SC 13D 1 sc13d06297302_09272021.htm THE SCHEDULE 13D

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. )¹

Huntsman Corporation

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

447011107

(CUSIP Number)

JEFFREY C. SMITH

STARBOARD VALUE LP

777 Third Avenue, 18th Floor

New York, New York 10017

(212) 845-7977

STEVE WOLOSKY, ESQ.

ANDREW FREEDMAN, 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)

September 15, 2021

(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).

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD VALUE LP

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

18,602,818

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

18,602,818

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

18,602,818*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

8.4%

TYPE OF REPORTING PERSON

* Includes 7,004,674 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD VALUE AND OPPORTUNITY MASTER FUND LTD

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

CAYMAN ISLANDS

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

8,174,516

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

8,174,516

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

8,174,516*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

3.7%

TYPE OF REPORTING PERSON

* Includes 4,481,449 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD VALUE AND OPPORTUNITY S LLC

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

1,390,834

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

1,390,834

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,390,834*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

Less than 1%

TYPE OF REPORTING PERSON

* Includes 546,525 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD VALUE AND OPPORTUNITY C LP

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

830,599

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

830,599

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

830,599*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

Less than 1%

TYPE OF REPORTING PERSON

* Includes 326,981 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD P FUND LP

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

CAYMAN ISLANDS

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

1,267,328

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

1,267,328

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,267,328

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

Less than 1%

TYPE OF REPORTING PERSON

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD VALUE P GP LLC

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

1,267,328

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

1,267,328

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,267,328

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

Less than 1%

TYPE OF REPORTING PERSON

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD VALUE R LP

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

2,097,927

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

2,097,927

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

2,097,927*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

Less than 1%

TYPE OF REPORTING PERSON

* Includes 326,981 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD VALUE AND OPPORTUNITY MASTER FUND L LP

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

CAYMAN ISLANDS

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

581,804

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

581,804

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

581,804*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

Less than 1%

TYPE OF REPORTING PERSON

* Includes 244,072 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD VALUE L LP

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

581,804

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

581,804

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

581,804*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

Less than 1%

TYPE OF REPORTING PERSON

* Includes 244,072 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD VALUE R GP LLC

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

2,679,731

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

2,679,731

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

2,679,731*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

1.2%

TYPE OF REPORTING PERSON

* Includes 571,053 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD LEADERS ECHO II LLC

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

190,258

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

190,258

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

190,258

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

Less than 1%

TYPE OF REPORTING PERSON

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD LEADERS FUND LP

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

190,258

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

190,258

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

190,258

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

Less than 1%

TYPE OF REPORTING PERSON

CUSIP No. 447011107


	1	NAME OF REPORTING PERSON

			STARBOARD VALUE A LP
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐

	3	SEC USE ONLY


	4	SOURCE OF FUNDS

			OO
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐


	6	CITIZENSHIP OR PLACE OF ORGANIZATION

			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					2,917,373
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER

					2,917,373
			10	SHARED DISPOSITIVE POWER

					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			2,917,373
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐


	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

			1.3%
	14	TYPE OF REPORTING PERSON

			PN

CUSIP No. 447011107


	1	NAME OF REPORTING PERSON

			STARBOARD VALUE A GP LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐

	3	SEC USE ONLY


	4	SOURCE OF FUNDS

			OO
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐


	6	CITIZENSHIP OR PLACE OF ORGANIZATION

			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					2,917,373
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER

					2,917,373
			10	SHARED DISPOSITIVE POWER

					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			2,917,373
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐


	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

			1.3%
	14	TYPE OF REPORTING PERSON

			OO

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD X MASTER FUND LTD

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

CAYMAN ISLANDS

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

1,572,656

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

1,572,656

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,572,656*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

Less than 1%

TYPE OF REPORTING PERSON

* Includes 614,065 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107


	1	NAME OF REPORTING PERSON

			STARBOARD G FUND, L.P.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐

	3	SEC USE ONLY


	4	SOURCE OF FUNDS

			WC
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐


	6	CITIZENSHIP OR PLACE OF ORGANIZATION

			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					2,727,115
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER

					2,727,115
			10	SHARED DISPOSITIVE POWER

					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			2,727,115
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐


	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

			1.2%
	14	TYPE OF REPORTING PERSON

			PN

CUSIP No. 447011107


	1	NAME OF REPORTING PERSON

			STARBOARD VALUE G GP, LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐

	3	SEC USE ONLY


	4	SOURCE OF FUNDS

			OO
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐


	6	CITIZENSHIP OR PLACE OF ORGANIZATION

			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					2,727,115
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER

					2,727,115
			10	SHARED DISPOSITIVE POWER

					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			2,727,115
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐


	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

			1.2%
	14	TYPE OF REPORTING PERSON

			OO

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD VALUE GP LLC

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

18,602,818

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

18,602,818

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

18,602,818*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

8.4%

TYPE OF REPORTING PERSON

* Includes 7,004,674 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD PRINCIPAL CO LP

