SUMMARY

This summary highlights selected information contained in this joint proxy statement/circular and does not contain all the information that may be important to you. Whiting and Kodiak urge you to read carefully this joint proxy statement/circular in its entirety, including the annexes. Additional, important information, which Whiting and Kodiak also urge you to read, is contained in the documents incorporated by reference into this joint proxy statement/circular. See “Where You Can Find More Information” beginning on page 192. Unless stated otherwise, all references in this joint proxy statement/circular to Whiting are to Whiting Petroleum Corporation, all references to Kodiak are to Kodiak Oil & Gas Corp. and all references to the arrangement agreement are to the arrangement agreement, dated as of July 13, 2014, by and among Whiting, 1007695 B.C. Ltd. and Kodiak, a copy of which is attached as Annex C to this joint proxy statement/circular. In addition, definitions for certain terms relating to the oil and gas business can be found in “Glossary of Certain Oil and Natural Gas Definitions.”

The Parties

Whiting

Whiting is an independent oil and gas company engaged in exploration, development, acquisition and production activities primarily in the Rocky Mountains and Permian Basin regions of the United States. Whiting’s largest projects are in the Bakken and Three Forks plays in North Dakota, the Niobrara play in northeast Colorado and its Enhanced Oil Recovery field in Texas. Since Whiting’s inception in 1980, it has built a strong asset base and achieved steady growth through property acquisitions, development and exploration activities. Whiting believes the combination of acquisitions, subsequent development and organic drilling provides it with a broad set of growth alternatives and allows it to direct its capital resources to what Whiting believes to be the most advantageous investments.

As of December 31, 2013, Whiting’s estimated proved reserves totaled 438.5 MMBOE. Whiting’s second quarter 2014 average daily production was 109.8 MBOE/d. For the six months ended June 30, 2014 and year ended December 31, 2013, Whiting had total revenues of approximately $1.6 billion and $2.8 billion and net income available to common shareholders of approximately $260.5 million and $365.5 million, respectively.

Whiting’s principal offices are located at 1700 Broadway, Suite 2300, Denver, Colorado 80290, and its telephone number is (303) 837-1661. Whiting common stock is listed on the NYSE, trading under the symbol “WLL.”

Kodiak

Kodiak is an independent energy company focused on the exploration, exploitation, acquisition and production of crude oil and natural gas in the United States. Kodiak has developed an oil and natural gas asset base of proved reserves, as well as a portfolio of development and exploratory drilling opportunities within a high-potential resource play. Kodiak’s oil and natural gas reserves and operations are concentrated in the Williston Basin of North Dakota.

As of December 31, 2013, Kodiak’s estimated proved reserves totaled 167.3 MMBOE. Kodiak’s second quarter 2014 average daily production was 38.3 MBOE/d. For the six months ended June 30, 2014 and year ended December 31, 2013, Kodiak had total revenues of approximately $557.1 million and $904.6 million and net income of approximately $50.3 million and $141.4 million, respectively.

Kodiak’s principal offices are located at 1625 Broadway, Suite 250, Denver, Colorado 80202, and its telephone number is (303) 592-8075. Kodiak common stock is listed on the NYSE, trading under the symbol “KOG.”

Whiting Canadian Sub

Whiting Canadian Sub, a wholly-owned subsidiary of Whiting, is a company organized and existing under the laws of British Columbia, Canada. Whiting Canadian Sub was incorporated for the purpose of effecting the arrangement and has not conducted any activities other than those incidental to its formation and the matters contemplated by the arrangement agreement.

The Arrangement

On July 13, 2014, Whiting, Whiting Canadian Sub and Kodiak entered into the arrangement agreement, which provides that, subject to the terms and conditions of the arrangement agreement and in accordance with the approval by the court under Division 5 of Part 9 of the BCBCA, Whiting Canadian Sub will acquire all of the outstanding shares of Kodiak and amalgamate with Kodiak to form one corporate entity with Kodiak surviving the amalgamation as a direct wholly-owned subsidiary of Whiting. The arrangement agreement also provides that prior to the completion of the arrangement and assuming the continuance resolution is approved by Kodiak shareholders, Kodiak will continue from the Yukon Territory to the Province of British Columbia.

