We have a DDA account that has not had any deposits or withdrawals for over 5 years. Statements are sent out monthly and none have been returned to the back as undeliverable.
Under Oklahoma Statutes would this be considered abandoned and subject to escheatment to the State Treasurer?

735:80-3-10. Banks, savings and loans or other financial institutions; reporting requirements

I don't see mailing statements gets you out of it.

So you are saying that by sending a monthly statement to the customer with no deliverable mail returned is not considered "contact with the customer" and the account should be considered abandoned?

This was in a October 2014 OBA Legal Briefs By Pauli D. Loeffler.

If the bank has sent a statement or other business communication concerning the account or property to the owner by first-class mail, and the statement or communication has not been returned for inability to make delivery to the addressee, the property shall not be presumed to be abandoned. The five-year period begins to run at the later of when the business communication to the owner has been returned as undeliverable or on the last date the owner has communicated with the bank. (§ 652 A. 5. b.)