In December a federal regulator sued JPMorgan Chase, Wells Fargo and Bank of America, claiming the banks failed to protect hundreds of thousands of consumers from rampant fraud on Zelle, in violation of consumer financial laws.

Shares of JPMorgan Chase ( JPM -3.98%), the largest bank in the U.S. by assets, traded nearly 5% lower as of 10:52 a.m. ET. Shares of Wells Fargo ( WFC -4.84%) traded 6.5% lower at that time, while shares of Citigroup ( C -6.25%) were down 7.5%.

The U.S. Consumer Financial Protection Bureau told a federal court on Tuesday it was dropping a lawsuit filed in December against three of the nation's largest banks over their handling of the payment service Zelle,