EXHIBIT 4.1

January 24, 2011

Dear Sirs,

The purpose of this letter agreement (this “Confirmation”) is to confirm the terms and conditions of the transaction entered into between us on the Trade Date specified below (the “Transaction”). This Confirmation constitutes a “Confirmation” as referred to in the ISDA Master Agreement specified below.

This Confirmation evidences a complete and binding agreement between Party A and Party B as to the terms of the Transaction to which this Confirmation relates. This Confirmation shall supplement, form a part of, and be subject to an agreement in the form of the 2002 ISDA Master Agreement (the “Agreement”) as if Party A and Party B had executed an agreement in such form on the Trade Date (but without any Schedule except for the election of the laws of the State of New York as the governing law). In the event of any inconsistency between provisions of that Agreement and this Confirmation, this Confirmation will prevail for the purpose of the Transaction to which this Confirmation relates. The parties hereby agree that no Transaction other than the Transaction to which this Confirmation relates shall be governed by the Agreement. For purposes of the 2002 Definitions, the Transaction is a Share Forward Transaction.

JPMorgan Chase Bank, National Association

Organised under the laws of the United States as a National Banking Association

Main Office 1111 Polaris Parkway, Columbus, Ohio 43271

Registered as a branch in England & Wales branch No. BR000746

Registered Branch Office 125 London Wall, London EC2Y 5AJ

Authorised and regulated by the Financial Services Authority

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Party A and Party B each represents to the other that it has entered into the Transaction in reliance upon such tax, accounting, regulatory, legal, and financial advice as it deems necessary and not upon any view expressed by the other.

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Conditions to Effectiveness:

The effectiveness of this Confirmation on the Effective Date shall be subject to (i) the condition that the representations and warranties of Party B contained in the Underwriting Agreement dated January 20, 2011 among Party B and J.P. Morgan Securities LLC as representative of the several underwriters party thereto (the “Underwriting Agreement”) and any certificate delivered pursuant thereto by Party B are true and correct on the Effective Date as if made as of the Effective Date, (ii) the condition that Party B has performed all of the obligations required to be performed by it under the Underwriting Agreement on or prior to the Effective Date, (iii) the condition that Party B has delivered to Party A opinion of counsel dated as of the Trade Date with respect to matters set forth in Section 3(a) of the Agreement, (iv) the satisfaction of all of the conditions set forth in Section 6 of the Underwriting Agreement and (v) the condition that neither of the following has occurred (A) in Party A’s sole reasonable judgment, Party A (or its affiliate) is unable to borrow and deliver for sale a number of Shares equal to the Base Amount, or (B) in Party A’s sole reasonable judgment, Party A (or its affiliate) would incur a stock loan cost of more than a rate equal to 100 basis points per annum to borrow and deliver for sale a number of Shares equal to the Base Amount (in which event this Confirmation shall be effective but the Base Amount for the Transaction shall be the number of Shares an affiliate of Party A is required to deliver in accordance with Section 2(c) of the Underwriting Agreement, unless Party B has agreed in writing

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on or prior to the Effective Date to reimburse Party A for its costs in borrowing and delivering for sale such number of Shares in excess of a rate equal to 100 basis points per annum).

Representations and Agreements of Party B:

Party B (i) has such knowledge and experience in financial and business affairs as to be capable of evaluating the merits and risks of entering into the Transaction; (ii) has consulted with its own legal, financial, accounting and tax advisors in connection with the Transaction; and (iii) is entering into the Transaction for a bona fide business purpose.

Party B is not and has not been the subject of any civil proceeding of a judicial or administrative body of competent jurisdiction that could reasonably be expected to impair materially Party B’s ability to perform its obligations hereunder.

