EX-15: LETTER OF AWARENESS
Published on November 7, 2007
    Exhibit 15
    November 7,
    2007
    
    Merrill Lynch & Co., Inc.
    
    4 World Financial Center
    
    New York, NY 10080
    
    We have reviewed, in accordance with the standards of the Public
    Company Accounting Oversight Board (United States), the
    unaudited condensed consolidated interim financial information
    of Merrill Lynch & Co., Inc. and subsidiaries
    (Merrill Lynch) as of September 28, 2007 and
    for the three-month and nine-month periods ended
    September 28, 2007 and September 29, 2006, as
    indicated in our report dated November 7, 2007 (which report
    includes an explanatory paragraph regarding the adoption of
    Statement of Financial Accounting Standards No. 157,
    Fair Value Measurement, Statement of
    Financial Accounting Standards No. 159, The Fair
    Value Option for Financial Assets and Financial
    Liabilities  Including an amendment of FASB Statement
    No. 115, and FASB Interpretation No. 48,
    Accounting for Uncertainty in Income Taxes, an
    Interpretation of FASB Statement No. 109);
    because we did not perform an audit, we expressed no opinion on
    that information.
    We are aware that our report referred to above, which is
    included in your Quarterly Report on
    Form 10-Q
    for the quarter ended September 28, 2007, is incorporated
    by reference in the following Registration Statements, as
    amended:
    Filed on
    Form S-8
    Registration Statement
    No. 33-41942
    (1986 Employee Stock Purchase Plan)
    Registration Statement
    No. 33-17908
    (Incentive Equity Purchase Plan)
    Registration Statement
    No. 33-33336
    (Long-Term Incentive Compensation Plan)
    Registration Statement
    No. 33-51831
    (Long-Term Incentive Compensation Plan)
    Registration Statement
    No. 33-51829
    (401(k) Savings and Investment Plan)
    Registration Statement
    No. 33-54154
    (Non-Employee Directors Equity Plan)
    Registration Statement
    No. 33-54572
    (401(k) Savings and Investment Plan (Puerto Rico))
    Registration Statement
    No. 33-56427
    (Amended and Restated 1994 Deferred Compensation Plan for a
    Select Group of Eligible Employees)
    Registration Statement
    No. 33-55155
    (1995 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 33-60989
    (1996 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-00863
    (401(k) Savings & Investment Plan)
    Registration Statement
    No. 333-09779
    (1997 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-13367
    (Restricted Stock Plan for Former Employees of Hotchkis and
    Wiley)
    
    125
    Registration Statement
    No. 333-15009
    (1997 KECALP Deferred Compensation Plan for a Select Group of
    Eligible Employees)
    Registration Statement
    No. 333-17099
    (Deferred Unit and Stock Unit Plan for Non-Employee Directors)
    Registration Statement
    No. 333-18915
    (Long-Term Incentive Compensation Plan for Managers and
    Producers)
    Registration Statement
    No. 333-32209
    (1998 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-33125
    (Employee Stock Purchase Plan for Employees of Merrill Lynch
    Partnerships)
    Registration Statement
    No. 333-41425
    (401(k) Savings & Investment Plan)
    Registration Statement
    No. 333-56291
    (Long-Term Incentive Compensation Plan for Managers and
    Producers)
    Registration Statement
    No. 333-60211
    (1999 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-62311
    (Replacement Options; Midland Walwyn Inc.)
    Registration Statement
    No. 333-85421
    (401(k) Savings and Investment Plan)
    Registration Statement
    No. 333-85423
    (2000 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-92663
    (Long-Term Incentive Compensation Plan for Managers and
    Producers)
    Registration Statement
    No. 333-44912
    (2001 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-64676
    (1986 Employee Stock Purchase Plan)
    Registration Statement
    No. 333-64674
    (Long-Term Incentive Compensation Plan for Managers and
    Producers)
    Registration Statement
    No. 333-68330
    (2002 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-99105
    (2003 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-108296
    (2004 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-109236
    (Employee Stock Compensation Plan)
    Registration Statement
    No. 333-118615
    (2005 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-125109
    (2006 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-125181
    (Deferred Stock Unit Plan for Non-Employees)
    
