Whether or not a regulatory record retention requirement applies to documents that are subject to a subpoena request would not be relevant. While we cannot comment on the exact requirements of the subpoena that your bank received, it is likely that the subpoena requires the bank to produce any relevant documents that it does possess, regardless of whether the bank has retained documents beyond any legally-required retention period.

Further, the bank would not be violating customer privacy rights by responding to the subpoena. Both federal and Illinois privacy laws allow banks to disclose customer financial records in response to a lawful subpoena. 205 ILCS 5/48.1(c)(2)15 USC 6802(e)(8). Note that the Illinois law also requires that the bank mail a copy of the subpoena to the customer that is the subject of the subpoena, unless the subpoena specifically prohibits the bank from doing so. 205 ILCS 5/48.1(d).