Additional Representations, Warranties and Agreements of Party B: Party B hereby represents and warrants to, and agrees with, Party A as of the date hereof that:

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Covenant of Party B:

Unless the provisions set forth below under “Private Placement Procedures” shall be applicable, the parties acknowledge and agree that any Shares delivered by Party B to Party A on any Settlement Date will be newly issued Shares and when such Shares previously delivered by Party B are delivered by Party A (or an affiliate of Party A) to securities lenders from whom Party A (or an affiliate of Party A) borrowed Shares in connection with hedging its exposure to the Transaction will be freely saleable without further registration or other restrictions under the Securities Act, in the hands of those securities lenders, irrespective of whether such stock loan is effected by Party A or an affiliate of Party A. Accordingly, Party B agrees that the Shares that it delivers to Party A on each Settlement Date will not bear a restrictive legend and that such Shares will be deposited in, and the delivery thereof shall be effected through the facilities of, the Clearance System.

Covenants of Party A:

Insolvency Filing:

Notwithstanding anything to the contrary herein, in the Agreement or in the Definitions, upon any Insolvency Filing in respect of the Issuer, the Transaction shall automatically terminate on the date thereof without further liability of either party to this Confirmation to the other party (except for any liability in respect of any breach of representation or covenant by a party under this Confirmation prior to the date of such Insolvency Filing).

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The parties hereto agree and acknowledge that (1) at any point prior to any Insolvency Filing in respect of Party B, Party B shall have the unilateral right to elect Physical Settlement of this Transaction pursuant to the provisions set forth above under the heading “Settlement Terms”; and (2) this Transaction shall automatically terminate on the date of any Insolvency Filing pursuant to the provisions set forth in the immediately preceding paragraph solely to the extent that Party B failed to elect Physical Settlement of this Transaction pursuant to the provisions set forth above under the heading “Settlement Terms” prior to the relevant Insolvency Filing.

Extraordinary Dividends:

If an ex-dividend date for an Extraordinary Dividend occurs on or after the Trade Date and on or prior to the Maturity Date (or, if later, the last date on which Shares are delivered by Party B to Party A in settlement of the Transaction), Party B shall pay an amount, as determined by the Calculation Agent, in cash equal to the product of such Extraordinary Dividend and the Base Amount to Party A on the earlier of (i) the date on which such Extraordinary Dividend is paid by the Issuer to holders of record of the Shares or (ii) the Maturity Date. “Extraordinary Dividend” means the per Share amount of any cash dividend or distribution declared by the Issuer with respect to the Shares that is specified by the board of directors of the Issuer as an “extraordinary” dividend. Party A and Party B agree that such specification, or the lack thereof, by the board of directors of the Issuer shall be conclusive and binding upon them as to whether any cash dividend or distribution is, or is not, an “Extraordinary Dividend.”

Acceleration Events:

The following events shall each constitute an “Acceleration Event”:

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For purposes of clause (e) above, the “Share Amount” as of any day is the number of Shares that Party A and any person whose ownership position would be aggregated with that of Party A (Party A or any such person, a “Party A Person”) under any law, rule, regulation or regulatory order that for any reason becomes applicable to ownership of Shares after the Trade Date (“Applicable Laws”), owns, beneficially owns, constructively owns, controls, holds the power to vote or otherwise meets a relevant definition of ownership of under the Applicable Laws, as determined by Party A in its reasonable discretion. The “Post-Effective Limit” means (x) the minimum number of Shares that would give rise to reporting or registration obligations or other requirements (including obtaining prior approval from any person or entity) of a Party A Person, or would result in an adverse effect on a Party A Person, under the Applicable Laws, as determined by Party A in its reasonable discretion, minus (y) 1% of the number of Shares outstanding.

Termination Settlement:

Upon the occurrence of any Acceleration Event, Party A shall have the right to designate, upon at least one Scheduled Trading Day’s notice, any Scheduled Trading Day following such occurrence to be a Settlement Date hereunder (a “Termination Settlement Date”) to which Physical Settlement shall apply, and to select the number of Settlement Shares relating to such Termination Settlement Date; provided that (i) in the case of an Acceleration Event arising out of an Ownership Event, the number of Settlement Shares so designated by Party A shall not exceed the number of Shares necessary to reduce the Share Amount to the Post-Effective Limit, (ii) in the case of an Acceleration Event arising out of a Stock Borrow Event the number of Settlement Shares so designated by Party A shall not exceed the number of Shares as to which such Stock Borrow Event exists and (iii) in the case of an Acceleration Event arising out of a Dividend Event that occurs during an Unwind Period, Party A may designate a Termination Settlement Date only if, in its sole reasonable judgment, the ex-date for the relevant dividend or distribution will occur during such Unwind Period (in which case such ex-date will be the Termination Settlement Date in respect of such Acceleration Event, and up until such ex-date Party A will use commercially reasonable efforts to unwind its hedge with respect to as many Settlement Shares as possible prior to such ex-date, notwithstanding any intervening determination by Party A that the ex-date will (or may) occur during such Unwind Period). If, upon designation of a Termination Settlement Date by Party A pursuant to the preceding sentence, Party B fails to deliver the Settlement Shares relating

