Contract

Execution Version WEIL:\99037057\16\18434.0011 THIS TRANSACTION SUPPORT AGREEMENT IS NOT AND SHALL NOT BE DEEMED AN OFFER OR ACCEPTANCE WITH RESPECT TO ANY SECURITIES. ANY SUCH OFFER OR SOLICITATION WILL COMPLY WITH ALL APPLICABLE SECURITIES LAWS. NOTHING CONTAINED IN THIS TRANSACTION SUPPORT AGREEMENT SHALL BE AN ADMISSION OF FACT OR LIABILITY OR, UNTIL THE OCCURRENCE OF THE SUPPORT EFFECTIVE DATE (AS DEFINED HEREIN), DEEMED BINDING ON ANY OF THE PARTIES TO THIS AGREEMENT ON THE TERMS DESCRIBED IN THIS AGREEMENT. TRANSACTION SUPPORT AGREEMENT This TRANSACTION SUPPORT AGREEMENT (together with all exhibits, schedules, and attachments hereto, as amended, supplemented, amended and restated, or otherwise modified from time to time in accordance with the terms hereof, this “Agreement”), dated as of March 15, 2023, is entered into by and among: (i) ATI Physical Therapy Inc. (“Topco”), ATI Holdings Acquisition, Inc. (the “Borrower”), Wilco Intermediate Holdings, Inc. (“Holdings”) and the Guarantors under the Credit Agreement (each, a “Company Party” and collectively, the “Company” or the “Company Parties”); (ii) Barclays Bank PLC (“Barclays”), as lender under the Credit Agreement; (iii) Barclays, as Administrative Agent under the Credit Agreement (pursuant to Section 28 hereof); (iv) HPS Investment Partners, LLC, as Lender Representative under the Credit Agreement and each HPS Lender under the Credit Agreement (“HPS” and together with Barclays, the “Consenting First Lien Lenders”); (v) Certain entities affiliated with or managed by, or affiliates of each of (a) Knighthead Capital Management, LLC, (b) Marathon Asset Management LP, (c) Onex Credit Management LLC and Onex Credit Partners, LLC, and (d) Caspian Capital L.P., as holders of 100% of the Preferred Stock and, to the extent specified on the signature pages hereto, as lenders under the Credit Agreement; and (vi) The undersigned investment entities affiliated with Advent International Corporation (“Advent” and together with the Consenting First Lien Lenders and the Consenting Preferred Equityholders, the “Consenting Stakeholders”), as holder of the majority of the Common Stock issued and outstanding as of the date hereof. Each Company Party and Consenting Stakeholder is referred to as a “Party” and collectively, the “Parties.” WHEREAS, the Parties have agreed to undertake the Transaction (as defined herein) on the terms and subject to the conditions set forth herein, including as set forth in the Transaction Exhibit 10.1

-3- WEIL:\99037057\16\18434.0011 equitization, recapitalization, refinancing, material amendment, new money financing transaction or restructuring of any of the Company Parties or their assets other than the Transaction, as set forth in the Transaction Term Sheet. (d) “Assignment and Assumption Agreement” means the Master Assignment and Assumption Agreement, the terms and conditions of which are materially set forth in the Transaction Term Sheet. (e) “Certificate of Designation Amendment” means that certain Certificate of Amendment to Certificate of Designation of Series A Senior Preferred Stock of Topco, filed with the Delaware Secretary of State on or prior to the Closing Date. (f) “Claim” means, except as otherwise defined solely for the purposes of section 6 of this Agreement, any right to payment, whether or not such right is reduced to judgment, liquidated, unliquidated, fixed, contingent, matured, unmatured, disputed, undisputed, legal, equitable, secured, or unsecured. (g) “Closing Date” means the date on which the Transaction is consummated. (h) “Common Stock” means Topco’s issued and outstanding Class A common stock. (i) “Consenting Crossholder” means any party to this agreement which is both a lender under the Credit Agreement and a holder of Preferred Stock, in each case as indicated on the signature page or applicable Joinder Agreement for such party. (j) “Consenting Preferred Equityholder” means any party to this agreement which is a holder of Preferred Stock, as indicated on the signature page or applicable Joinder Agreement for such party. (k) “Consenting Preferred Equityholders’ Consent” means that certain Action by Written Consent of the Series A Senior Preferred Stockholders of the Company approving the Transaction and certain related matters. (l) “Credit Agreement” means that certain Credit Agreement, dated as of February 24, 2022, by and among the Borrower, Holdings, the lenders party thereto, Barclays, as Administrative Agent (together with its permitted successors and assigns in such capacity, the “Administrative Agent”), and HPS Investment Partners LLC, as Lender Representative, as amended by that certain Amendment No. 1 to Credit Agreement dated as of March 30, 2022. (m) “Credit Agreement Amendment” means Amendment No. 2 to the Credit Agreement, the material terms and conditions of which are set forth in the Transaction Term Sheet and Exhibit B to the Transaction Term Sheet. (n) “Default” has the meaning assigned to such term in the Credit Agreement. (o) “Definitive Documents” means the material agreements that are necessary to implement the Transaction, including, but not limited to: (a) the Credit Agreement Amendment, (b) the Assignment and Assumption Agreement, (c) any documents relating to the New Money Exhibit 10.1

-4- WEIL:\99037057\16\18434.0011 Financing, including, without limitation, the Second Lien Note Purchase Agreement, the Intercreditor Agreement, and the Registration Rights Agreement, (d) any documents relating to the Preferred Stock, including, without limitation, the Investors’ Rights Agreement Amendment, the Certificate of Designation Amendment, and the Consenting Preferred Equityholders’ Consent, (e) the Management Incentive Program, (f) any other documents related to the amendment and/or restatement of the Organizational Documents of the Company required to implement the Transaction, (g) an amendment to the Agreement Among Lenders and (h) such other related documents and ancillary agreements required to implement the Transaction. (p) “Event of Default” has the meaning assigned to such term in the Credit Agreement. (q) “Fees and Expenses” has the meaning set forth in Section 4(v). (r) “First Lien Loans” means the Term Loans and the Revolving Loans. (s) “First Lien Termination Event” means, solely with respect to the Consenting First Lien Lenders, any of the following: (i) if (a) any Default that is, in the good faith determination of the Company, incapable of being cured or (b) an Event of Default shall occur under the Credit Agreement; provided, that, clause (i) shall not apply to any Specified Default; or (ii) notice of the occurrence of a Consenting Stakeholder Termination Event by any other Consenting Stakeholder. (t) “Governmental Authority” means any federal, state, local or other governmental authority having jurisdiction over any of the Company Parties. (u) “Intercreditor Agreement” means the subordination and intercreditor agreement, to be entered as of the Closing Date, by and among the Administrative Agent on behalf of the holders of the First Lien Loans and an agent to be determined on behalf of the New Second Lien PIK Exchangeable Notes. (v) “Interest” means any capital stock, membership interest, partnership interest, or other equity security or rights exercisable or exchangeable into capital stock or any other equity security, whether vested or unvested, of a Company Party. (w) “Investors’ Rights Agreement” means that certain Investors’ Rights Agreement, dated February 24, 2022, by and among Topco and the Consenting Preferred Equityholders, among others. (x) “Investors’ Rights Agreement Amendment” means that certain First Amendment to the Investors’ Rights Agreement, to be entered as of the Closing Date, by and among Topco and the Consenting Preferred Equityholders party thereto. (y) “Joinder Agreement” means a joinder to this Agreement substantially in the form attached to this Agreement as Exhibit B providing, among other things, that such Person signatory thereto is bound by the terms of this Agreement. For the avoidance of doubt, any party that executes a Joinder Agreement shall be a “Consenting Stakeholder” and “Party” under this Agreement as provided therein. Exhibit 10.1

-5- WEIL:\99037057\16\18434.0011 (z) “Loan Documents” has the meaning assigned to such term in the Credit Agreement. (aa) “Majority Consenting Preferred Equityholders” means, at any time, Consenting Preferred Equityholders that collectively beneficially own or control more than at least 50% of all issued and outstanding Preferred Stock at such time. (bb) “Management Incentive Program” means that certain management incentive program to be adopted by Xxxxx as of the Closing Date on terms and conditions reasonably acceptable to each of the Consenting Stakeholders. (cc) “New Money Financing” has the meaning set forth in the Transaction Term Sheet. (dd) “New Second Lien PIK Exchangeable Notes” means the new second lien PIK exchangeable notes to be issued by the Borrower (or, upon the request of the Majority Consenting Preferred Equityholders, Topco) to the Consenting Preferred Equityholders, the material terms of which are set forth in the Transaction Term Sheet. (ee) “Organizational Documents” means (a) with respect to a corporation, the charter, articles or certificate of incorporation, as applicable, and bylaws thereof, (b) with respect to a limited liability company, the certificate of formation or organization, as applicable, and the operating or limited liability company agreement thereof, (c) with respect to a partnership, the certificate of formation and the partnership agreement, and (d) with respect to any other Person the organizational, constituent and/or governing documents and/or instruments of such Person. (ff) “Outside Closing Date” means June 15, 2023. (gg) “Outside Signing Date” means April 15, 2023. (hh) “Person” means any “person” as defined in section 101(41) of the Bankruptcy Code, including any individual, corporation, limited liability company, partnership, joint venture, association, joint-stock company, trust, unincorporated organization or government or any agency or political subdivision thereof or other entity. (ii) “Preferred Equity Held Term Loans” means the Term Loans held by the Consenting Crossholders or their respective affiliates. (jj) “Preferred Stock” means Topco’s issued and outstanding Series A Preferred Stock. (kk) “Registration Rights Agreement” means a registration rights agreement to be entered as of the Closing Date, by and among Topco and the Consenting Preferred Equityholders for the benefit of the holders of the New Second Lien PIK Exchangeable Notes and the shares of Common Stock into which such notes are exchangeable. (ll) “Revolving Credit Facility” means the “Revolving Facility” as defined in the Credit Agreement. Exhibit 10.1

