He tipped off an Oregon retiree about the firm's planned trades in stocks in a six-year plot involving over 1,000 trades.
The retiree sent Billimek a share of the profits through checks and wire transfers totaling about $12 million.
The scheme was one of the first uncovered by the Consolidated Audit Trail, a database of trading information launched by the SEC in the wake of the 2010 Flash Crash.