13D Filing: 40 North Management Springs for More Shares of Mattress Firm Holding Corp. (MFRM)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Amendment No. 10)*

Under the Securities Exchange Act of
1934

MATTRESS FIRM HOLDING CORP.

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

57722W106

(CUSIP Number)

David S. Winter

40 North Management LLC

9 West 57th Street, 30th Floor

New York, New York 10019

(212) 821-1600

(Name, Address and Telephone Number of
Person Authorized to Receive Notices and Communications)

COPIES TO:

Robert W. Downes, Esq.

Sullivan & Cromwell LLP

125 Broad Street

New York, New York 10004-2498

(212) 558-4312

February 17,
2016

(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 Rule §240.13d-7 for other parties to whom copies
are to be sent.

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).

Continued on following pages

Page 1 of 13 Pages

AMENDMENT NO. 10 TO SCHEDULE 13D

This Amendment No. 10 supplements the
information set forth in the Schedule 13D filed by 40 North Management LLC, a Delaware limited liability company, 40 North
Investments LP, a Delaware limited partnership, David S. Winter, an American citizen, and David J. Millstone, an American
citizen, with the United States Securities and Exchange Commission (the “SEC”) on August 6, 2013, as
heretofore amended (the “Schedule 13D”), relating to Common Stock, par value $0.01 per share (the
“Shares”), of Mattress Firm Holding Corp., a Delaware corporation (the
“Issuer”).  All capitalized terms contained herein but not otherwise defined shall have the
meanings ascribed to such terms in the Schedule 13D.

The information set forth in response to
each separate Item below shall be deemed to be a response to all Items where such information is relevant.  The Schedule
13D is hereby supplementally amended as follows:

This statement on Schedule 13D is filed on
behalf of 40 North Management LLC, a Delaware limited liability company (“40 North Management”), 40 North Latitude
Master Fund Ltd., a Cayman Islands exempted company incorporated with limited liability (“40 North Latitude Master”),
40 North Latitude SPV-B LLC, a Delaware limited liability company (“40 North Latitude SPV”), 40 North Latitude
Fund LP, a Delaware limited partnership (“40 North Latitude Feeder”), 40 North GP III LLC, a Delaware limited
liability company (“40 North GP III”), David S. Winter, an American citizen, and David J. Millstone, an American
citizen (collectively, the “Reporting Persons”).  This statement relates to Shares held by (i) 40
North Latitude SPV, a wholly owned subsidiary of 40 North Latitude Master, the “master” fund in a “master-feeder”
structure in which 40 North Latitude Feeder is a “feeder” fund, and (ii) 40 North Latitude Master.

The principal business of each of 40 North
Latitude Feeder, 40 North Latitude Master and 40 North Latitude SPV is the making of investments in securities and other assets.  The
principal business of 40 North GP III is to serve as general partner of 40 North Latitude Feeder.  40 North Management
serves as principal investment manager to 40 North Latitude Feeder and 40 North Latitude Master. As such, 40 North Management has
been granted investment discretion over various portfolio investments, including the Shares.  David S. Winter and David
J. Millstone serve as the sole members and principals of each of 40 North Management and 40 North GP III, as the principals of
40 North Latitude SPV and as the sole directors of 40 North Latitude Master.  The principal business address of each
of the Reporting Persons is 9 West 57th Street, 30th Floor, New York, New York 10019.  A joint filing agreement of the
Reporting Persons is attached hereto as Exhibit 1.

During the last five years, none of the
Reporting Persons has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors) or has been
a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding
was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject
to, federal or state securities laws or finding any violation with respect to such laws.

The responses to Items 4, 5 and 6 of this Schedule 13D are incorporated
herein by reference.

2,421,345 of the Shares reported herein were
acquired by 40 North Latitude Feeder on September 1, 2015 via distributions from 40 North Investments LP and 40 North Investment
Partners LP (other investment subsidiaries of 40 North Latitude Feeder), and then contributed by 40 North Latitude Feeder to 40
North Latitude Master.  Of such Shares, 2,293,356 were then contributed by 40 North Latitude Master to 40 North Latitude
SPV. 1,036,302 of the Shares reported herein were purchased by 40 North Latitude Master using its working capital and on margin,
and 172,615 of the Shares reported herein were purchased by 40 North Latitude SPV using its working capital. The total purchase
price for the Shares reported herein was $138,966,727. The Reporting Persons’ margin transactions are with 40 North Latitude
Master’s usual brokers, on such brokers’ usual terms and conditions. All or part
of the Shares owned by the Reporting Persons may from time to time be pledged with one or more banking institutions or brokerage
firms as collateral for loans made by such bank(s) or brokerage firm(s) to the Reporting Persons. Such indebtedness may be refinanced
with other banks or broker-dealers.

