Exhibit 10(mm)
 2009 Performance Option Plan
 1.
    
    PURPOSE OF PLANPotash Corporation of Saskatchewan Inc. (the Corporation) by resolution of its Board of
Directors (the Board) has established, subject to shareholder approval at the Corporations
2009 Annual and Special Meeting of shareholders, this Potash Corporation of Saskatchewan Inc.
2009 Performance Option Plan (the Plan) to support the Corporations compensation philosophy of
providing selected employees and officers with an opportunity to: promote the growth and
profitability of the Corporation; align their interests with shareholders; and earn compensation
commensurate with corporate performance. The Corporation believes this Plan will directly assist
in supporting the Corporations compensation philosophy by providing participants with the
opportunity through stock options, which will vest, if at all, based on corporate performance
over a three-year period, to acquire common shares of the Corporation (Common Shares).2.
    
    DURATION OF THIS PLANThis Plan was adopted by the Board on February 20, 2009 to be effective as of January 1, 2009
(the Effective Date), subject to shareholder approval at the Corporations 2009 Annual and
Special Meeting of shareholders, and shall remain in effect, unless sooner terminated as provided
herein, until one (1) year from the Effective Date, at which time it will terminate. After this
Plan is terminated, no stock options may be granted but stock options previously granted shall
remain outstanding in accordance with their applicable terms and conditions and this Plans terms
and conditions.3.
    
    ADMINISTRATIONThis Plan shall be administered by the Compensation Committee of the Board or any other committee
designated by the Board to administer this Plan (the Committee). The Committee shall be
responsible for administering this Plan, subject to this Section 3 and the other provisions of
this Plan. The Committee may employ attorneys, consultants, accountants, agents, and other
individuals, any of whom may be an employee, and the Committee, the Corporation, and its officers
and directors shall be entitled to rely upon the advice, opinions, or valuations of any such
individuals. All actions taken and all interpretations and determinations made by the Committee
shall be made in the Committees sole discretion and shall be final and binding upon the
participants, the Corporation, and all other interested individuals. To the extent applicable,
the Plan shall be administered with respect to optionees subject to the laws of the U.S. so as to
avoid the application of penalties pursuant to Section 409A of the Internal Revenue Code, and
stock options hereunder may be subject to such restrictions as the Committee determines are
necessary to avoid application of such Section 409A.4.
    
    AUTHORITY OF THE COMMITTEEThe Committee shall have full and exclusive discretionary power to interpret the terms and the
intent of this Plan and any Stock Option Award Agreement or other agreement or document ancillary
to or in connection with this Plan, to determine eligibility for stock options and to adopt such
rules, regulations, forms, instruments, and guidelines for administering this Plan as the
Committee may deem necessary or proper. Such authority shall include adopting modifications and
amendments to any Stock Option Award Agreement that are necessary to comply with the laws of the
countries and other jurisdictions in which the Corporation and/or its subsidiaries operate.5.
    
    SHARES SUBJECT TO STOCK OPTIONSThe aggregate number of Common Shares issuable after February 20, 2009 pursuant to stock options
under this Plan may not exceed 1,000,000 Common Shares. The aggregate number of Common Shares in
respect of which stock options have been granted to any one person pursuant to this Plan and
which remain outstanding shall not at any time exceed 250,000. The authorized limits under this
Plan shall be subject to adjustment under Sections 12 and 13.If any stock option granted under this Plan, or any portion thereof, expires or terminates for
any reason without having been exercised in full, the Common Shares with respect to which such
option has not been exercised shall again be




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available for further stock options under this Plan; provided, however, that any stock option
that is granted under this Plan that does not vest as a result of a failure to satisfy the
Performance Measures, shall not be again available for grant under this Plan.
 6.
    
    GRANT OF STOCK OPTIONSFrom time to time the Board may designate individual officers and employees of the Corporation
and its subsidiaries eligible to be granted options to purchase Common Shares and the number of
Common Shares which each such person will be granted a stock option to purchase; provided that
the aggregate number of Common Shares subject to such stock options may not exceed the number
provided for in Section 5 of this Plan. Non-employee directors and other non-employee contractors
and third party vendors are not eligible to participate in this Plan.7.
    
