UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2003) TRUSTMARK CORPORATION (Name of Issuer) COMMON STOCK (Title of Class of Securities) 898402102 (CUSIP Number) December 31, 2003 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [X] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). CUSIP No. 898402102 1. NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Trustmark National Bank, as trustee 64-0180810 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [ ] 3. SEC USE ONLY 4. CITIZENSHIP OR PLACE OF ORGANIZATION Organized under the laws of the United States NUMBER OF 5. SOLE VOTING POWER 1,724,423 SHARES BENEFICIALLY 6. SHARED VOTING POWER 159,673 OWNED BY EACH 7. SOLE DISPOSITIVE POWER 1,724,423 REPORTING PERSON 8. SHARED DISPOSITIVE POWER 159,673 WITH 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,884,096 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES [ ] 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 3.2% 12. TYPE OF REPORTING PERSON BK CUSIP No. 898402102 Item 1(a) Name of Issuer: Trustmark Corporation Item 1(b) Address of Issuer's Principal Executive Offices: 248 East Capitol Street Jackson, Mississippi 39201 Item 2(a) Name of Person Filing: Trustmark National Bank, as trustee Item 2(b) Address of Principal Business Office: 248 East Capitol Street Jackson, Mississippi 39201 Item 2(c) Citizenship: Organized under the laws of the United States Item 2(d) Title of Class of Securities: Common Stock Item 2(e) CUSIP Number: 898402102 Item 3 Type of Person: (b) Bank [x] Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c). Item 4 Ownership: (a) Amount beneficially owned: 1,884,096 (b) Percent of class: 3.2% (c) Number of shares as to which the person has: (i) Sole power to vote or to direct the vote 1,724,423 (ii) Shared power to vote or to direct the vote 159,673 (iii) Sole power to dispose or to direct the disposition of 1,724,423 (iv) Shared power to dispose or to direct the disposition of 159,673 Item 5 Ownership of Five Percent or Less of a Class: N/A CUSIP No. 898402102 Item 6 Ownership of More than Five Percent on Behalf of Another Person: The shares referred to in this Schedule 13G are held by Trustmark National Bank as trustee of various trust accounts. Trustmark National Bank does not have the right to receive the dividends from these shares or to receive proceeds from the sale of these shares. Trustmark National Bank is not aware of any individual trust or beneficiary or related group of trusts or beneficiaries who own more than 5% of this stock. Item 7 Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company: N/A Item 8 Identification and Classification of Members of the Group: N/A Item 9 Notice of Dissolution of Group: N/A Item 10 Certification: By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. Signature: After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Date: February 13, 2004 Signature: /s/ Louis E. Greer ------------------ Name and Title: Louis E. Greer Senior Vice President And Chief Accounting Officer