-9- WEIL:\99037057\16\18434.0011 Lenders to insist upon compliance with this Agreement or any Loan Document during the TSA Support Period. (2) Nothing has occurred that constitutes or otherwise can be construed or interpreted as a waiver of, or, except as expressly set forth in this Section 3(b)(ii) with respect to any Specified Default, otherwise to limit in any respect, any rights, remedies, powers, privileges and defenses that the Administrative Agent, the Consenting First Lien Lenders or any other lenders under the Credit Agreement have or may have arising as the result of any Default or Event of Default (including any Specified Default) that has occurred or that may occur under the Credit Agreement, the other Loan Documents or applicable law. Except as expressly set forth in this Section 3(b)(ii) with respect to any Specified Default, the Consenting First Lien Lenders’ actions in entering into this Agreement are without prejudice to the rights of any of the Administrative Agent, the Consenting First Lien Lenders or any other lenders under the Credit Agreement to pursue any and all remedies under the Loan Documents pursuant to applicable law or in equity available to it in its sole discretion upon the termination (whether upon expiration thereof, upon acceleration or otherwise) of the TSA Support Period. (3) All of the assets pledged, assigned, conveyed, mortgaged, hypothecated or transferred to the Administrative Agent pursuant to the Collateral Documents (as defined in the Credit Agreement) are (and shall continue to be) subject to valid and enforceable, subject to the Legal Reservations (as defined in the Credit Agreement), liens and security interests of the Administrative Agent, as collateral security for all of the Secured Obligations (as defined in the Credit Agreement), subject to no Liens other than Liens permitted by Section 6.02 of the Credit Agreement, and all of the Secured Obligations are secured by unavoidable, subject to the Legal Reservations, first-priority, subject to Liens permitted by Section 6.02 of the Credit Agreement, security interest in and liens on the Collateral, as described in the Collateral Documents. Each Company Party (for itself and for each of their respective subsidiaries) hereby reaffirms and ratifies its prior conveyance to the Administrative Agent of a continuing security interest in and lien on the Collateral (as defined in the Credit Agreement). There are no offsets, counterclaims or defenses (other than any defense arising from the permitted release of any Loan Party from its obligations under the Loan Documents in accordance with the express terms thereof) to any of the Secured Obligations, nor are there any bases for any arguments for avoidance, recharacterization, subordination or any other claim, cause of action or other challenge of any kind to the Secured Obligations or the security interests in and liens on the Collateral, as applicable, under the Bankruptcy Code or under any other applicable law or otherwise. (4) Except as expressly set forth herein in this Section 3(b)(ii) with respect to any Specified Default, the Company Parties understand and accept the temporary nature of the forbearance provided hereby and that the Consenting First Lien Lenders have given no assurances that they will extend such forbearance beyond the TSA Support Period or provide waivers under or amendments to the Exhibit 10.1

-13- WEIL:\99037057\16\18434.0011 (iii) not (A) solicit, initiate or encourage the submission of any proposal or offer from any Person relating to an Alternative Transaction or (B) participate in any discussions or negotiations regarding, furnish any information with respect to, assist or participate in, or facilitate in any other manner any effort or attempt by any Person to do or seek any of the foregoing, provided that, the foregoing shall not limit the Company’s rights under section 8(e)(ii) in connection with the Fiduciary Out; (iv) not, nor encourage any other person or entity to, take any action which would, or would reasonably be expected to, breach or be inconsistent with this Agreement or delay, impede, appeal, or take any other negative action, directly or indirectly, to interfere with the consummation or implementation of the Transaction and, if such person or entity takes any action inconsistent with any Company Party’s obligations under this Agreement, the Company Party shall direct and use commercially reasonable efforts to cause such person or entity to cease, withdraw, and refrain from taking any such action; (v) (a) (I) no less than three (3) business days after the Support Effective Date and (II) during the TSA Support Period promptly (and no later than within five (5) business days after request) pay or reimburse the reasonable and documented, fees and out-of-pocket expenses of (1) Milbank LLP, counsel to HPS, (2) Xxxxx Xxxx & Xxxxxxxx LLP, counsel to the Consenting Preferred Equityholders, (3) Ropes & Gray LLP, counsel to Advent, and (4) Xxxxxx Xxxxxx & Xxxxxxx LLP, counsel to Barclays and the Administrative Agent (collectively, the “Fees and Expenses”), and (b) upon the Closing Date, pay or reimburse any unpaid Fees and Expenses, in each case incurred pursuant to the representation of their respective client in connection with the negotiation, implementation, or closing of the Transaction and in each case by wire transfer to the applicable professional of immediately available funds; (vi) prepare such proxy statements, information statements or other disclosure documents with respect to solicitations of the Topco’s existing shareholders necessary or advisable to implement the Transaction, including providing any and all information reasonably required in connection therewith; (vii) to the extent any legal or structural impediment arises that would prevent, hinder, or delay the consummation of the Transaction, negotiate in good faith appropriate additional or alternative provisions to address any such impediment; (viii) consent to the releases set forth in Section 6 hereof; (ix) provide prompt written notice (in accordance with Section 22 hereof) to the Consenting First Lien Lenders, the Consenting Preferred Equityholders and Advent between the date hereof and the Closing Date of (A) receipt of any written notice from any Governmental Authority in connection with this Agreement or the Transaction; and (B) receipt of any written notice of any proceeding commenced, or, to the actual knowledge of the Company Parties, threatened against the Company Parties, that, if successful, would prevent or materially interfere with, delay, or impede the consummation of the Transaction; (x) without limiting the generality of the foregoing, except as expressly contemplated by this Agreement or otherwise in the ordinary course of business consistent with Exhibit 10.1

-15- WEIL:\99037057\16\18434.0011 (vi) the Fees and Expenses as of such date shall be paid by the Company by wire transfer or immediately available funds. In addition, solely with respect to Barclays, the closing of the Transaction and the obligations of Barclays connection therewith are subject to the condition that each party to the Agreement Among Lenders shall have executed an amendment to the Agreement Among Lenders if required or reasonably requested by Barclays in connection with the Credit Agreement Amendment (which condition may be waived by Barclays). 6. Releases. (a) In consideration of the agreements of the Company, HPS, the Consenting Preferred Equityholders, Advent and Barclays contained herein and in the Definitive Documents, and for other good and valuable consideration the receipt and sufficiency of which are hereby acknowledged, except with respect to the representations, warranties and/or covenants of the Company, HPS, the Consenting Preferred Equityholders, Advent and Barclays contained in the Definitive Documents and any other related transaction documents, (I) each Company Party, on behalf of itself and its successors, assigns, and other legal representatives (the “Company Releasing Parties”), hereby absolutely, unconditionally and irrevocably releases, remises and forever discharges HPS, Barclays, each Consenting Preferred Equityholder, and Advent, and, in each case, its successors and assigns, and its present and former shareholders, direct and indirect owners, partners, members, managers, consultants, affiliates, subsidiaries, divisions, predecessors, directors, officers, employees, agents, attorneys, accountants, investment bankers, consultants and other representatives, and all Persons acting by, through, under or in concert with any of them, and each solely in their capacity as such (the “Company Released Parties”), (II) HPS, on behalf of itself and its successors, assigns, and other legal representatives (the “HPS Releasing Parties”), hereby absolutely, unconditionally and irrevocably releases, remises and forever discharges each Company Party, Consenting Preferred Equityholders (solely in such equityholder’s capacity as a Consenting Preferred Equityholder), Barclays and Advent, and, in each case, its successors and assigns, and its present and former shareholders, direct and indirect owners, partners, members, managers, consultants, affiliates, subsidiaries, divisions, predecessors, directors, officers, employees, agents, attorneys, accountants, investment bankers, consultants and other representatives, and all Persons acting by, through, under or in concert with any of them, and each solely in their capacity as such (the “HPS Released Parties”), (III) each Consenting Preferred Equityholder, on behalf of itself and its successors, assigns, and other legal representatives (the “Consenting Preferred Equityholder Releasing Parties”), hereby absolutely, unconditionally and irrevocably releases, remises and forever discharges each Company Party, HPS, Barclays and Advent and, in each case, its successors and assigns, and its present and former shareholders, direct and indirect owners, partners, members, managers, consultants, affiliates, subsidiaries, divisions, predecessors, directors, officers, employees, agents, attorneys, accountants, investment bankers, consultants and other representatives, and all Persons acting by, through, under or in concert with any of them, and each solely in their capacity as such (the “Consenting Preferred Equityholder Released Parties”), (IV) Advent, on behalf of itself and its successors, assigns, and other legal representatives (the “Advent Releasing Parties”), hereby absolutely, unconditionally and irrevocably releases, remises and forever discharges each Company Party, HPS, Barclays and each Consenting Preferred Equity Holder, and, in each case, its successors and assigns, and its present and former shareholders, direct and indirect owners, partners, members, Exhibit 10.1