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

18,602,818

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

18,602,818

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

18,602,818*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

8.4%

TYPE OF REPORTING PERSON

* Includes 7,004,674 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

STARBOARD PRINCIPAL CO GP LLC

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

DELAWARE

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

18,602,818

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

- 0 -

PERSON WITH

SOLE DISPOSITIVE POWER

18,602,818

SHARED DISPOSITIVE POWER

- 0 -

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

18,602,818*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

8.4%

TYPE OF REPORTING PERSON

* Includes 7,004,674 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

JEFFREY C. SMITH

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

USA

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

- 0 -

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

18,602,818

PERSON WITH

SOLE DISPOSITIVE POWER

- 0 -

SHARED DISPOSITIVE POWER

18,602,818

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

18,602,818*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

8.4%

TYPE OF REPORTING PERSON

* Includes 7,004,674 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

NAME OF REPORTING PERSON

PETER A. FELD

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☐

(b) ☐

SEC USE ONLY

SOURCE OF FUNDS

CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)

☐

CITIZENSHIP OR PLACE OF ORGANIZATION

USA

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

- 0 -

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

18,602,818

PERSON WITH

SOLE DISPOSITIVE POWER

- 0 -

SHARED DISPOSITIVE POWER

18,602,818

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

18,602,818*

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

8.4%

TYPE OF REPORTING PERSON

* Includes 7,004,674 Shares underlying certain forward purchase contracts exercisable within 60 days hereof.

CUSIP No. 447011107

The following constitutes the Schedule 13D filed by the undersigned (the “Schedule 13D”).

Item 1.

Security and Issuer.

This statement relates to the Common Stock, par value $0.01 per share (the “Shares”), of Huntsman Corporation, a Delaware corporation (the “Issuer”). The address of the principal executive offices of the Issuer is 10003 Woodloch Forest Drive, The Woodlands, Texas 77380.

Item 2.

Identity and Background.

(a) This statement is filed by:

(i)

Starboard Value and Opportunity Master Fund Ltd, a Cayman Islands exempted company (“Starboard V&O Fund”), with respect to the Shares directly and beneficially owned by it;

(ii)

Starboard Value and Opportunity S LLC, a Delaware limited liability company (“Starboard S LLC”), with respect to the Shares directly and beneficially owned by it;

(iii)

Starboard Value and Opportunity C LP, a Delaware limited partnership (“Starboard C LP”), with respect to the Shares directly and beneficially owned by it;

(iv)

Starboard P Fund LP, a Cayman Islands exempted limited partnership (“Starboard P LP”), with respect to the Shares directly and beneficially owned by it;

(v)

Starboard Value P GP LLC (“Starboard P GP”), as the general partner of Starboard P LP;

(vi)

Starboard Value R LP (“Starboard R LP”), as the general partner of Starboard C LP and the managing member of Starboard P GP;

(vii)

Starboard Value and Opportunity Master Fund L LP, a Cayman Islands exempted limited partnership (“Starboard L Master”), with respect to the Shares directly and beneficially owned by it;

(viii)

Starboard Value L LP (“Starboard L GP”), as the general partner of Starboard L Master;

(ix)

Starboard Value R GP LLC (“Starboard R GP”), as the general partner of Starboard R LP and Starboard L GP;

(x)

Starboard Leaders Echo II LLC, a Delaware limited liability company (“Starboard Echo II LLC”), with respect to the Shares directly and beneficially owned by it;

(xi)

Starboard Leaders Fund LP (“Starboard Leaders Fund”), as a member of Starboard Echo II LLC;

CUSIP No. 447011107

(xii)

Starboard Value A LP (“Starboard A LP”), as the general partner of Starboard Leaders Fund and the managing member of Starboard Echo II LLC and Starboard Value G GP, LLC;

(xiii)

Starboard Value A GP LLC (“Starboard A GP”), as the general partner of Starboard A LP;

(xiv)

Starboard X Master Fund Ltd, a Cayman Islands exempted company (“Starboard X Master”), with respect to the Shares directly and beneficially owned by it;

(xv)

Starboard G Fund, L.P., a Delaware limited partnership (“Starboard G LP”), with respect to the Shares directly and beneficially owned by it;

(xvi)

Starboard Value G GP, LLC (“Starboard G GP”), as the general partner of Starboard G LP;

(xvii)

Starboard Value LP, as the investment manager of Starboard V&O Fund, Starboard C LP, Starboard P LP, Starboard L Master, Starboard Echo II LLC, Starboard Leaders Fund, Starboard X Master, Starboard G LP and of a certain managed account (the “Starboard Value LP Account”) and the manager of Starboard S LLC;

(xviii)

Starboard Value GP LLC (“Starboard Value GP”), as the general partner of Starboard Value LP;

(xix)

Starboard Principal Co LP (“Principal Co”), as a member of Starboard Value GP;

(xx)

Starboard Principal Co GP LLC (“Principal GP”), as the general partner of Principal Co;

(xxi)

Jeffrey C. Smith, as a member of Principal GP and as a member of each of the Management Committee of Starboard Value GP and the Management Committee of Principal GP; and

(xxii)

Peter A. Feld, as a member of Principal GP and as a member of each of the Management Committee of Starboard Value GP and the Management Committee of Principal GP.

