Master Confirmation for Forward Stock SaleTransactions

Exhibit 10.1

April 2, 2010

Master Confirmation for Forward Stock Sale Transactions

Dear Sir/Madam:

The purpose of this letter agreement (this “Master Confirmation”) is to confirm the terms and conditions of the transactions to be entered into from time to time between The Bank of New York Mellon (“Party A” or “BNY”) and Westar Energy, Inc. (“Party B”) in accordance with the terms of the Sales Agency Financing Agreement, dated as of April 2, 2010, among BNY Mellon Capital Markets, LLC, Party A and Party B (the “Sales Agency Financing Agreement”) on the Trade Dates specified below (collectively, the “Transactions”, and each, a “Transaction”). Each Transaction will be evidenced by a supplemental confirmation (each, a “Supplemental Confirmation”, and each such Supplemental Confirmation, together with this Master Confirmation, a “Confirmation” for purposes of the Agreement specified below) substantially in the form of Exhibit A hereto.

The definitions and provisions contained in the 2002 ISDA Equity Derivatives Definitions (as published by the International Swaps and Derivatives Association, Inc. (“ISDA”)) (the “Equity Definitions”) are incorporated into each Confirmation. In the event of any inconsistency between the Equity Definitions and any Confirmation, such Confirmation will govern to the extent of such inconsistency. Any reference to a currency shall have the meaning contained in Annex A to the 1998 ISDA FX and Currency Option Definitions, as published by ISDA.

GENERAL TERMS:

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Conditions to Effectiveness:

The effectiveness of each Supplemental Confirmation on the Effective Date for such Supplemental Confirmation shall be subject to (i) the condition that the representations and warranties of Party B contained in Section 3(a) of the Agreement and in the Sales Agency Financing Agreement, and any certificate delivered pursuant to the Sales Agency Financing Agreement by Party B, be true and correct on such Effective Date as if made as of such Effective Date, (ii) the condition that the representations and warranties of Party A contained in Section 3(a) of the Agreement be true and correct on such Effective

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Date as if made as of such Effective Date, (iii) the condition that Party B have delivered to Party A an opinion of counsel (which may include internal counsel to Party B) dated on or prior to the first Trade Date for a Transaction hereunder with respect to matters set forth in Section 3(a)(ii) and Section 3(a)(v) of the Agreement (as if references therein to “this Agreement” were instead references to “this Master Confirmation”), (iv) the condition that Party B have performed all of the obligations required to be performed by it under the Sales Agency Financing Agreement on or prior to such Effective Date, (v) delivery by Party A to Party B of a properly executed Internal Revenue Service Form W-9 or similar documentation establishing an exemption from backup withholding under the Internal Revenue Code of 1986, as amended, and (vi) the satisfaction of all of the conditions set forth in Section 5.01 of the Sales Agency Financing Agreement. For purposes hereof, the representation in Section 3(a)(iv) of the Agreement shall, for avoidance of doubt, extend to this Master Confirmation and each Supplemental Confirmation.

Representations and Warranties of Party B: Party B hereby represents and warrants to Party A (each of such representations to be deemed part of Section 3(a) of the Agreement) as of the date hereof and on the Effective Date of each Transaction, and, in the case of clause (b), on such dates and on each Settlement Date for such Transaction, that:

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Covenants of Party B: Party B hereby agrees that, so long as either party has or may have any obligation under any Transaction, that:

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In addition, Party B covenants to notify Party A in writing (which shall include email) at least ten Exchange Business Days prior to the ex-dividend or ex date, as applicable, of a distribution, issue or dividend to existing holders of the Shares, which ex-dividend date or ex date occurs at any time from, and including, the date hereof and ends on the final Settlement Date under this Master Confirmation.

Covenants and Representation of Party A:

Acceleration Events: An Acceleration Event shall occur if:

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Notwithstanding anything to the contrary herein, in the Agreement or in the Equity Definitions, if Party A designates, pursuant to clause (d) or clause (e) above, a Settlement Date with respect to a Transaction and such Settlement Date is to occur before the date that is one Settlement Cycle after the last day of the Forward Hedge Selling Period for such Transaction, then, for purposes of such Settlement Date, (i) a Supplemental Confirmation relating to such Transaction shall, notwithstanding the provisions under “Conditions to Effectiveness” above, be deemed to be effective; and (ii) the Forward Price shall be deemed to be the Initial Forward Price (calculated assuming that the last Trading Day of such Forward Hedge Selling Period occurs on the date that is deemed, pursuant to clause (d) or clause (e) above, as applicable, to be the Trade Date for such Transaction for purposes of such Settlement Date).