-16- WEIL:\99037057\16\18434.0011 managers, consultants, affiliates, subsidiaries, divisions, predecessors, directors, officers, employees, agents, attorneys, accountants, investment bankers, consultants and other representatives, and all Persons acting by, through, under or in concert with any of them, and each solely in their capacity as such (the “Advent Released Parties”), and (V) Barclays, on behalf of itself and its successors, assigns, and other legal representatives (together with the Company Releasing Parties, the HPS Releasing Parties, the Consenting Preferred Equityholder Releasing Parties and the Advent Releasing Parties, the “Releasing Parties”) (each of (I)-(V) in their capacities as such), hereby absolutely, unconditionally and irrevocably releases, remises and forever discharges each Company Party, HPS, each Consenting Preferred Equity Holder and Advent, and, in each case, its successors and assigns, and its present and former shareholders, direct and indirect owners, partners, members, managers, consultants, affiliates, subsidiaries, divisions, predecessors, directors, officers, employees, agents, attorneys, accountants, investment bankers, consultants and other representatives, and all Persons acting by, through, under or in concert with any of them, and each solely in their capacity as such (together with the Company Released Parties, the HPS Released Parties, the Consenting Preferred Equityholder Released Parties and the Advent Released Parties, each in their capacities as such, the “Released Parties”), in each case, of and from all demands, actions, causes of action, suits, covenants, contracts, controversies, agreements, promises, sums of money, accounts, bills, reckonings, damages and any and all other claims, counterclaims, defenses, recoupment, rights of setoff, demands and liabilities whatsoever (individually, a “Claim” and collectively, “Claims”) of every name and nature, known or unknown, contingent or mature, suspected or unsuspected, both at law and in equity which any Releasing Party may now or hereafter own, hold, have or claim to have against the applicable Released Parties (as specified in this section 6(a)) or any of them for or on account of, or in relation to, or in any way in connection with the Company, the Company’s subsidiaries, the Transaction, actions taken to consummate the Transaction or any of the transactions contemplated thereunder or related thereto, and entry into the Definitive Documents; provided, that, (i) the release set forth in this Section 6(a) shall not be effective unless the Closing Date shall have occurred and (ii) nothing in this Section 6(a) shall be construed to (x) release the Released Parties from any (1) gross negligence, willful misconduct, or actual fraud, in each case as determined by a final order of a court of competent jurisdiction where such order is not subject to appeal, (2) Claims that arise solely from or relate to acts or omissions occurring after the Closing Date, (3) liability arising from or in connection with any pending shareholder or derivative actions filed against the Company or any of its officers and directors or any pending SEC inquiry or demand for information, or (4) obligations under, or waive any right to enforce, the terms of the Definitive Documents; or (y) (1) impact any Parties’ rights, as applicable and if any, to enforce the terms of the Loan Documents, including, without limitation, the indemnification provisions set forth therein, (2) constitute a waiver of any default or Event of Default arising thereunder or limit in any respect, any rights, remedies, powers, privileges and defenses that the Administrative Agent, the Consenting First Lien Lenders or any other lenders under the Credit Agreement have or may have arising as the result of any Default or Event of Default that has occurred or that may occur under the Credit Agreement or the other Loan Documents or (3) waive or release any indemnification and other obligations that are expressly stated in the Credit Agreement or any other Loan Document as surviving that respective agreement’s termination which shall remain in full force and effect. (b) Each Releasing Party understands, acknowledges and agrees that the release set forth above may be pleaded as a full and complete defense and may be used as a basis for an Exhibit 10.1

-19- WEIL:\99037057\16\18434.0011 representations, warranties, or covenants set forth herein in any material respect that remains uncured for a period of five (5) business days after the receipt of written notice of such breach pursuant to Section 22 hereof (as applicable); (ii) the Special Committee, boards of directors, or members (as applicable) of the Company Parties reasonably determines in good faith based upon the advice of outside counsel that continued performance under this Agreement or pursuit of the Transaction would be inconsistent with the exercise of its fiduciary duties under applicable law; provided, however, that in the event a Company Party desires to terminate this Agreement pursuant to this Section 8(e)(ii) (such right to terminate this Agreement pursuant to this Section 8(e)(ii), the “Fiduciary Out”), the Company Party shall as soon as reasonably practicable but in no event less than one (1) day advance written notice to the Consenting First Lien Lenders, the Consenting Preferred Equityholders and Advent prior to the date such Company Party elects to terminate this Agreement pursuant to the Fiduciary Out advising the Consenting First Lien Lenders, the Consenting Preferred Equityholders and Advent that such Company Party intends to terminate this Agreement pursuant to the Fiduciary Out; (iii) the issuance by any Governmental Authority, including any regulatory authority or court of competent jurisdiction, of any ruling, judgment or order declaring this Agreement to be unenforceable, enjoining the consummation of a material portion of the Transaction or rendering illegal this Agreement or the Transaction, where such ruling, judgment or order has not been not stayed, reversed or vacated within twenty-five (25) calendar days after such issuance and where the Company has used commercially reasonable efforts to cause such ruling to be stayed, reversed, or vacated; (iv) if any Consenting Stakeholder (A) publicly announces their intention not to support the Transaction or (B) validly terminates this Agreement as to themselves pursuant to Section 8(b), in which case the Company can terminate as to such Consenting Stakeholder; (v) if the Definitive Documents shall not have been executed by the requisite parties by the Outside Signing Date; or (vi) if the Transaction shall not have been consummated by the Outside Closing Date. Notwithstanding the foregoing, any of the dates or deadlines set forth in this Section 8 may be extended in writing by agreement of the Company, the Consenting First Lien Lenders, the Consenting Preferred Equityholders and Advent (email being sufficient), provided, for the avoidance of doubt, that the Outside Signing Date and Outside Closing Date shall only be extended in accordance with the terms of section 12 of this Agreement. (f) A “Consenting Stakeholder Termination Event” shall mean any of the following: (i) the material breach by any Company Party or another Consenting Stakeholder of (A) any covenant contained in this Agreement or (B) any other obligations of the Company Parties set forth in this Agreement, and, in each case, such breach remains uncured for Exhibit 10.1

-20- WEIL:\99037057\16\18434.0011 a period of five (5) business days after receipt of written notice thereof pursuant to Section 22 hereof (as applicable); (ii) the representations or warranties made by the Company will have been untrue in any material respect when made; (iii) the representations or warranties made by any Consenting Stakeholder will have been untrue in any material respect when made; (iv) the Definitive Documents and any amendments, modifications, or supplements thereto include terms that are materially inconsistent with the Transaction Term Sheet and are not otherwise reasonably acceptable to the Consenting Stakeholders who have consent rights over the applicable Definitive Document in accordance with Section 2(b) hereof, and such event remains unremedied for a period of five (5) business days following the Company Parties’ receipt of notice pursuant to Section 22 hereof (as applicable); (v) the issuance by any Governmental Authority, including any regulatory authority or court of competent jurisdiction, of any ruling, judgment or order declaring this Agreement to be unenforceable, enjoining the consummation of the Transaction or rendering illegal this Agreement or the Transaction, and either (A) such ruling, judgment or order has been issued at the request of or with the acquiescence of a Company Party, or (B) in all other circumstances, such ruling, judgment or order has not been not stayed, reversed or vacated within twenty-five (25) calendar days after such issuance; (vi) if any Company Party (A) proposes, supports or agrees in writing to pursue (including, for the avoidance of doubt, as may be evidenced by a duly executed term sheet, letter of intent, or similar document) an Alternative Transaction, or (B) validly terminates this Agreement as to themselves pursuant to Section 8(b); (vii) [reserved]; (viii) if the Definitive Documents shall not have been executed by the requisite parties by the Outside Signing Date; (ix) if the Transaction shall not have been consummated on or before the Outside Closing Date; (x) solely with respect to the Consenting First Lien Lenders, a First Lien Termination Event; (xi) with respect to any Consenting Stakeholder other than the Consenting First Lien Lenders, obligations under the Credit Agreement shall have been accelerated and/or one or more lenders shall have exercised remedies thereof; or (xii) with respect to Advent, this Agreement is terminated by (i) any of the Consenting First Lien Lenders or (ii) Consenting Preferred Equityholders that collectively beneficially own or control more than 50% of all issued and outstanding Preferred Stock as of the date of such termination. Exhibit 10.1