    OPTION PRICEThe option price for any option granted under this Plan to any optionee shall be fixed by the
Board when the option is granted and shall be not less than the fair market value of the Common
Shares at such time which, for optionees resident in the United States and any other optionees
designated by the Board, shall be deemed to be the closing price per Common Share on the New York
Stock Exchange on the last trading day immediately preceding the day the option is granted and,
for all other optionees, shall be deemed to be the closing price per Common Share on the Toronto
Stock Exchange on the last trading day immediately preceding the day the option is granted;
provided that, in either case, if the Common Shares did not trade on such exchange on such day
the option price shall be the closing price per share on such exchange on the last day on which
the Common Shares traded on such exchange prior to the day the option is granted.8.
    
    VESTING OF STOCK OPTIONSSubject to achievement of Performance Measures as certified and approved by the Audit Committee
of the Board, stock options granted under this Plan will vest no later than thirty (30) days
after the audited financial statements for the applicable Performance Period have been approved
by the Board.9.
    
    PERFORMANCE MEASURES FOR VESTING OF STOCK OPTIONS
 (a)
    
    The Performance Measures which will be used to determine the degree to which stock
options will vest over the three-year period beginning the first day of the fiscal year in
which they are granted (the Performance Period) shall be cash flow return on investment
(CFROI) and weighted average cost of net debt and equity capital (WACC).
 (i)
    
    CFROI is the ratio of after tax operating cash flow to average gross investment
over the fiscal year, calculated as A divided by B, where (1) A equals operating income
less/plus nonrecurring or unusual items less/plus change in unrealized gains/losses on
derivative instruments included in net income plus accrued incentive awards plus
depreciation and amortization less current taxes, and (2) B equals the average of total
assets less/plus the fair value adjustment for investments in available for sale
securities less the fair value of derivative instrument assets plus accumulated
depreciation plus accumulated amortization less cash and cash equivalents less non
interest bearing current liabilities excluding derivatives.(ii)
    
    WACC is the weighted average cost of net debt and equity capital, calculated as
[A times the product of B divided by C] plus [D times the product of E divided by C],
where (1) A equals the after-tax market yield cost of debt, (2) B equals the market
value of debt less cash and cash equivalents (3) C equals the market value of debt less
cash and cash equivalents, plus the market value of equity, (4) D equals the cost of
equity, and (5) E equals the market value of equity.
 (b)
    
    In determining the number of stock options that will actually vest based on the degree to
which the Performance Measures have been attained during the applicable Performance Period,
the following chart shall be utilized which shows the three year average excess of CFROI
being greater than WACC and the respective portion of the stock option that will vest:




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Performance Measure
    
    Vesting Scale3 year average excess of
    
    % of Stock OptionCFROI > WACC
    
    Grant Vesting<0%
    
    0%0.20%
    
    30%1.20%
    
    70%2.20%
    
    90%2.50%
    
    100%
 (c)
    
    In assessing the portion of the stock options that shall vest in accordance with the
above chart, the following shall be done:
 (i)
    
    Each year, the CFROI and WACC will be calculated in accordance with the
definitions herein, based on the audited financial statements and approved by the
Audit Committee.(ii)
    
    In each Performance Period, the average of the three fiscal years shall be
calculated by taking the simple average of the individual years results.(iii)
    
    The resulting three-year average will then be applied, using the scale above
to determine the number of stock options, if any, that will vest as of the end of the
Performance Period.(iv)
    
    For results falling between the reference points in the chart above, the
level of vesting shall be mathematically interpolated between the reference points.
 10.
    
