Several U.S. attorneys have begun courting False Claims Act litigation in recent years, according to lawyers who practice in the area, chipping away at the dominance that Philadelphia and Boston once had on whistleblower cases.

The Eastern District of Pennsylvania and the District of Massachusetts are still in the top three districts for FCA litigation, but the Southern District of New York might now be No. 1, said Patrick Burns, co-director of Taxpayers Against Fraud Education Fund, a nonprofit group that advocates for strong whistleblower protections.