STOCK PURCHASE AGREEMENT

Exhibit 10.28

STOCK PURCHASE AGREEMENT

(First Quadrant Mercury, L.P.)

This Agreement is made and entered into as of December 30, 2008 by and among (i) PHC, Inc., a Massachusetts corporation (the “ Company ”) and (ii) First Quadrant Mercury, L.P. (“ Shareholder ”).

1.1         Purchase and Sale . At the Closing, the Company shall purchase from the Shareholder and the Shareholder shall sell to the Company, 53,976 shares of Class A Common Stock, $0.01 par value per share (the “ Shares ”) at a price of $1.46 per Share (the aggregate purchase price of $78,804.96) (the “ Purchase Price ”) and on such other terms and conditions set forth in this Agreement.

1.2         Closing; Closing Date . The closing of the transactions contemplated by this Agreement (the “ Closing ”) shall take place at the offices of Arent Fox LLP, 1050 Connecticut Avenue, NW, Washington, DC 20036 at 10:00 a.m., Eastern Time on December 30, 2008 (the “ Closing Date ”).

2.1         Deliveries by Company . At the Closing, the Company will deliver to Shareholder payment of the Purchase Price in immediately available funds by wire transfer in accordance with the wire transfer instructions set forth on Schedule 1 .

2.2         Deliveries by Shareholder . At the Closing, Shareholder and will deliver to the Company stock certificates representing all of the Shares by electronic transfer in accordance with the Company’s written instructions.

3.           REPRESENTATIONS AND WARRANTIES OF COMPANY . The Company represents to Shareholder that the statements in this Section 3 are correct and complete as of the date hereof and as of the Closing Date, except as set forth in the Company’s disclosure schedule attached hereto:

3.1         Organization of Company . The Company is a corporation duly organized, validly existing and in good standing under the laws of the Commonwealth of Massachusetts.

3.2         Authorization of Transaction . The Company has full corporate power and authority to execute and deliver this Agreement and to perform its obligations hereunder. This Agreement constitutes the valid and legally binding obligation of the Company, enforceable in accordance with its terms and conditions.

Noncontravention . Except as set forth on Schedule 3.3, the execution and delivery of this Agreement and the consummation of the transactions contemplated by this Agreement, do not and will not, with or without the giving of notice or the passage of time or both, (A) violate any law to which the Company is subject or any provision of its charter or bylaws or (B) conflict with, result in a breach of, constitute a default under, result in the acceleration of, create in any party the right to accelerate, terminate, modify or cancel, or require any notice under any agreement, contract, lease, license, instrument or other arrangement to which the Company is a party or by which it is bound or to which any of its assets is subject.

4.1         Representations and Warranties of Shareholder . Shareholder represents and warrants to the Company that the statements in this Section 4.1 are correct and complete as of the date hereof and as of the Closing Date:

(a)         Organization of Shareholder . Shareholder is a limited partnership duly organized, validly existing and in good standing under the laws of its jurisdiction of formation.

(b)         Authorization of Transaction . Shareholder has full power and authority to execute and deliver this Agreement and to perform its obligations hereunder. This Agreement constitutes the valid and legally binding obligation of each Shareholder, enforceable in accordance with its terms and conditions.

(c)         Noncontravention . The execution and delivery of this Agreement and the consummation of the transactions contemplated by this Agreement, do not and will not, with or without the giving of notice or the passage of time or both, (A) violate any law to which Shareholder is subject or any provision of its charter or partnership agreement or (B) conflict with, result in a breach of, constitute a default under, result in the acceleration of, create in any party the right to accelerate, terminate, modify or cancel, or require any notice under any agreement, contract, lease, license, instrument or other arrangement to which Shareholder is a party or by which it is bound or to which any of its assets is subject.

(d)         Title to Shares . Shareholder has good and marketable title to, and is the sole record and beneficial owner of the Shares, which Shares are owned free and clear of any restrictions on the right to vote, sell or otherwise dispose of the Shares (other than any restrictions under the Securities Act and state securities laws), rights of first refusal, taxes, liens or other encumbrances, options, warrants, purchase rights, contracts, commitments, equities, claims, and demands (collectively, “ Encumbrances ”). Upon consummation of the Closing in accordance with the terms set forth in this Agreement, the Company shall acquire good, valid and marketable title to the Shares, free and clear of any Encumbrances. Shareholder is not a party to any option, warrant, purchase right, or other contract or commitment that could require a Shareholder to sell, transfer, or otherwise dispose of any of the Shares (other than this Agreement). Shareholder is not a party to any voting trust, proxy, or other agreement or understanding with respect to the voting of the Shares.

(e)         Access to Information . Shareholder has had access to all information regarding the Company and its present and prospective business, assets, liabilities and financial condition that Shareholder reasonably considers important in making the decision to sell the Shares, and Shareholder has had ample opportunity to ask questions of the Company’s representatives concerning such matters and this investment.

(f)        For purposes of this Agreement, a “Person” means a natural person; partnership, limited partnership, trust, estate, association, limited liability company, or corporation; any custodian, nominee, trustee, executor, administrator, or other fiduciary; or any other individual or entity in its own or any representative capacity.

(g)         Tax Consequences . Shareholder understands the tax consequences of the transactions contemplated by this Agreement. Shareholder confirms that it is not relying on any statements or representations of the Company or any of its agents with respect to the tax effect of the transactions contemplated by this Agreement. Shareholder has had the opportunity to consult with its own legal counsel, accounting, tax, investment and other advisors, who are unaffiliated with the Company, with respect to the tax treatment of the transactions contemplated by this Agreement. Shareholder also acknowledges that it is solely responsible for any of its own tax liability that may arise as a result of the transactions contemplated by this Agreement.

CLOSING CONDITIONS .

6.1         Conditions to Obligation of Company . The obligation of the Company to consummate the transactions contemplated by this Agreement is subject to satisfaction of the following conditions.

(a)         Accuracy of Representations and Warranties . The representations and warranties of Shareholder set forth in Section 4 shall be true and accurate in every material respect on and as of the Closing with the same force and effect as if they had been made at the Closing, except for those representations and warranties that address matters only as of a particular date (which shall remain true and correct as of such particular date).

(b)         Covenants . Shareholder shall have performed and complied with all of its covenants hereunder that are required to be performed prior to Closing in all material respects through the Closing.

(c)         No Action . No action, suit, or proceeding shall be pending or threatened before any stock exchange, court or quasi-judicial or administrative agency of any federal, state, local, or foreign jurisdiction or before any arbitrator wherein an unfavorable injunction, judgment, order, decree, ruling, or charge would (A) prevent consummation of any of the transactions contemplated by this Agreement or (B) cause any of the transactions contemplated by this Agreement to be rescinded following consummation (and no such injunction, judgment, order, decree, ruling, or charge shall be in effect);

(d)         Consents . There shall have been obtained at or prior to the Closing Date consent of Capital Source Finance LLC to the transactions contemplated hereby.

6.2         Conditions to Obligation of Shareholder . The obligation of Shareholder to consummate the transactions contemplated by this Agreement is subject to satisfaction of the following conditions.

(a)         Accuracy of Representations and Warranties . The representations and warranties of the Company