    TERMS OF STOCK OPTIONSThe period during which a stock option is exercisable (the Term) may not exceed 10 years from
the date the stock option is granted (the Initial Exercise Period), plus any Additional
Exercise Period (as defined below). If such Initial Exercise Period would otherwise expire
(i) during a Blackout Period (as defined below) applicable to the relevant optionee or
(ii) within 10 trading days after the expiration of the Blackout Period applicable to the
relevant optionee, the Term of the related stock option shall expire on the date that is the
tenth trading day after the end of such Blackout Period (an Additional Exercise Period). For
purposes of this Plan, Blackout Period means any period during which the relevant optionee is
prohibited by the Corporations trading policy from trading in the Corporations securities. The
Stock Option Award Agreement may contain provisions limiting the number of Common Shares with
respect to which stock options may be exercised in any one year. Each stock option agreement
shall contain provisions to the effect that:
 (a)
    
    if the employment of an optionee as an officer or employee of the Corporation or a
subsidiary terminates, by reason of his or her death, or if an optionee who is a retiree
pursuant to Section 10(b) dies, the legal personal representatives of the optionee will be
entitled to exercise any unexercised vested options, including such stock options that may
vest after the date of death, during the period ending at the end of the twelfth calendar
month following the calendar month in which the optionee dies, failing which exercise the
stock options terminate;(b)
    
    subject to the terms of Section 10(a) above, if the employment of an optionee as an
officer or employee of the Corporation or a subsidiary terminates, by reason of retirement
in accordance with the then prevailing retirement policy of the Corporation or subsidiary,
the optionee will be entitled to exercise any unexercised vested stock options, including
such stock options that may vest after the date of retirement, during the period ending at
the end of the 36th month following the calendar month in which the optionee
retires, failing which exercise the stock options terminate;(c)
    
    subject to the terms of Section 14 below, if the employment of an optionee as an officer
or employee of the Corporation or a subsidiary terminates, for any reason other than as
provided in Sections 10(a) or (b), the optionee will be entitled to exercise any unexercised
vested stock options, to the extent exercisable at the date of such event, during the period
ending at the end of the calendar month immediately following the calendar month in which
the event occurs, failing which exercise the stock options terminate;




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(d)
    
    for greater certainty and for these purposes, an optionees employment with the
Corporation or a subsidiary shall be considered to have terminated effective on the last day
of the optionees actual and active employment with the Corporation or subsidiary whether
such day is selected by agreement with the optionee or unilaterally by the Corporation or
subsidiary and whether with or without advance notice to the optionee. For the avoidance of
doubt, no period of notice that is given or ought to have been given under applicable law in
respect of such termination of employment will be utilized in determining an optionees
entitlement under the Plan. The employment of an optionee with the Corporation shall be
deemed to have terminated for all purposes of the Plan if such person is employed by or
provides services to a person that is a subsidiary of the Corporation and such person ceases
to be a subsidiary of the Corporation, unless the Committee determines otherwise; and(e)
    
    each stock option is personal to the optionee and is not assignable, except (i) as
provided in Section 10(a), and (ii) at the election of the Board, a stock option may be
assignable to the spouse, children and grandchildren of the original optionee and to a
trust, partnership or limited liability company, the entire beneficial interest of which is
held by one or more of the foregoing.
 Nothing contained in Sections 10(a), (b) or (c) shall extend the Term beyond its stipulated
expiration date or the date on which it is otherwise terminated in accordance with the provisions
of this Plan.If a stock option is assigned pursuant to Section 10(e)(ii), the references in Sections 10(a),
(b) and (c) to the termination of employment or death of an optionee shall not relate to the
assignee of a stock option but shall relate to the original optionee. In the event of such
assignment, legal personal representatives of the original optionee shall not be entitled to
exercise the assigned stock option, but the assignee of the stock option or the legal personal
representatives of the assignee may exercise the stock option during the applicable specified
period.11.
    
    EXERCISE OF STOCK OPTIONSSubject to the provisions of this Plan, a vested stock option may be exercised from time to time
by delivering to the Corporation at its registered office a written notice of exercise specifying
the number of Common Shares with respect to which the stock option is being exercised and
accompanied by payment in cash or certified cheque in full of the purchase price of the Common
Shares then being purchased.12.
    
