Okla. Stat. tit. 60, § 60-175.61
Prudent investor rule
Prudent Investor Rule.
A. Except as otherwise provided in subsection B of this
section, a trustee who invests and manages trust assets owes a duty
to the beneficiaries of the trust to comply with the prudent
investor rule set forth in the Oklahoma Uniform Prudent Investor
Act.
B. The prudent investor rule, a default rule, may be expanded,
restricted, eliminated, or otherwise altered by the provisions of a
trust. A trustee is not liable to a beneficiary to the extent that
the trustee acted in reasonable reliance on the provisions of the
trust.