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. 8)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

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)

July 13, 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 544,674 Shares issuable upon the conversion
of the Convertible Notes.

^* Includes 544,674 Shares issuable upon the conversion
of the Convertible Notes.

^* Includes 544,674 Shares issuable upon the conversion
of the Convertible Notes.

^* Includes 605,693 Shares issuable upon the conversion
of the Convertible Notes.

^* Includes 605,693 Shares issuable upon the conversion
of the Convertible Notes.

^* Includes 605,693 Shares issuable upon the conversion
of the Convertible Notes.

The following constitutes
Amendment No. 8 to the Schedule 13D filed by the undersigned (“Amendment No. 8”). This Amendment No. 8 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 1,381,734 Shares directly beneficially owned by Engaged Capital Flagship
Master is approximately $7,703,652, including brokerage commissions. The aggregate purchase price of the 119,578 Shares held in
the Engaged Capital Account is approximately $658,982, including brokerage commissions.

Engaged Capital Flagship
Master purchased $4,496,288 principal amount of the Issuer’s 5.00% Exchangeable Senior Notes due 2021 (the “Convertible
Notes”) that are convertible to 544,674 Shares. The Engaged Capital Account purchased $503,712 principal amount of the Convertible
Notes that are convertible to 61,019 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.

Items 5(a) –
(c) are hereby amended and restated to read as follows:

(a)       The
aggregate percentage of Shares reported owned by each person named herein is based upon 33,956,021 Shares outstanding as of May
25, 2017, which is the total number of Shares outstanding as reported in the Issuer’s definitive proxy statement filed with
the Securities and Exchange Commission on May 31, 2017.

As of the close of
business on July 17, 2017, Engaged Capital Flagship Master beneficially owned 1,926,408 Shares, including 544,674 Shares issuable
upon the conversion of the Convertible Notes, constituting approximately 5.6% 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 1,926,408
Shares beneficially owned directly by Engaged Capital Flagship Master, constituting approximately 5.6% of the Shares outstanding.

As of the close of
business on July 17, 2017, 180,597 Shares were held in the Engaged Capital Account, including 61,019 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 544,674 Shares and 61,019 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 605,693 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 2,107,005 Shares directly beneficially owned in the aggregate by Engaged Capital
Flagship Master and held in the Engaged Capital Account, constituting approximately 6.1% of the Shares outstanding. Engaged Holdings,
as the managing member of Engaged Capital, may be deemed to beneficially own the 2,107,005 Shares directly beneficially owned
in the aggregate by Engaged Capital Flagship Master and held in the Engaged Capital Account, constituting approximately 6.1% 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 2,107,005 Shares directly beneficially owned in the aggregate by Engaged Capital Flagship Master and held
in the Engaged Capital Account, constituting approximately 6.1% 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)       Schedule
A annexed hereto lists all transactions in securities of the Issuer by the Reporting Persons since the filing of Amendment No.
7 to the Schedule 13D. All of such transactions were effected in the open market.

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: July 17, 2017

SCHEDULE A

Transactions in Securities of
the Issuer Since the Filing of Amendment No. 7 to the Schedule 13D

Engaged
Capital Flagship Master Fund, LP 

Engaged
Capital, LLC

(Through the Engaged Capital Account)