    ADJUSTMENTSAppropriate adjustments to the authorized limits set forth in Section 5, in the number, class
and/or type of Common Shares optioned and in the option price per share, both as to stock options
granted or to be granted, shall be made by the Board to give effect to adjustments in the number
of Common Shares which result from subdivisions, consolidations or reclassifications of the
Common Shares, the payment of share dividends by the Corporation, the reconstruction,
reorganization or recapitalization of the Corporation or other relevant changes in the capital of
the Corporation.13.
    
    MERGERSIf the Corporation proposes to amalgamate or merge with another body corporate, the Corporation
shall give written notice thereof to optionees in sufficient time to enable them to exercise
outstanding vested stock options, to the extent they are otherwise exercisable by their terms,
prior to the effective date of such amalgamation or merger if they so elect. The Corporation
shall use its best efforts to provide for the reservation and issuance by the amalgamated or
continuing corporation of an appropriate number of Common Shares, with appropriate adjustments,
so as to give effect to the continuance of the stock options to the extent reasonably
practicable. In the event that the Board determines in good faith that such continuance is not in
the circumstances practicable, it may upon 30 days notice to optionees terminate the stock
options.14.
    
    CIRCUMSTANCES FOR ACCELERATED VESTINGIf a change of control of the Corporation occurs and at least one of the two additional
circumstances described below occurs, each then outstanding stock option granted under this Plan
may be exercised, in whole or in part, even if such option is not otherwise exercisable by its
terms.




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(a)
    
    Additional circumstances include:
 (i)
    
    Upon a change of control the potential successor fails to assume the
obligations with respect to each option or fails to convert or replace the options
with equivalent options; or(ii)
    
    During the two-year period following the effective date of a change of
control, the optionee is terminated without Cause (as defined below) or the optionee
resigns employment for Good Reason (as defined below).
 (b)
    
    For purposes of this Plan, a change of control of the Corporation shall be deemed to have
occurred if any of the following occur, unless the Board adopts a plan after the Effective
Date of this Plan that has a different definition (in which case such definition shall be
applied), or the Committee decides to modify or amend the following definition through an
amendment of this Plan:
 (i)
    
    within any period of two consecutive years, individuals who at the beginning
of such period constituted the Board and any new directors whose appointment by the
Board or nomination for election by shareholders of the Corporation was approved by a
vote of at least a majority of the directors then still in office who either were
directors at the beginning of the period or whose appointment or nomination for
election was previously so approved, cease for any reason to constitute a majority of
the Board;(ii)
    
    there occurs an amalgamation, merger, consolidation, wind-up, reorganization
or restructuring of the Corporation with or into any other entity, or a similar event
or series of such events, other than any such event or series of events which results
in securities of the surviving or consolidated corporation representing 50% or more of
the combined voting power of the surviving or consolidated corporations then
outstanding securities entitled to vote in the election of directors of the surviving
or consolidated corporation being beneficially owned, directly or indirectly, by the
persons who were the holders of the Corporations outstanding securities entitled to
vote in the election of directors of the Corporation prior to such event or series of
events in substantially the same proportions as their ownership immediately prior to
such event of the Corporations then outstanding securities entitled to vote in the
election of directors of the Corporation;(iii)
    
    50% or more of the fixed assets (based on book value as shown on the most
recent available audited annual or unaudited quarterly consolidated financial
statements) of the Corporation are sold or otherwise disposed of (by liquidation,
dissolution, dividend or otherwise) in one transaction or series of transactions
within any twelve month period;(iv)
    
    any party, including persons acting jointly or in concert with that party,
becomes (through a take-over bid or otherwise) the beneficial owner, directly or
indirectly, of securities of the Corporation representing 20% or more of the combined
voting power of the Corporations then outstanding securities entitled to vote in the
election of directors of the Corporation, unless in any particular situation the Board
determines in advance of such event that such event shall not constitute a change of
control; or(v)
    
    the Board approves and/or recommends that shareholders accept, approve or
adopt any transaction that would constitute a change of control under clause (ii),
(iii) or (iv) of this Section 14(b) and determines that the change of control
resulting from such transaction will be deemed to have occurred as of a specified date
earlier than the date under (ii), (iii) or (iv), as applicable.
 (c)
    
