Exhibit 21 BOK FINANCIAL CORPORATION EXHIBIT 21 SUBSIDIARIES OF THE REGISTRANT BANKING SUBSIDIARIES Bank of Albuquerque, National Association (1) Bank of Arkansas, National Association (1) Bank of Oklahoma, National Association (1) Bank of Texas, National Association (1) Colorado State Bank and Trust, National Association (1) OTHER SUBSIDIARIES OF BOK FINANCIAL CORPORATION BOK Capital Services Corporation BOK Plaza Holding Corporation BOSC, Inc. CNBT Bancshares, Inc. CNBT Bancshares (Delaware), Inc. First of Muskogee Insurance Corporation Park Cities Bancshares, Inc. (2) Park Cities Corporation (5) BOKF Equity, LLC BOKF Private Equity, LP SUBSIDIARIES OF BANK OF OKLAHOMA, N.A. Affiliated BancServices, Inc. Affiliated Financial Holding Company Affiliated Financial Insurance Agency, Inc. BancOklahoma Agri-Service Corporation BancOklahoma Mortgage Corporation BOK Delaware, Inc. (3) BOK Equipment Finance, Inc. BOK Funding Trust (3) BOSC Agency, Inc. (Oklahoma) BOSC Agency, Inc. (New Mexico) (4) BOSC Agency, Inc. (Texas) (2) CVV Management, Inc. CVV Partnership, an Oklahoma General Partnership Cottonwood Valley Ventures, Inc. Investment Concepts, Inc. Pacesetter Leasing Company Southwest Trust Company SUBSIDIARIES OF BANK OF TEXAS, N.A. Bank of Texas Trust Company, National Association (1) Tanglewood Financial Services (2) All Subsidiaries listed above were incorporated in Oklahoma, except as noted. (1) Chartered by the United States Government (2) Incorporated in Texas (3) Incorporated in Delaware (4) Incorporated in New Mexico (5) Incorporated in Nevada