SC 13G

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. )*

Avantor, Inc.

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

05352A100

(CUSIP Number)

December 31, 2019

(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)

*	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 the disclosures provided in a prior cover page.

The information required in 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. 05352A100		SCHEDULE 13G		Page 2 of 12


1	NAME OF REPORTING PERSON OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON New Mountain Partners III, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐ (b) ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 110,477,989
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 110,477,989
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 110,477,989
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 19.3%
12	TYPE OF REPORTING PERSON PN


CUSIP No. 05352A100		SCHEDULE 13G		Page 3 of 12


1	NAME OF REPORTING PERSON OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON New Mountain Investments III, L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐ (b) ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 110,477,989
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 110,477,989
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 110,477,989
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 19.3%
12	TYPE OF REPORTING PERSON OO


CUSIP No. 05352A100		SCHEDULE 13G		Page 4 of 12


1	NAME OF REPORTING PERSON OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON New Mountain Capital, L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐ (b) ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 110,477,989
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 110,477,989
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 110,477,989
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 19.3%
12	TYPE OF REPORTING PERSON OO


CUSIP No. 05352A100		SCHEDULE 13G		Page 5 of 12


1	NAME OF REPORTING PERSON OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON New Mountain Capital Group, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐ (b) ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 110,477,989
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 110,477,989
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 110,477,989
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 19.3%
12	TYPE OF REPORTING PERSON PN


CUSIP No. 05352A100		SCHEDULE 13G		Page 6 of 12


1	NAME OF REPORTING PERSON OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON NM Holdings GP, L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐ (b) ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 110,477,989
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 110,477,989
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 110,477,989
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 19.3%
12	TYPE OF REPORTING PERSON OO


CUSIP No. 05352A100		SCHEDULE 13G		Page 7 of 12


1	NAME OF REPORTING PERSON OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Steven B. Klinsky
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐ (b) ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION United States of America
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 110,477,989
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 110,477,989
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 110,477,989
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 19.3%
12	TYPE OF REPORTING PERSON IN


Item 1.	(a).	Name of Issuer:

		Avantor, Inc. (the “Issuer”).

	(b).	Address of issuer’s principal executive offices:

		Radnor Corporate Center, Building One, Suite 200 100 Matsonford Road Radnor, Pennsylvania 19087

Item 2.	(a).	Name of person filing:

		This Schedule 13G (this “Statement”) is being filed by the following persons (the “Reporting Persons”):

		(i)	New Mountain Partners III, L.P.;
		(ii)	New Mountain Investments III, L.L.C.;
		(iii)	New Mountain Capital, L.L.C.;
		(iv)	New Mountain Capital Group, L.P.;
		(v)	NM Holdings GP, L.L.C.; and
		(vi)	Steven B. Klinsky.

	(b).	Address or principal business office or, if none, residence:

		787 Seventh Avenue, 49th Floor New York, NY 10019

	(c).	Citizenship:

		The citizenship of each Reporting Person is set out in Item 4 of its cover page.

	(d).	Title of class of securities:

		Common stock, par value $0.01 per share (the “Common Stock”)

	(e).	CUSIP No.:

		05352A100

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:

	Not applicable.

Item 4.	Ownership.

	The information required by Items 4(a)-4(c) is set forth in Rows 5-11 of the cover page for each of the Reporting Persons and is incorporated herein by reference for each of the Reporting Persons.


		New Mountain Partners III, L.P. directly holds 110,477,989 shares of Common Stock. The general partner of New Mountain Partners III, L.P. is New Mountain Investments III, L.L.C. and the manager of New Mountain Partners III, L.P. is New Mountain Capital, L.L.C. Steven B. Klinsky is the managing member of New Mountain Investments III, L.L.C. The managing member of New Mountain Capital, L.L.C. is New Mountain Capital Group, L.P. The general partner of New Mountain Capital Group, L.P. is NM Holdings GP, L.L.C. Steven B. Klinsky is the managing member of NM Holdings GP, L.L.C. Calculation of the percentage of Common Stock beneficially owned is based on 571,734,767 shares of Common Stock outstanding as of October 30, 2019, as reported in the Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 5, 2019.

Item 5.		Ownership of Five Percent or Less of a Class.

		Not Applicable.

Item 6.		Ownership of More Than Five 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.

		Not Applicable.

Item 9.		Notice of Dissolution of Group.

		Not Applicable.

Item 10.		Certification.

		Not Applicable.

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.

Dated: February 14, 2020


NEW MOUNTAIN PARTNERS III, L.P.
By:		New Mountain Investments III, L.L.C., its general partner

By:		/s/ Steven B. Klinsky
Name:		Steven B. Klinsky
Title:		Managing Member

NEW MOUNTAIN INVESTMENTS III, L.L.C.

By:		/s/ Steven B. Klinsky
Name:		Steven B. Klinsky
Title:		Managing Member

NEW MOUNTAIN CAPITAL, L.L.C.
By:		New Mountain Capital Group, L.P., its managing member
By:		NM Holdings GP, L.L.C., its general partner

By:		/s/ Steven B. Klinsky
Name:		Steven B. Klinsky
Title:		Managing Member

NEW MOUNTAIN CAPITAL GROUP, L.P.
By:		NM Holdings GP, L.L.C., its general partner

By:		/s/ Steven B. Klinsky
Name:		Steven B. Klinsky
Title:		Managing Member

NM HOLDINGS GP, L.L.C.

By:		/s/ Steven B. Klinsky
Name:		Steven B. Klinsky
Title:		Managing Member

/s/ Steven B. Klinsky Steven B. Klinsky

EXHIBIT A

JOINT FILING AGREEMENT

The undersigned acknowledge and agree that the foregoing statement on Schedule 13G with respect to the common stock, par value $0.01 per share, of Avantor, Inc., is filed on behalf of each of the undersigned and that all subsequent amendments to this statement shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

This agreement may be executed in counterparts and each of such counterparts taken together shall constitute one and the same instrument.

IN WITNESS WHEREOF, the undersigned have executed this Agreement as of February 14, 2020.


NEW MOUNTAIN PARTNERS III, L.P.
By:		New Mountain Investments III, L.L.C., its general partner

By:		/s/ Steven B. Klinsky
Name:		Steven B. Klinsky
Title:		Managing Member

NEW MOUNTAIN INVESTMENTS III, L.L.C.

By:		/s/ Steven B. Klinsky
Name:		Steven B. Klinsky
Title:		Managing Member

NEW MOUNTAIN CAPITAL, L.L.C.
By:		New Mountain Capital Group, L.P., its managing member
By:		NM Holdings GP, L.L.C., its general partner

By:		/s/ Steven B. Klinsky
Name:		Steven B. Klinsky
Title:		Managing Member

NEW MOUNTAIN CAPITAL GROUP, L.P.
By:		NM Holdings GP, L.L.C., its general partner

By:		/s/ Steven B. Klinsky
Name:		Steven B. Klinsky
Title:		Managing Member



NM HOLDINGS GP, L.L.C.

By:		/s/ Steven B. Klinsky
Name:		Steven B. Klinsky
Title:		Managing Member

/s/ Steven B. Klinsky Steven B. Klinsky