UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

Genesis Healthcare, Inc.

(formerly known as Skilled Healthcare Group, Inc.)

(Name of Issuer)

Class A Common Stock, par value $0.001 per share

(Title of Class of Securities)

37185X 106

(CUSIP Number)

Andrea Daly, Esq.

c/o Onex Corporation

161 Bay Street

P.O. Box 700

Toronto, Ontario M5J 2S1

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

February 2, 2015

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f), or 240.13d-1(g), check the following box. ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

(Continued on following pages)

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This Schedule 13D (the “Amendment”) amends the Schedule 13D dated September 13, 2012, filed by Onex Corporation, Onex Partners LP, Onex US Principals LP, Onex Real Estate Holdings III Inc., Onex Skilled Holdings II Limited and Gerald W. Schwartz with respect to beneficial ownership of shares of Skilled Healthcare Group, Inc. (now known as Genesis Healthcare, Inc.) (the “Original Schedule 13D”).

Except as specifically provided herein, this Amendment does not modify any of the information previously reported on the Original Schedule 13D.

Item 1. Security and Issuer.

Item 1 of the Original Schedule 13D is hereby amended and restated as follows:

This Statement on Schedule 13D (this “Statement”) is being filed on behalf of the Reporting Persons (as defined in Item 2(a) below) with respect to the shares of the Class A common stock (the “Class A Common Stock”), issuable on conversion of Class B common stock (“Class B Common Stock”) of Genesis Healthcare, Inc., a Delaware corporation formerly known as Skilled Healthcare Group, Inc. (the “Issuer” or the “Company”). The Company’s principal executive offices are located at 101 East State Street, Kennett Square, PA 19348. The Reporting Persons may be deemed to be a group for the purposes of Section 13 of the Securities and Exchange Act of 1934, as amended, with each of such Reporting Persons being deemed to have beneficial ownership of all of the shares owned by the group.

Item 2. Identity and Background.

Item 2 of the Original Schedule 13D is hereby amended and restated as follows:

This Statement is being filed by the following persons (each a “Reporting Person” and, collectively, the “Reporting Persons”): (i) Onex Corporation, an Ontario, Canada corporation (“Onex”); (ii) Onex Partners LP, a Delaware limited partnership (“OPLP”); (iii) Onex US Principals LP, a Delaware limited partnership (“USLP”); (iv) Onex Real Estate Holdings III Inc., a Delaware corporation (“OREH”); and (v) Gerald W. Schwartz. The agreement among the Reporting Persons relating to the joint filing of this Statement is attached as Exhibit 1 hereto.

Onex’s principal business is to act as a diversified company that operates through autonomous subsidiaries, associated companies and strategic partnerships. Information relating to the directors and executive officers of Onex is set forth on Schedule A hereto which is incorporated herein by reference. Onex controls, directly or indirectly, each of OPLP, Onex Partners GP LP, Onex Partners GP Inc., USLP, Onex American Holdings GP LLC, and OREH. The address of the principal business and principal offices of Onex is 161 Bay Street, P.O. Box 700, Toronto, Ontario, Canada M5J 2S1.

OPLP’s principal business is investing in securities. The address of the principal business and principal offices of OPLP is 712 Fifth Avenue, New York, NY 10019. The general partner of OPLP is Onex Partners GP LP.

Onex Partners GP LP is a Delaware limited partnership. Onex Partners GP LP’s principal business is being the general partner of OPLP. The address of the principal business and principal offices of Partners GP LP is c/o Onex Investment Corp., 712 Fifth Avenue, New York, NY 10019. The general partner of Onex Partners GP LP is Onex Partners GP Inc.

Onex Partners GP Inc. is a Delaware corporation. Onex Partners GP Inc.’s principal business is being the general partner of Onex Partners GP LP. The address of the principal business and principal offices of Onex Partners GP Inc. is c/o Onex Investment Corp., 712 Fifth Avenue, New York, NY 10019. Information relating to the directors and executive officers of Onex Partners GP Inc. is set forth on Schedule B hereto which is incorporated herein by reference.

USLP’s principal business is investing in securities. The address of the principal business and principal offices of USLP is 421 Leader Street, Marion, Ohio 43302. The general partner of USLP is Onex American Holdings GP LLC.

Onex American Holdings GP LLC is a Delaware limited liability company. Onex American Holdings GP LLC’s principal business is being the general partner of USLP. The address of the principal business and principal offices of Onex American Holdings GP LLC is 421 Leader Street, Marion, Ohio 43302.

OREH’s principal business is a holding company that owns indirect interests in a variety of Onex’s investments. The address of the principal business and principal offices of OREH is 421 Leader Street, Marion, Ohio 43302. Information relating to the directors and executive officers of OREH is set forth on Schedule C hereto which is incorporated herein by reference.