-23- WEIL:\99037057\16\18434.0011 (iii) the execution, delivery and performance by such Party of this Agreement does not and will not require any registration or filing with, consent or approval of, or notice to, or other action, with or by, any federal, state or Governmental Authority or regulatory body; (iv) this Agreement is the legally valid and binding obligation of such Party, enforceable against it in accordance with its terms, except as enforcement may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or limiting creditors’ rights generally or by equitable principles relating to enforceability; (v) such Party (A) is a sophisticated party with respect to the subject matter of this Agreement and the transactions contemplated hereby, (B) has adequate information concerning the matters that are the subject of this Agreement and the transactions contemplated hereby, (C) has such knowledge and experience in financial and business matters of this type that it is capable of evaluating the merits and risks of entering into this Agreement and of making an informed investment decision, and has independently and without reliance upon any warranty or representation by, or information from, any other Party or any officer, employee, agent or representative thereof, of any sort, oral or written, except the warranties and representations expressly set forth in this Agreement, and based on such information as such Party has deemed appropriate, made its own analysis and decision to enter into this Agreement and the transaction contemplated hereby, and (D) acknowledges that it has entered into this Agreement voluntarily and of its own choice and not under coercion or duress; (vi) with respect to the Company, such Party is not aware of the occurrence of any event, fact or circumstance that, due to any fiduciary or similar duty to any other Person, would prevent it from taking any action required of it under this Agreement; and (vii) such Party is not currently engaged in any discussions, negotiations or other arrangements with respect to any Alternative Transaction. (b) Each Consenting First Lien Lender, severally and not jointly, represents and warrants to the other Parties that such Consenting First Lien Lender is the beneficial owner of the aggregate principal amount of Term Loans or Revolving Loans, as applicable, set forth below its name on the signature page hereto, free and clear of any restrictions on transfer, liens, or options, warrants, purchase rights, contracts, commitments, claims, demands, and other encumbrances and does not own any other First Lien Loans, and/or (B) has sole investment and/or voting discretion and/or authority to vote on and provide consent or waivers with respect to such Term Loans or Revolving Loans. (c) Each Consenting Preferred Equityholder, severally and not jointly, represents and warrants to the other Parties that, as of the date hereof, each Consenting Preferred Equityholder (i) is the owner of the number of shares of Preferred Stock set forth below its name on the signature page hereto, free and clear of any restrictions on transfer, liens or options, warrants, purchase rights, contracts, commitments, claims, demands, and other encumbrances and does not own any other existing equity interests and (ii) has (A) sole investment or voting discretion with respect thereto, and (B) full power and authority to vote on and consent to matters concerning such equity interests or to exchange, assign, and transfer such equity interests. Exhibit 10.1

-26- WEIL:\99037057\16\18434.0011 14. Governing Law; Jurisdiction; Waiver of Jury Trial (a) This Agreement shall be construed and enforced in accordance with, and the rights of the Parties shall be governed by, the law of the State of New York, without giving effect to the conflict of laws principles thereof. Each of the Parties irrevocably agrees that any legal action, suit or proceeding arising out of or relating to this Agreement brought by any Party or its successors or assigns shall be brought and determined in any federal or state court in the Borough of Manhattan in the State of New York, and, in the event the Company becomes the subject of any bankruptcy cases under chapter 11 of title 11 of the United States Code, the presiding bankruptcy court, and each of the Parties hereby irrevocably submits to the exclusive jurisdiction of the aforesaid courts for itself and with respect to its property, generally and unconditionally, with regard to any such proceeding arising out of or relating to this Agreement or the Transaction. Each of the Parties agrees not to commence any proceeding relating hereto or thereto except in the courts described above, other than proceedings in any court of competent jurisdiction to enforce any judgment, decree or award rendered by any such court as described herein. Each of the Parties further agrees that notice as provided herein shall constitute sufficient service of process and the Parties further waive any argument that such service is insufficient. Each of the Parties hereby irrevocably and unconditionally waives, and agrees not to assert, by way of motion or as a defense, counterclaim or otherwise, in any proceeding arising out of or relating to this Agreement or the Transaction, (i) any claim that it is not personally subject to the jurisdiction of the courts in New York as described herein for any reason, (ii) that it or its property is exempt or immune from jurisdiction of any such court or from any legal process commenced in such courts (whether through service of notice, attachment prior to judgment, attachment in aid of execution of judgment, execution of judgment or otherwise) and (iii) that (A) the proceeding in any such court is brought in an inconvenient forum, (B) the venue of such proceeding is improper or (C) this Agreement, or the subject matter hereof, may not be enforced in or by such courts. (b) EACH PARTY HEREBY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN ANY LEGAL PROCEEDING DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY (WHETHER BASED ON CONTRACT, TORT OR ANY OTHER THEORY). EACH PARTY (I) CERTIFIES THAT NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER AND (II) ACKNOWLEDGES THAT IT AND THE OTHER PARTIES HAVE BEEN INDUCED TO ENTER INTO THIS AGREEMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION. 15. Specific Performance/Remedies. It is understood and agreed by the Parties that money damages would not be a sufficient remedy for any breach of this Agreement by any Party and each non-breaching Party shall be entitled to specific performance and injunctive or other equitable relief. Each Party also agrees Exhibit 10.1

-28- WEIL:\99037057\16\18434.0011 acknowledge that any confidentiality agreements (if any) heretofore executed between the Company Parties, on the one hand, and each Consenting Stakeholder, on the other hand, as applicable, shall continue in full force and effect; provided, that, in the event of a conflict between this Agreement and the Transaction Term Sheet, the Transaction Term Sheet shall control in all respects. 21. Counterparts. This Agreement may be executed in counterparts, each of which shall be deemed to be an original, and all of which together shall be deemed to be one and the same agreement, with the effect as if all Parties had signed the same agreement. Execution copies of this Agreement may be delivered by electronic mail in portable document format (pdf), which shall be deemed to be an original for the purposes of this paragraph. 22. Notices. All notices hereunder shall be deemed given if in writing and delivered, if contemporaneously sent by electronic mail, by overnight courier or by registered or certified mail (return receipt requested) to the following addresses: (a) If to the Company Parties: ATI Physical Therapy, Inc. 000 Xxxxxxxxx Xxxx Xxxxxxxxxxx, XX 00000 Attention: Xxxx Xxxxx Email: Xxxx.Xxxxx@xxxxx.xxx With a copy to (which shall not constitute notice): Xxxx, Xxxxxxx & Xxxxxx LLP 000 Xxxxx Xxxxxx Xxx Xxxx, XX 00000 Attention: Xxx X. Xxxxxxx, P.C. Xxxxxxx X. Xxxxxxx Email: Xxx.Xxxxxxx@xxxx.xxx Xxxxxxx.Xxxxxxx@xxxx.xxx (b) If to HPS: HPS Investment Partners, LLC 00 Xxxx 00xx Xxxxxx Xxx Xxxx, XX XX 00000 Attn: Xxxx Xxxxx with a copy to: Milbank LLP 00 Xxxxxx Xxxxx Xxx Xxxx, XX XX 00000-2163 Exhibit 10.1

