13D Filing: Steel Partners and Aerojet Rocketdyne Holdings Inc. (AJRD)

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. 24)¹

Aerojet Rocketdyne Holdings, Inc.

(Name
of Issuer)

Common Stock, par value $0.10

(Title of Class of Securities)

007800 10 5

(CUSIP Number)

Warren G. Lichtenstein

Steel Partners Holdings L.P.

590 Madison Avenue, 32nd Floor

New York, New York 10022

(212) 520-2300

(Name, Address and Telephone Number of Person

Authorized to Receive Notices
and Communications)

December 19, 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).

The following constitutes
Amendment No. 24 to the Schedule 13D filed by the undersigned (“Amendment No. 24”). This Amendment No. 24 amends the
Schedule 13D as specifically set forth herein.

Item 1 is hereby
amended and restated to read as follows:

This statement
relates to the common stock, $0.10 par value per share (the “Shares”), of Aerojet Rocketdyne Holdings, Inc., a Delaware
corporation (the “Issuer”). The address of the principal executive offices of the Issuer is 222 N. Sepulveda Blvd.,
Suite 500, El Segundo, California 90245.

Item 2 is hereby amended
and restated to read as follows:

(a)       This
statement is filed by Steel Partners Holdings L.P., a Delaware limited partnership (“Steel Holdings”), SPH Group LLC,
a Delaware limited liability company (“SPHG”), SPH Group Holdings LLC, a Delaware limited liability company (“SPHG
Holdings”), Steel Partners Holdings GP Inc., a Delaware corporation (“Steel Holdings GP”), Steel Excel, Inc.,
a Delaware corporation (“Steel Excel”), Steel Partners, Ltd., a Delaware corporation (“SPL”), and Warren
G. Lichtenstein. Each of the foregoing is referred to as a “Reporting Person” and collectively as the “Reporting
Persons.”

Steel Holdings owns
99% of the membership interests of SPHG. SPHG is the sole member of SPHG Holdings. Steel Holdings GP is the general partner of
Steel Holdings, the managing member of SPHG and the manager of SPHG Holdings. SPHG Holdings owns 100% of the outstanding shares
of common stock of Steel Excel. Accordingly, for purposes of this statement, each of Steel Holdings, SPHG, SPHG Holdings and Steel
Holdings GP may be deemed to beneficially own the Shares owned directly by Steel Excel.

Warren G. Lichtenstein,
Chairman of Steel Excel and Executive Chairman of Steel Holdings GP, is a director of the Issuer. Mr. Lichtenstein is also the
Chief Executive Officer of SPL. Accordingly, for purposes of this statement, Mr. Lichtenstein may be deemed to
beneficially own the Shares owned directly by SPL.

Each Reporting Person
disclaims beneficial ownership of the Shares owned directly by another Reporting Person, except to the extent of his or its pecuniary
interest therein.

Set forth on Schedule
A annexed hereto (“Schedule A”) is the name and present principal business, occupation or employment and
the name, principal business and address of any corporation or other organization in which such employment is conducted of (i)
the executive officers and directors of Steel Holdings GP, (ii) the executive officers and directors of Steel Excel and (iii) the
executive officers and directors of SPL. To the best of the Reporting Persons’ knowledge, except as otherwise set forth herein,
none of the persons listed on Schedule A beneficially owns any securities of the Issuer or is a party to any contract, agreement
or understanding required to be disclosed herein.

(b)       The
principal business address of the Reporting Persons is 590 Madison Avenue, 32nd Floor, New York, New York 10022.

(c)       Steel
Holdings is a global diversified holding company that engages or has interests in a variety of operating businesses through its
subsidiary companies. Steel Holdings may seek to obtain majority or primary control, board representation or other significant
influence over the businesses in which it holds an interest. The principal business of SPHG Holdings is holding securities for
the account of Steel Holdings. The principal business of SPHG is serving as the sole member of SPHG Holdings and other affiliates.
The principal business of Steel Holdings GP is serving as the general partner of Steel Holdings, the managing member of SPHG and
the manager of SPHG Holdings. Steel Excel provides drilling and production services to the oil and gas industry and owns a youth
sports business. SPL is a holding company. The principal occupation of Warren G. Lichtenstein is serving as Executive Chairman
of Steel Holdings GP.

(d)       No
Reporting Person nor any person listed on Schedule A has, during the last five years, been convicted in a criminal proceeding
(excluding traffic violations or similar misdemeanors).

(e)       No
Reporting Person nor any person listed on Schedule A has, during the last five years, been 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.