Mr. Schwartz’s business address is c/o Onex Corporation, 161 Bay Street, P.O. Box 700, Toronto, Ontario, Canada M5J 2S1. His present principal occupation is Chairman of the Board, President and Chief Executive Officer of Onex Corporation. Mr. Schwartz is a citizen of Canada. Mr. Schwartz is the indirect holder of all of the issued and outstanding shares of Multiple Voting Shares and 17.6% of the issued and outstanding Subordinate Voting Shares of Onex, ownership of which entitles Mr. Schwartz to elect a majority of the members of Onex’s Board of Directors.

During the past five years, none of the Reporting Persons or other persons identified in this Item 2 (i) has been convicted in any criminal proceeding (excluding traffic violations or similar misdemeanors) or (ii) was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

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Item 3. Source and Amount of Funds or Other Consideration

The Original Schedule 13D is hereby supplemented and amended by the information below:

No purchase of securities of the Issuer by any Reporting Person was involved in the transaction which necessitated the filing of this Amendment to the Original Schedule 13D.

Item 4. Purpose of the Transaction.

Item 4 of the Original Schedule 13D is hereby supplemented and amended as follows:

Purchase and Contribution Agreement

On August 18, 2014, the Company entered into a Purchase and Contribution Agreement (the “Original Purchase Agreement”) with FC-GEN Operations Investment, LLC, a Delaware limited liability company (“Genesis”), pursuant to which the businesses and operations of the Company and Genesis would be combined (the “Combination”) and the common stock, par value $0.001 per share, of the Company (the “Company Common Stock”) and options to purchase shares of Company Common Stock, which remained outstanding, would represent 25.75% of the equity of the combined entity and the holders of equity interests of Genesis, together with Health Care REIT, Inc., a Delaware corporation, and the participants under Genesis’ management incentive compensation plan would hold 74.25% of the equity of the combined entity, calculated on an as-exchanged and as-converted basis as set forth in the Original Purchase Agreement. On January 5, 2015, the Company and Genesis entered into Amendment No. 1 (“Amendment No. 1”) to the Original Purchase Agreement (the Original Purchase Agreement, as amended, the “Purchase Agreement”). The Purchase Agreement does not provide for the acquisition of any securities of the Issuer by the Reporting Persons.

On August 18, 2014, following execution and delivery of the Original Purchase Agreement by the parties thereto, OREH, OPLP and USLP, which on such date owned shares of Company Common Stock representing approximately 82% of the voting power of the outstanding shares of Company Common Stock, delivered an irrevocable written consent to the Company approving in all respects the Original Purchase Agreement and the transactions and agreements contemplated thereby, including the Combination. On January 5, 2015, following execution and delivery of Amendment No. 1 by the parties thereto, OREH, OPLP and USLP delivered an irrevocable written consent to the Company approving such amendment.

On February 2, 2015, the Company closed the transactions (the “Transactions”) contemplated by Purchase Agreement (the “Closing”). As a result of the Closing, the number of outstanding shares of the Company has increased, causing the percentage of each Reporting Person’s beneficial ownership to decrease.

On February 3, 2015, the New York Stock Exchange ticker symbol for the Class A Common Stock changed to “GEN.”

In connection with the Transactions, the Company’s board of directors approved a restated certificate of incorporation (the “Restated Charter”) and restated bylaws (the “Restated Bylaws”), which became effective upon the consummation of the Transactions. The Restated Charter changed the name of the Company to “Genesis Healthcare, Inc.” and changed the shares of capital stock that the Company is authorized to issue. Specifically, the Company now has the authority to issue a total of 1,200,000,000 shares of capital stock, consisting of the following classes of capital stock: (1) 1,000,000,000 shares of Class A Common Stock; (2) 20,000,000 shares of Class B Common Stock; (3) 150,000,000 shares of Class C common stock, par value $0.001 per share (the “Class C Common Stock”); and (4) 30,000,000 shares of preferred stock, par value $0.001 per share. Each holder of Class A Common Stock, Class B Common Stock and Class C Common Stock is entitled to one vote for each share of such Company Common Stock, held of record by such holder. This represents a change from the former charter of the Company, which provided that each holder of Class B Common Stock was entitled to 10 votes per share.

Furthermore, the affirmative vote of the holders of at least 66 2/3% of the combined voting power of the shares entitled to vote in connection with the election of directors of the Company is required to amend, alter, change, or repeal, or to adopt any provision inconsistent with the purpose and intent of certain articles of the Restated Charter relating to:

The Restated Bylaws provide that the Company’s board of directors consists of not less than three nor more than 19 members, divided into three classes, designated Class I, Class II and Class III. Directors in each class serve for a term of three years. The Restated Bylaws may be amended, altered, changed or repealed, in whole or in part, or new bylaws may be adopted by either (1) the affirmative vote of a majority of the entire board of directors or (2) the affirmative vote of the holders of a majority of the voting power of the shares of capital stock of the Company entitled to vote in connection with the election of directors of the Company.