    For purposes of this Plan, Cause means dishonest or willful misconduct or lack of good
faith resulting in material harm to the Corporation, financial or otherwise.(d)
    
    For purposes of this Plan, Good Reason means:
 (i)
    
    a substantial diminution in the optionees authorities, duties,
responsibilities, status (including offices, titles, and reporting requirements) from
those in effect immediately prior to the change of control;(ii)
    
    the Corporation requires the optionee to be based at a location in excess of
fifty (50) miles from the location of the optionees principal job location or office
immediately prior to the change of control, except for required travel on Corporation
business to an extent substantially consistent with the optionees business
obligations immediately prior to the change of control;(iii)
    
    a reduction in the optionees base salary, or a substantial reduction in
optionees target compensation under any incentive compensation plan, as in effect as
of the date of the change of control;




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(iv)
    
    the failure to increase the optionees base salary in a manner consistent
(both as to frequency and percentage increase) with practices in effect immediately
prior to the change of control or with practices implemented subsequent to the change
of control with respect to similarly positioned employees; or(v)
    
    the failure of the Corporation to continue in effect the optionees
participation in the Corporations short- and long-tem incentive plans, stock option
plans, and employee benefit and retirement plans, policies or practices, at a level
substantially similar or superior to and on a basis consistent with the relative
levels of participation of other similarly-positioned employees, as existed
immediately prior to the change of control.
 A termination of employment by the optionee for one of the reasons set forth in clause (i), (ii),
(iii), (iv) or (v) of this Section 14(d), will not constitute Good Reason unless, within the
30-day period immediately following the occurrence of such Good Reason event, the optionee has
given written notice to the Corporation of the event relied upon for such termination and the
Corporation has not remedied such event within 30 days (the Cure Period) of the receipt of such
notice. For the avoidance of doubt, the optionees employment shall not be deemed to terminate
for Good Reason unless and until the Cure Period has expired and the Corporation has not remedied
the applicable Good Reason event. The Corporation and the optionee may mutually waive in writing
any of the foregoing provisions with respect to an event that otherwise would constitute Good
Reason.15.
    
    RECOUPMENT POLICYEach stock option granted under this Plan to an optionee that, as of the date the option is
granted, participates in the Corporations Medium-Term Incentive Plan shall be subject to the
terms and conditions of the Corporations Policy on Recoupment of Unearned Compensation (as
previously adopted and, from time to time, amended by the Board) attached to such optionees
Stock Option Award Agreement (as defined below).16.
    
    AMENDMENT OR DISCONTINUANCE OF THIS PLANThe Board may amend or discontinue the Plan at any time, without obtaining the approval of
shareholders of the Corporation unless required by the relevant rules of the Toronto Stock
Exchange, provided that, subject to Sections 12, 13, and 14, no such amendment may increase the
aggregate maximum number of Common Shares that may be subject to stock options under this Plan,
change the manner of determining the minimum option price, extend the Term under any option
beyond 10 years (plus any Additional Exercise Period) or the date on which the option would
otherwise expire under the Plan, expand the assignment provisions of the Plan, permit
non-employee directors to participate in the Plan or, without the consent of the holder of the
option, alter or impair any option previously granted to an optionee under this Plan; and,
provided further, for greater certainty, that, without the prior approval of the Corporations
shareholders, stock options issued under this Plan shall not be repriced, replaced, or regranted
through cancellation, or by lowering the option price of a previously granted stock option.
Pre-clearance of the Toronto Stock Exchange of amendments to the Plan will be required to the
extent provided under the relevant rules of the Toronto Stock Exchange.17.
    
    EVIDENCE OF STOCK OPTIONSEach stock option granted under this Plan shall be evidenced by a written stock option agreement
between the Corporation and the optionee which shall give effect to the provisions of this Plan
and include such other terms as the Committee shall determine (Stock Option Award Agreement).18.
    