-31- WEIL:\99037057\16\18434.0011 connection with the foregoing, the Consenting Stakeholders and the Borrower hereto acknowledge and agree that the terms of Article 8 and Article 9 of the Credit Agreement shall apply to the acknowledgment by the Administrative Agent of this Agreement and any action taken by the Administrative Agent in furtherance of this Agreement and the transactions described herein. [Signature Pages to Follow] Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] IN WITNESS WHEREOF, the Parties have caused this Agreement to be executed and, as applicable, delivered by their respective duly authorized officers, solely in their respective capacities as officers of the undersigned and not in any other capacity, as of the date first set forth above. ATI PHYSICAL THERAPY, INC. By:____________________________ Name: Xxxxxx Xxxxxx Title: Chief Financial Officer ATI HOLDINGS ACQUISITION, INC. By:____________________________ Name: Xxxxxx Xxxxxx Title: Chief Financial Officer WILCO INTERMEDIATE HOLDINGS, INC. By:____________________________ Name: Xxxxxx Xxxxxx Title: Chief Financial Officer DocuSign Envelope ID: C267CFC5-30A2-4898-9EF0-A76FDBC50EFA Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] Subsidiary Guarantors: ATI HOLDINGS OF ALABAMA, LLC IDEAL PHYSICAL THERAPY OF TEXAS, LLC ATI HOLDINGS, INC. TOUCHSTONE HOLDCO LLC ATI HOLDINGS MISSOURI, LLC PROAXIS THERAPY, LLC ADIENT ALASKA, LLC ATI OF NEVADA AT DESERT VALLEY THERAPY, LLC ATI HOLDINGS OF ARIZONA, LLC ATI HOLDINGS, LLC ATHLETIC & THERAPEUTIC INSTITUTE OF BOLINGBROOK, LLC ATHLETIC & THERAPEUTIC INSTITUTE OF NAPERVILLE, LLC ATHLETIC & THERAPEUTIC INSTITUTE OF MILWAUKEE, LLC ATHLETIC & THERAPEUTIC INSTITUTE OF BOURBONNAIS, LLC OHIO CENTERS FOR HAND AND PHYSICAL REHABILITATION, LLC ADVANCED PHYSICAL THERAPY, LLC COMMUNITY REHAB OF IOWA, LLC PERFORMANCE REHABILITATION OF WESTERN NEW ENGLAND, LLC MICHIGAN REHABILITATION SPECIALISTS OF FOWLERVILLE, LLC QUANTUM PHYSICAL THERAPY CENTERS – YPSILANTI LLC COMMUNITY REHAB, LLC NEW CENTURY REHABILITATION, LLC PHYSICAL THERAPY AT XXXX, LLC XXXXXXX PHYSICAL THERAPY AND SPORTS MEDICINE, LLC WILLAMETTE SPINE CENTER PHYSICAL THERAPY AND REHABILITATION, LLC XXXXXXXXXXX PHYSICAL THERAPY & SPORTS MEDICINE, LLC PROAXIS GREENVILLE, LLC PROAXIS THERAPY NC, LLC PROAXIS THERAPY SC, LLC MCM REHABILITATION, LLC APPLE PHYSICAL THERAPY, LLC By: ____________________________ Name: Xxxxxx Xxxxxx Title: Chief Financial Officer DocuSign Envelope ID: 50FE94F9-759A-4322-85A7-018672A932FC Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] HPS INVESTMENT PARTNERS, LLC By: Name: Xxxx Xxxxx Title: Managing Director Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] HPS SPECIALTY LOAN FUND V, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $58,200,172.81 HPS SPECIALTY LOAN FUND X-X, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $60.63 SLIF V HOLDINGS, LLC By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $29,923,116.81 HPS SPECIALTY LOAN EUROPE FUND V, SCSP By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $10,924,153.86 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] HPS SPECIALTY LOAN ONTARIO FUND V, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $6,972,864.15 HPS SPECIALTY LOAN MASTER FUND (EUR) V L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $4,365,633.53 XXXXXX XXXXXX XXXXXX XXXXXXX XXXX, X.X. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $5,410,873.75 SPECIALTY LOAN VG FUND, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $2,806,480.28 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] FALCON CREDIT FUND, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $1,326,699.76 SAFETY NATIONAL CASUALTY CORPORATION By: HPS Investment Partners, LLC, as Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $4,066,996.61 HALITE 2020 DIRECT LIMITED By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $10,180,381.67 HC DIRECT LENDING FUND, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $6,062,603.65 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] HPS OCOEE SPECIALTY LOAN FUND, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $5,926,934.54 HPS ELBE UNLEVERED DIRECT LENDING FUND SCSP By: HPS Investment Partners, LLC, its Portfolio Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $4,546,952.72 HPS SPECIALTY LOAN FUND TX, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $9,320,395.10 PHILADELPHIA INDEMNITY INSURANCE COMPANY By: HPS Investment Partners, LLC, as Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $1,161,999.02 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] BUILD PRIVATE CREDIT, L.P. By: HPS Investment Partners, LLC, as Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $580,999.52 HPS CORPORATE LENDING FUND By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $40,675,040.90 CACTUS DIRECT HOLDINGS, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $15,194,400.38 SLF CX-2 HOLDINGS, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $7,624,027.22 BRICKYARD DIRECT HOLDINGS, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $3,046,458.34 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] SLF V INTERNATIONAL-L HOLDINGS, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $18,416,856.64 SLF X-X HOLDINGS, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $16,016,087.89 SLF X-X HOLDINGS B, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $16,016,027.26 SLF V INTERNATIONAL-L HOLDINGS B, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $18,416,856.65 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] PRESIDIO LOAN HOLDINGS, L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $3,827,018.54 VG HPS PRIVATE DEBT FUND L.P. By: HPS Investment Partners, LLC, its Investment Manager By: Name: Xxxx Xxxxx Title: Managing Director Principal Amount of Term Loans: $27,380,938.38 Exhibit 10.1

Exhibit 10.1

KNIGHTHEAD ANNUITY & LIFE ASSURANCE COMPANY By: Knighthead Capital Management, LLC, its investment advisor +-t-j \ By: \JVi:::_A -----��----- Name: Xxxxx Xxxxxxx Title: General Counsel Principal Amount of Term Loans: $17,866,077.93 Shares of Preferred Stock: 14,755 Amount of New Money Financing commitment: $5,304,456.00 Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: $17,866,077.93 Exhibit 10.1

KNIGHTHEAD DISTRESSED OPPORTUNITIES FUND, L.P. By: Knighthead Capital Management, LLC, its investment manager By: t�lli Name�xxx Xxxxxxx Title: General Counsel Principal Amount of Term Loans: Shares of Preferred Stock: 19,232 Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: Exhibit 10.1

KNIGHTHEAD MASTER FUND, L.P. By: Knighthead Capital Management, LLC, its investment manager By:_@___:__:,c:._, ----°"----- Name: Xxxxx Xxxxxxx Title: General Counsel Principal Amount of Term Loans: $17,412,801.02 Shares of Preferred Stock: 32,116 Amount of New Money Financing commitment: $5,169,898.00 Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: $17,412,801.02 Exhibit 10.1

KNIGHTHEAD (NY) FUND, L.P. By: Knighthead Capital Management, LLC, its investment advisor Byf{tl Name: Xxxxx Xxxxxxx Title: General Counsel Principal Amount of Term Loans: $5,138,548.68 Shares of Preferred Stock: 9,477 Amount of New Money Financing commitment: $1,525,646.00 Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: $5,138,548.68 Exhibit 10.1

ONEX CAPITAL SOLUTIONS HOLDINGS, LP By: Onex Capital Solutions GP, LP, its general partner By: Onex Capital Solutions GP, LLC, its general partner By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 8,841,296.99 Shares of Preferred Stock: 22,145.30 Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 8,841,296.99 Exhibit 10.1

ONEX SENIOR CREDIT II, LP By: Onex Credit Partners, LLC, its investment manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 816,430.64 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 317,835.79 Exhibit 10.1

Onex Senior Credit Fund, LP. By: Onex Credit Partners, LLC its investment manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 7,571,181.66 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 2,947,454.88 Exhibit 10.1

OCM Loan Holdings LLC By: Onex Credit Management LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 240,483.28 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 93,619.95 Exhibit 10.1

Xxxx Mutual Insurance Company By: Onex Credit Management LLC, as Investment Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 213,201.57 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 82,999.20 Exhibit 10.1

OCP CLO 2014-5, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 915,453.17 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 356,385.18 Exhibit 10.1

OCP CLO 2014-6, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 2,249,195.10 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 875,609.83 Exhibit 10.1

OCP CLO 2015-9, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 950,818.36 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 370,152.81 Exhibit 10.1

OCP CLO 2015-10, Ltd. By: By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 953,849.66 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 371,332.90 Exhibit 10.1

OCP CLO 2016-12, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 1,666,106.59 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 648,613.94 Exhibit 10.1

OCP CLO 2017-14, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 1,424,711.88 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 554,639.18 Exhibit 10.1

OCP CLO 2018-15, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 1,424,711.88 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 554,639.18 Exhibit 10.1

OCP CLO 2019-16, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 1,186,249.47 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 461,805.96 Exhibit 10.1

OCP CLO 2019-17, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 1,191,301.64 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 463,772.76 Exhibit 10.1

OCP CLO 2020-8R, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 834,618.45 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 324,916.29 Exhibit 10.1

OCP CLO 2020-18, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 953,849.66 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 371,332.90 Exhibit 10.1

OCP CLO 2020-19, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 1,191,301.64 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 463,772.76 Exhibit 10.1

OCP CLO 2021-22, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 1,310,532.85 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 510,189.37 Exhibit 10.1

OCP CLO 2022-25, Ltd. By: Onex Credit Partners, LLC, as Portfolio Manager By:____________________________ Name: Xxxxxx Xxxxxx Title: General Counsel Principal Amount of Term Loans: 1,427,833.73 Shares of Preferred Stock: Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: 555,854.51 Exhibit 10.1

MAM PT LLC By:____________________________ Name: Title: Principal Amount of Term Loans: Shares of Preferred Stock: 45,590 Amount of New Money Financing commitment: Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: Exhibit 10.1

MARATHON DISTRESSED CREDIT MASTER FUND By:____________________________ Name: Title: Principal Amount of Term Loans: $34,112,249.81 Shares of Preferred Stock: Amount of New Money Financing commitment: $6,752,000 Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: $34,112,250 Exhibit 10.1

MARATHON STEPSTONE MASTER FUND LP By:____________________________ Name: Title: Principal Amount of Term Loans: $2,738,275.98 Shares of Preferred Stock: Amount of New Money Financing commitment: $542,400 Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: $2,738,276 Exhibit 10.1

MCSP Sub, LLC By:____________________________ Name: Title: Principal Amount of Term Loans: $3,566,831.83 Shares of Preferred Stock: 4,410 Amount of New Money Financing commitment: $705,600 Amount of Preferred Equity Held Term Loans to be exchanged for New Second Lien PIK Convertible Notes: $3,566,832 Exhibit 10.1