(a) – (b) 40 North Latitude SPV
may be deemed to be the beneficial owner of  2,465,971 of the Shares reported herein, which
represent approximately 6.7% of the Issuer’s outstanding Shares.  Each of 40 North Management, 40
North Latitude Master, 40 North Latitude Feeder, 40 North GP III, Mr. Winter and Mr. Millstone may be deemed the beneficial
owner of all of the 3,630,262 Shares reported herein, which represent approximately 9.8% of the Issuer’s
outstanding Shares.  40 North Management may be deemed to have sole power to vote and sole power to dispose of all
of such Shares, whereas the other Reporting Persons having beneficial ownership may be deemed to have shared power to vote
and shared power to dispose of such Shares as they may be deemed to have beneficial ownership of.

The percentages in the immediately foregoing
paragraph are calculated based on a total of 37,034,504 Shares outstanding,
which is equal to the sum of 35,272,268 Shares outstanding as of December 7, 2015 (based on the Issuer’s Quarterly
Report on Form 10-Q filed with the SEC on December 8, 2015) and the issuance of an aggregate of 1,762,236 shares of common stock of the Company on February 5, 2016 (as
reported in the Issuer’s Current Report on Form 8-K filed with the SEC on February 3, 2016).

(c)           Except
as set forth on Exhibit 2 attached hereto, there have been no transactions with respect to the Shares during the sixty days
prior to the date hereof by any of the Reporting Persons.

(d)           In
addition to the Reporting Persons, the limited partners of (or investors in) 40 North Latitude Feeder or its respective subsidiaries
or affiliated entities have the right to participate in the receipt of dividends from, or proceeds from the sale of, the Shares
held for the account of 40 North Latitude Feeder in accordance with their respective limited partnership interests (or investment
percentages).

The responses to Items 3, 4 and 5 of this
Schedule 13D are incorporated herein by reference.

40 North Latitude SPV has entered into swaps
with respect to the Shares. Under the terms of the swaps, (i) 40 North Latitude SPV will be obligated to pay to the counterparty
any negative price performance of the specified notional number of Shares subject to the swaps as of the expiration date of such
swaps, plus interest rates set forth in the applicable contracts, and (ii) the counterparty will be obligated to pay 40 North
Latitude SPV any positive price performance of the specified notional number of Shares subject to the swaps as of the expiration
date of the swaps. Any dividends received by the counterparty on such notional Shares during the term of the swaps will be paid
to 40 North Latitude SPV. All balances will be settled in cash. 40 North Latitude SPV’s counterparty for the swaps is Morgan
Stanley Capital Services LLC. The number of Shares specified in such swaps is 30,900.

The swaps do not give 40 North Latitude
SPV or any of the other Reporting Persons direct or indirect voting, investment or dispositive control over any securities of the
Issuer and do not require the counterparty thereto to acquire, hold, vote or dispose of any securities of the Issuer. Accordingly,
40 North Latitude SPV and the other Reporting Persons disclaim any beneficial ownership of any Shares that may be referenced in
the swap contracts or Shares or other securities or financial instruments that may be held from time to time by any counterparty
to the contracts.

Except for the arrangements described herein,
to the best knowledge of the Reporting Persons, there are no contracts, arrangements, understandings or relationships (legal or
otherwise) among the persons named in Item 2 and between such persons and any other person with respect to any securities of the
Issuer, including but not limited to, transfer or voting of any of the securities, finder’s fees, joint ventures, loan or
option arrangements, puts or calls, guarantees of profits, division of profits or loss or the giving or withholding of proxies.

Exhibit 1 – Agreement between 40 North Management
LLC, 40 North Latitude Master Fund Ltd., 40 North Latitude SPV-B LLC, 40 North Latitude Fund LP, 40 North GP III LLC, David S.
Winter, and David J. Millstone to file this Schedule 13D and any amendments thereto jointly on behalf of each of them.

Exhibit 2 – Transactions in the Shares effected
in the past 60 days.

Exhibit 3 – Letter to the Board of
Directors of the Issuer, dated February 8, 2016 (incorporated by reference to Exhibit 3 to Schedule 13D (Amendment No. 9)
filed on February 8, 2016 by the Reporting Persons).

SIGNATURES

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