    WITHHOLDINGTo the extent that the Corporation is required to withhold federal, provincial, state, local or
foreign taxes in connection with any payment made or benefit realized by an optionee or other
person hereunder, and the amounts available to the Corporation for such withholding are
insufficient, it shall be a condition to the receipt of such payment or the realization of such
benefit that the optionee or such other person make arrangements satisfactory to the Corporation
for payment of the balance of such taxes required to be withheld, which arrangements (in the
discretion of the Board) may include relinquishment of a portion of such benefit. Participants
shall also make such arrangements in connection with the disposition of Common Shares acquired
upon the exercise of option rights with respect to this Plan.




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This certificate evidences and confirms the grant to   (the Optionee) of options to purchase the number of Common Shares of the Corporation specified under Paragraph (1) on
the terms and subject to the conditions of the Potash Corporation of Saskatchewan Inc. 2009 Performance Option Plan (the 2009 Plan) and the terms and conditions set forth below. In the event of
any inconsistency between the terms of the 2009 Plan and those set forth below, the terms of the 2009 Plan shall control. Capitalized terms used below that are not defined in this certificate
shall have the meanings specified in the 2009 Plan.
 1.
    
    Number of Shares:The Optionee is hereby granted options under the 2009 Plan to Purchase  Common Shares.2.
    
    Option Exercise Price:The exercise price for each Common Share is .3.
    
    Time and Conditions to Vesting:The options will become vested following the end of the Performance Period January 1, 2009 through December 31, 2011 if, and to the extent, the applicable
Performance Measures for the Performance Period are achieved. Subject to applicable conditions under the 2009 Plan with respect to continued employment during the Performance Period and
achievement of the minimum Performance Measures, the date for vesting will be determined but will not be later than 30 days after the audited financial statements of the Corporation for the
2011 fiscal year of the Corporation have been approved by the Board. Upon vesting, the Optionee will have the right to purchase a number of Common Shares covered by the option equal to the
percentage determined in accordance with the performance matrix and vesting scale provided under the 2009 Plan.4.
    
    Once vested, the options will continue to be exercisable until the expiry date for the options of May 7, 2019.5.
    
    Notwithstanding the provisions of paragraph 4 above, this option will terminate as provided in paragraph 10 of the 2009 Plan in the event that the actual and active employment of the
Optionee ceases. The option is personal to the Optionee and is not assignable, except in accordance with the conditions attached hereto as Appendix I.6.
    
    Notice of exercise of the option is to be given in accordance with paragraph 11 of the 2009 Plan.7.
    
    Adjustments to the option may be made as provided in paragraph 12 of the 2009 Plan, the provisions of paragraph 13 of the 2009 Plan shall apply in the event of a proposed amalgamation or
merger of the Corporation, and the provisions of paragraph 14 of the 2009 Plan will apply in the event of a change of control of the Corporation as defined in that paragraph.8.
    
    This grant of option is subject to receipt of any necessary regulatory approvals and shall be governed by the laws of Saskatchewan.
 Potash Corporation of Saskatchewan Inc.Date: May 7, 2009
    
    By:President and Chief Executive Officer




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2009 Performance Option Plan
 1. PURPOSE OF PLAN.
 2. DURATION OF THIS PLAN.
 3. ADMINISTRATION.
 4. AUTHORITY OF THE COMMITTEE.
 5. SHARES SUBJECT TO STOCK OPTIONS.
  6. GRANT OF STOCK OPTIONS.
 7. OPTION PRICE.
 8. VESTING OF STOCK OPTIONS.
 9. PERFORMANCE MEASURES FOR VESTING OF STOCK OPTIONS.
     Performance Measure
    
    Vesting Scale3 year average excess of
    
    % of Stock OptionCFROI > WACC
    
    Grant Vesting<0%
    
    0%0.20%
    
    30%1.20%
    
    70%2.20%
    
    90%2.50%
    
    100%
      10. TERMS OF STOCK OPTIONS.
  th
      11. EXERCISE OF STOCK OPTIONS.
 12. ADJUSTMENTS.
 13. MERGERS.
 14. CIRCUMSTANCES FOR ACCELERATED VESTING.
                  15. RECOUPMENT POLICY
 16. AMENDMENT OR DISCONTINUANCE OF THIS PLAN.
 17. EVIDENCE OF STOCK OPTIONS.
 18. WITHHOLDING.