<PAGE>
PROSPECTUS SUPPLEMENT NO. 5 Filed Pursuant to Rule 424(b)(3)
(To Prospectus dated November 24, 2000) Registration No. 333-48030
[INTERNATIONAL RECTIFIER LOGO]
INTERNATIONAL RECTIFIER CORPORATION
$550,000,000 4 1/4% CONVERTIBLE SUBORDINATED NOTES DUE 2007
AND
7,438,967 SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION OF THE NOTES
This prospectus supplement relates to the resale by holders of our 4 1/4%
Convertible Subordinated Notes Due 2007 and shares of common stock issuable upon
the conversion of the notes. This prospectus supplement may only be delivered or
used in connection with our prospectus dated November 24, 2000. Our common stock
is listed on The New York Stock Exchange and the Pacific Exchange under the
symbol "IRF."
NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR PASSED UPON THE
ADEQUACY OR ACCURACY OF THIS PROSPECTUS SUPPLEMENT OR THE RELATED PROSPECTUS.
ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
PROSPECTUS SUPPLEMENT DATED JANUARY 9, 2001
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The information appearing in the following table supplements or supersedes
in part the information in the table under the heading "Selling Holders" in our
prospectus and was provided by or on behalf of the selling holders.
<TABLE>
<CAPTION>
COMMON
STOCK
BENEFICIALLY
OWNED AFTER
PRINCIPAL AMOUNT OF COMMON STOCK OFFERING
NOTES BENEFICIALLY BENEFICIALLY OWNED COMMON STOCK -------------------
NAME AND ADDRESS OWNED AND OFFERED BEFORE OFFERING OFFERED(1) AMOUNT %
---------------- ------------------- ------------------ -------------- -------- --------
<S> <C> <C> <C> <C> <C>
Arkansas Teacher Retirement System......... $ 4,249,000 0 57,469 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
Baptist Health of South Florida............ $ 218,000 0 2,949 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
Boston Museum of Fine Art.................. $ 111,000 0 1,501 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
Engineers Joint Pension Fund............... $ 455,000 0 6,154 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
GLG Market Neutral Fund.................... $ 16,000,000 0 216,406 0 *
GLG Partners
6 Broadgate
London, EC2M 7HA
Lumberman's Mutual Casualty Company........ $ 442,000 0 5,978 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
New York Life Insurance And Annuity
Corporation.............................. $ 1,050,000 0 14,202 0 *
51 Madison Avenue
Room 200
New York, NY 10021
New York Life Insurance Company............ $ 6,450,000 0 87,239 0 *
51 Madison Avenue
Room 200
New York, NY 10021
Nicholas Applegate Convertible Fund........ $ 1,348,000 0 18,232 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
Nicholas Applegate Global Holdings Co.
LP....................................... $ 60,000 0 812 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
Physicians Life............................ $ 357,000 0 4,829 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
San Diego City Retirement.................. $ 915,000 0 12,376 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
</TABLE>
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<TABLE>
<CAPTION>
COMMON
STOCK
BENEFICIALLY
OWNED AFTER
PRINCIPAL AMOUNT OF COMMON STOCK OFFERING
NOTES BENEFICIALLY BENEFICIALLY OWNED COMMON STOCK -------------------
NAME AND ADDRESS OWNED AND OFFERED BEFORE OFFERING OFFERED(1) AMOUNT %
---------------- ------------------- ------------------ -------------- -------- --------
<S> <C> <C> <C> <C> <C>
San Diego County Convertible............... $ 1,985,000 0 26,848 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
Screen Actors Guild--Producers Pension and
Health Plans............................. $ 484,000 0 6,546 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
Wake Forest University..................... $ 866,000 0 11,713 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
Writers Guild Industry Health Fund......... $ 283,000 0 3,828 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
Wyoming State Treasurer.................... $ 978,000 0 13,228 0 *
c/o Nicholas-Applegate Capital Management
600 W. Broadway, 29th Floor
San Diego, CA 92101
Any other holder of notes or future
transferee, pledgee, donee or successor
of any holder (2)(3)..................... $ 32,527,000 0 439,941 0 *
</TABLE>
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* Less than 1%.
(1) Assumes conversion of all the holder's notes at a conversion price of
$73.935 per share of common stock and resale of all shares of common stock
offered hereby.
(2) Information about other selling security holders will be set forth in
prospectus supplements, if required.
(3) Assumes that any other holders of notes, or any future transferees,
pledgees, donees or successors of or from any such other holders of notes,
do not beneficially own any common stock other than the common stock
issuable upon conversion of the notes at the initial conversion rate.
Information concerning the selling holders may change from time to time and
any changed information will be set forth in supplements or amendments to the
prospectus if necessary. In addition, the per share conversion price, and
therefore the number of shares of common stock issuable upon conversion of the
notes, is subject to adjustment. As a result, the aggregate principal amount of
the notes and the number of shares of common stock into which the notes are
convertible may increase or decrease.
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