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The Purchase Agreement provided that Genesis and the Company would each take all actions necessary so that, at the Closing, the Board of Directors would consist of two individuals designated by the Company, four individuals designated by Genesis and five individuals designated jointly by the Company and Genesis. On February 2, 2014, immediately prior to the Closing, Messrs. Robert Le Blanc, Michael Boxer, M. Bernard Puckett and Bruce Yarwood and Linda Rosenstock, M.D. resigned from the Company’s Board of Directors, and the remaining directors (Messrs. Glenn Schafer and Robert Fish) set the number of members of the Board of Directors at eleven and appointed the following individuals to fill the board vacancies: Messrs. Jim Bloem, John DePodesta, Steven Fishman, George Hager, Arnold Whitman, Robert Hartman, Joshua Hausman, Jim McKeon and David Reis. Mr. Hausman is a Managing Director of Onex.

The foregoing descriptions of the Purchase Agreement, Restated Charter and Restated Bylaws do not purport to be complete and is qualified in its entirety by references to the Purchase Agreement, Restated Charter and Restated Bylaws, copies of which are filed as Exhibits 2, 3, and 4 to this Statement and are incorporated herein by reference.

In connection with the Transactions, the following agreements were entered into by OREH, OPLP and USLP:

Registration Rights Agreement

OREH, OPLP and USLP entered into an Amended and Restated Registration Rights Agreement, dated as of August 18, 2014, by and among the Company, certain holders of the Class B Common Stock listed on Schedule A attached thereto (the “Onex Holders”) and certain holders of equity securities of Genesis listed on Schedule B attached thereto (collectively, the “Genesis Holders” and, together with the Onex Holders, the “Investors”; the Investors, together with their respective permitted transferees, the “Holders”), which became effective as of the Closing.

Lock-up Agreements

Pursuant to the Registration Rights Agreement, each Holder of Registrable Securities (as defined below) has agreed that, except for transfers to permitted transferees and transfers in connection with registration statements filed by the Company, it shall not, during the period commencing on the date of Closing until the Lock-up Expiration (as defined below), (1) offer, pledge (other than to a financial institution in exchange for borrowed money), sell, contract to sell, grant any option or contract to purchase, purchase any option or contract to sell, hedge the beneficial ownership of or otherwise dispose of, directly or indirectly, any Registrable Securities, or (2) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of such securities, whether any such transaction described in (1) or (2) above is to be settled by delivery of Registrable Securities or such other securities, in cash or otherwise.

Under the Registration Rights Agreement:

Demand Registration Rights

Under the Registration Rights Agreement, the Onex Holders are entitled to request two demand registrations during the 18 month period following the Closing Date, and the Genesis Holders are entitled to request one demand registration during the 18 month period following the Closing Date; provided, however, that, if the notice of election to exercise a demand registration right is delivered by the Genesis Holders prior to the Lock-up Expiration, the number of Registrable Securities registered on such registration statement by the Genesis Holders (or their successors) is not to exceed 10% of the total outstanding Class A Common Stock on a fully-diluted and as-exchanged basis. The amount specified in any request for demand registration (net of applicable underwriting discounts, selling commissions and stock transfer taxes), is required to be at least $30,000,000 or, if less than $30,000,000, an amount sufficient to permit after taking into account the allocation procedures described below, the sale of all of the Registrable Securities held by whichever of the Onex Holders or the Genesis Holders are requesting such demand registration

In addition, following the Lock-up Expiration, the Genesis Holders are entitled to request unlimited demand registrations until such time as the Genesis Holders no longer hold any Registrable Securities; provided, that, if either (1) prior thereto, the Genesis Holders have exercised their right to request one demand registration as described above or (2) the notice of demand registration by the Genesis Holders is delivered following the 18-month period following the Closing Date, the Holders selling Registrable Securities are required to pay for or reimburse the Company for expenses incurred in connection with the applicable registration statement (a “Seller Expense Paid Registration”).

Allocation of Securities; Priority on Demand Registrations

In any demand registration effectuated pursuant to the terms of the Registration Rights Agreement, the Registrable Securities to be included in such registration shall be allocated (1) 74.25% to the Onex Holders and (2) 25.75% to the Genesis Holders; provided, however, that if the non-initiating holder declines to sell its maximum allocation in such demand registration, then such unused allotment shall be allocated (1) first, to Registrable Securities held by the initiating holder and (2) second, if the initiating holder declines to sell an amount of Registrable Securities equal to the unused allotment, to shares of Class A Common Stock to be issued by the Company if it, in its sole discretion, determines to sell such shares.

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If a demand registration involves an underwritten offering and the managing underwriter shall advise the Company that in its opinion the number of securities requested to be included in such registration exceeds the number that can be sold in such offering without having an adverse effect on such offering, including the price at which such securities can be sold, then, the Company shall include in such registration the maximum number of shares that such underwriter advises can be so sold without having such effect, allocated (1) first, to Registrable Securities requested by the Holders to be included in such registration and (2) second, among all shares of Class A Common Stock requested to be included in such registration by any other persons (including securities to be sold for the account of the Company).