Each of the foregoing is referred to as a “Reporting Person” and collectively as the “Reporting Persons.” Each of the Reporting Persons is party to that certain Joint Filing Agreement, as further described in Item 6. Accordingly, the Reporting Persons are hereby filing a joint Schedule 13D.

(b) The address of the principal office of each of Starboard V&O Fund, Starboard S LLC, Starboard C LP, Starboard P LP, Starboard P GP, Starboard R LP, Starboard L Master, Starboard L GP, Starboard R GP, Starboard Echo II LLC, Starboard Leaders Fund, Starboard A LP, Starboard A GP, Starboard X Master, Starboard G LP, Starboard G GP, Starboard Value LP, Starboard Value GP, Principal Co, Principal GP, and Messrs. Smith and Feld is 777 Third Avenue, 18th Floor, New York, New York 10017. The officers and directors of Starboard V&O Fund and Starboard X Master and their principal occupations and business addresses are set forth on Schedule A and are incorporated by reference in this Item 2.

CUSIP No. 447011107

(c) The principal business of Starboard V&O Fund is serving as a private investment fund. Starboard V&O Fund has been formed for the purpose of making equity investments and, on occasion, taking an active role in the management of portfolio companies in order to enhance shareholder value. Starboard S LLC, Starboard C LP, Starboard P LP, Starboard L Master, Starboard Echo II LLC, Starboard X Master and Starboard G LP have been formed for the purpose of investing in securities and engaging in all related activities and transactions. The principal business of Starboard Leaders Fund is serving as a private investment partnership. Starboard Value LP provides investment advisory and management services and acts as the investment manager of Starboard V&O Fund, Starboard C LP, Starboard P LP, Starboard L Master, Starboard Echo II LLC, Starboard Leaders Fund, Starboard X Master, Starboard G LP and the Starboard Value LP Account and the manager of Starboard S LLC. The principal business of Starboard Value GP is providing a full range of investment advisory, pension advisory and management services and serving as the general partner of Starboard Value LP. The principal business of Principal Co is providing investment advisory and management services. Principal Co is a member of Starboard Value GP. Principal GP serves as the general partner of Principal Co. Starboard P GP serves as the general partner of Starboard P LP. Starboard R LP serves as the general partner of Starboard C LP and the managing member of Starboard P GP. Starboard L GP serves as the general partner of Starboard L Master. Starboard R GP serves as the general partner of Starboard R LP and Starboard L GP. Starboard A LP serves as the general partner of Starboard Leaders Fund and as the managing member of Starboard Echo II LLC and Starboard G GP. Starboard A GP serves as the general partner of Starboard A LP. Starboard G GP serves as the general partner of Starboard G LP. Messrs. Smith and Feld serve as members of Principal GP and the members of each of the Management Committee of Starboard Value GP and the Management Committee of Principal GP.

(d) No Reporting Person, nor any person listed on Schedule A, annexed hereto, 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, annexed hereto, 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) Messrs. Smith and Feld are citizens of the United States of America. The citizenship of the persons listed on Schedule A is set forth therein.

Item 3.

Source and Amount of Funds or Other Consideration.

The Shares purchased by each of Starboard V&O Fund, Starboard S LLC, Starboard C LP, Starboard P LP, Starboard L Master, Starboard Echo II LLC, Starboard X Master, Starboard G LP and held in the Starboard Value LP 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 otherwise noted, as set forth in Schedule B, which is incorporated by reference herein.

