EXHIBIT 23.5 MCCONNELL, BUDD & DOWNES, INC. 365 SOUTH STREET MORRISTOWN, NEW JERSEY 07960 201-538-7800 FAX: 201-538-0522 CONSENT OF FINANCIAL ADVISOR We hereby consent to the inclusion of the Opinion of McConnell, Budd & Downes, Inc. on the Form S-4 Registration Statement of SIS Bancorp, Inc. ("SIS") to be filed with the Securities and Exchange Commission in connection with the proposed merger of SIS Interim Bank, a subsidiary of SIS, with Glastonbury Bank & Trust Company ("GBT"), and to the references to our firm as Financial Advisor to GBT in the text of the related Joint Proxy Statement-Prospectus. In giving such consent, we do not thereby admit that we come within the category of persons whose consent is required under Section 7 of the Securities Act of 1933 or the rules and regulations of the Securities and Exchange Commission. McConnell, Budd & Downes, Inc. October 24, 1997 By: /s/David A. Budd --------------------------------- David A. Budd Managing Director