Termination Settlement:

If a Settlement Date with respect to any Transaction is specified following an Acceleration Event with respect to such Transaction (a “Termination Settlement Date”), Party B will be deemed to have irrevocably elected that Physical Settlement shall apply to such Transaction with respect to such Termination Settlement Date as set forth above, subject to the provisions described under “Limit on Beneficial Ownership” below. If, upon designation of a Termination Settlement Date by Party A with respect to any Transaction, Party B fails to deliver the Settlement Shares relating to such Termination Settlement Date when due or otherwise fails to perform its obligations in connection therewith, it shall be an Event of Default with respect to Party B and

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Section 6 of the Agreement shall apply to such Transaction. If an Acceleration Event occurs during an Unwind Period of any Transaction relating to a number of Settlement Shares of such Transaction to which Cash Settlement or Net Share Settlement applies, then on the Termination Settlement Date of such Transaction 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 (for avoidance of doubt, such portion of such Settlement Shares to be a number of Settlement Shares with respect which Party A would be deemed, pursuant to the second paragraph under “Settlement Date” above, to have completely unwound it 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 with respect to such Transaction in respect of such Termination Settlement Date. If Party A designates a Termination Settlement Date (other than pursuant to clause (a) under “Acceleration Events” above), then all Settlement Dates theretofore designated by Party B to occur after such Termination Settlement Date shall instead occur on such Termination Settlement Date and shall, except to the extent (and only to the extent) provided in the immediately preceding sentence, be subject to Physical Settlement, notwithstanding any election to the contrary by Party B.

Certain Changes In Law:

Upon the occurrence of any Change In Law specified in clause (Y) of the definition thereof, Party A and Party B agree to negotiate in good faith for at least 30 calendar days to amend this Master Confirmation to take account of the resulting “materially increased cost” as such phrase is used in clause (Y) of the definition of “Change In Law.” Such amendment may, if agreed by Party A and Party B, result in a Change In Law specified in clause (Y) of the definition thereof being treated as if it were a Change In Law specified in clause (X) of the definition thereof, as described in clause (e) under the heading “Acceleration Events” above. If, after negotiating in good faith for at least 30 calendar days to so amend this Master Confirmation, Party A and Party B do not agree on such an amendment, the relevant Change In Law specified in clause (Y) of the definition thereof shall treated as if it were a Change In Law specified in clause (X) of the definition thereof, as described in clause (e) under the heading “Acceleration Events” above.

Rule 10b5-1:

It is the intent of Party A and Party B that the purchase of Shares by Party A during any Unwind Period of any Transaction comply with the requirements of Rule 10b5-1(c)(1)(i)(B) under the Exchange Act and that this Master Confirmation and each Supplemental Confirmation be interpreted to comply with the requirements of Rule 10b5-1(c).

Party B acknowledges that, except as otherwise provided herein, (i) during any Unwind Period of any Transaction, 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 Master Confirmation or the Supplemental Confirmation for such Transaction and (ii) Party B is entering into the Agreement and this Master Confirmation and will enter into all Supplemental Confirmations 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 under the Exchange Act.

Party B hereby agrees with Party A that during any Unwind Period for any Transaction, Party B shall not communicate, directly or indirectly, any material non-public information (within the meaning of federal securities laws) to any Equity Personnel (as defined below). 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 any Transaction, “Equity Personnel” means any employee in The Bank of New York Mellon Global Markets Equity Derivatives Trading Desk but does not include Daniel C. de Menocal, Jr.

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Interpretive Letter:

The parties intend for this Master Confirmation and each Supplemental Confirmation to constitute a “Contract” as described in the letter dated October 6, 2003 submitted by Robert W. Reeder and Leslie N. Silverman to Paula Dubberly of the staff of the Securities and Exchange Commission (the “Staff”), to which the Staff responded in an interpretive letter dated October 9, 2003.