Furthermore, if such underwriter determines that the Registrable Securities requested by the Holders to be included in such registration exceeds the number that can be sold in such offering without having an adverse effect on such offering, including the price at which such securities can be sold, then the Registrable Securities that are included in such offering shall be (1) in the case of a demand registration initiated by the Onex Holders or the Genesis Holders during the 18-month period following the Closing Date, apportioned 74.25% to the Onex Holders and 25.75% to the Genesis Holders, and further apportioned among the Onex Holders, on the one hand, and the Genesis Holders, on the other hand, on a pro rata basis in accordance with the number of Registrable Securities held by each such Onex Holder and Genesis Holder, as applicable, and (2) in the case of a demand registration initiated by the Genesis Holders following the Lock-up Expiration, apportioned among the Onex Holders, on the one hand, and the Genesis Holders, on the other hand, on a pro rata basis in accordance with the number of Registrable Securities held by each such Onex Holder and Genesis Holder, as applicable, and further apportioned in such other proportions as shall be mutually be agreed to by all such selling Holders; provided, however, that in the event that the Genesis Holders make the first request of a demand registration during the 18-month period following the Closing Date, then in the case of the first demand registration by the Genesis Holders following the Lock-up Expiration, the Registrable Securities that are included in such offering shall be apportioned 50% to the Onex Holders and 50% to the Genesis Holders, and further apportioned among the Onex Holders, on the one hand, and the Genesis Holders, on the other hand, on a pro rata basis in accordance with the number of Registrable Securities held by each such Onex Holder and Genesis Holder, as applicable.

Piggy-back Registration Rights

The Holders are entitled to piggy-back registration rights whenever the Company proposes to publicly sell or register for sale any of its common equity securities pursuant to a registration statement under the Securities Act (other than a registration statement on Form S-8 or on Form S-4 or any similar successor forms thereto).

Priority on Piggy-back Registrations

If a piggy-back registration is initiated as an underwritten primary registration on behalf of the Company where the primary use of proceeds does not include the repurchase, redemption, subscription or retirement of capital stock of the Company, and the managing underwriter advises the Company in writing that in its opinion the number of securities requested to be included in such registration exceeds the number that can be sold in such offering without having an adverse effect on such offering, including the price at which such securities can be sold, then the Company shall include in such registration the maximum number of shares that such underwriter advises can be so sold without having such effect, allocated (1) first, to the securities the Company proposes to sell, (2) second, to the Registrable Securities requested to be included therein by the Holders and (3) third, among other securities requested to be included in such registration by other security holders of the Company on such basis as such Holders may agree among themselves and the Company.

Furthermore, if such underwriter determines that the Registrable Securities requested by the Holders to be included in such registration exceeds the number that can be sold in such offering without having an adverse effect on such offering, including the price at which such securities can be sold, then the Registrable Securities that are included in such offering shall be (1) if the Company proposes to sell or register for sale such securities prior to the Lock-up Expiration, apportioned 74.25% to the Onex Holders and 25.75% to the Genesis Holders, and further apportioned among the Onex Holders, on the one hand, and the Genesis Holders, on the other hand, on a pro rata basis in accordance with the number of Registrable Securities held by each such Onex Holder and Genesis Holder, as applicable, and (2) if the Company proposes to sell or register for sale such securities after the Lock-up Expiration, apportioned to such Holders on a pro rata basis in accordance with the number of Registrable Securities held by each such Holder, or in each case in such other proportions as shall mutually be agreed to by all such selling Holders.

Shelf Registration Statement

Pursuant to the Registration Rights Agreement, at the request of any Holder, the Company is obligated to use its best efforts to promptly file a registration statement on Form S-3 or such other form under the Securities Act then available to the Company providing for (1) the issuance of Class A Common Stock upon an exchange, from time to time, of Genesis Class A Units held by any Genesis Holder or their respective permitted assigns and (2) the resale pursuant to Rule 415 of the Securities Act from time to time by the requesting Holder of such number of shares of Registrable Securities requested by such Holder to be registered thereby (a “Shelf Registration Statement”). The Company is required to use its best efforts to cause the Shelf Registration Statement to be declared effective by the SEC as of immediately following the Lock-up Expiration. the Company is obligated to maintain the effectiveness of the Shelf Registration Statement (or a replacement thereof) for as long as any Holder owns any Registrable Securities.

Indemnity; Expenses

In connection with any registration described above, the Company is obligated to indemnify holders selling Registrable Securities in connection with such registration and, except for any Seller Expense Paid Registration, the Company is required to bear all fees, costs and expenses (other than any underwriting discounts or commissions or transfer taxes, if any, and fees of counsel to the selling stockholders, attributable to the sale of Registrable Securities) in connection with such registration.

The foregoing description of the Registration Rights Agreement does not purport to be complete and is qualified in its entirety by reference to the Registration Rights Agreement, a copy of which is filed as Exhibit 5 to this Statement and is incorporated herein by reference.

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Support Agreement

Concurrently with the execution of the Original Purchase Agreement, the Company, Genesis, OREH, OPLP and USLP executed and delivered a support agreement (the “Support Agreement”) pursuant to which OREH, OPLP and USLP agreed to, among other things,

The Support Agreement terminated, by its terms, upon the Closing.

