Sec Form 13G Filing - Deerfield Mgmt, L.P. @ MALLINCKRODT PLC SHS

Insider filing report for Changes in Beneficial Ownership

Schedule 13G & 13D forms are used to report a party's ownership of stock which exceeds 5% of a company's total stock issue.
Schedule 13G is a shorter version of Schedule 13D with fewer reporting requirements.

"Insiders might sell their shares for any number of reasons, but they buy them for only one: they think the price will rise"
- Peter Lynch
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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 3)*

Mallinckrodt plc

(Name of Issuer)

Ordinary Shares, par value $0.01 per share

(Title of Class of Securities)

G5890A102

(CUSIP Number)

03/31/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No.

G5890A102

Names of Reporting Persons

Deerfield Mgmt, L.P.

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

Sec Use Only

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 804,258.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 804,258.00

Aggregate Amount Beneficially Owned by Each Reporting Person

804,258.00

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in row (9)

4.07 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person: Comprised of ordinary shares, par value $0.01 per share ("Ordinary Shares") held by Deerfield Partners, L.P., of which Deerfield Mgmt, L.P. is the general partner.

SCHEDULE 13G

CUSIP No.

G5890A102

Names of Reporting Persons

Deerfield Mgmt IV, L.P.

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

Sec Use Only

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1.00

Aggregate Amount Beneficially Owned by Each Reporting Person

1.00

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in row (9)

0 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person: Comprised of 1 Ordinary Share held by Deerfield Private Design Fund IV, L.P., of which Deerfield Mgmt IV, L.P. is the general partner.

SCHEDULE 13G

CUSIP No.

G5890A102

Names of Reporting Persons

Deerfield Partners, L.P.

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

Sec Use Only

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 804,258.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 804,258.00

Aggregate Amount Beneficially Owned by Each Reporting Person

804,258.00

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in row (9)

4.07 %

Type of Reporting Person (See Instructions)

SCHEDULE 13G

CUSIP No.

G5890A102

Names of Reporting Persons

Deerfield Private Design Fund IV, L.P.

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

Sec Use Only

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1.00

Aggregate Amount Beneficially Owned by Each Reporting Person

1.00

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in row (9)

0 %

Type of Reporting Person (See Instructions)

SCHEDULE 13G

CUSIP No.

G5890A102

Names of Reporting Persons

Deerfield Management Company, L.P.

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

Sec Use Only

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 804,259.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 804,259.00

Aggregate Amount Beneficially Owned by Each Reporting Person

804,259.00

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in row (9)

4.07 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person: Comprised of 804,258 Ordinary Shares held by Deerfield Partners, L.P. and 1 Ordinary Share held by Deerfield Private Design Fund IV, L.P., of which Deerfield Management Company, L.P. is the investment advisor.

SCHEDULE 13G

CUSIP No.

G5890A102

Names of Reporting Persons

James E. Flynn

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

Sec Use Only

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 804,259.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 804,259.00

Aggregate Amount Beneficially Owned by Each Reporting Person

804,259.00

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in row (9)

4.07 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person: Comprised of 804,258 Ordinary Shares held by Deerfield Partners, L.P. and 1 Ordinary Share held by Deerfield Private Design Fund IV, L.P.

SCHEDULE 13G

Item 1.

(a)

Name of issuer:

Mallinckrodt plc

(b)

Address of issuer's principal executive offices:

College Business & Technology Park, Cruiserath, Blanchardstown, Dublin 15, Ireland

Item 2.

(a)

Name of person filing:

James E. Flynn, Deerfield Mgmt, L.P., Deerfield Mgmt IV, L.P., Deerfield Management Company, L.P., Deerfield Partners, L.P. and Deerfield Private Design Fund IV, L.P.

