UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 13F FORM 13F COVER PAGE REPORT FOR THE CALENDAR YEAR OR QUARTER ENDED: 3/31/12 CHECK HERE IF AMENDMENT ( ); AMENDMENT NUMBER: THIS AMENDMENT (CHECK ONLY ONE.): ( ) RESTATEMENT. ( ) ADDS NEW HOLDINGS ENTRIES. INSTITUTIONAL INVESTMENT MANAGER FILING THIS REPORT: NAME: COMMERCE BANCSHARES, INC. ADDRESS: 1000 WALNUT, P.O. BOX 13686 KANSAS CITY, MO 64199 FORM 13F FILE NUMBER: 28-642 THE INSTITUTIONAL INVESTMENT MANAGER FILING THIS REPORT AND THE PERSON BY WHOM IT IS SIGNED HEREBY REPRESENT THAT THE PERSON SIGNING THE REPORT IS AUTHORIZED TO SUBMIT IT, THAT ALL INFORMATION CONTAINED HEREIN IS TRUE, CORRECT AND COMPLETE, AND THAT IT IS UNDERSTOOD THAT ALL REQUIRED ITEMS, STATEMENTS SCHEDULES, LISTS, AND TABLES, ARE CONSIDERED INTEGRAL PARTS OF THIS FORM. PERSON SIGNING THIS REPORT ON BEHALF OF REPORTING MANAGER: NAME: JEFFERY D. ABERDEEN TITLE: CONTROLLER PHONE: 816-234-2081 SIGNATURE, PLACE, AND DATE OF SIGNING: JEFFERY D. ABERDEEN KANSAS CITY, MO 4/27/12 REPORT TYPE (CHECK ONLY ONE.): ( ) 13F HOLDINGS REPORT (X) 13F NOTICE ( ) 13F COMBINATION REPORT LIST OF OTHER MANAGERS REPORTING FOR THIS MANAGER: 28-05260 COMMERCE BANK, N.A. (MISSOURI) I AM SIGNING THIS REPORT AS REQUIRED BY THE SECURITIES EXCHANGE ACT OF 1934.