12 CFR § 150.135
How do I determine which state's laws apply to my operations?
November 10, 2020
(a) The state laws that apply to you by virtue of 12 U.S.C. 1464(n) are the laws of the states in which you conduct fiduciary activities. For each individual state, you may conduct fiduciary activities in the capacity of trustee, executor, administrator, guardian, or in any other fiduciary capacity the state permits for its state banks, trust companies, or other corporations that compete with Federal savings associations in the state.
(b) For each fiduciary relationship, the state referred to in 12 U.S.C. 1464(n) is the state in which you conduct fiduciary activities for that relationship.