X0206 3 2021-06-16 0 0001815849 ATI Physical Therapy, Inc. ATIP 0001034196 ADVENT INTERNATIONAL CORP/MA PRUDENTIAL TOWER, 800 BOYLSTON STREET, SUITE 3300 BOSTON MA 02199 0 0 1 0 0001551275 Advent International GPE VII-A Limited Partnership C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 BOSTON MA 02199 0 0 1 0 0001551364 Advent International GPE VII-E Limited Partnership C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 BOSTON MA 02199 0 0 1 0 0001553021 Advent International GPE VII-H Limited Partnership C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 BOSTON MA 02199 0 0 1 0 0001616580 GPE VII GP Limited Partnership C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 BOSTON MA 02199 0 0 1 0 0001616578 Advent Partners GPE VII 2014 Limited Partnership C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 BOSTON MA 02199 0 0 1 0 0001616563 Advent Partners GPE VII 2014 Cayman Limited Partnership C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 BOSTON MA 02199 0 0 1 0 0001616577 Advent Partners GPE VII-A 2014 Limited Partnership C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 BOSTON MA 02199 0 0 1 0 0001616564 Advent Partners GPE VII-A 2014 Cayman Limited Partnership C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 BOSTON MA 02199 0 0 1 0 0001561808 Advent Partners GPE VII Cayman Limited Partnership C/O ADVENT INTERNATIONAL CORPORATION 800 BOYLSTON STREET, SUITE 3300 BOSTON MA 02199 0 0 1 0 Class A Common Stock, par value $0.0001 per share 130300000 I See Footnotes Earnout Shares Class A Common Stock, par value $0.0001 per share 15000000 I See notes See Exhibit 99.1 for text of footnote (1) See Exhibit 99.1 for text of footnote (2) See Exhibit 99.1 for text of footnote (3) See Exhibit 99.1 for text of footnote (4) 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 2021-06-28