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to such Termination Settlement Date when due or otherwise fails to perform obligations within its control in respect of the Transaction, it shall be an Event of Default with respect to Party B and Section 6 of the Agreement shall apply. If an Acceleration Event occurs during an Unwind Period relating to a number of Settlement Shares to which Cash Settlement or Net Share Settlement applies, then on the Termination Settlement Date relating to such Acceleration Event, notwithstanding any election to the contrary by Party B, Cash Settlement or Net Share Settlement shall apply to the portion of the Settlement Shares relating to such Unwind Period as to which Party A has unwound its hedge and Physical Settlement shall apply in respect of (x) the remainder (if any) of such Settlement Shares and (y) the Settlement Shares designated by Party A in respect of such Termination Settlement Date.

Private Placement Procedures

If Party B is unable to comply with the provisions of “Covenant of Party B” above because of a change in law or a change in the policy of the Securities and Exchange Commission or its staff, or Party A otherwise determines that in its reasonable opinion any Settlement Shares to be delivered to Party A by Party B may not be freely returned by Party A or its affiliates to securities lenders as described under “Covenant of Party B” above, then delivery of any such Settlement Shares (the “Restricted Shares”) shall be effected pursuant to Annex A hereto, unless waived by Party A.

Rule 10b5-1:

It is the intent of Party A and Party B that following any election of Cash Settlement or Net Share Settlement by Party B, the purchase of Shares by Party A during any Unwind Period comply with the requirements of Rule 10b5-1(c)(1)(i)(B) of the Exchange Act and that this Confirmation shall be interpreted to comply with the requirements of Rule 10b5-1(c).

Party B acknowledges that (i) during any Unwind Period Party B does not have, and shall not attempt to exercise, any influence over how, when or whether to effect purchases of Shares by Party A (or its agent or affiliate) in connection with this Confirmation and (ii) Party B is entering into the Agreement and this Confirmation in good faith and not as part of a plan or scheme to evade compliance with federal securities laws including, without limitation, Rule 10b-5 promulgated under the Exchange Act.

Party B hereby agrees with Party A that during any Unwind Period Party B shall not communicate, directly or indirectly, any Material Non-Public Information (as defined herein) to any EDG Personnel (as defined below). For purposes of the Transaction, “Material Non-Public Information” means information relating to Party B or the Shares that (a) has not been widely disseminated by wire service, in one or more newspapers of general circulation, by communication from Party B to its shareholders or in a press release, or contained in a public filing made by Party B with the Securities and Exchange Commission and (b) a reasonable investor might consider to be of importance in making an investment decision to buy, sell or hold Shares. For the avoidance of doubt and solely by way of illustration, information should be presumed “material” if it relates to such matters as dividend increases or decreases, earnings estimates, changes in previously released earnings estimates, significant expansion or curtailment of operations, a significant increase or decline of orders, significant merger or acquisition proposals or agreements, significant new products or discoveries, extraordinary borrowing, major litigation, liquidity problems, extraordinary management developments, purchase or sale of substantial assets, or other similar information For purposes of the Transaction, “EDG Personnel” means any employee on the trading side of the Equity Derivatives Group of J.P. Morgan Securities LLC and does not include Messrs. David Aidelson, Greg Batista, David Seaman, James Rothschild and Elliot Chalom (or any other person or persons designated from time to time by the Compliance Group of Party).

