13D Filing: Engaged Capital and Magnachip Semiconductor Corp (MX)

UNITED STATES

SECURITIES AND EXCHANGE
COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED
IN STATEMENTS FILED PURSUANT

TO § 240.13d-1(a)
AND AMENDMENTS THERETO FILED PURSUANT TO

§ 240.13d-2(a)

(Amendment No. 9)¹

MagnaChip Semiconductor Corporation

(Name
of Issuer)

Common Stock, $0.01 par value per share

(Title of Class of Securities)

55933J203

(CUSIP Number)

glenn
w. welling

engaged
capital, llc

610 Newport Center Drive, Suite 250

Newport Beach, California 92660

(949) 734-7900

STEVE
WOLOSKY, ESQ.

OLSHAN
FROME WOLOSKY LLP

1325
Avenue of the Americas

New
York, New York 10019

(212)
451-2300

(Name, Address and Telephone Number of Person

Authorized to Receive Notices
and Communications)

November 3, 2017

(Date of Event Which Requires
Filing of This Statement)

If
the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule
13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following
box ¨.

Note:  Schedules
filed in paper format shall include a signed original and five copies of the schedule, including all exhibits.  See
§ 240.13d-7 for other parties to whom copies are to be sent.

1
The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to
the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided
in a prior cover page.

The information required
on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities
Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject
to all other provisions of the Act (however, see the Notes).

^* Includes 166,334 Shares issuable upon the conversion
of the Convertible Notes (as defined below).

^* Includes 166,334 Shares issuable upon the conversion of the Convertible Notes.

^* Includes 166,334 Shares issuable upon the conversion of the Convertible Notes.

^* Includes 181,707 Shares issuable upon the conversion
of the Convertible Notes.

^* Includes 181,707 Shares issuable upon the conversion
of the Convertible Notes.

^* Includes 181,707 Shares issuable upon the conversion
of the Convertible Notes.

The following constitutes
Amendment No. 9 to the Schedule 13D filed by the undersigned (“Amendment No. 9”). This Amendment No. 9 amends the Schedule
13D as specifically set forth herein.

Item 3 is hereby amended
and restated to read as follows:

The securities owned
by Engaged Capital Flagship Master and held in the Engaged Capital Account were purchased with working capital (which may, at any
given time, include margin loans made by brokerage firms in the ordinary course of business) in open market purchases, except as
has been otherwise noted. The aggregate purchase price of the 1,363,117 Shares directly beneficially owned by Engaged Capital Flagship
Master is approximately $7,598,263, including brokerage commissions. The aggregate purchase price of the 118,108 Shares held in
the Engaged Capital Account is approximately $650,881, including brokerage commissions.

Engaged Capital Flagship
Master purchased $1,373,094 principal amount of the Issuer’s 5.00% Exchangeable Senior Notes due 2021 (the “Convertible
Notes”) that are convertible to 166,334 Shares. The Engaged Capital Account purchased $126,906 principal amount of the Convertible
Notes that are convertible to 15,373 Shares. The Convertible Notes have an exercise price of approximately $8.2550 per Share, subject
to adjustment in certain circumstances, and will expire on March 1, 2021.

Item 5 is hereby amended
and restated to read as follows:

(a)       The
aggregate percentage of Shares reported owned by each person named herein is based upon 34,036,978 Shares outstanding as of July
31, 2017, which is the total number of Shares outstanding as reported in the Issuer’s quarterly report on Form 10-Q filed
with the Securities and Exchange Commission on August 4, 2017.

As of the close of
business on November 6, 2017, Engaged Capital Flagship Master beneficially owned 1,529,451 Shares, including 166,334 Shares issuable
upon the conversion of the Convertible Notes, constituting approximately 4.5% of the Shares outstanding. Each of Engaged Capital
Fund and Engaged Capital Offshore, as feeder funds of Engaged Capital Flagship Master, may be deemed to beneficially own the 1,529,451
Shares beneficially owned directly by Engaged Capital Flagship Master, constituting approximately 4.5% of the Shares outstanding.