CUSIP No. 447011107

The aggregate purchase price of the 3,693,067 Shares beneficially owned by Starboard V&O Fund is approximately $95,952,817, excluding brokerage commissions. The aggregate purchase price of the entered into over-the-counter forward purchase contracts providing for the purchase of 4,481,449 Shares by Starboard V&O Fund is approximately $118,395,386, excluding brokerage commissions. The aggregate purchase price of the 844,309 Shares beneficially owned by Starboard S LLC is approximately $22,154,560, excluding brokerage commissions. The aggregate purchase price of the entered into over-the-counter forward purchase contracts for the purchase of 546,525 Shares by Starboard S LLC is approximately $14,488,974, excluding brokerage commissions. The aggregate purchase price of the 503,618 Shares beneficially owned by Starboard C LP is approximately $13,212,184, excluding brokerage commissions. The aggregate purchase price of the entered into over-the-counter forward purchase contracts for the purchase of 326,981 Shares by Starboard C LP is approximately $8,666,942, excluding brokerage commissions. The aggregate purchase price of the 1,267,328 Shares beneficially owned by Starboard P LP is approximately $33,744,231, excluding brokerage commissions. The aggregate purchase price of the 337,732 Shares beneficially owned by Starboard L Master is approximately $8,865,577, excluding brokerage commissions. The aggregate purchase price of the entered into over-the-counter forward purchase contracts for the purchase of 244,072 Shares by Starboard L Master is approximately $6,479,750, excluding brokerage commissions. The aggregate purchase price of the 190,258 Shares beneficially owned by Starboard Echo II LLC is approximately $5,052,407, excluding brokerage commissions. The aggregate purchase price of the 958,951 Shares beneficially owned by Starboard X Master is approximately $25,153,331, excluding brokerage commissions. The aggregate purchase price of the entered into over-the-counter forward purchase contracts for the purchase of 614,065 Shares by Starboard X Master is approximately $16,273,730, excluding brokerage commissions. The aggregate purchase price of the 2,727,115 Shares beneficially owned by Starboard G LP is approximately $72,391,285, excluding brokerage commissions. The aggregate purchase price of the 1,076,126 Shares held in the Starboard Value LP Account is approximately $28,350,874, excluding brokerage commissions. The aggregate purchase price of the entered into over-the-counter forward purchase contracts for the purchase of 791,582 Shares by Starboard Value LP through the Starboard Value LP Account is approximately $21,095,660, excluding brokerage commissions.

Item 4.

Purpose of Transaction.

The Reporting Persons purchased the Shares based on the Reporting Persons’ belief that the Shares, when purchased, were undervalued and represented an attractive investment opportunity. Depending upon overall market conditions, other investment opportunities available to the Reporting Persons, and the availability of Shares at prices that would make the purchase or sale of Shares desirable, the Reporting Persons may endeavor to increase or decrease their position in the Issuer through, among other things, the purchase or sale of Shares on the open market or in private transactions or otherwise, on such terms and at such times as the Reporting Persons may deem advisable.

No Reporting Person has any present plan or proposal which would relate to or result in any of the matters set forth in subparagraphs (a) - (j) of Item 4 of Schedule 13D except as set forth herein or such as would occur upon or in connection with completion of, or following, any of the actions discussed herein. The Reporting Persons intend to review their investment in the Issuer on a continuing basis. Depending on various factors including, without limitation, the Issuer’s financial position and investment strategy, the price levels of the Shares, conditions in the securities markets and general economic and industry conditions, the Reporting Persons may in the future take such actions with respect to their investment in the Issuer as they deem appropriate including, without limitation, engaging in communications with management and the Board of Directors of the Issuer, engaging in discussions with stockholders of the Issuer or other third parties about the Issuer and the Reporting Persons’ investment, including potential business combinations or dispositions involving the Issuer or certain of its businesses, making recommendations or proposals to the Issuer concerning changes to the capitalization, ownership structure, board structure (including board composition), potential business combinations or dispositions involving the Issuer or certain of its businesses, or suggestions for improving the Issuer’s financial and/or operational performance, purchasing additional Shares, selling some or all of their Shares, engaging in short selling of or any hedging or similar transaction with respect to the Shares, including swaps and other derivative instruments, or changing their intention with respect to any and all matters referred to in Item 4.

CUSIP No. 447011107

Item 5.

Interest in Securities of the Issuer.

The aggregate percentage of Shares reported owned by each person named herein is based upon 221,929,899 Shares outstanding, as of July 21, 2021, 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 July 30, 2021.

Starboard V&O Fund

(a)

As of the close of business on September 27, 2021, Starboard V&O Fund beneficially owned 8,174,516 Shares, including 4,481,449 Shares underlying certain forward purchase contracts.

Percentage: Approximately 3.7%

(b)

1. Sole power to vote or direct vote: 8,174,516
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 8,174,516
4. Shared power to dispose or direct the disposition: 0

(c)

The transactions in the Shares by Starboard V&O Fund during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard S LLC

(a)

As of the close of business on September 27, 2021, Starboard S LLC beneficially owned 1,390,834 Shares, including 546,525 Shares underlying certain forward purchase contracts.

Percentage: Less than 1%

(b)

1. Sole power to vote or direct vote: 1,390,834
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 1,390,834
4. Shared power to dispose or direct the disposition: 0

(c)

The transactions in the Shares by Starboard S LLC during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard C LP

(a)

As of the close of business on September 27, 2021, Starboard C LP beneficially owned 830,599 Shares, including 326,981 Shares underlying certain forward purchase contracts.

