The trader got 90 months in prison, but was out years before the banks settled their case.
Bloomberg News reports that AIB had sought $872m in the lawsuit filed in Manhattan federal court.
AIB and Citibank agreed to drop lawsuits against each other, according to a filing with the court Wednesday.
AIB accused Citigroup's Citibank unit, which was Allfirst's prime broker, of furthering the fraud by enabling Rusnak's sham transactions, including disguised cash advances and fake trades.
It said this let Rusnak trade more than Allfirst allowed, while pretending his currency bets were legitimate.
Citigroup countered that the evidence did not come close to suggesting it contributed to Rusnak's losses.