(b)

Address or principal business office or, if none, residence:

James E. Flynn, Deerfield Mgmt, L.P., Deerfield Mgmt IV, L.P., Deerfield Management Company, L.P., Deerfield Partners, L.P. and Deerfield Private Design Fund IV, L.P., 345 Park Avenue South, 12th Floor, New York, NY 10010

(c)

Citizenship:

Deerfield Mgmt, L.P., Deerfield Mgmt IV, L.P., Deerfield Management Company, L.P., Deerfield Partners, L.P. and Deerfield Private Design Fund IV, L.P. - Delaware limited partnerships; James E. Flynn - United States citizen

(d)

Title of class of securities:

Ordinary Shares, par value $0.01 per share

(e)

CUSIP No.:

G5890A102

Item 3.

If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

(a)

Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);

(b)

Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);

(c)

Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);

(d)

Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);

(e)

An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);

(f)

An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);

(g)

A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

(h)

A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i)

A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j)

A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:

(k)

Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).

Item 4.

Ownership

(a)

Amount beneficially owned:

Deerfield Mgmt, L.P. - 804,258 shares Deerfield Mgmt IV, L.P. - 1 share Deerfield Management Company, L.P. - 804,259 shares Deerfield Partners, L.P. - 804,258 shares Deerfield Private Design Fund IV, L.P. - 1 share James E. Flynn - 804,258 shares

(b)

Percent of class:

Deerfield Mgmt, L.P. - 4.07% Deerfield Mgmt IV, L.P. - 0.00% Deerfield Management Company, L.P. - 4.07% Deerfield Partners, L.P. - 4.07% Deerfield Private Design Fund IV, L.P. - 0.00% James E. Flynn - 4.07% %

(c)

Number of shares as to which the person has:

(i) Sole power to vote or to direct the vote:

All Reporting Persons - 0

(ii) Shared power to vote or to direct the vote:

Deerfield Mgmt, L.P. - 804,258 Deerfield Mgmt IV, L.P. - 1 Deerfield Management Company, L.P. - 804,259 Deerfield Partners, L.P. - 804,258 Deerfield Private Design Fund IV, L.P. - 1 James E. Flynn - 804,259

(iii) Sole power to dispose or to direct the disposition of:

All Reporting Persons - 0

(iv) Shared power to dispose or to direct the disposition of:

Item 5.

Ownership of 5 Percent or Less of a Class.

Ownership of 5 percent or less of a class

Item 6.

Ownership of more than 5 Percent on Behalf of Another Person.

Not Applicable

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

Not Applicable

Item 8.

Identification and Classification of Members of the Group.

If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group.

See Exhibit B

Item 9.

Notice of Dissolution of Group.

Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

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

Deerfield Mgmt, L.P.

Signature:	/s/ Jonathan Isler
Name/Title:	Jonathan Isler, Attorney-In-Fact
Date:	05/13/2025

Deerfield Mgmt IV, L.P.

Signature:	/s/ Jonathan Isler
Name/Title:	Jonathan Isler, Attorney-In-Fact
Date:	05/13/2025

Deerfield Partners, L.P.

Signature:	/s/ Jonathan Isler
Name/Title:	Jonathan Isler, Attorney-In-Fact
Date:	05/13/2025

Deerfield Private Design Fund IV, L.P.

Signature:	/s/ Jonathan Isler
Name/Title:	Jonathan Isler, Attorney-In-Fact
Date:	05/13/2025

Deerfield Management Company, L.P.

Signature:	/s/ Jonathan Isler
Name/Title:	Jonathan Isler, Attorney-In-Fact
Date:	05/13/2025

James E. Flynn

Signature:	/s/ Jonathan Isler
Name/Title:	Jonathan Isler, Attorney-In-Fact
Date:	05/13/2025

Exhibit Information

Exhibit A. Joint Filing Agreement. Exhibit B. Item 8 Statement. Exhibit C. Power of Attorney (1). (1) Power of Attorney previously filed as Exhibit 24 to a Form 3 with regard to BiomX Inc. filed with the Securities and Exchange Commission on March 19, 2024 by Deerfield Private Design Fund V, L.P., Deerfield Healthcare Innovations Fund II, L.P., Deerfield Mgmt V, L.P., Deerfield Mgmt HIF II, L.P., Deerfield Management Company, L.P. and James E. Flynn.

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Sec Form 13G Filing - Deerfield Mgmt, L.P. filing for - 2025-05-13