Okla. Stat. tit. 6, § 6-1715: Out-of-state trust institutions permitted to engage in

trust business.

An out-of-state trust institution may act as a fiduciary in this

state or engage in a trust business at an office in this state only

if it maintains:

1. A trust office in this state as permitted by this section

through Section 20 of this act; or

2. A branch in this state.