SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person* ADVENT INTERNATIONAL CORP/MA (Last) (First) (Middle) PRUDENTIAL TOWER, 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 06/16/2021	3. Issuer Name and Ticker or Trading Symbol ATI Physical Therapy, Inc. [ ATIP ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Class A Common Stock, par value $0.0001 per share	130,300,000(1)	I	See Footnotes(2)(4)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Earnout Shares	(3)	(3)	Class A Common Stock, par value $0.0001 per share	15,000,000	(3)	I	See notes(2)(4)

1. Name and Address of Reporting Person* ADVENT INTERNATIONAL CORP/MA (Last) (First) (Middle) PRUDENTIAL TOWER, 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Advent International GPE VII-A Limited Partnership (Last) (First) (Middle) C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Advent International GPE VII-E Limited Partnership (Last) (First) (Middle) C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Advent International GPE VII-H Limited Partnership (Last) (First) (Middle) C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* GPE VII GP Limited Partnership (Last) (First) (Middle) C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Advent Partners GPE VII 2014 Limited Partnership (Last) (First) (Middle) C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Advent Partners GPE VII 2014 Cayman Limited Partnership (Last) (First) (Middle) C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Advent Partners GPE VII-A 2014 Limited Partnership (Last) (First) (Middle) C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Advent Partners GPE VII-A 2014 Cayman Limited Partnership (Last) (First) (Middle) C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Advent Partners GPE VII Cayman Limited Partnership (Last) (First) (Middle) C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 (Street) BOSTON MA 02199 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. See Exhibit 99.1 for text of footnote (1)

2. See Exhibit 99.1 for text of footnote (2)

3. See Exhibit 99.1 for text of footnote (3)

4. See Exhibit 99.1 for text of footnote (4)

Remarks:

Exhibit 99.1 (Signatures and Joint Filer Information) and Exhibit 99.2 (Joint Filer Information) are incorporated herein by reference. This Form 3 is the second of three Forms 3 being filed relating to the same event. The Form 3 has been split into three filings because there are more than 10 Reporting Persons in total, and the SEC's EDGAR filing system limits a single Form 3 to a maximum of 10 Reporting Persons. Each Form 3 will be filed by Designated Filer Advent International Corporation. Form 2 of 3

	Advent International Corporation, /s/ James Westra, Name: James Westra, Title: General Counsel and Managing Partner	06/28/2021
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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