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                                                                    EXHIBIT 99.4


                                 CONSENT OF MERRILL LYNCH


We hereby consent to the inclusion of our opinion letter to the Board of
Directors of M&T Bank Corporation ("M&T"), to be dated the date of the Proxy
Statement/Prospectus which forms a part of the Registration Statement on Form
S-4 relating to the proposed merger of Keystone Financial, Inc. with M&T, as
Appendix D to the Proxy Statement/Prospectus, and to the references to such
opinion in such Proxy Statement/Prospectus under the captions "SUMMARY - For M&T
Shareholders: The Transaction is Fair to M&T According to M&T's Investment
Advisor," and "THE MERGER - Background and Reasons for the Merger;
Recommendations of the Board of Directors;" and "Opinion of M&T's Financial
Advisor." In giving such consent, we do not admit that we come within the
category of persons whose consent is required under Section 7 of the Securities
Act of 1933, as amended, or the rules and regulations of the Securities and
Exchange Commission thereunder, nor do we thereby admit that we are experts with
respect to any part of such Registration Statement within the meaning of the
term "experts" as used in the Securities Act of 1933, as amended, or the rules
and regulations of the Securities and Exchange Commission thereunder.




                                     /s/ MERRILL LYNCH, PIERCE, FENNER & SMITH
                                                 INCORPORATED

                                     MERRILL LYNCH, PIERCE, FENNER & SMITH
                                                 INCORPORATED






June 28, 2000