(f)       Each
of the individuals who are Reporting Persons or listed on Schedule A is a citizen of the United States of America. Each
of the entities who are Reporting Persons are organized under the laws of the State of Delaware.

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

The aggregate purchase
price of the 4,180,997 Shares owned directly by Steel Excel is approximately $47,519,535, including brokerage commissions. The
Shares owned directly by Steel Excel were acquired with funds of an entity affiliated with SPHG Holdings that initially purchased
the Shares prior to being contributed to SPHG Holdings and subsequently contributed to Steel Excel.

The aggregate purchase
price of the 60,546 Shares owned directly by SPL is approximately $1,081,073, including brokerage commissions. The Shares owned
directly by SPL were acquired with the working capital of SPL.

Warren G. Lichtenstein
owns directly 39,771 Shares and currently exercisable stock options to purchase 243,546 Shares, all of which were awarded to him
in his capacity as a director of the Issuer.

Steel Excel and SPL
effect purchases of securities primarily through margin accounts maintained for them with prime brokers, which may extend margin
credit to them as and when required to open or carry positions in the margin accounts, subject to applicable federal margin regulations,
stock exchange rules and the prime brokers’ credit policies. In such instances, the positions held in the margin accounts
are pledged as collateral security for the repayment of debit balances in the accounts.

Item 5(a) 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 75.1 million Shares outstanding, which
is the total number of Shares outstanding as of October 26, 2017 as reported in the Issuer’s Form 10-Q filed with the Securities
and Exchange Commission on November 2, 2017.

As of the close of
business on the date hereof, Steel Excel owned directly 4,180,997 Shares, constituting approximately 5.6% of the Shares outstanding.
By virtue of their relationships with Steel Excel, each of Steel Holdings, SPHG, SPHG Holdings and Steel Holdings GP may be deemed
to beneficially own the Shares owned directly by Steel Excel.

As of the close of
business on the date hereof, SPL owned directly 60,546 Shares, constituting less than 1% of the Shares outstanding. By virtue of
his relationship with SPL discussed in further detail in Item 2, Warren G. Lichtenstein may be deemed to beneficially own the Shares
owned directly by SPL.

As of the close of
business on the date hereof, Warren G. Lichtenstein directly owned 39,771 Shares and may be deemed to beneficially own an additional
243,546 Shares underlying currently exercisable stock options, which, together with the 60,546 Shares owned directly by SPL that
Mr. Lichtenstein may also be deemed to beneficially own, constitutes less than 1% of the Shares outstanding. An additional 465,931
Shares are held by a “rabbi trust,” the receipt of which has been deferred by Mr. Lichtenstein pursuant to the Issuer’s
Deferred Compensation Plan for Nonemployee Directors. Such 465,931 Shares are not deemed to be beneficially owned by Mr. Lichtenstein.

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

(b)       Each
of Steel Excel, SPHG Holdings, SPHG, Steel Holdings and Steel Holdings GP is deemed to have shared power to vote and dispose of
the Shares owned directly by Steel Excel. Each of SPL and Mr. Lichtenstein is deemed to have shared power to vote and dispose of
the Shares owned directly by SPL. Mr. Lichtenstein has the sole power to vote and dispose all Shares he directly owns.

Item 5(c) is hereby
amended to add the following:

(c)       Effective
December 19, 2017, SPHG Holdings contributed its ownership of 4,180,997 Shares to Steel Excel in exchange for newly issued shares
of common stock of Steel Excel. On November 8, 2017 and November 30, 2017, Mr. Lichtenstein gifted 3,312 Shares and 4,064 Shares,
respectively. There have been no other transactions by the Reporting Persons in the securities of the Issuer during the past 60
days.

Item 6 is hereby amended
to add the following:

On the date hereof,
the Reporting Persons entered into a Joint Filing Agreement in which the Reporting Persons agreed to the joint filing on behalf
of each of them of statements on Schedule 13D with respect to securities of the Issuer. A copy of this agreement is attached as
an exhibit hereto and is incorporated herein by reference.

Mr. Lichtenstein owns
Stock Appreciation Rights (“SARs”) for 62,390 Shares, all of which are vested. Such SARs were awarded to Mr. Lichtenstein
in his capacity as a director of the Issuer.

Item 7 is hereby amended
to add the following exhibit:

SIGNATURES

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

SCHEDULE A

Executive Officers and Directors
of Steel Partners Holdings GP Inc.

Executive Officers and Directors
of Steel Excel, Inc.

Executive Officers and Directors
of Steel Partners, Ltd.