CASPIAN CAPITAL L.P. in its capacity as manager, advisor, sub-advisor or similar capacity on behalf of certain funds and accounts By:____________________________ Name: Xxxxxxxx Xxxxxxxxx Title: Authorized Signatory Shares of Preferred Stock: 19,420 Shares of Preferred Stock Per Caspian Fund Caspian PT Holdings LLC: 10,704 Caspian Solitude Master Fund, L.P.: 1,353 Caspian HLSC1, LLC: 1,072 Caspian SC Holdings, L.P.: 849 Spring Creek Capital, LLC: 2,403 Blackstone Alternative Multi-Strategy Fund IV L.L.C. II: 1,516 Blackstone Alternative Multi-Strategy Fund IV L.L.C. IIA: 1,523 Amount of New Money Financing Total: $5,000,000.00 Amount of New Money Financing Per Caspian Fund Caspian Select Credit Master Fund, Ltd.: $1,826,725.03 Caspian Solitude Master Fund, L.P.: $348,352.21 Caspian HLSC1, LLC: $276,004.12 Caspian SC Holdings, L.P.: $218,589.08 Spring Creek Capital, LLC: $618,692,07 Caspian Focused Opportunities Fund, L.P.: $413,491.25 Caspian Keystone Focused Fund, L.P.: $515,705.46 Blackstone Alternative Multi-Strategy Fund IV L.L.C. II: $390,319.26 Blackstone Alternative Multi-Strategy Fund IV L.L.C. IIA: $392,121.52 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] Restricted - External Acknowledged pursuant to the direction in Section 28: BARCLAYS BANK PLC, as Administrative Agent By:____________________________ Name: Xxxxxx Xxxxx Title: Director Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] Restricted - External BARCLAYS BANK PLC, as Revolving Lender By:____________________________ Name: Xxxxxx Xxxxx Title: Director Principal Amount of Revolving Loans: $30,000,000 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] ADVENT INTERNATIONAL GPE VII LIMITED PARTNERSHIP By: GPE VII GP S.à x.x., General Partner By: Advent International GPE VII, LLC, _____________________________ Manager Xxxxxx Xxxxxx By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 11,324,692 ADVENT INTERNATIONAL GPE VII-B LIMITED PARTNERSHIP By: GPE VII GP S.à x.x., General Partner By: Advent International GPE VII, LLC, _____________________________ Manager Xxxxxx Xxxxxx By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 30,970,374 Exhibit 10.1 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] ADVENT INTERNATIONAL GPE VII-C LIMITED PARTNERSHIP By: GPE VII GP S.à x.x., General Partner By: Advent International GPE VII, LLC, ____________________________ Manager Xxxxxx Xxxxxx By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 9,845,475 ADVENT INTERNATIONAL GPE VII-D LIMITED PARTNERSHIP By: GPE VII GP S.à x.x., General Partner By: Advent International GPE VII, LLC, ____________________________ Manager Xxxxxx Xxxxxx By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 6,777,137 Exhibit 10.1 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] ADVENT INTERNATIONAL GPE VII-F LIMITED PARTNERSHIP By: GPE VII GP S.à x.x., General Partner By: Advent International GPE VII, LLC, ____________________________ Manager Xxxxxx Xxxxxx By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 2,873,509 ADVENT INTERNATIONAL GPE VII-G LIMITED PARTNERSHIP By: GPE VII GP S.à x.x., General Partner By: Advent International GPE VII, LLC, ____________________________ Manager Xxxxxx Xxxxxx By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 2,873,509 Exhibit 10.1 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] ADVENT INTERNATIONAL GPE VII-A LIMITED PARTNERSHIP By: GPE VII GP Limited Partnership, General Partner By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Title: Chief Legal Officer Shares of Common Stock: 10,481,755 ADVENT INTERNATIONAL GPE VII-E LIMITED PARTNERSHIP By: GPE VII GP Limited Partnership, General Partner By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Title: Chief Legal Officer Shares of Common Stock: 22,316,206 Exhibit 10.1 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] ADVENT INTERNATIONAL GPE VII-H LIMITED PARTNERSHIP By: GPE VII GP Limited Partnership, General Partner By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Title: Chief Legal Officer Shares of Common Stock: 1,743,884 ADVENT PARTNERS GPE VII LIMITED PARTNERSHIP By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 45,267 Exhibit 10.1 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] ADVENT PARTNERS GPE VII CAYMAN LIMITED PARTNERSHIP By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 806,132 ADVENT PARTNERS GPE VII-A LIMITED PARTNERSHIP By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 107,151 Exhibit 10.1 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] ADVENT PARTNERS GPE VII-A CAYMAN LIMITED PARTNERSHIP By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 212,875 ADVENT PARTNERS VII-B CAYMAN LIMITED PARTNERSHIP By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 1,063,662 Exhibit 10.1 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] ADVENT PARTNERS GPE VII 2014 LIMITED PARTNERSHIP By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 65,045 ADVENT PARTNERS GPE VII 2014 CAYMAN LIMITED PARTNERSHIP By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 155,782 Exhibit 10.1 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] ADVENT PARTNERS GPE VII-A 2014 LIMITED PARTNERSHIP By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 179,333 ADVENT PARTNERS GPE VII-A 2014 CAYMAN LIMITED PARTNERSHIP By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 109,904 Exhibit 10.1 Exhibit 10.1

[SIGNATURE PAGE TO TRANSACTION SUPPORT AGREEMENT] GPE VII ATI CO-INVESTMENT (DELAWARE) LIMITED PARTNERSHIP By: Advent International GPE VII, LLC, General Partner By: Advent International Corporation, Manager By:____________________________ Name: Xxxxxx XxXxxxx Xxxxxxxx Title: Chief Legal Officer Shares of Common Stock: 13,878,964 Exhibit 10.1 Exhibit 10.1

WEIL:\99037057\16\18434.0011 Exhibit A Transaction Term Sheet Exhibit 10.1

2 (b) the New Second Lien PIK Exchangeable Notes shall have substantially similar terms (provided that such terms shall reflect the payment and lien subordination of the New Second Lien PIK Exchangeable Notes to the Existing Credit Facility, shall be consistent with the Intercreditor Agreement, shall contain customary cushions to the Existing Credit Facility and shall not contain financial covenants) and the same Loan Parties and Collateral as the Existing Credit Facility and shall be subordinated in right of payment and lien priority to the Existing Credit Facility subject to an intercreditor and subordination agreement, the material terms of which are set forth in the intercreditor term sheet annexed hereto as Exhibit A (the “Intercreditor Term Sheet” and such agreement, the “Intercreditor Agreement”); (c) the New Second Lien PIK Exchangeable Notes shall have a maturity date occurring at least 6 months after the Initial Term Loan Maturity Date under the Existing Credit Facility; (d) the New Second Lien PIK Exchangeable Notes will be exchangeable, at the option of the holders thereof, into shares Class A common stock of Topco at a fixed price of $0.25; (e) prior to exchange, the New Second Lien PIK Exchangeable Notes will have voting rights on an “as-exchanged” basis, as if exchanged into common stock; provided that if the voting rights afforded to holders of the New Second Lien PIK Exchangeable Notes prior to exchange (as contemplated by clause (e) above) are capped under applicable NYSE listing rules in a manner that would result in a holder of a New Second Lien PIK Exchangeable Note having less voting power immediately prior to an exchange than such holder would have immediately following such exchange, the Borrower and Topco shall take any and all such other steps as are lawful and necessary to provide the holders of the New Second Lien PIK Exchangeable Notes with the voting rights they would have been afforded under clause (e) above but for such NYSE listing rule limitations (such voting rights, the “Equivalent Voting Rights”), including without limitation by (x) amending, supplementing, modifying or otherwise altering the terms of the Preferred Topco Stock to provide the holders thereof with the right to vote together with the holders of common stock as a single class, (y) issuing to holders of the New Second Lien PIK Exchangeable Notes additional equity securities issued by Topco (or options or warrants to purchase additional equity securities issued by Topco) and/or (z) taking any and all such other actions lawful and necessary, in each case in a manner that would result in the aggregate voting rights afforded to the holders of the New Second Lien PIK Exchangeable Notes (including via the issuance or modification of any such other securities) prior to exchange being equal to the aggregate voting rights that would be afforded to such holders immediately following such exchange; provided further that it is understood and agreed that the Preferred Equityholders, Topco and the Borrower shall negotiate in good faith in order to achieve the Equivalent Voting Rights to the extent possible without modifying the existing economic rights of the Parties; provided further still that (xx) any modification providing for Equivalent Voting Rights that would otherwise have a non de minimis impact on Advent’s economic position with respect to the Transaction (including Advent’s pro forma equity ownership) shall require Advent’s prior written consent and (yy) the Preferred Equityholders will not be required to agree to the terms of the New Second Lien PIK Exchangeable Notes if the Equivalent Voting Rights cannot be achieved and if the Preferred Equityholders deliver written notice to the Parties that they do not otherwise agree, then the Transaction Support Agreement shall automatically be terminated; and (f) the New Second Lien PIK Exchangeable Notes will not provide for a “forced exchange” right during the first two years of issuance and will not be redeemable prior to maturity. Exhibit 10.1

