Dynex's defense lawyers claim that six confidential witnesses cited by the plaintiffs in their complaint now deny making these statements. Cohen Milstein counters that Hunton & Williams's attack on the integrity of its lawyers is "scandalous" and threatens to seek sanctions.

Really, it's no wonder the plaintiffs bar is filing all those get-rich-quick post-merger announcement suits. It's just too hard these days to succeed with old-fashioned securities fraud class actions.

Plaintiffs lawyers at Cohen Millstein and Scott + Scott won a rare class certification ruling in their mortgage-backed securities suit against Washington Mutual. But WaMu's lawyers at Cravath, Swaine & Moore and Bingham McCutchen persuaded Judge Marsha Pechman to whittle the case down to just a fraction of its former size.