Scott Levine, of Florida, was convicted by jury on Friday of unauthorized access to data, obstruction of justice and access device fraud.
"We think it's the appropriate verdict," said U.S. attorney Bud Cummins to reporters outside U.S. District Court. "These are very serious crimes, a huge amount of data that was stolen for monetary gain and he should be held accountable. The jury apparently saw it that way."
The jury cleared Levine of 13 counts of unauthorized access of a personal computer and further counts of conspiracy and money-laundering. Levine's now defunct company, Snipermail, raided Acxiom's data centre in an attempt to enlarge its contact lists. It then attempted to sell its contacts to credit bureaus.
Federal prosecutors said Snipermail stole 1.6 billion customer records. Six of Levine's colleagues pleaded guilty to conspiracy and testified against their former boss.
Levine will be sentenced on January 9 next year. He faces a maximum of 640 years in prison and a fine of over $30 million.