Consideration to be Received in the Arrangement by Kodiak Shareholders

At the effective time of the arrangement, Kodiak shareholders will receive 0.177 shares of Whiting common stock for each share of Kodiak common stock. No fractional shares of Whiting common stock will be issued as part of the arrangement. Instead, where the aggregate number of Whiting common stock to be issued to a Kodiak shareholder as consideration would result in a fraction of securities of Whiting being issuable, the number of shares of Whiting common stock to be received by such Kodiak shareholder shall be rounded down to the nearest whole share of Whiting common stock. The exchange ratio is fixed and will not be adjusted to reflect changes in the stock price of either company before the arrangement is completed. Whiting stockholders will continue to own their existing shares of Whiting common stock, and the Whiting common stock will not be affected by the arrangement.

Treatment of Equity Awards

Kodiak

In connection with the arrangement, each RSU, option and restricted stock award relating to Kodiak common stock that is outstanding immediately prior to the completion of the arrangement (whether vested or unvested) will be assumed by Whiting and converted automatically at the effective time of the arrangement into an RSU, option, or restricted stock award, as applicable (an “assumed award”), denominated in shares of Whiting common stock based on the exchange ratio and subject to terms and conditions substantially identical to those in effect at the effective time of the arrangement, except that:

Whiting

The arrangement will not affect Whiting’s outstanding equity awards. All such awards will remain outstanding subject to the same terms and conditions that are applicable prior to the arrangement.

Recommendations of the Whiting Board of Directors

After careful consideration, the Whiting board of directors recommends that holders of Whiting common stock vote “FOR” the share issuance proposal and “FOR” the Whiting adjournment proposal.

For a more complete description of Whiting’s reasons for the arrangement and the recommendations of the Whiting board of directors, see “The Arrangement—Whiting Recommendation and Reasons for the Arrangement” beginning on page 51.

Recommendations of the Kodiak Board of Directors

After careful consideration, the Kodiak board of directors recommends that Kodiak shareholders vote “FOR” the continuance resolution, Kodiak securityholders vote “FOR” the arrangement resolution, Kodiak shareholders vote “FOR” the arrangement-related compensation proposal and Kodiak shareholders vote “FOR” the Kodiak adjournment proposal.

For a more complete description of Kodiak’s reasons for the arrangement and the recommendation of the Kodiak board of directors, see “The Arrangement—Kodiak Recommendation and Reasons for the Arrangement” beginning on page  53.

Opinion of J.P. Morgan Securities LLC to the Whiting Board

In connection with the arrangement, J.P. Morgan Securities LLC (“J.P. Morgan”), rendered an opinion, dated July 13, 2014, to the Whiting board of directors as to the fairness, from a financial point of view and as of such date and based upon and subject to the factors, assumptions, limitations and qualifications set forth in such opinion (which are also summarized in this joint proxy statement/circular), to Whiting of the exchange ratio. The full text of J.P. Morgan’s written opinion is attached to this joint proxy statement/circular as Annex G. J.P. Morgan’s written opinion is addressed to the Whiting board of directors (in its capacity as such), is directed only to the exchange ratio and does not constitute a recommendation to any Whiting stockholder as to how such stockholder should vote with respect to the transactions contemplated by the arrangement agreement. For a more complete description of J.P. Morgan’s opinion, see “The Arrangement—Opinion of J.P. Morgan Securities LLC to the Whiting Board” beginning on page 57.

Opinion of Petrie Partners Securities, LLC to the Kodiak Board

On July 13, 2014, at a meeting of the Kodiak board of directors, Petrie Partners Securities, LLC (“Petrie Partners”) rendered its oral opinion, subsequently confirmed by delivery of a written opinion, that, as of July 13, 2014, and based upon and subject to the factors, procedures, assumptions, qualifications and limitations set forth in its opinion, the exchange ratio was fair, from a financial point of view, to the shareholders of Kodiak.