The foregoing description of the Support Agreement does not purport to be complete and is qualified in its entirety by reference to the Support Agreement, a copy of which is filed as Exhibit 6 to this Statement and is incorporated herein by reference.

Item 5. Interest in Securities of the Issuer.

Item 5 of the Original Schedule 13D is hereby amended and restated as follows:

Amount beneficially owned:

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Percent of class (based on 71,100,511 shares of Class A Common Stock outstanding as of February 6, 2015 and assuming exchange of the Reporting Persons’ Class B Common Stock into Class A Common Stock):

Number of shares as to which the person has:

None of the Reporting Persons nor, to the best knowledge of the Reporting Persons, any of the other persons named in Item 2 of this Statement has engaged in any transaction during the past 60 days in any shares of the Class A Common Stock.

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

Item 6 of the Original Schedule 13D is hereby supplemented and amended by the information below:

The information contained in Item 4 with respect to the Registration Rights Agreement and Support Agreement is hereby incorporated herein by reference into this Item 6.

In connection with the Transactions, effective as of the Closing, the Investor Stockholders Agreement, dated as of December 27, 2005 (the “Stockholders Agreement”), between the Company and certain of its then current stockholders and any other stockholder or option holder who becomes a party to the Stockholders Agreement by execution of a joinder agreement was terminated.

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Item 7. Material to be Filed as Exhibits.

Item 7 of the Original Schedule 13D is hereby amended and restated as follows:

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SIGNATURE

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

DATE: February 11, 2015

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Schedule A

Directors and Executive Officers of Onex Corporation (“Onex”)

The name, business address and present principal occupation of each director and executive officer of Onex are set forth below. All executive officers and directors listed on this Schedule A are Canadian citizens, except as specifically indicated below. All occupation or employment positions are with Onex, except as specifically indicated below.

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Schedule B

Directors and Executive Officers of Onex Partners GP Inc. (“Partners GP”)

The name, business address and present principal occupation of each director and executive officer of Partners GP are set forth below. All executive officers and directors listed on this Schedule B are United States citizens, except as specifically indicated below.

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Schedule C

Directors and Executive Officers of Onex Real Estate Holdings III Inc. (“OREH”)

The name, business address and present principal occupation of each director and executive officer of OREH are set forth below. All executive officers and directors listed on this Schedule C are Canadian citizens, except as specifically indicated below.

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EXHIBIT INDEX

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Exhibit 1

AGREEMENT

JOINT FILING OF SCHEDULE 13D

The undersigned acknowledge and agree that the foregoing statement on Schedule 13D is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13D shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning others, except to the extent that it knows or has reason to believe that such information is inaccurate. This agreement may be executed in any number of counterparts and all of such counterparts taken together shall constitute one and the same instrument.

IN WITNESS WHEREOF, each of the undersigned has executed this Agreement as of the 11th day of February, 2015.

Exhibit 6

Execution Version

SUPPORT AGREEMENT

This SUPPORT AGREEMENT (the “Agreement”) is made as of August 18, 2014, among FC-GEN Operations Investment, LLC, a Delaware limited liability company (“Greystone”), Skilled Healthcare Group, Inc., a Delaware corporation (“Sonoma”), and the other parties appearing on the signature pages hereto (each a “Stockholder” and collectively, the “Stockholders”).

WHEREAS, Greystone and Sonoma, have entered into a Purchase and Contribution Agreement, dated as of the date hereof (as the same may be amended or supplemented, the “Purchase Agreement”), pursuant to which, among other things, through a series of transactions the businesses, assets and liabilities of Greystone and Sonoma will be combined;

WHEREAS, capitalized terms used but not defined herein shall have the meanings set forth in the Purchase Agreement;

WHEREAS, each Stockholder is currently a holder of shares of Sonoma Class B Stock (all shares so held or hereafter acquired, the “Subject Shares”); and

WHEREAS, as a condition to its willingness to enter into the Purchase Agreement, Greystone has requested that the Stockholders enter into this Agreement.

NOW, THEREFORE, the parties hereto agree as follows:

Section 1. Representations and Warranties of the Stockholders. Each Stockholder, severally and not jointly, hereby represents and warrants, as to itself, to Greystone as follows:

(a) Authority; Execution and Delivery; Enforceability. Such Stockholder has all requisite power and authority to execute this Agreement and to consummate the transactions contemplated hereby. The execution and delivery by such Stockholder of this Agreement and consummation of the transactions contemplated hereby have been duly authorized by all necessary action on the part of such Stockholder. Such Stockholder has duly executed and delivered this Agreement and, assuming the due authorization, execution and delivery of this Agreement by Greystone, this Agreement constitutes the legal, valid and binding obligation of such Stockholder, enforceable against such Stockholder in accordance with its terms, subject, as to enforcement of remedies, to bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the rights and remedies of creditors generally and to the effect of general principles of equity. The execution and delivery by such Stockholder of this Agreement do not, and the consummation of the transactions contemplated hereby and compliance with the terms hereof will not, conflict with, or result in any violation of, or default (with or without notice or lapse of time, or both) under, or give rise to a right of termination, cancellation or acceleration of any obligation or to loss of a material benefit under, or result in the creation of any Lien upon any of the properties or assets of such Stockholder under, any provision of any note, bond, mortgage, indenture, contract, agreement, lease, license, permit, franchise or other instrument or obligation to which such Stockholder is a party or by which any properties or assets of such Stockholder are bound or, subject to the filings and other matters referred to in the next sentence, any provision of any Law applicable to such Stockholder or the

properties or assets of such Stockholder. No consent, approval, order, authorization or permit of, or registration, declaration or filing with, or notification to, any Governmental Authority is required to be obtained or made by or with respect to such Stockholder in connection with the execution, delivery and performance of this Agreement or the consummation of the transactions contemplated hereby, other than such reports under Sections 13(d) and 16 of the Exchange Act as may be required in connection with this Agreement and the transactions contemplated hereby.

(b) The Subject Shares. Such Stockholder is the record and beneficial owner of, and has good and valid title to, its Subject Shares, free and clear of any Liens. Such Stockholder has the sole right to vote such Subject Shares, and none of such Subject Shares is subject to any voting trust or other agreement, arrangement or restriction with respect to the voting of such Subject Shares, except for that certain Investor Stockholders Agreement dated December 27, 2005 or as contemplated by this Agreement.

Section 2. Covenants of the Stockholders. Each Stockholder, severally and not jointly, covenants and agrees as follows:

(a) Such Stockholder shall deliver the Written Consent pursuant to Section 228 of the DGCL.

(b) Such Stockholder shall not (i) sell, transfer, pledge, encumber, assign or otherwise dispose of (including by gift) (collectively, “Transfer”) or, other than this Agreement, enter into any contract, option or other arrangement (including any profit sharing arrangement) with respect to the Transfer of, any of such Stockholder’s Subject Shares to any person (other than pursuant to the Purchase Agreement and the Ancillary Agreements) unless the transferee is an Affiliate of such Stockholder and assumes such Stockholder’s obligations under this Agreement, (ii) convert such Stockholder’s Subject shares into shares of Sonoma Class A Stock or (iii) other than as expressly contemplated by the Purchase Agreement, enter into any new voting arrangement, whether by proxy, voting agreement or otherwise, with respect to any shares of Sonoma Common Stock, and shall not commit or agree to take any of the foregoing actions.

(c)

(i) Except as permitted by Section 4.02 of the Purchase Agreement, such Stockholder shall, and shall cause each of its Subsidiaries and Representatives to, immediately cease and cause to be terminated all existing discussions and negotiations with any person conducted heretofore with respect to any Competing Proposal. From and after the date of this Agreement until the earlier of the Closing or the date, if any, on which this Agreement is terminated, and except as otherwise provided for in this Agreement or the Purchase Agreement, such Stockholder agrees that it shall not (and shall not permit any of its Subsidiaries to), and that it shall use its reasonable best efforts to cause its Representatives not to, directly or indirectly: (i) solicit, initiate, cause or knowingly facilitate or encourage (including by way of furnishing information) the submission of any Competing Proposal; (ii) participate in any negotiations, or furnish to any person any information relating to Sonoma or any of its

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Subsidiaries, in each case, knowingly in connection with a Competing Proposal; (iii) engage in discussions with any person in an effort to or attempt to facilitate or encourage a person to make a Competing Proposal; (iv) approve or recommend, or propose publicly to approve or recommend, any Competing Proposal; or (v) enter into any letter of intent, agreement, agreement in principle, memorandum of understanding or similar document or any agreement or commitment providing for any Competing Proposal.

(ii) Notwithstanding anything to the contrary in this Agreement, to the extent Sonoma is permitted to take any actions as set forth in Section 4.02 of the Purchase Agreement with respect to a Competing Proposal and such stockholder has not breached Section 2(c)(i), such Stockholder and its Representatives will be free to participate in any discussions or negotiations regarding such Competing Proposal (including, without limitation, any related stockholders’ consent or voting agreement) with the Person making such Competing Proposal and to otherwise take action to the extent Sonoma may take such action, provided that such action by such Stockholder and its Representatives would be permitted to be taken by Sonoma pursuant to Section 4.02(c) of the Purchase Agreement.

(iii) For purposes of this Section 2(c), Sonoma and its Representatives will be deemed not to be Representatives of any Stockholder. For the avoidance of doubt, nothing in this Section 2(c) shall affect in any way the obligations of any Person (including Sonoma) under Section 4.02 of the Purchase Agreement.

(iv) Notwithstanding the foregoing, the phrase “cause its Subsidiaries”, “not permit its Subsidiaries” or similar phrases in this Section 2(c) shall not include an obligation of such Stockholder to cause or not permit Sonoma or its Subsidiaries to take any such action.

