So far this year, the number new accounts opened on E*Trade has surpassed the total number of accounts that were opened in the third and fourth quarters of last year, Pruzan said.

E*Trade, which Morgan Stanley acquired in 2020, is a new and growing business for the firm, and its growth comes as the recent trading frenzy centered on GameStop Corp has sparked a wave of interest from mom-and-pop investors.

"More clients, more engagement, more activity, more cash," Pruzan said. "It's been off the charts."

Morgan Stanley gets roughly half of its revenues from its wealth management business. But until the E*Trade acquisition, announced last February, it did not have a self-directed trading platform.

(Reporting by Elizabeth Dilts Marshall; Editing by Jan Harvey and Nick Zieminski)

By Elizabeth Dilts Marshall