The full text of the written opinion of Petrie Partners, dated as of July 13, 2014, is attached as Annex H to this joint proxy statement/circular and sets forth, among other things, the procedures followed, assumptions made, matters considered and qualifications and limitations on the scope of review undertaken in rendering its opinion (which are also summarized in this joint proxy statement/circular). Petrie Partners’ opinion was addressed to, and provided for the information and benefit of, the Kodiak board of directors in connection with its evaluation of whether the exchange ratio was fair, from a financial point of view, to the shareholders of Kodiak. Petrie Partners’ opinion does not address the fairness of the proposed arrangement (for purposes of this joint proxy statement/circular, as defined in the arrangement agreement), or any consideration received in connection with the proposed arrangement, to the creditors or other constituencies of Kodiak, nor does it address the fairness of the amount or nature of any compensation to be paid or payable to any of the officers, directors or employees of Kodiak, or any

class of such persons, whether relative to the exchange ratio or otherwise. Petrie Partners assumed that any modification to the structure of the arrangement would not vary in any respect material to its analysis. Petrie Partners’ opinion does not address the relative merits of the arrangement as compared to any other alternative business transaction or strategic alternative that might be available to Kodiak, nor does it address the underlying business decision of Kodiak to engage in the arrangement. Petrie Partners’ opinion does not constitute a recommendation to the Kodiak board of directors or to any other persons in respect of the arrangement, including as to how any holder of shares of voting common stock of Kodiak should act or vote in respect of any of the transactions contemplated by the arrangement agreement. Finally, Petrie Partners did not express any opinion as to the price at which shares of Kodiak or Whiting common stock will trade at any time. For a more complete description of Petrie Partners’ opinion, see “The Arrangement—Opinion of Petrie Partners Securities, LLC to the Kodiak Board” beginning on page 69.

Opinion of Credit Suisse Securities (USA) LLC to the Kodiak Board

On July 13, 2014, Credit Suisse Securities (USA) LLC (“Credit Suisse”) rendered its oral opinion to the Kodiak board of directors (which was subsequently confirmed in writing by delivery of Credit Suisse’s written opinion addressed to the Kodiak board of directors dated the same date) as to, as of July 13, 2014, the fairness, from a financial point of view, to the holders of Kodiak common stock of the exchange ratio in the arrangement pursuant to the arrangement agreement.

Credit Suisse’s opinion was directed to the Kodiak board of directors (in its capacity as such), and only addressed the fairness, from a financial point of view, to the holders of Kodiak common stock of the exchange ratio in the arrangement pursuant to the arrangement agreement and did not address any other aspect or implication (financial or otherwise) of the arrangement. The full text of Credit Suisse’s written opinion is included as Annex I to this joint proxy statement/circular and sets forth the procedures followed, assumptions made, qualifications and limitations on the review undertaken and other matters considered by Credit Suisse in preparing its opinion (which are also summarized in this joint proxy statement/circular). However, neither Credit Suisse’s written opinion nor the summary of its opinion and the related analyses set forth in this joint proxy statement/circular are intended to be, and they do not constitute, advice or a recommendation to any holder of Kodiak common stock as to how such holder should vote or act on any matter relating to the arrangement. See “The Arrangement—Opinion of Credit Suisse Securities (USA) LLC to the Kodiak Board” beginning on page 84.

Governance Following Completion of the Arrangement

The Whiting senior management team will lead the combined company after the completion of the arrangement. Lynn A. Peterson, the President and Chief Executive Officer and a director of Kodiak, and James E. Catlin, the Executive Vice President of Business Development and a director of Kodiak, will be appointed to the board of directors of Whiting at the completion of the arrangement for terms to expire at Whiting’s annual meetings in 2017 and 2016, respectively, and until their successors are duly elected and qualified.

Interests of Directors and Executive Officers of Kodiak in the Arrangement

You should be aware that some of the directors and executive officers of Kodiak have interests in the arrangement that are different from, or are in addition to, the interests of securityholders generally, including without limitation the following:

Except as disclosed herein, no informed person of Kodiak (as defined in NI 51-102) or any associate or affiliate of any informed person has or had any material interest, direct or indirect, in any transaction since the commencement of Kodiak’s most recently completed financial year or any proposed transaction that has materially affected or would materially affect Kodiak.

For a further discussion of the interests of Kodiak directors and executive officers in the arrangement, see “The Arrangement—Interests of Directors and Executive Officers of Kodiak in the Arrangement” beginning on page 98.

