POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS:

That the undersigned, DEREK MARTIN, hereinafter referred to as
"Principal", has made, constituted, and appointed, and by these
presents does make, constitute and appoint FREDERIC DORWART AND
TAMARA R. WAGMAN, hereinafter referred to as "Attorney", whether
one or more than one acting jointly, the true and lawful attorney
for Principal and in the name, place and stead of Principal to
do or perform any act which a Principal may lawfully do or
perform through any attorney-in-fact, such power to be limited
to the following:

To execute, on Principal's behalf, Forms 3, 4 and 5, and to file
such forms with the Securities and Exchange Commission and such
other regulating organizations or governmental agencies as may be
required and to obtain and maintain any filing codes related to
filing of the same with respect to all BOK Financial stock ownership.

HEREBY GIVING AND GRANTING UNTO ATTORNEY, full power and authority
to do and perform all and every act and thing whatsoever requisite
and necessary to be done in and about the premises as fully and to
all intents and purposes as Principal might or could do if personally
present, with full power of substitution and revocation, hereby
ratifying and confirming all that Attorney  may do as it relates
solely to the power enumerated above.

This Power of Attorney may be revoked by Principal by an instrument
in writing signed by Principal.

IN WITNESS WHEREOF, I have hereunto set my hand this 4th day of
December, 2018.


                    By /s/ Derek Martin
                    DEREK MARTIN

State of  Oklahoma

County of Tulsa

     This Power of Attorney was acknowledged before me on this
4 day of December, 2018 by Derek Martin, Individually.

[SEAL]

                    /s/ Kim Rutledge
                    Notary Public

                    My commission expires 6/26/2022
                    My commission number 06006212