5 X. Xxxxxxx shall have received from the Borrower a budget (including an initial 13-week cash flow budget) in form reasonably acceptable to HPS, Barclays, the Administrative Agent and the Preferred Equityholders. D. After giving effect to the Transactions, (a) the capitalization and governance of Topco and its subsidiaries shall be materially consistent with this term sheet and otherwise reasonably satisfactory to HPS, Barclays, the Preferred Equityholders, Advent and the Borrower, (b) Xxxx Xxxxxxxxx will not seek re-election to the board of directors of Topco (the “Topco Board”) at the 2023 shareholders meeting of Topco, (c) HPS shall have the right to appoint one board observer to the Topco Board, (d)(i) the Preferred Equityholders shall have the right to appoint three additional directors to the Topco Board (resulting in the right of the Preferred Equityholders to appoint a total of four directors to the Topco Board and such that the Topco Board shall consist of 10 directors (or 11 directors if Xxxxxx X. XxXxxxxx remains on the Topco Board) in total) and (ii) the EBITDA based fall-away provision for the director designation rights of the Preferred Equityholders set forth in clause (i) of the proviso in Section 3(a) of the certificate of designation for the Preferred Topco Stock will be deleted, (e) the Topco Board will be declassified to effect, among other things, that all go-forward appointments of directors to the Topco Board will be for terms of one year (for the avoidance of doubt, without affecting the length of the terms of directors of the Topco Board that are in effect on the date on which the Transactions are consummated), and (f) Advent will no longer have the right to appoint five directors to the Topco Board and the Topco stockholders agreement will be terminated. E. Execution of customary, mutual releases with respect to Preferred Equityholders, HPS, Barclays, the Administrative Agent, Borrower, and the Sponsors. F. Payment of reasonable fees and expenses incurred by the Sponsors, HPS, Barclays, the Administrative Agent and the Preferred Equityholders in connection with the transactions contemplated by this term sheet. G. The consents required pursuant to the Existing Credit Agreement and that certain Agreement Among Lenders, dated as of February 24, 2022, by and among the Administrative Agent, HPS and each of the revolving lenders under the Existing Credit Agreement (the “Agreement Among Lenders”) to consummate the Transactions and amend the Existing Credit Agreement shall have been obtained. H. If reasonably requested by Barclays or HPS, the Agreement Among Lenders shall be amended in a manner to be reasonably agreed among the parties thereto, including, without limitation, an amendment to modify clause (e)(ii) of the definition of “Waterfall/Voting Triggering Event” in a manner reasonably acceptable to the parties thereto. Exhibit 10.1

Exhibit A Intercreditor Agreement Term Sheet Exhibit 10.1

Intercreditor Term Sheet Summary of Principal Terms and Conditions of the Intercreditor Agreement Parties: (i) Barclays Bank PLC, as collateral agent (the “First Lien Collateral Agent”) for the lenders under the Existing Credit Facility (the “First Lien Credit Agreement”; the agents and lenders under the First Lien Credit Agreement, collectively, the “First Lien Secured Parties”); and (ii) a person to be agreed, as collateral agent (the “Second Lien Collateral Agent”) for the holders of the New Second Lien PIK Exchangeable Notes (the “Second Lien Note Purchase Agreement”; the collateral agent, notes trustee and holders of the Second Lien Notes, collectively, the “Second Lien Secured Parties”). The Loan Parties shall acknowledge the terms of the Intercreditor Agreement. All documents entered into in connection with the First Lien Credit Agreement, including collateral documents, shall be referred to as the “First Lien Loan Documents” and all documents entered into in connection with the New Second Lien PIK Exchangeable Notes, including collateral documents, shall be referred to as the “Second Lien Note Documents”. Purpose: To establish payment subordination and the relative rights and privileges of the parties with respect to the collateral for the obligations under the First Lien Credit Agreement (the “First Lien Obligations”; including any refinancings, replacements, extensions, or increases thereof) and for the obligations under the New Second Lien PIK Exchangeable Notes and the documents governing New Second Lien PIK Exchangeable Notes (the “Second Lien Obligations”) (collectively, the “Collateral”). Priority of Obligations: The Intercreditor shall provide for (a) the payment subordination of the Second Lien Obligations to the First Lien Obligations and (b) the lien subordination of the liens securing the Second Lien Obligations to the liens securing the First Lien Obligations. Until the payment of the First Lien Obligations (other than contingent obligations for which no claim has been made) in full in cash and termination of all commitments and termination or cash collateralization of all letters of credit (the “Discharge of First Lien Obligations”): (i) all Second Lien Obligations shall be junior and subordinated in right and time of payment in all respects to the First Lien Obligations; (ii) the liens securing the Second Lien Obligations shall be junior and subordinated in all respects to the liens securing the First Lien Obligations; (iii) until the date that is 180 days after notice from the Second Lien Collateral Agent to the First Lien Collateral Agent of the occurrence of an acceleration of the Second Lien Obligations (the “Standstill Exhibit 10.1

- 2 - Period”), the Second Lien Collateral Agent shall not exercise or seek to exercise any rights or remedies (including setoff, recoupment, the right to credit bid its debt (other than as specifically described below under “Exercise of Remedies/No Contest”) and foreclosure on any Collateral) (other than acceleration, the filing of a proof of claim or statement of interest, and actions to preserve, create or perfect liens and the filing of defensive or responsive pleadings, so long as such pleadings are not adverse to, or could impair the rights and remedies and priority status of, the First Lien Secured Parties and are not inconsistent with the terms of the Intercreditor Agreement) against any Loan Party and shall not institute any action or proceeding against any Loan Party with respect to such rights or remedies (collectively, “Enforcement Action”); provided that the Standstill Period shall be tolled if an insolvency or bankruptcy proceeding shall have commenced against a Loan Party or if the First Lien Secured Parties are then diligently pursuing an enforcement action against the Loan Parties (this clause (iii), the “Standstill Clause”); (iv) the Second Lien Collateral Agent will not take or receive any payment or other distribution (whether in cash, securities or other property, including, without limitation, Collateral, any proceeds of Collateral or assets that are not Collateral or any proceeds of avoidance actions) (a “Distribution”) on account of the Second Lien Obligations (other than (i) customary agency and administration fees, (ii) reimbursement of reasonable out-of-pocket fees and expenses of legal counsel to the Second Lien Secured Parties relating to the transactions to be consummated on the Closing Date or otherwise prior to an Event of Default under the First Lien Loan Documents and (iii) interest that is paid in kind on the New Second Lien PIK Exchangeable Notes); and (v) if any Distribution in respect of any Second Lien Obligation shall be received by a Second Lien Secured Party in contravention of the Intercreditor Agreement, then such Distribution shall be held in trust for the benefit of, and shall be paid over or delivered to, the First Lien Collateral Agent for distribution to the First Lien Secured Parties, in such order as specified in the relevant First Lien Loan Documents, to the extent necessary to pay all First Lien Obligations in full in cash. Exercise of Remedies/No contest: Until the Discharge of First Lien Obligations and subject to the Standstill Clause, the First Lien Collateral Agent shall have the sole and exclusive right to commence and maintain any enforcement action or otherwise enforce rights or exercise remedies against the Loan Parties (including set-off, recoupment, the right to credit bid its debt and foreclosure on any Collateral) and the holders of the Second Lien Obligations will not contest, protest or object to, or otherwise interfere with, any foreclosure proceeding or action brought by the First Lien Collateral Agent or any holders of the First Lien Obligations against any Loan Party. No Second Lien Secured Party (or anyone acting on their behalf) shall initiate, prosecute or participate in any claim, action or other proceeding challenging the enforceability, validity, perfection or priority of the First Lien Obligations, the First Lien Debt Documents Exhibit 10.1