(d) Prior to the Closing, such Stockholder shall consult with Greystone before issuing, and give Greystone the opportunity to review and comment upon, any press release or other public statements with respect to the Transactions or the Ancillary Transactions, and shall not issue any such press release or make any such public statement prior to such consultation, except as may be required by applicable Law, court process or by obligations pursuant to any listing agreement with any securities exchange or securities quotation system.

(e) Such Stockholder hereby agrees not to commence or participate in, and to take all actions necessary to opt out of any class in any class action with respect to, any claim, derivative or otherwise, against Sonoma, Greystone or any of their respective successors relating to the negotiation, execution and delivery of this Agreement or the Purchase Agreement or the consummation of the transactions contemplated hereby, the Transactions or any Ancillary Transaction (other than any claims against Greystone to the extent relating to or based upon any alleged breach by Greystone of this Agreement).

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(f) In furtherance of this Agreement, such Stockholder hereby authorizes and instructs Sonoma to instruct its transfer agent to enter a stop transfer order with respect to all of the Subject Shares with respect to any Transfer not permitted hereunder, and Sonoma hereby agrees to so instruct its transfer agent.

(g) Such Stockholder hereby authorizes Sonoma and Greystone to publish and disclose in any announcement or disclosure required by the SEC and in the Information Statement information with respect to such Stockholder’s identity and ownership of the Subject Shares, this Agreement and such Stockholder’s obligations under this Agreement.

Section 3. Termination.

(a) This Agreement shall terminate with regard to each Stockholder upon the earliest of (i) the termination of this Agreement by the mutual written consent of Greystone and such Stockholder, (ii) the Closing and (iii) the termination of the Purchase Agreement in accordance with its terms.

(b) Notwithstanding the foregoing, (i) termination of this Agreement shall not prevent any party hereunder from seeking any remedies (at law or in equity) against any other party hereto for such party’s breach of this Agreement and (ii) Section 2(e) and Section 5 of this Agreement shall survive the termination of this Agreement. In no event shall any of the representations, warranties, covenants and other agreements in this Agreement (other than the covenants and other agreements set forth in Section 2(e) and Section 5), including any rights arising out of any breach of such representations, warranties, covenants and other agreements (other than the covenants and other agreements set forth in Section 2(e) and Section 5), survive the Closing.

Section 4. Additional Matters.

(a) Each Stockholder is executing this Agreement solely in its capacity as the record holder and beneficial owner of such Stockholder’s shares of Sonoma Common Stock, and nothing in this Agreement shall limit or otherwise restrict any officer or director of such Stockholder or any of its Affiliates from taking or not taking any action in his or her capacity as an officer of Sonoma or any Subsidiary of Sonoma or a member of the Sonoma Board (or any committee thereof) or the board of directors of any Subsidiary of Sonoma (or any committee thereof).

(b) From and after the Closing, solely for regulatory, financial reporting and Tax reporting and filing purposes of any of the Stockholders or their affiliates, for a period of seven (7) years after the Closing, Sonoma shall, and shall cause its Subsidiaries to, (i) retain the books and records relating to Sonoma and its Subsidiaries with respect to periods prior to the Closing in a manner reasonably consistent with the prior practice of Sonoma and its Subsidiaries, and (ii) upon reasonable advance notice and subject to applicable Law relating to the exchange of information (it being agreed that Sonoma shall, and shall cause its Subsidiaries to, use commercially reasonable efforts to make reasonable and appropriate substitute disclosure arrangements under circumstances in which such Laws apply), Sonoma shall, and shall cause its Subsidiaries to, afford to the Stockholders and their respective Representatives, during normal

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business hours following the Closing Date, and in a manner as to not unreasonably interfere with the normal operation of Sonoma and its Subsidiaries, reasonable access to Sonoma’s and each of its Subsidiaries’ properties, books, Contracts and records, and to their officers, employees, accountants, counsel and other Representatives and, during such period Sonoma shall, and shall cause its Subsidiaries to, make available to the Stockholders all information concerning their businesses, properties and personnel as they may reasonably request for the purposes described above, provided, however, that such right shall not (x) apply to information related to any dispute between any Stockholder or its affiliates, on the one hand, and Sonoma or its Subsidiaries, on the other hand, (y) apply to information subject to an attorney-client privilege except if such privilege is shared with the requesting Stockholder or (z) cause Sonoma or any of its Subsidiaries to violate any applicable confidentiality obligations (it being further agreed that at the request of any Stockholder, Sonoma shall use its commercially reasonable efforts to make reasonable and appropriate substitute disclosure arrangements). Any such request for access under this Section 4(b) shall be made to the Chief Financial Officer or General Counsel of Sonoma.

Section 5. General Provisions.

(a) Amendments. This Agreement may not be amended except by an instrument in writing signed by each of the parties hereto.

(b) Notice. All notices and other communications hereunder shall be in writing and shall be deemed given (and shall be deemed to have been given upon receipt) if delivered personally or sent by overnight courier (providing proof of delivery) to Greystone or Sonoma in accordance with Section 8.02 of the Purchase Agreement and to any Stockholder at its address as set forth in Sonoma’s stock records (or at such other address for a party as shall be specified by like notice).

