent of public M&A deals worth more than $100 million were sued an average of seven times each.

To be sure, there are instances of what may have been true M&A misbehavior that harmed shareholders. Certainly that was the conclusion when the Delaware Court of Chancery awarded a $1.2 billion judgment (and $300 million plaintiffs' attorney fee award) in the class action lawsuit over Grupo México, S.A.B. de C.V's acquisition of Southern Peru Copper.

However, it is unlikely that almost 100 percent of M&A deals involve breaches of fiduciary duties. Directors could fight the non-meritorious claims. Unfortunately, it often doesn't make sense for directors to fight when they can instead settle a case by paying an immaterial amount compared to the size of the M&A deal at stake. Of course, this dynamic merely emboldens plaintiffs to bring more cases, and—presumably—attempt to hold out for ever higher settlement amounts.