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                                                                       EXHIBIT 6
 
Goldman, Sachs & Co. / 85 Broad Street / New York, New York 10004
Tel: 212-902-1000 / Fax: 212-357-4449
 
                                                            [GOLDMAN SACHS LOGO]
 
PERSONAL AND CONFIDENTIAL
 
March 5, 1997
 
Board of Directors
Great Western Financial Corporation
9200 Oakdale Avenue
Chatsworth, California 91311
 
Gentlemen and Madame:
 
     You have requested our opinion as to the fairness to the holders of the
outstanding shares of Common Stock, par value $1.00 per share (the "Shares"), of
Great Western Financial Corporation (the "Company") of the exchange ratio of 0.9
shares of Common Stock, no par value, of Washington Mutual, Inc. ("Washington
Mutual") to be received for each Share (the "Exchange Ratio") pursuant to the
merger (the "Merger") contemplated by the Agreement and Plan of Merger dated as
of March 5, 1997 by and among Washington Mutual, New American Capital, Inc. and
the Company (the "Agreement").
 
     Goldman, Sachs & Co., as part of its investment banking business, is
continually engaged in the valuation of businesses and their securities in
connection with mergers and acquisitions, negotiated underwritings, competitive
biddings, secondary distributions of listed and unlisted securities, private
placements and valuations for estate, corporate and other purposes. We are
familiar with the Company having provided certain investment banking services to
the Company from time to time, including having acted as managing underwriter of
its $300 million issue of Capital Securities in January 1997, and having acted
as its financial advisor in connection with, and participated in certain of the
negotiations leading to, the Agreement. We also have provided certain investment
banking services to Washington Mutual from time to time and may provide
investment banking services to Washington Mutual in the future. In addition,
Goldman, Sachs & Co. is a full service securities firm and in the course of its
trading activities it may from time to time effect transactions, for its own
account or the account of customers, and hold positions in securities or options
on securities of the Company and Washington Mutual.
 
     In connection with this opinion, we have reviewed, among other things, the
Agreement; Annual Reports to Stockholders and Annual Reports on Form 10-K of the
Company for the five years ended December 31, 1995; Annual Reports to
Stockholders and Annual Reports on Form 10-K of Washington Mutual for the two
years ended December 31, 1995; Annual Reports to Stockholders and Annual Reports
to the FDIC on Form F-2 of Washington Mutual Savings Bank, predecessor to
Washington Mutual, for the three years ended December 31, 1993; certain interim
reports to stockholders and Quarterly Reports on Form 10-Q of the Company and
Washington Mutual; certain other communications from the Company and Washington
Mutual to their respective stockholders; and certain internal financial analyses
and forecasts for the Company and Washington Mutual prepared by their respective
managements, including analyses and forecasts of certain cost savings, operating
efficiencies, revenue effects and financial synergies (collectively, the
"Synergies"). We also have held discussions with members of the senior
managements of the Company and Washington Mutual regarding the past and current
business operations, financial condition and future prospects of their
respective companies and each senior managements' assessment of the future
prospects of the combined company. In addition, we have reviewed the reported
price and trading activity for the Shares and Washington Mutual Common Stock,
compared certain financial and stock market information for the Company and
Washington Mutual with similar information for certain other companies the
securities of which are publicly traded,
 
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reviewed the financial terms of certain recent business combinations in the
savings and loan industry specifically and in other industries generally and
performed such other studies and analyses as we considered appropriate.
 
     We have relied without independent verification upon the accuracy and
completeness of all of the financial and other information reviewed by us for
purposes of this opinion. In that regard, we have assumed, with your consent,
that the financial forecasts, including, without limitation, the Synergies and
projections regarding under-performing and non-performing assets and net
charge-offs have been reasonably prepared on a basis reflecting the best
currently available judgments and estimates of the Company and Washington Mutual
and that such forecasts will be realized in the amounts and at the times
contemplated thereby. We are not experts in the evaluation of loan and lease
portfolios for purposes of assessing the adequacy of the allowances for losses
with respect thereto and have assumed, with your consent, that such allowances
for each of the Company and Washington Mutual are in the aggregate adequate to
cover all such losses. In addition, we have not reviewed individual credit files
nor have we made an independent evaluation or appraisal of the assets and
liabilities of the Company or Washington Mutual or any of their subsidiaries and
we have not been furnished with any such evaluation or appraisal. We also have
assumed, with your consent, that the Merger will be accounted for as a pooling
of interests under generally accepted accounting principles. Our advisory
services and the opinion expressed herein are provided for the information and
assistance of the Board of Directors of the Company in connection with its
consideration of the transaction contemplated by the Agreement.
 
     Based upon and subject to the foregoing and based upon such other matters
as we consider relevant, it is our opinion that as of the date hereof the
Exchange Ratio pursuant to the Agreement is fair to the holders of Shares.
 
Very truly yours,
 
/s/ GOLDMAN, SACHS & CO.
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GOLDMAN, SACHS & CO.
 
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