BOK Financial Corporation, based in Tulsa, Oklahoma, is a financial services company in the West South Central States region of the United States. The corporate headquarters is located in the BOK Tower in downtown Tulsa. BOK Financial's holdings include BOKF, NA, BOSC, Inc, Cavanal Hill Investment Management and Southwest Trust Company. BOKF, NA operates seven banking divisions: Bank of Albuquerque, Bank of Arizona, Bank of Arkansas, Bank of Kansas City, Bank of Oklahoma, Bank of Texas, and Colorado State Bank and Trust. BOKF, NA has full-service banks located in eight states. BOSC, Inc., the broker/dealer subsidiary, provides brokerage services in 10 states.  Wikipedia