Percentage: Less than 1%

(b)

1. Sole power to vote or direct vote: 830,599
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 830,599
4. Shared power to dispose or direct the disposition: 0

CUSIP No. 447011107

(c)

The transactions in the Shares by Starboard C LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard P LP

(a)

As of the close of business on September 27, 2021, Starboard P LP beneficially owned 1,267,328 Shares.

Percentage: Less than 1%

(b)

1. Sole power to vote or direct vote: 1,267,328
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 1,267,328
4. Shared power to dispose or direct the disposition: 0

(c)

The transactions in the Shares by Starboard P LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard P GP

(a)

Starboard P GP, as the general partner of Starboard P LP, may be deemed the beneficial owner of the 1,267,328 Shares owned by Starboard P LP.

Percentage: Less than 1%

(b)

(c)

Starboard P GP has not entered into any transactions in the Shares during the past sixty days. The transactions in the Shares on behalf of Starboard P LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard R LP

(a)

Starboard R LP, as the general partner of Starboard C LP and the managing member of Starboard P GP, may be deemed the beneficial owner of the (i) 830,599 Shares owned by Starboard C LP and (ii) 1,267,328 Shares owned by Starboard P LP.

Percentage: Less than 1%

(b)

1. Sole power to vote or direct vote: 2,097,927
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 2,097,927
4. Shared power to dispose or direct the disposition: 0

(c)

Starboard R LP has not entered into any transactions in the Shares during the past sixty days. The transactions in the Shares on behalf of each of Starboard C LP and Starboard P LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

CUSIP No. 447011107

Starboard L Master

(a)

As of the close of business on September 27, 2021, Starboard L Master beneficially owned 581,804 Shares, including 244,072 Shares underlying certain forward purchase contracts.

Percentage: Less than 1%

(b)

1. Sole power to vote or direct vote: 581,804
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 581,804
4. Shared power to dispose or direct the disposition: 0

(c)

The transactions in the Shares by Starboard L Master during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard L GP

(a)

Starboard L GP, as the general partner of Starboard L Master, may be deemed the beneficial owner of the 581,804 Shares owned by Starboard L Master.

Percentage: Less than 1%

(b)

(c)

Starboard L GP has not entered into any transactions in the Shares during the past sixty days. The transactions in the Shares on behalf of Starboard L Master during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard R GP

(a)

Starboard R GP, as the general partner of Starboard R LP and Starboard L GP, may be deemed the beneficial owner of the (i) 830,599 Shares owned by Starboard C LP, (ii) 1,267,328 Shares owned by Starboard P LP and (iii) 581,804 Shares owned by Starboard L Master.

Percentage: Approximately 1.2%

(b)

1. Sole power to vote or direct vote: 2,679,731
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 2,679,731
4. Shared power to dispose or direct the disposition: 0

(c)

Starboard R GP has not entered into any transactions in the Shares during the past sixty days. The transactions in the Shares on behalf of each of Starboard C LP, Starboard P LP and Starboard L Master during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

CUSIP No. 447011107

Starboard Echo II LLC

(a)

As of the close of business on September 27, 2021, Starboard Echo II LLC beneficially owned 190,258 Shares.

Percentage: Less than 1%

(b)

1. Sole power to vote or direct vote: 190,258
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 190,258
4. Shared power to dispose or direct the disposition: 0

(c)

The transactions in the Shares by Starboard Echo II LLC during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard Leaders Fund

(a)

Starboard Leaders Fund, as a member of Starboard Echo II LLC, may be deemed the beneficial owner of the 190,258 Shares owned by Starboard Echo II LLC.

Percentage: Less than 1%

(b)

(c)

Starboard Leaders Fund has not entered into any transactions in the Shares during the past sixty days. The transactions in the Shares on behalf of Starboard Echo II LLC during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard A LP

(a)

Starboard A LP, as the general partner of Starboard Leaders Fund and the managing member of Starboard Echo II LLC and Starboard G GP, may be deemed the beneficial owner of the (i) 190,258 Shares owned by Starboard Echo II LLC and (ii) 2,727,115 Shares owned by Starboard G LP.

Percentage: Approximately 1.3%

(b)

1. Sole power to vote or direct vote: 2,917,373
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 2,917,373
4. Shared power to dispose or direct the disposition: 0

(c)

Starboard A LP has not entered into any transactions in the Shares during the past sixty days. The transactions in the Shares on behalf of each of Starboard Echo II LLC and Starboard G LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

CUSIP No. 447011107

Starboard A GP

(a)

Starboard A GP, as the general partner of Starboard A LP, may be deemed the beneficial owner of the (i) 190,258 Shares owned by Starboard Echo II LLC and (ii) 2,727,115 Shares owned by Starboard G LP.

Percentage: Approximately 1.3%

(b)

(c)

Starboard A GP has not entered into any transactions in the Shares during the past sixty days. The transactions in the Shares on behalf of each of Starboard Echo II LLC and Starboard G LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard X Master

(a)

As of the close of business on September 27, 2021, Starboard X Master beneficially owned 1,572,656 Shares, including 614,065 Shares underlying certain forward purchase contracts.