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Maximum Share Delivery:

Notwithstanding any other provision of this Confirmation, in no event will Party B be required to deliver on any Settlement Date, whether pursuant to Physical Settlement, Net Share Settlement, Termination Settlement or any Private Placement Settlement, more than a number of Shares equal to twice the initial Base Amount to Party A, subject to reduction by the amount of any Shares delivered by Party B on any prior Settlement Date.

Transfer and Assignment:

Party A may assign or transfer any of its rights or delegate any of its duties hereunder to any affiliate of Party A or any entity organized or sponsored by Party A without the prior written consent of Party B. Notwithstanding any other provision in this Confirmation to the contrary requiring or allowing Party A to purchase, sell, receive or deliver any Shares or other securities to or from Party B, Party A may designate any of its affiliates to purchase, sell, receive or deliver such Shares or other securities and otherwise to perform Party A’s obligations in respect of the Transaction and any such designee may assume such obligations. Party A shall be discharged of its obligations to Party B to the extent of any such performance.

Matters Relating to Agent:

Each party agrees and acknowledges that (i) J.P. Morgan Securities LLC, as agent, (the “Agent”) acts solely as agent on a disclosed basis with respect to the transactions contemplated hereunder, and (ii) the Agent has no obligation, by guaranty, endorsement or otherwise, with respect to the obligations of either Party B or Party A hereunder, either with respect to the delivery of cash or Shares, either at the beginning or the end of the transactions contemplated hereby. In this regard, each of Party A and Party B acknowledges and agrees to look solely to the other for performance hereunder, and not to the Agent.

Indemnity

Party B agrees to indemnify Party A and its affiliates and their respective directors, officers, agents and controlling parties (Party A and each such affiliate or person being an “Indemnified Party”) from and against any and all losses, claims, damages and liabilities, joint and several, incurred by or asserted against such Indemnified Party arising out of, in connection with, or relating to, the execution or delivery of this Confirmation, the performance by the parties hereto of their respective obligations under the Transaction, any breach of any covenant or representation made by Party B in this Confirmation or the Agreement or the consummation of the transactions contemplated hereby and will reimburse any Indemnified Party for all reasonable expenses (including reasonable legal fees and expenses) as they are incurred in connection with the investigation of, preparation for, or defense of any pending or threatened claim or any action or proceeding arising therefrom, whether or not such Indemnified Party is a party thereto. Party B will not be liable under this Indemnity paragraph to the extent that any loss, claim, damage, liability or expense is found in a final and nonappealable judgment by a court to have resulted from Party A’s gross negligence or willful misconduct.

Notice

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Agreements and Acknowledgments

Regarding Hedging Activities:                                         Applicable

No Collateral or Setoff.:

Notwithstanding Section 6(f) or any other provision of the Agreement or any other agreement between the parties to the contrary, the obligations of Party B hereunder are not secured by any collateral. Obligations under the Transaction shall not be set off against any other obligations of the parties, whether arising under the Agreement, this Confirmation, under any other agreement between the parties hereto, by operation of law or otherwise, and no other obligations of the parties shall be set off against obligations under the Transaction, whether arising under the Agreement, this Confirmation, under any other agreement between the parties hereto, by operation of law or otherwise, and each party hereby waives any such right of setoff. In calculating any amounts under Section 6(e) of the Agreement, notwithstanding anything to the contrary in the Agreement, (a) separate amounts shall be calculated as set forth in such Section 6(e) with respect to (i) the Transaction and (ii) all other Transactions, and (b) such separate amounts shall be payable pursuant to Section 6(d)(ii) of the Agreement.

Status of Claims in Bankruptcy:

Party A acknowledges and agrees that this confirmation is not intended to convey to Party A rights with respect to the transactions contemplated hereby that are senior to the claims of common stockholders in any U.S. bankruptcy proceedings of Party B; provided, however, that nothing herein shall limit or shall be deemed to limit Party A’s right to pursue remedies in the event of a breach by Party B of its obligations and agreements with respect to this Confirmation and the Agreement; and provided further, that nothing herein shall limit or shall be deemed to limit Party A’s rights in respect of any transaction other than the Transaction.

