Fifth Third CFO Bryan Preston said concerns around AI-driven cash optimization are "likely overblown," but the $301 billion-asset bank isn't dismissing the issue. Fifth Third's median household checking account balance is $3,000, so there's little excess that might be moved around in search of higher yield, Preston said.

The bank's average core deposits grew 3% sequentially to $236 billion, according to an earnings release. Third-quarter deposit costs rose 10 basis points to 1.64%, while interest-bearing deposit costs increased 11 basis points to 2.24%.

Fifth Third doesn't currently allow AI agents to initiate transactions in customer accounts, and accountability questions need to be settled before agents carry out transactions on behalf of customers, Preston said.

CEO Tim Spence said the banks most at risk related to artificial intelligence-driven cash optimization concerns are online-only lenders — "the ones that have nothing but pricing defining their value propositions."