Percentage: Less than 1%

(b)

1. Sole power to vote or direct vote: 1,572,656
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 1,572,656
4. Shared power to dispose or direct the disposition: 0

(c)

The transactions in the Shares by Starboard X Master during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard G LP

(a)

As of the close of business on September 27, 2021, Starboard G LP beneficially owned 2,727,115 Shares.

Percentage: Approximately 1.2%

(b)

1. Sole power to vote or direct vote: 2,727,115
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 2,727,115
4. Shared power to dispose or direct the disposition: 0

(c)

The transactions in the Shares by Starboard G LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard G GP

(a)

Starboard G GP, as the general partner of Starboard G LP, may be deemed the beneficial owners of the 2,727,115 Shares owned by Starboard G LP.

Percentage: Approximately 1.2%

CUSIP No. 447011107

(b)

(c)

Starboard G GP has not entered into any transaction in the Shares during the past sixty days. The transactions in the Shares on behalf of Starboard G LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard Value LP

(a)

As of the close of business on September 27, 2021, 1,867,708 Shares were held in the Starboard Value LP Account, including 791,582 Shares underlying certain forward purchase contracts. Starboard Value LP, as the investment manager of Starboard V&O Fund, Starboard C LP, Starboard P LP, Starboard L Master, Starboard Echo II LLC, Starboard X Master, Starboard G LP and the Starboard Value LP Account and the manager of Starboard S LLC, may be deemed the beneficial owner of the (i) 8,174,516 Shares owned by Starboard V&O Fund, (ii) 1,390,834 Shares owned by Starboard S LLC, (iii) 830,599 Shares owned by Starboard C LP, (iv) 1,267,328 Shares owned by Starboard P LP, (v) 581,804 Shares owned by Starboard L Master, (vi) 190,258 Shares owned by Starboard Echo II LLC, (vii) 1,572,656 Shares owned by Starboard X Master, (viii) 2,727,115 Shares owned by Starboard G LP and (ix) 1,867,708 Shares held in the Starboard Value LP Account.

Percentage: Approximately 8.4%

(b)

1. Sole power to vote or direct vote: 18,602,818
2. Shared power to vote or direct vote: 0
3. Sole power to dispose or direct the disposition: 18,602,818
4. Shared power to dispose or direct the disposition: 0

(c)

The transactions in the Shares by Starboard Value LP through the Starboard Value LP Account and on behalf of each of Starboard V&O Fund, Starboard S LLC, Starboard C LP, Starboard P LP, Starboard L Master, Starboard Echo II LLC, Starboard X Master and Starboard G LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Starboard Value GP

(a)

Starboard Value GP, as the general partner of Starboard Value LP, may be deemed the beneficial owner of the (i) 8,174,516 Shares owned by Starboard V&O Fund, (ii) 1,390,834 Shares owned by Starboard S LLC, (iii) 830,599 Shares owned by Starboard C LP, (iv) 1,267,328 Shares owned by Starboard P LP, (v) 581,804 Shares owned by Starboard L Master, (vi) 190,258 Shares owned by Starboard Echo II LLC, (vii) 1,572,656 Shares owned by Starboard X Master, (viii) 2,727,115 Shares owned by Starboard G LP and (ix) 1,867,708 Shares held in the Starboard Value LP Account.

Percentage: Approximately 8.4%

CUSIP No. 447011107

(b)

(c)

Starboard Value GP has not entered into any transactions in the Shares during the past sixty days. The transactions in the Shares by Starboard Value LP through the Starboard Value LP Account and on behalf of each of Starboard V&O Fund, Starboard S LLC, Starboard C LP, Starboard P LP, Starboard L Master, Starboard Echo II LLC, Starboard X Master and Starboard G LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Principal Co

(a)

Principal Co, as a member of Starboard Value GP, may be deemed the beneficial owner of the (i) 8,174,516 Shares owned by Starboard V&O Fund, (ii) 1,390,834 Shares owned by Starboard S LLC, (iii) 830,599 Shares owned by Starboard C LP, (iv) 1,267,328 Shares owned by Starboard P LP, (v) 581,804 Shares owned by Starboard L Master, (vi) 190,258 Shares owned by Starboard Echo II LLC, (vii) 1,572,656 Shares owned by Starboard X Master, (viii) 2,727,115 Shares owned by Starboard G LP and (ix) 1,867,708 Shares held in the Starboard Value LP Account.

