1
 
                                            FILED PURSUANT TO RULE NO. 424(B)(3)
                                            REG. NO. 333-47261
 
PROSPECTUS SUPPLEMENT NO. 12
(TO THE PROSPECTUS DATED MAY 14, 1998)
 
                        10,000,000 PREFERRED SECURITIES
 
NEWELL LOGO                 NEWELL FINANCIAL TRUST I
            5 1/4% CONVERTIBLE QUARTERLY INCOME PREFERRED SECURITIES
                      (CONVERTIBLE QUIPS(SM)* SECURITIES)
              (LIQUIDATION PREFERENCE $50 PER PREFERRED SECURITY)
   GUARANTEED TO THE EXTENT SET FORTH IN THE PROSPECTUS REFERENCED HEREIN BY,
                     AND CONVERTIBLE INTO COMMON STOCK OF,
 
                                   NEWELL CO.
                            ------------------------
 
     This Prospectus Supplement No. 12 supplements and amends the Prospectus
dated May 14, 1998, as it has previously been supplemented by Prospectus
Supplements dated June 5, 1998, June 25, 1998, July 13, 1998, July 23, 1998,
August 12, 1998, September 8, 1998, October 8, 1998, November 6, 1998, December
8, 1998, January 11, 1999 and February 5, 1999. The initial May 14, 1998
Prospectus and all twelve Prospectus Supplements constitute the current
Prospectus.
 
     The Prospectus relates to: (1) the 5 1/4% Convertible Quarterly Income
Preferred Securities (The Preferred Securities represent preferred undivided
beneficial ownership interests in the assets of Newell Financial Trust I.); and
(2) the shares of common stock of Newell Co. that may be issued on conversion of
the Preferred Securities.
 
     The Selling Holder Table in the Prospectus is amended so that the following
line items read as follows:
 


                                                                                      SHARES OF COMPANY
                                                                  NUMBER OF              COMMON STOCK
                                                             PREFERRED SECURITIES       ISSUABLE UPON
                                                                  OWNED AND             CONVERSION OF
                     NAME OF SELLING HOLDER                     OFFERED HEREBY       PREFERRED SECURITIES
                     ----------------------                  --------------------    --------------------
                                                                            
 91.  Merrill Lynch Pierce Fenner & Smith Inc. ............         32,053                  31,620
180.  Salomon Smith Barney Inc. ...........................         18,600                  18,348
Additionally, the following new line item is hereby added to the Selling Holder Table:
216.  Montgomery Mutual Insurance Company..................          5,000                   4,932

 
     SEE "RISK FACTORS" BEGINNING ON PAGE 6 OF THE PROSPECTUS FOR A DISCUSSION
OF CERTAIN FACTORS TO BE CONSIDERED IN CONNECTION WITH AN INVESTMENT IN THE
OFFERED SECURITIES.
                            ------------------------
 
     THE SECURITIES AND EXCHANGE COMMISSION AND STATE SECURITIES REGULATORS HAVE
NOT APPROVED OR DISAPPROVED THESE SECURITIES, OR DETERMINED IF THIS PROSPECTUS
SUPPLEMENT OR THE ACCOMPANYING PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY
REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
 
                            ------------------------
- ---------------------
* QUIPS is a servicemark of Goldman, Sachs & Co.
                            ------------------------
 
           The date of this Prospectus Supplement is March 15, 1999.