(c) Interpretation. When a reference is made in this Agreement to a Section or subsection, such reference shall be to a Section or subsection of this Agreement unless otherwise indicated. The headings contained in this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation of this Agreement. Wherever the words “include”, “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation”.

(d) Severability. If any term or other provision of this Agreement is invalid, illegal or incapable of being enforced by any rule or law, or public policy, all other conditions and provisions of this Agreement shall nevertheless remain in full force and effect so long as the economic or legal substance of the transactions contemplated hereby is not affected in any manner materially adverse to any party. Upon such determination that any term or other provision is invalid, illegal or incapable of being enforced, the parties hereto shall negotiate in good faith to modify this Agreement so as to effect the original intent of the parties as closely as possible in an acceptable manner to the end that the transactions contemplated hereby are fulfilled to the extent possible.

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(e) Counterparts. This Agreement may be executed in one or more counterparts, all of which shall be considered one and the same agreement. This Agreement shall become effective against Greystone when one or more counterparts have been signed by Greystone and delivered to the Stockholders. This Agreement shall become effective against any Stockholder when one or more counterparts have been executed by such Stockholder and delivered to Greystone. Each party need not sign the same counterpart. Facsimile signatures or signatures received as a .pdf attachment to electronic mail shall be treated as original signatures for all purposes of this Agreement.

(f) Entire Agreement; No Third-Party Beneficiaries. This Agreement (i) constitutes the entire agreement and supersedes all prior agreements and understandings, both written and oral, among the parties with respect to the subject matter hereof and (ii) is not intended to confer upon any person other than the parties hereto any rights or remedies hereunder.

(g) Governing Law. This Agreement shall be governed by, and construed in accordance with, the Laws of the State of Delaware, regardless of the Laws that might otherwise govern under applicable principles of conflicts of laws thereof.

(h) Assignment. Neither this Agreement nor any of the rights, interests or obligations under this Agreement shall be assigned, in whole or in part, by operation of law or otherwise, by Greystone without the prior written consent of the Stockholders or by any Stockholder without the prior written consent of Greystone, and any purported assignment without such consent shall be void. Subject to the preceding sentences, this Agreement will be binding upon, inure to the benefit of, and be enforceable by, the parties and their respective successors and permissible assigns.

(i) Expenses. All costs and expenses incurred in connection with the transactions contemplated by this Agreement shall be paid by the party incurring such costs and expenses.

(j) Enforcement; Jurisdiction. The parties hereto agree that irreparable damage would occur and that they would not have any adequate remedy at Law in the event that any of the provisions of this Agreement were not performed in accordance with their specific terms or were otherwise breached. It is accordingly agreed that the parties hereto shall be entitled to an injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions of this Agreement in the Chancery Court of the State of Delaware (or in the event, but only in the event, that such court does not have subject matter jurisdiction over such action or proceeding, the Superior Court of the State of Delaware or the United States District Court for the District of Delaware) (such courts, the “Chosen Courts”), without proof of actual damages, this being in addition to any other remedy to which they are entitled at law or in equity. In addition, each of the parties irrevocably (i) submits itself to the exclusive jurisdiction of the Chosen Courts for the purpose of any litigation directly or indirectly based upon, relating to or arising out of this Agreement or the transactions contemplated hereby or the negotiation, execution or performance hereof, (ii) agrees that it will not attempt to deny or defeat such personal jurisdiction by motion or other request for leave from the Chosen Courts and (iii) agrees that it will not bring any action relating to this Agreement or the transactions contemplated hereby in any court other than the Chosen Courts. Each of the parties hereby irrevocably waives, and agrees not to assert, by way of motion, as a defense, counterclaim or otherwise, in any litigation with respect to this Agreement, (x) any claim that it is not personally subject to the jurisdiction of the Chosen Courts for any reason other than the failure to serve in

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accordance with this Section 5(j), (y) any claim that it or its property is exempt or immune from jurisdiction of any such court or from any legal process commenced in Chosen Courts (whether through service of notice, attachment prior to judgment, attachment in aid of execution of judgment, execution of judgment or otherwise) and (z) to the fullest extent permitted by the applicable Law, any claim that (A) the suit, action or proceeding in such court is brought in an inconvenient forum, (B) the venue of such suit, action or proceeding is improper or (C) this Agreement, or the subject matter of this Agreement, may not be enforced in or by such courts. Each of the parties hereby irrevocably consents to service being made through the notice procedures set forth in Section 5(b) and agrees that service of any process, summons, notice or document by personal delivery pursuant to the provisions set forth in Section 5(b) shall be effective service of process for any litigation in connection with this Agreement. Nothing in this Section 5(j) shall affect the right of any party to serve legal process in any other manner permitted by Law.

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IN WITNESS WHEREOF, each party has duly executed this Agreement, all as of the date first written above.

[Signature Pages to Support Agreement]

[Signature Pages to Support Agreement]