Percentage: Approximately 8.4%

(b)

(c)

Principal Co has not entered into any transactions in the Shares during the past sixty days. The transactions in the Shares by Starboard Value LP through the Starboard Value LP Account and on behalf of each of Starboard V&O Fund, Starboard S LLC, Starboard C LP, Starboard P LP, Starboard L Master, Starboard Echo II LLC, Starboard X Master and Starboard G LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Principal GP

(a)

Principal GP, as the general partner of Principal Co, may be deemed the beneficial owner of the (i) 8,174,516 Shares owned by Starboard V&O Fund, (ii) 1,390,834 Shares owned by Starboard S LLC, (iii) 830,599 Shares owned by Starboard C LP, (iv) 1,267,328 Shares owned by Starboard P LP, (v) 581,804 Shares owned by Starboard L Master, (vi) 190,258 Shares owned by Starboard Echo II LLC, (vii) 1,572,656 Shares owned by Starboard X Master, (viii) 2,727,115 Shares owned by Starboard G LP and (ix) 1,867,708 Shares held in the Starboard Value LP Account.

Percentage: Approximately 8.4%

(b)

CUSIP No. 447011107

(c)

Principal GP has not entered into any transactions in the Shares during the past sixty days. The transactions in the Shares by Starboard Value LP through the Starboard Value LP Account and on behalf of each of Starboard V&O Fund, Starboard S LLC, Starboard C LP, Starboard P LP, Starboard L Master, Starboard Echo II LLC, Starboard X Master and Starboard G LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

Messrs. Smith and Feld

(a)

Each of Messrs. Smith and Feld, as a member of Principal GP and as a member of each of the Management Committee of Starboard Value GP and the Management Committee of Principal GP, may be deemed the beneficial owner of the (i) 8,174,516 Shares owned by Starboard V&O Fund, (ii) 1,390,834 Shares owned by Starboard S LLC, (iii) 830,599 Shares owned by Starboard C LP, (iv) 1,267,328 Shares owned by Starboard P LP, (v) 581,804 Shares owned by Starboard L Master, (vi) 190,258 Shares owned by Starboard Echo II LLC, (vii) 1,572,656 Shares owned by Starboard X Master, (viii) 2,727,115 Shares owned by Starboard G LP and (ix) 1,867,708 Shares held in the Starboard Value LP Account.

Percentage: Approximately 8.4%

(b)

1. Sole power to vote or direct vote: 0
2. Shared power to vote or direct vote: 18,602,818
3. Sole power to dispose or direct the disposition: 0
4. Shared power to dispose or direct the disposition: 18,602,818

(c)

None of Messrs. Smith or Feld has entered into any transactions in the Shares during the past sixty days. The transactions in the Shares by Starboard Value LP through the Starboard Value LP Account and on behalf of each of Starboard V&O Fund, Starboard S LLC, Starboard C LP, Starboard P LP, Starboard L Master, Starboard Echo II LLC, Starboard X Master and Starboard G LP during the past sixty days are set forth in Schedule B and are incorporated herein by reference.

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 Securities Exchange Act of 1934, as amended, the beneficial owners of any securities of the Issuer that 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.

(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)

Not applicable.

CUSIP No. 447011107

Item 6.

Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.

Each of Starboard V&O Fund, Starboard S LLC, Starboard C LP, Starboard L Master, Starboard X Master and Starboard Value LP through the Starboard Value LP Account entered into forward purchase contracts with Bank of America as the counterparty providing for the purchase of an aggregate of 3,081,449 Shares, 546,525 Shares, 326,981 Shares, 244,072 Shares, 614,065 Shares and 791,582 Shares, respectively, having an aggregate purchase price of approximately $81,596,141, $14,488,974, $8,666,942, $6,479,750, $16,273,730 and $21,095,660, respectively (each a “BA Forward Contract”). Each of the BA Forward Contracts has a final valuation date of September 6, 2022, however, each of Starboard V&O Fund, Starboard S LLC, Starboard C LP, Starboard L Master, Starboard X Master and Starboard Value LP through the Starboard Value LP Account has the ability to elect early settlement after serving notice to the counter-party of such intention at least two scheduled trading days in advance of the desired early final valuation date. Each of the BA Forward Contracts provides for physical settlement. Until the settlement date, none of the BA Forward Contracts give the Reporting Persons voting and dispositive control over the Shares to which such contracts relate.

Starboard V&O Fund entered into forward purchase contracts with UBS as the counterparty providing for the purchase of an aggregate of 1,400,000 Shares having an aggregate purchase price of approximately $36,799,245 (each a “UBS Forward Contract”). Each of the UBS Forward Contracts has a final valuation date of March 15, 2023, however, Starboard V&O Fund has the ability to elect early settlement after serving notice to the counterparty of such intention at least two scheduled trading days in advance of the desired early final valuation date. Each of the UBS Forward Contracts provides for physical settlement. Until the settlement date, none of the UBS Forward Contracts give the Reporting Persons voting and dispositive control over the Shares to which such contracts relate.

On September 27, 2021, 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 the securities of the Issuer to the extent required by applicable law. The Joint Filing Agreement is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Other than as described herein, there are no contracts, arrangements, understandings or relationships among the Reporting Persons, or between the Reporting Persons and any other person, with respect to the securities of the Issuer

Item 7.

