Exhibit 15 STATE STREET BOSTON CORPORATION Independent Accountants' Acknowledgment Letter The Stockholders and Board of Directors State Street Boston Corporation We are aware of the incorporation by reference in the Registration Statement (Form S-8 Nos. 33-38672, 33-38671, 33-2882, 2-93157, 2-88641 and 2-68698) and the Post-Effective Amendment No. 2 to Registration Statement (Form S-8 No. 2-68696) pertaining to various stock option and performance share plans, and in the Registration Statement (Form S-3 No. 33-49885) pertaining to the registration of debt securities of State Street Boston Corporation, of our report dated October 17, 1994 relating to the unaudited consolidated interim financial statements of State Street Boston Corporation which are included in its Form 10-Q for the quarter ended September 30, 1994. Pursuant to Rule 436(c) of the Securities Act of 1933, our report is not a part of the registration statement prepared or certified by accountants within the meaning of Section 7 or 11 of the Securities Act of 1933. ERNST & YOUNG LLP Boston, Massachusetts November 9, 1994