- 3 - or any liens and security interests in property securing the First Lien Obligations and no First Lien Secured Party (or anyone acting on their behalf) shall initiate, prosecute or participate in any claim, action or other proceeding challenging the enforceability, validity, perfection or priority of the Second Lien Obligations, the Second Lien Debt Documents or any liens and security interests in property securing the Second Lien Obligations. For the avoidance of doubt, nothing provided for in the preceding sentence shall be interpreted or construed under any circumstances to impair, limit, prevent, restrict or contradict the rights of the First Lien Collateral Agent to enforce the Intercreditor Agreement. Distributions: Until the Discharge of First Lien Obligations, all Distributions received in connection with the exercise of remedies or in any bankruptcy or insolvency proceeding, shall be applied by the First Lien Collateral Agent to the First Lien Obligations in such order as specified in the relevant First Lien Loan Documents. Upon the Discharge of First Lien Obligations, the First Lien Collateral Agent shall deliver to the Second Lien Collateral Agent all remaining proceeds of Distributions held by it to be applied by the Second Lien Collateral Agent to the Second Lien Obligations in such order as specified in the Second Lien Note Documents. Restrictions on Amendments: Neither the First Lien Loan Documents nor the Second Lien Note Documents may be amended or refinanced without the consent of the Second Lien Collateral Agent or First Lien Collateral Agent, respectively, to the extent such amendment or refinancing would violate the provisions of the Intercreditor Agreement or contravene other matters as may be agreed. Any waivers, amendments or consents with respect to any provision of the collateral documents securing the First Lien Obligations shall be deemed to automatically apply to any applicable provisions of the collateral documents securing the Second Lien Obligations; provided no such waiver, amendment or consent shall (i) remove or release assets subject to the lien of the Second Lien Note Documents, except to the extent that a release of such lien is permitted by the Intercreditor Agreement and the Second Lien Note Documents and there is a corresponding release of the liens securing the First Lien Obligations, (ii) impose duties on the Second Lien Collateral Agent without its consent, or (iii) permit other liens on the Collateral not permitted under the terms of the Second Lien Note Documents or the Intercreditor Agreement. Releases: The Intercreditor Agreement will provide that if (i) in connection with (x) any sale of other disposition of Collateral by any Loan Party permitted under the terms of the First Lien Credit Agreement and the Second Lien Note Documents or (y) any Enforcement Action or other exercise of remedies by the First Lien Collateral Agent against a Loan Party, the First Lien Collateral Agent releases any of its liens on any part of the Collateral of such Loan Party, then the liens, if any, of the Second Lien Collateral Agent on such Collateral, shall be automatically, unconditionally and simultaneously released, or (ii) the Exhibit 10.1

- 4 - equity interests of any Loan Party are foreclosed upon or otherwise disposed of, or any Loan Party is release from its guaranty, in a manner permitted under the terms of the First Lien Credit Agreement and the Second Lien Note Documents or in connection with any Enforcement Action or other exercise of remedies by the First Lien Collateral Agent against a Loan Party and the First Lien Collateral Agent releases its lien on the equity interests, property or assets of such Loan Party and the obligations of such Loan Party under its guaranty of the First Lien Obligations, then the liens, if any, of the Second Lien Collateral Agent on such equity interests, property or assets, and the obligations of such Loan Party under its guaranty of the Second Lien Obligations, shall be automatically, unconditionally and simultaneously released; provided, that the proceeds of such foreclosure, sale or disposition are applied pursuant to the payments waterfall or in the case of a permitted asset sale, in accordance with the terms of the First Lien Credit Agreement. Bankruptcy: In the event of an insolvency or liquidation proceeding of the Borrower, whether voluntary or involuntary, if the First Lien Collateral Agent or any other First Lien Secured Party shall desire to permit the use of cash collateral or to permit the Borrower to obtain debtor-in-possession financing (a “DIP Financing”), then, if the principal amount of such DIP Financing does not exceed 20% of the principal amount of the then outstanding First Lien Obligations, plus the amount of any First Lien Obligations that are rolled-up into or refinanced by such DIP Financing, the Second Lien Collateral Agent, on behalf of itself and the Second Lien Secured Parties, agrees that it will (i) raise no objection to such use of cash collateral or DIP Financing, (ii) will not request adequate protection or any other relief in connection therewith (unless (A) the First Lien Collateral Agent is granted a senior lien on such adequate protection lien and (B) such adequate protection is subordinated to the adequate protection requested by the First Lien Collateral Agent, in each case to the same extent as the Second Lien Obligations are subordinated to the First Lien Obligations) and (iii) the Second Lien Collateral Agent will subordinate its liens in the Collateral to the liens securing such DIP Financing (and all obligations relating thereto) to the extent the liens securing the First Lien Obligations are subordinated or pari passu with such DIP Financing. No Second Lien Collateral Agent or Second Lien Secured Party may provide a DIP Financing. Each of the Second Lien Secured Parties shall be deemed to have consented to, and agrees that it will raise no objection to or contest (or support any other Person in objecting to or contesting), (i) any disposition (whether under Sections 363, 1123 or 1129 of the Bankruptcy Code) of any Collateral free and clear of any Liens, claims or interests held by or on behalf of the Second Lien Collateral Agent or the Second Lien Secured Parties, to the extent that such disposition has been consented to by the First Lien Collateral Agent (and so long as the proceeds of such Collateral, if any, are applied in accordance with the payments waterfall), (ii) any motion for bid procedures or other procedures related to any such disposition, or (iii) any credit bid by the Exhibit 10.1

- 6 - such Specified Junior Debt shall be treated as additional Second Lien Obligations (it being understood that in the case of Specified Junior Debt in the form of unsecured indebtedness, the Intercreditor Agreement shall provide that such Indebtedness is not subject to the lien subordination provisions for therein). Governing Law: The State of New York. The foregoing is intended to summarize certain basic terms of the Intercreditor Agreement and is not intended to be a definitive list of all of the terms of the Intercreditor Agreement. Exhibit 10.1

Exhibit B Credit Agreement Modifications Term Sheet Exhibit 10.1

- 3 - WEIL:\99050386\7\18434.0011 No. Item Modification Restricted Payments / Restricted Debt Payments 16. Shared RP and RDP basket (§6.04(a)(x) and (§6.04(b)(iv)) Reduce the general RP and RDP baskets in clauses (a)(x) and (b)(iv) of Section 6.04 to $1m and limit use of RP basket to payments to ATI Physical Therapy, Inc., but not to any shareholders of ATI Physical Therapy, Inc.. 17. Specified Junior Debt Credit Agreement to be modified to provide that: (i) no payments (including, without limitation, any refinancing, exchange or similar transaction ) shall be permitted to be made under the Specified Junior Debt prior to the payment in full in cash of the Obligations (subject to exceptions for (a) customary administrative agency fees, (b) provided no Event of Default under the Credit Agreement has occurred, payment of reasonable legal fees and (c) conversions to equity issued by ATI Physical Therapy, Inc.); and (ii) No amendments may be made to the documentation governing the Specified Junior Debt that are adverse to the interests of the Lenders without the consent of the Administrative Agent and the Lender Representative (the “Second Lien Amendment Provision”) Investments 18. Similar Businesses Investments basket (§6.06(d)) Limit clause (d) of Section 6.06 to investments in joint ventures and reduce cap to $3.5m and eliminate grower. Affiliate Transactions 19. Sponsor Management Fees (§6.09(f)(i)) Delete clause (i) of Section 6.09(f). 20. Reimbursement of Sponsor Expenses (§6.09(f)(ii)) Modify clause (ii) to include a $500,000 cap on the reimbursement of Sponsor expenses (which cap shall not, for the avoidance of doubt, apply to indemnification obligations). 21. Advisory Fees (§6.09(h)) Delete clause (h) of Section 6.09. 22. Fairness Opinion (§6.09(o)) Delete clause (o) of Section 6.09. Other 23. N/A Other modifications as needed to implement the Transaction Term Sheet and as otherwise agreed. If the New Second Lien PIK Exchangeable Notes are issued by ATI Physical Therapy Inc., ATI Physical Therapy Inc. will be added as a guarantor and grantor on a senior basis to the New Second Lien PIK Exchangeable Notes. 24. Certain Amendments (i) Consent of the Required Term Lenders and the Required Revolving Lenders shall be required for any amendments to (i) the Intercreditor Exhibit 10.1

- 4 - WEIL:\99050386\7\18434.0011 No. Item Modification Agreement, (ii) the Second Lien Amendment Provision and (iii) the covenant restricting payments on junior debt in the Credit Agreement to permit payments under the Specified Junior Debt. (ii) Consent of the Required Revolving Lenders shall be required for any amendment to the restricted payment covenant that would permit any “restricted payment” (as defined in the Existing Credit Agreement) to any shareholder of the Borrower, Holdings or ATI Physical Therapy, Inc. Exhibit 10.1

-2- WEIL:\99037057\16\18434.0011 Exhibit B FORM OF JOINDER AGREEMENT FOR CONSENTING STAKEHOLDER This Joinder Agreement to the Transaction Support Agreement, dated as of March [●], 2023 (as amended, supplemented, or otherwise modified from time to time, the “Agreement”), by and among the Company and the Consenting Stakeholders, is executed and delivered by_______________________ (the “Joining Party”) as of ____________, 2023. Each capitalized term used herein but not otherwise defined shall have the meaning set forth in the Agreement. 1. Agreement to be Bound. The Joining Party hereby agrees to be bound by all of the terms of the Agreement, a copy of which is attached to this Joinder Agreement as Annex I (as the same has been or may be hereafter amended, restated, or otherwise modified from time to time in accordance with the provisions hereof). The Joining Party shall hereafter be deemed to be a (i) “Consenting Stakeholder” and (ii) a “Party” for all purposes under the Agreement and with respect to any and all indebtedness or share of stock held by such Joining Party. 2. Representations and Warranties. With respect to the aggregate principal amount of indebtedness or number of shares of stock, in each case, set forth below its name on the signature page hereto, the Joining Party hereby makes the representations and warranties set forth in Section 11 of the Agreement to each other Party to the Agreement. 3. Governing Law. This Joinder Agreement shall be governed by and construed in accordance with the internal laws of the State of New York, without regard to any conflict of laws provisions that would require the application of the law of any other jurisdiction. [Signature Page Follows] Exhibit 10.1