Limit on Beneficial Ownership:

Notwithstanding any other provisions hereof, Party A shall not be entitled to take delivery of any Shares deliverable hereunder (whether in connection with the purchase of Shares on any Settlement Date or any Termination Settlement Date, any Private Placement Settlement or otherwise) to the extent (but only to the extent) that, after such receipt of any Shares hereunder, (i) the Share Amount would exceed the Post-Effective Limit, (ii) Party A and its affiliates would directly or indirectly own or control, for purposes of the Bank Holding Company Act of 1956, as amended (the “BHCA”), in excess of 4.0% of the outstanding Shares, or (iii) Party A and each person subject to aggregation of Shares with Party A under Section 13 or Section 16 of the Exchange Act and rules promulgated thereunder (the “Party A Group”) would directly or indirectly beneficially own (as such term is defined for purposes of Section 13 or Section 16 of the Exchange Act and rules promulgated thereunder) in excess of 7.5% of the then outstanding Shares (the “Threshold Number of Shares”). Any purported delivery hereunder shall be void and have no effect to the extent (but only to the extent) that, after such delivery, (i) the Share Amount would exceed the Post-Effective Limit, (ii) Party A and its affiliates would directly or indirectly own or control, for purposes of the BHCA, in excess of 4.0% of the outstanding Shares, or (iii) Party A Group would directly or indirectly so beneficially own in excess of the Threshold Number of Shares. If any delivery owed to Party A hereunder is not made, in whole or in part, as a result of this provision, Party B’s obligation to make such delivery shall not be extinguished and Party B shall make such delivery as promptly as practicable after, but in no event later than one Exchange Business Day after, Party A gives notice to Party B that, after such delivery, (i) the Share Amount would not exceed the Post-Effective Limit, (ii) Party A and its affiliates would not directly or indirectly own or control, for purposes of the BHCA, in excess of 4.0% of the outstanding Shares,

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and (iii) Party A Group would not directly or indirectly so beneficially own in excess of the Threshold Number of Shares.

In addition, notwithstanding anything herein to the contrary, if any delivery owed to Party A hereunder is not made, in whole or in part, as a result of the immediately preceding paragraph, Party A shall be permitted to make any payment due in respect of such Shares to Party B in two or more tranches that correspond in amount to the number of Shares delivered by Party B to Party A pursuant to the immediately preceding paragraph.

Wall Street Transparency and Accountability Act:

In connection with Section 739 of the Wall Street Transparency and Accountability Act of 2010 (“WSTAA”), the parties hereby agree that neither the enactment of WSTAA or any regulation under the WSTAA, nor any requirement under WSTAA or an amendment made by WSTAA, shall limit or otherwise impair either party’s otherwise applicable rights to terminate, renegotiate, modify, amend or supplement this Confirmation or the Agreement, as applicable, arising from a termination event, force majeure, illegality, increased costs, regulatory change or similar event under this Confirmation, the 2002 Definitions incorporated herein, or the Agreement (including, but not limited to, rights arising from Change in Law, any Acceleration Event or Illegality (as defined in the Agreement)).

Miscellaneous:

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Acknowledgements.

The parties hereto intend for:

Severability.

If any term, provision, covenant or condition of this Confirmation, or the application thereof to any party or circumstance, shall be held to be invalid or unenforceable in whole or in part for any reason, the remaining terms, provisions, covenants, and conditions hereof shall continue in full force and effect as if this Confirmation had been executed with the invalid or unenforceable provision eliminated, so long as this Confirmation as so modified continues to express, without material change, the original intentions of the parties as to the subject matter of this Confirmation and the deletion of such portion of this Confirmation will not substantially impair the respective benefits or expectations of parties to this Agreement; provided, however, that this severability provision shall not be applicable if any provision of Section 2, 5, 6 or 13 of the Agreement (or any definition or provision in Section 14 to the extent that it relates to, or is used in or in connection with any such Section) shall be so held to be invalid or unenforceable.

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Please confirm that the foregoing correctly sets forth the terms of our agreement by signing and returning this Confirmation.

Confirmed as of the date first written above:

ANNEX A

PRIVATE PLACEMENT PROCEDURES

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