Restricted Shares:

With respect to any Transaction, if Party B is unable to comply with clause (h) of “Covenants of Party B” above in this Section 3 because of a change in law or a change in interpretation or the policy of the Securities and Exchange Commission or its staff, or Party A otherwise determines in its reasonable, good faith opinion based on the advice of outside counsel that any Shares to be delivered to Party A by Party B may not be freely returned by Party A to securities lenders as described in clause (h) of “Covenants of Party B” above in this Section 3, then the Calculation Agent may, in consultation with Party B, make adjustments to the terms of such Transaction to preserve the economic intent of the parties, including adjustments to the Forward Price for such Transaction to reflect any lack of liquidity in restricted Shares, and the parties shall work together in good faith to effect settlement for such Transaction in a commercially reasonable manner and in compliance with applicable law and regulations.

Maximum Share Delivery:

Notwithstanding any other provision of this Master Confirmation, in no event will Party B be required to deliver on any Settlement Date of any Transaction, whether pursuant to Physical Settlement, Net Share Settlement, Termination Settlement or otherwise, more than the number of Base Shares of such Transaction to Party A, subject to reduction by the aggregate number of Shares delivered by Party B in respect of such Transaction on all prior Settlement Dates of such Transaction.

Assignment:

Party A may assign or transfer any of its rights or delegate any of its duties under this Master Confirmation and any Supplemental Confirmation relating to a Transaction to any affiliate of Party A without the prior written consent of Party B, so long as the senior unsecured debt rating (“Credit Rating”) of such affiliate (or any guarantor of its obligations under such Transaction) is equal to or greater than the Credit Rating of Party A, as specified by Standard and Poor’s Rating Services or Moody’s Investor Service, Inc., at the time of such assignment or transfer. In connection with any assignment or transfer pursuant to the immediately preceding sentence, the guarantee of any guarantor of the relevant transferee’s obligation shall constitute a Credit Support Document under the Agreement. If Party A so assigns or transfers any of its rights or delegates any of its duties under this Master Confirmation and any Supplemental Confirmation relating to a Transaction, as the case may be, Party A shall give prompt written notice to Party B of such assignment, transfer or delegation, as applicable.

Notwithstanding anything to the contrary herein, in the Agreement or in the Equity Definitions, (i) Party A may designate any of its affiliates to purchase or receive such Shares or otherwise to perform Party A’s obligations in respect of any Transaction and any such designee may assume such obligations, and Party A shall be discharged of its obligations to Party B only to the extent of any such performance; and (ii) to the extent Physical Settlement applies to any portion of a Transaction (or Net Share Settlement applies to any portion of a Transaction and Party B would be obligated to deliver any Shares to Party A in connection therewith), such Transaction shall, effective three Business Days prior to the applicable Settlement Date, be deemed to be automatically assigned by Party A to BNY Mellon Capital Markets, LLC (“BNYMCM”) or any of Party A’s other broker-dealer affiliates selected by Party A, and delivery of the Shares shall be made to an account of BNYMCM to be advised.

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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 or several, incurred by or asserted against such Indemnified Party arising out of, in connection with, or relating to, any breach of any covenant or representation made by Party B in this Master Confirmation, any Supplemental Confirmation or the Agreement (including, without limitation, losses, claims, damages and liabilities incurred by Party A in connection with the failure of a Supplemental Confirmation to become effective pursuant to the provisions set forth under the heading “Conditions to Effectiveness” above on account of any breach of the representations and covenants of Party B set forth thereunder as conditions precedent to such effectiveness). In addition, Party B will reimburse any Indemnified Party for all reasonable expenses (including reasonable legal fees and reasonable expenses) 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) at the time, and only to the extent, that the relevant loss, claim, damage, liability or expense is found in a final and nonappealable judgment by a court of competent jurisdiction to have resulted from a breach of a covenant or representation made by Party B in this Master Confirmation, any Supplemental Confirmation or the Agreement. For the avoidance of doubt, 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 of competent jurisdiction to have resulted from Party A’s gross negligence, fraud, bad faith and/or willful misconduct or a breach of any representation or covenant of Party A contained in this Master Confirmation, any Supplemental Confirmation or the Agreement.

Miscellaneous:

Without limiting the generality of Sections 13.1 and 13.4 of the Equity Definitions, Party B acknowledges that Party A is not making any representations or warranties with respect to the treatment of any Transaction under any accounting rules, policies, guidelines, principles or statements, including, without limitation, Topic 815 of the FASB Accounting Standards Codification.

Agreement Regarding Set-off and Collateral:

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 under this Master Confirmation and any Supplemental Confirmation are not secured by any collateral. Obligations under any Transaction shall not be set off against any other obligations of the parties, whether arising under the Agreement, this Master Confirmation, any Supplemental Confirmation or 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 such Transaction, whether arising under the Agreement, this Master Confirmation, any Supplemental Confirmation or 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) any Transaction and (ii) all other Transactions, and (b) such separate amounts shall be payable pursuant to Section 6(d)(ii) of the Agreement.