Material to be Filed as Exhibits.

99.1

Joint Filing Agreement by and among Starboard Value and Opportunity Master Fund Ltd, Starboard Value and Opportunity S LLC, Starboard Value and Opportunity C LP, Starboard P Fund LP, Starboard Value P GP LLC, Starboard Value R LP, Starboard Value and Opportunity Master Fund L LP, Starboard Value L LP, Starboard Value R GP LLC, Starboard Leaders Echo II LLC, Starboard Leaders Fund LP, Starboard Value A LP, Starboard Value A GP LLC, Starboard X Master Fund Ltd, Starboard G Fund, L.P., Starboard Value G GP, LLC, Starboard Value LP, Starboard Value GP LLC, Starboard Principal Co LP, Starboard Principal Co GP LLC, Jeffrey C. Smith and Peter A. Feld, dated September 27, 2021.

99.2

Power of Attorney for Jeffrey C. Smith and Peter A. Feld, dated September 27, 2021.

CUSIP No. 447011107

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.

Dated: September 27, 2021

STARBOARD VALUE AND OPPORTUNITY MASTER FUND LTD

By: Starboard Value LP,

its investment manager

Starboard Value and Opportunity S LLC

By: Starboard Value LP,

its manager

Starboard Value and Opportunity C LP

By: Starboard Value R LP,

its general partner

STARBOARD VALUE R LP

By: Starboard Value R GP LLC,

its general partner

Starboard Value and Opportunity Master Fund L LP

By: Starboard Value L LP,

its general partner

Starboard Leaders Echo II LLC

By: Starboard Value A LP,

its managing member

Starboard Leaders Fund lp

By: Starboard Value A LP,

its managing member

Starboard Value A LP

By: Starboard Value A GP LLC,

its general partner

STARBOARD P FUND LP

By: Starboard Value P GP LLC,

its general partner

STARBOARD VALUE P GP LLC

By: Starboard Value R LP,

its member

STARBOARD G FUND, L.P.

By: Starboard Value G GP, LLC,

its general partner

Starboard Value L LP

By: Starboard Value R GP LLC,

its general partner

Starboard X MASTER FUND LTD

By: Starboard Value LP,

its investment manager

Starboard Value G GP, LLC

By: Starboard Value A LP,

its managing member

STARBOARD VALUE LP

By: Starboard Value GP LLC,

its general partner

STARBOARD VALUE GP LLC

By: Starboard Principal Co LP,

its member

STARBOARD PRINCIPAL CO LP

By: Starboard Principal Co GP LLC,

its general partner

STARBOARD PRINCIPAL CO GP LLC

Starboard Value A GP LLC

Starboard Value R GP LLC

CUSIP No. 447011107



By:	/s/ Jeffrey C. Smith
	Name:	Jeffrey C. Smith
	Title:	Authorized Signatory

/s/ Jeffrey C. Smith

Jeffrey C. Smith

Individually and as attorney-in-fact for Peter A. Feld

CUSIP No. 447011107

SCHEDULE A

Directors and Officers of Starboard Value and Opportunity Master Fund Ltd and Starboard X Master Fund Ltd

Name and Position	Principal Occupation	Principal Business Address	Citizenship
Patrick Agemian Director	Director of Global Funds Management, Ltd.	PO Box 10034, Harbour Place 2nd Floor 103 South Church Street Grand Cayman Cayman Islands, KY1-1001	Canada
Kenneth R. Marlin Director	Chief Financial Officer, Starboard Value LP	777 Third Avenue, 18th Floor New York, New York 10017	United States of America
Alaina Danley Director	Managing Director of Waystone Governance Ltd.	Waystone Governance Ltd. Suite 5B201, 2nd Floor One Nexus Way P.O. Box 2587 Grand Cayman Cayman Islands, KY1-1103	Cayman Islands

CUSIP No. 447011107

SCHEDULE B

Transactions in the Shares During the Past Sixty Days

Nature of the Transaction

Amount of Securities

Purchased/(Sold)

Price ($)

Date of

Purchase/Sale

STARBOARD VALUE AND OPPORTUNITY MASTER FUND LTD

Purchase of Forward Contract	85,500	25.9928	08/02/2021
Purchase of Forward Contract	28,500	25.4313	08/03/2021
Purchase of Forward Contract	57,000	25.3757	08/04/2021
Purchase of Forward Contract	171,000	26.1454	08/11/2021
Purchase of Forward Contract	114,000	25.9427	08/12/2021
Purchase of Forward Contract	71,250	25.6779	08/13/2021
Purchase of Forward Contract	142,500	25.3363	08/16/2021
Purchase of Forward Contract	171,000	25.0422

SEC Form SC 13D filed by Huntsman Corporation