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. 4)¹

Magellan Health, Inc.

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

559079207

(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)

January 4, 2022

(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. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD VALUE LP
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	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					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			PN

2

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD VALUE AND OPPORTUNITY MASTER FUND LTD
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			CAYMAN ISLANDS
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			CO

3

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD VALUE AND OPPORTUNITY S LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	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					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			OO

4

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD VALUE AND OPPORTUNITY C LP
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	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					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			PN

5

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD VALUE R LP
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	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					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			PN

6

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD VALUE AND OPPORTUNITY MASTER FUND L LP
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			CAYMAN ISLANDS
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			PN

7

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD VALUE L LP
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	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					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			PN

8

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD VALUE R GP LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	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					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			OO

9

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD X MASTER FUND LTD
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			CAYMAN ISLANDS
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			CO

10

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD VALUE GP LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	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					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			OO

11

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD PRINCIPAL CO LP
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	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					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			PN

12

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			STARBOARD PRINCIPAL CO GP LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	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					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			OO

13

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			JEFFREY C. SMITH
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			USA
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			IN

14

CUSIP No. 559079207

	1	NAME OF REPORTING PERSON
			PETER A. FELD
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☐
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			USA
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			- 0 -
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			0%
	14	TYPE OF REPORTING PERSON
			IN

15

CUSIP No. 559079207

The following constitutes Amendment No. 4 to the Schedule 13D filed by the undersigned (“Amendment No. 4”). This Amendment No. 4 amends the Schedule 13D as specifically set forth herein.

Item 4. Purpose of Transaction.

Item 4 is hereby amended to add the following:

As previously disclosed, on January 4, 2021, the Issuer entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Centene Corporation (“Centene”) and Mayflower Merger Sub, Inc., a wholly owned subsidiary of Centene (“Merger Sub”), providing for the merger of Merger Sub with and into the Issuer (the “Merger”), with the Issuer surviving the Merger as a wholly owned subsidiary of Centene. On January 4, 2022, pursuant to the terms and conditions of the Merger Agreement, Merger Sub was merged with and into the Issuer, with the Issuer surviving as a wholly owned subsidiary of Centene. At the effective time of the Merger (the “Effective Time”), each Share of the Issuer owned by the Reporting Persons immediately prior to the Effective Time was canceled and automatically converted into the right to receive $95 in cash, without interest, pursuant to the Merger Agreement. Accordingly, as a result of the Merger, the Reporting Persons no longer beneficially own any Shares of the Issuer.

Item 5. Interest in Securities of the Issuer.

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

(a) – (b) Effective January 4, 2022, as a result of the Merger, each Share owned by the Reporting Persons was converted into the right to receive $95 in cash, without interest, pursuant to the Merger Agreement. Accordingly, the Reporting Persons no longer beneficially own any Shares of the Issuer.

(c) The Reporting Persons have not entered into any transactions in the Shares during the past sixty days.

(d) Not applicable.

(e) As of the close of business on January 4, 2022, the Reporting Persons ceased to be the beneficial owners of more than 5% of the Shares of the Issuer.

16

CUSIP No. 559079207

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: January 6, 2022

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 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 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 R GP LLC

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

17