Okla. Stat. tit. 6, § 6-2203
Financial institutions prohibited from disclosing
financial records unless.
A financial institution is prohibited from giving, releasing or
disclosing any financial record to any government authority unless:
(a) it has written consent from the customer for the specific
record requested; or
(b) it has been served with a subpoena issued pursuant to
Section 4 for the specific record requested.