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Status of Claims in Bankruptcy:

Party A acknowledges and agrees that neither this Master Confirmation nor any Supplemental Confirmation is intended to convey to Party A rights with respect to the transactions contemplated hereby or by any Supplemental Confirmation that are senior to the claims of common stockholders in any U.S. bankruptcy proceedings of Party B; provided, however, that nothing herein or in any Supplemental Confirmation 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 Master Confirmation, any Supplemental Confirmation or the Agreement; and provided further, that nothing herein or in any Supplemental Confirmation shall limit or shall be deemed to limit Party A’s rights in respect of any transaction other than the Transactions.

Limit on Beneficial Ownership:

With respect to any Transaction, notwithstanding any other provisions in the Agreement, herein or in the Supplemental Confirmation for such Transaction, Party A shall not be entitled to receive Shares or any other class of voting securities of Party B (whether in connection with the purchase of Shares on any Settlement Date for such Transaction or any Termination Settlement Date for such Transaction or otherwise) to the extent (but only to the extent) that such receipt would result in Party A and each person subject to aggregation of Shares or other voting securities with Party A under Section 13 or Section 16 of the Exchange Act and the rules promulgated thereunder (the “Party A Group”) directly or indirectly beneficially owning (as such term is defined for purposes of Section 13(d) of the Exchange Act) at any time in excess of 4.0% of the outstanding Shares or any other class of voting securities of Party B. Any purported delivery under any Transaction shall be void and have no effect to the extent (but only to the extent) that such delivery would result in the Party A Group directly or indirectly so beneficially owning in excess of 4.0% of the outstanding Shares or any other class of voting securities of Party B. If any delivery owed to Party A under any Transaction 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 Clearance System Business Day after, Party A gives notice to Party B that such delivery would not result in the Party A Group directly or indirectly so beneficially owning in excess of 4.0% of the outstanding Shares or any other class of voting securities of Party B. If Net Share Settlement in respect of any Transaction would result in the Party A Group beneficially owning more than 4.0% of the outstanding Shares in connection with closing out its hedge position, Party A shall be allowed to partially settle such Transaction based on its purchase of that amount of Shares, and then to purchase the amount or amounts of additional Shares necessary to settle the remainder of such Transaction, and to make the associated deliveries at such times as determined by the Calculation Agent.

Severability:

If any term, provision, covenant or condition in this Master Confirmation or any Supplemental 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 or thereof shall continue in full force and effect as if this Master Confirmation and such Supplemental Confirmation had been executed with the invalid or unenforceable provision eliminated, so long as this Master Confirmation and such Supplemental Confirmation as so modified continue to express, without material change, the original intentions of the parties as to the subject matter of this Master Confirmation and such Supplemental Confirmation and the deletion of such portion of this Master Confirmation and such Supplemental Confirmation will not substantially impair the respective benefits or expectations of parties to this Master Confirmation and such Supplemental Confirmation; 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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Miscellaneous:

Address for notices or communications to Party A:

With respect to any notice sent to Party A under Sections 5, 6 or 13(c) of the Agreement, a copy shall also be sent to:

Address for notices or communications to Party B:

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Party B payment instructions:

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

Confirmed as of the date first written above:

EXHIBIT A

[Insert Date]

Supplemental Confirmation for Forward Stock Sale Transaction

Dear Sir/Madam:

The Bank of New York Mellon (“Party A” or “BNY”) and Westar Energy, Inc. (“Party B”) are parties to the Master Confirmation for Forward Stock Sale Transactions dated April 2, 2010 (the “Master Confirmation”) pursuant to which Party A and Party B have entered into a Transaction with the terms and conditions set forth therein and herein. This Supplemental Confirmation, together with the Master Confirmation, shall constitute a “Confirmation” for purposes of the Agreement. In the event of any inconsistency between the Master Confirmation and this Supplemental Confirmation, the Master Confirmation shall govern to the extent of such inconsistency. Capitalized terms used but not defined herein shall have the respective meanings assigned to them in the Master Confirmation.

The terms of the Transaction to which this Supplemental Confirmation relates are as follows:

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

Confirmed as of the date first written above:

EXHIBIT B

The Settlement Commission is equal to USD0.00 per Share.

SCHEDULE I