    126
    Registration Statement
    No. 333-134065
    (2007 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Registration Statement
    No. 333-142962
    (2008 Deferred Compensation Plan for a Select Group of Eligible
    Employees)
    Filed on
    Form S-3:
    Debt Securities, Warrants, Common Stock, Preferred Securities,
    and/or
    Depository Shares:
    Registration Statement
    No. 33-54218
    Registration Statement
    No. 2-78338
    Registration Statement
    No. 2-89519
    Registration Statement
    No. 2-83477
    Registration Statement
    No. 33-03602
    Registration Statement
    No. 33-17965
    Registration Statement
    No. 33-27512
    Registration Statement
    No. 33-33335
    Registration Statement
    No. 33-35456
    Registration Statement
    No. 33-42041
    Registration Statement
    No. 33-45327
    Registration Statement
    No. 33-45777
    Registration Statement
    No. 33-49947
    Registration Statement
    No. 33-51489
    Registration Statement
    No. 33-52647
    Registration Statement
    No. 33-55363
    Registration Statement
    No. 33-60413
    Registration Statement
    No. 33-61559
    Registration Statement
    No. 33-65135
    Registration Statement
    No. 333-13649
    Registration Statement
    No. 333-16603
    Registration Statement
    No. 333-20137
    Registration Statement
    No. 333-25255
    Registration Statement
    No. 333-28537
    Registration Statement
    No. 333-42859
    Registration Statement
    No. 333-44173
    Registration Statement
    No. 333-59997
    
    127
    Registration Statement
    No. 333-68747
    Registration Statement
    No. 333-38792
    Registration Statement
    No. 333-52822
    Registration Statement
    No. 333-83374
    Registration Statement
    No. 333-97937
    Registration Statement
    No. 333-105098
    Registration Statement
    No. 333-109802
    Registration Statement
    No. 333-122639
    Registration Statement
    No. 333-132911
    Medium Term Notes:
    Registration Statement
    No. 2-96315
    Registration Statement
    No. 33-03079
    Registration Statement
    No. 33-05125
    Registration Statement
    No. 33-09910
    Registration Statement
    No. 33-16165
    Registration Statement
    No. 33-19820
    Registration Statement
    No. 33-23605
    Registration Statement
    No. 33-27549
    Registration Statement
    No. 33-38879
    Other Securities:
    Registration Statement
    No. 333-02275
    (Long-Term Incentive Compensation Plan)
    Registration Statement
    No. 333-24889
    (Long-Term Incentive Compensation Plan, and Long-Term Incentive
    Compensation Plan for Managers and Producers)
    Registration Statement
    No. 333-36651
    (Hotchkis and Wiley Resale)
    Registration Statement
    No. 333-59263
    (Exchangeable Shares of Merrill Lynch & Co., Canada
    Ltd. re: Midland Walwyn Inc.)
    Registration Statement
    No. 333-67903
    (Howard Johnson & Company Resale)
    Registration Statement
    No. 333-45880
    (Herzog, Heine, Geduld, Inc. Resale)
    Registration Statement
    No. 333-142690
    (First Republic Merger)
    Registration Statement
    No. 333-146204
    (First Republic Bank Amended and Restated Employee Stock
    Purchase Plan)
    We are also aware that the aforementioned report, pursuant to
    Rule 436(c) under the Securities Act of 1933, is not
    considered a part of a Registration Statement prepared or
    certified by an accountant or a report prepared or certified by
    an accountant within the meaning of Sections 7 and 11 of
    that Act.
/s/  Deloitte &
    Touche LLP
    New York, New York
    
    128