<PAGE>
Prospectus Supplement No. 4 Filed Pursuant to Rule 424(b)(3)
(To Prospectus dated December 5, 1997) SEC File No. 333-38827
$200,000,000
TOWER AUTOMOTIVE, INC.
5% CONVERTIBLE SUBORDINATED NOTES DUE 2004
All capitalized terms used but not defined herein shall have the meanings
ascribed to them in the Prospectus, dated December 5, 1997, forming a part of
the Registration Statement on Form S-3 (Registration No. 333-38827), as
supplemented by Prospectus Supplement No. 1, dated January 9, 1998, Prospectus
Supplement No. 2, dated March 12, 1998 and Prospectus Supplement No. 3, dated
June 16, 1998 (together, the "Prospectus"). Any cross references in this
Prospectus Supplement refer to portions of the Prospectus.
The purpose of this Prospectus Supplement is to amend and supplement the
information set forth in the Prospectus regarding the Selling Securityholders.
In addition to the Selling Securityholders named in the Prospectus, the
following table sets forth the name of each additional Selling Securityholder
and relationship, if any, with the Company and (i) the amount of Notes owned by
each additional Selling Securityholder as of the dates indicated, (ii) the
maximum amount of Notes which may be offered for the account of such Selling
Securityholder as of the dates indicated, (iii) the number of shares of Common
Stock owned by each additional Selling Securityholder and (iv) the maximum
amount of Common Stock which may be offered for the account of such Selling
Securityholder under the Prospectus. Any information regarding a Selling
Securityholder contained herein shall be deemed to amend and supersede any
information regarding such Selling Securityholder contained in the Prospectus.
<TABLE>
<CAPTION>
NOTES BENEFICIALLY OWNED COMMON STOCK BENEFICIALLY OWNED
PRIOR TO THE OFFERING PRIOR TO THE OFFERING (1) (2)
-------------------------------------- ---------------------------------
Principal No. of
Aggregate Amount of Shares
Principal % of Notes Offered No. of % of Offered
Name of Selling Securityholder Amount Class Hereby Shares Class Hereby
------------------------------ ----------- ----- ------------- -------- ----- --------
<S> <C> <C> <C> <C> <C> <C>
California Public Employees Retirement
System (3) ................................. $ 1,500,000 * $ 1,500,000 82,759 * 57,959
Credit Suisse First Boston Corporation (4)..... 3,000,000 1.5 3,000,000 115,919 * 115,919
Lehman Brothers (5) ........................... 465,000 * 465,000 17,967 * 17,967
MFS Series Trust I - MFS Equity
Income Fund (6) ............................ 10,000 * 10,000 386 * 386
McMahan Securities Co., L.P. (7) .............. 1,500,000 * 1,500,000 57,959 * 57,959
Sage Capital (7) .............................. 1,900,000 * 1,900,000 73,415 * 73,415
</TABLE>
- ---------------------
*Less than one percent.
<PAGE>
(1) Reflects the shares of Common Stock into which the Notes held by such
Selling Securityholder are convertible at the conversion rate of 38.6399
shares per $1,000 principal amount (the "Adjusted Conversion Rate"). The
Conversion Price and the number of shares of Common Stock issuable upon
conversion of the Notes are subject to adjustment under certain
circumstances. See "Description of Notes--Conversion Rights."
Accordingly, the number of shares of Common Stock issuable upon
conversion of the Notes may increase or decrease from time to time. The
Conversion Rate was recently adjusted to reflect a two-for-one stock
split.
(2) Assumes conversion into Common Stock of the full amount of Notes held by
the Selling Securityholder at the Adjusted Conversion Rate and the
offering of such shares by such Selling Securityholder pursuant to this
Prospectus. The Conversion Price and the number of shares of Common
Stock issuable upon conversion of the Notes is subject to adjustment
under certain circumstances. See "Description of Notes--Conversion
Rights." Accordingly, the number of shares of Common Stock issuable upon
conversion of the Notes may increase or decrease from time to time.
Fractional shares will not be issued upon conversion of the Notes;
rather, cash will be paid in lieu of fractional shares, if any.
(3) As of July 31, 1998.
(4) As of July 20, 1998.
(5) As of July 10, 1998.
(6) As of July 27, 1998.
(7) As of July 17, 1998.
Because the Selling Securityholders may, pursuant to this Prospectus, offer
all or some portion of the Notes and Common Stock they presently hold or, with
respect to Common Stock, have the right to acquire upon conversion of such
Notes, no estimate can be given as to the amount of the Notes and Common Stock
that will be held by the Selling Securityholders upon termination of any such
sales. In addition, the Selling Securityholders identified above may have sold,
transferred or otherwise disposed of all or a portion of their Notes and Common
Stock since the date on which they provided the information regarding their
Notes and Common Stock, in transactions exempt from the registration
requirements of the Securities Act. See "Plan of Distribution."
The Company may from time to time, in accordance with the Registration
Rights Agreement, include additional Selling Securityholders in future
supplements to the Prospectus.
The date of this Prospectus Supplement is August 10, 1998.
S-2