As of the close of
business on November 6, 2017, 133,481 Shares were held in the Engaged Capital Account, including 15,373 Shares issuable upon the
conversion of the Convertible Notes, constituting less than 1% of the Shares outstanding.

Engaged Capital Flagship
Master and the Engaged Capital Account own Convertible Notes convertible into 166,334 Shares and 15,373 Shares, respectively. The
Convertible Notes are subject to a blocker provision that precludes the holders from converting the Convertible Notes to the extent
that the holder and its affiliates would beneficially own (as determined in accordance with Section 13(d) of the Securities Exchange
Act of 1934, as amended (the “Exchange Act”)) in excess of 9.99% of the Shares outstanding immediately after giving
effect to such conversion. The Reporting Persons’ aggregate beneficial ownership is under 9.99% and accordingly includes
all 181,707 Shares underlying the Convertible Notes.

Engaged Capital, as
the general partner and investment adviser of Engaged Capital Flagship Master and the investment adviser of the Engaged Capital
Account, may be deemed to beneficially own the 1,662,932 Shares directly beneficially owned in the aggregate by Engaged Capital
Flagship Master and held in the Engaged Capital Account, constituting approximately 4.9% of the Shares outstanding. Engaged Holdings,
as the managing member of Engaged Capital, may be deemed to beneficially own the 1,662,932 Shares directly beneficially owned in
the aggregate by Engaged Capital Flagship Master and held in the Engaged Capital Account, constituting approximately 4.9% of the
Shares outstanding. Mr. Welling, as the Founder and CIO of Engaged Capital and sole member of Engaged Holdings, may be deemed to
beneficially own the 1,662,932 Shares directly beneficially owned in the aggregate by Engaged Capital Flagship Master and held
in the Engaged Capital Account, constituting approximately 4.9% of the Shares outstanding.

Each of the Reporting
Persons, as a member of a “group” with the other Reporting Persons for purposes of the Exchange Act, may be deemed
to beneficially own the securities of the Issuer beneficially owned by the other Reporting Persons. The filing of this Schedule
13D shall not be deemed an admission that the Reporting Persons are, for purposes of Section 13(d) of the Exchange Act, the beneficial
owners of any securities of the Issuer he or it does not directly own. Each of the Reporting Persons specifically disclaims beneficial
ownership of the securities reported herein that he or it does not directly own.

(b)       By
virtue of their respective positions with Engaged Capital Flagship Master, each of Engaged Capital Fund, Engaged Capital Offshore,
Engaged Capital, Engaged Holdings and Mr. Welling may be deemed to have sole power to vote and dispose of the Shares reported owned
by Engaged Capital Flagship Master.

By virtue of their
respective positions with the Engaged Capital Account, each of Engaged Capital, Engaged Holdings and Mr. Welling may be deemed
to have sole power to vote and dispose of the Shares held in the Engaged Capital Account.

(c)       Except
as set forth in this paragraph, there were no transactions in the securities of the Issuer by the Reporting Persons during the
past 60 days. On November 2, 2017, Engaged Capital Flagship Master and the Engaged Capital Account sold, at $47.2783 above the
stated price, $1,292,500 principal amount and $207,500 principal amount, respectively, of the Convertible Notes, which are convertible
to 156,571 Shares and 25,136 Shares, respectively. On November 3, 2017, Engaged Capital Flagship Master and the Engaged Capital
Account sold, at $44.1702 above the stated price, $1,830,694 principal amount and $169,306 principal amount, respectively, of the
Convertible Notes, which are convertible to 221,767 Shares and 20,509 Shares, respectively. The Convertible Notes have an exercise
price of approximately $8.2550 per Share, subject to adjustment in certain circumstances, and will expire on March 1, 2021.

(d)       No
person other than the Reporting Persons is known to have the right to receive, or the power to direct the receipt of dividends
from, or proceeds from the sale of, the Shares.

(e)       As
of November 3, 2017, the Reporting Persons ceased to be the beneficial owners of more than 5% of the Shares of the Issuer.

SIGNATURES

After reasonable inquiry
and to the best of his knowledge and belief, the undersigned certifies that the information set forth in this statement is true,
complete and correct.

Dated: November 7, 2017