<PAGE>
SUPPLEMENT DATED OCTOBER 26, 1998
TO SUPPLEMENTS DATED OCTOBER 13, AUGUST 17, JULY 16,
MAY 22, MAY 4, APRIL 3, APRIL 1, MARCH 23,
FEBRUARY 25, AND JANUARY 21, 1998, AND DECEMBER 19, 1997,
TO PROSPECTUS DATED NOVEMBER 26, 1997
COSTCO COMPANIES, INC.
The following table sets forth certain information as of October 26, 1998
concerning additional securities that were acquired by Nomura International PLC
since it was last named as a Selling Securityholder in the Prospectus or the
Prospectus Supplements.
<TABLE>
<CAPTION>
FACE AMOUNT OF SHARES OF COMMON
NOTES OWNED PRIOR TO STOCK OWNED PRIOR TO
SELLING SECURITYHOLDER OFFERING ($) OFFERING(1)
---------------------- ------------ -----------
<S> <C> <C>
Nomura International PLC $31,000,000(2) 351,989(2)
</TABLE>
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(1) Includes the Shares into which the Notes are convertible.
(2) Includes securities previously registered, without adjustment for
securities that may have been sold.
The date of this Prospectus Supplement is October 26, 1998.
