EXHIBIT 23.3 CONSENT OF DONALDSON, LUFKIN & JENRETTE SECURITIES CORPORATION We hereby consent to (i) the inclusion of our opinion letter, dated as of March 18, 1999, to the Board of Directors of Pinnacle Banc Group, Inc. (the "Company") as Appendix C to the Proxy Statement/Prospectus of the Company relating to the merger among the Company, Old Kent Financial Corporation ("Old Kent") and OKFC Merger Corporation, a wholly owned subsidiary of Old Kent, and (ii) all references to Donaldson, Lufkin & Jenrette Securities Corporation in the sections captioned "Summary Information -- Pinnacle's Financial Advisor's Opinion that the Consideration is Fair," "The Merger and Merger Agreement -- Background of the Merger," "The Merger and Merger Agreement -- Opinion of Pinnacle's Financial Advisor," and "The Merger and Merger Agreement -- Exclusive Commitment to Old Kent" of the Prospectus and Proxy Statement of Pinnacle Banc Group, Inc. which forms a part of the Registration Statement on Form S-4. In giving such consent, we do not admit that we come within the category of persons whose consent is required under, and we do not admit that we are "experts" for purposes of, the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder. DONALDSON, LUFKIN & JENRETTE SECURITIES CORPORATION Chicago, Illinois By: /S/DAVID D. OLSON May 18, 1999 David D. Olson Managing Director