Laura Eimiller, an FBI spokeswoman in Los Angeles, says agents are making arrests Wednesday morning in Southern California, Nevada, North Carolina and overseas.
She says about 100 arrests are expected, many in the Los Angeles area.
Eimiller says an indictment accuses the suspects of running a "phishing" scheme. They allegedly used computer intrusion and fraud to obtain personal information that allowed them to withdraw money from bank accounts.
In "phishing," people answering an e-mail are directed to a bogus Web site where they are asked to update personal information, such as passwords and account numbers.