"All the big banks have these software systems," says Pete Balint, a cofounder of the Dominion Advisory Group, which helps banks develop strategies for combating money laundering and fraud. "Depending on their volume, they might have thousands of alerts a month."
Most of the systems follow fairly simple rules, looking for anomalies that trigger heightened scrutiny. Software company Metavante says that its software, for example, contains more than 70 "best-practice" rules, covering a wide variety of transaction types ranging from cash deposits to insurance purchases. . .
The simplest way to identify the unexpected is by contrast to the routine. A person who deposits just two paychecks a month for two years might be flagged if he suddenly deposits six large checks in two weeks, for example. . .
The most sophisticated software packages can sort people or accounts into several categories at once: a single customer might be compared to other schoolteachers; to people who bank mostly at a single regional branch; and to people who have stable, pension-based monthly incomes, for example.