Material U.S. Federal Income Tax Consequences

It is a condition to the obligation of both Whiting and Kodiak to complete the arrangement that Whiting receive a written opinion from Foley & Lardner LLP, counsel to Whiting, dated as of the closing date, to the effect that for U.S. federal income tax purposes the Arrangement Transactions should (i) be treated as a single integrated transaction for U.S. federal income tax purposes and (ii) qualify as a “reorganization” within the meaning of Section 368(a)(1)(A) and 368(a)(2)(E) of the Code (the “intended U.S. tax treatment”). Kodiak agreed to use commercially reasonable efforts to cause Dorsey & Whitney LLP, counsel to Kodiak, to deliver a written opinion to Kodiak dated as of the closing date, to the effect that for U.S. federal income tax purposes the Arrangement Transactions should (i) be treated as a single integrated transaction for U.S. federal income tax purposes and (ii) qualify as a “reorganization” within the meaning of Section 368(a)(1)(A) and 368(a)(2)(E) of the Code. The delivery of this opinion is not a condition to the closing of the arrangement.

Provided that the Arrangement Transactions so qualify, a U.S. Holder of Kodiak common stock will not recognize any gain or loss for U.S. federal income tax purposes upon the exchange of the holder’s shares of Kodiak common stock for shares of Whiting common stock in the Arrangement Transactions.

The discussion of U.S. federal income tax consequences of the arrangement contained in this joint proxy statement/circular (see “Certain Income Tax Consequences—Material U.S. Federal Income Tax Consequences” beginning on page 174) is intended to provide only a general summary and is not a complete analysis or description of all potential U.S. federal income tax consequences of the arrangement. The discussion does not address tax consequences that may vary with, or are contingent on, individual circumstances. In addition, it does not address the effects of any foreign, state or local tax laws.

Kodiak shareholders are strongly urged to consult with their tax advisors regarding the tax consequences of the arrangement to them, including the effects of U.S. federal, state, local, foreign and other tax laws.

For a further discussion of the U.S. federal income tax consequences, see “Certain Income Tax Consequences—Material U.S. Federal Income Tax Consequences” beginning on page 174.

Material Canadian Federal Income Tax Consequences

Holders of Kodiak common stock who are residents of Canada for purposes of the ITA and hold their shares of Kodiak common stock as capital property will be subject to tax under the ITA on any capital gain realized on the disposition of their shares of Kodiak common stock under the arrangement.

Holders of Kodiak common stock who are not residents of Canada for purposes of the ITA and hold their shares of Kodiak common stock as capital property will not be subject to tax under the ITA on any capital gain realized on the disposition of their shares of Kodiak common stock under the arrangement.

The material Canadian federal income tax consequences are described in “Certain Income Tax Consequences—Material Canadian Federal Income Tax Consequences” beginning on page 184. Tax matters are complicated and the tax consequences of the arrangement to you will depend upon the facts of your particular circumstances. Because particular circumstances may differ, Kodiak shareholders should consult with their tax advisors as to the specific Canadian tax consequences of the arrangement for them.

For a further discussion of the Canadian federal income tax consequences, see “Certain Income Tax Consequences—Material Canadian Federal Income Tax Consequences” beginning on page 184.

Accounting Treatment of the Arrangement

The arrangement will be accounted for as an acquisition of Kodiak by Whiting under the acquisition method of accounting in accordance with accounting principles generally accepted in the United States.

Court Approval Required for the Arrangement

The arrangement requires approval by the court under Division 5 of Part 9 of the BCBCA. Prior to the mailing of this joint proxy statement/circular, Kodiak obtained the interim order providing for the calling and holding of a special meeting of Kodiak securityholders and other procedural matters (the “interim order”). A copy of the interim order is attached hereto as Annex E.

Subject to the approval of the arrangement resolution by Kodiak securityholders at the Kodiak special meeting, the hearing in respect of the final order is expected to take place on or about December 5, 2014, or as soon thereafter as is reasonably practicable. A copy of the notice of hearing of petition for final order is attached hereto as Annex F.

Any Kodiak securityholder or other person who wishes to participate, to appear, or to be represented, and to present evidence or arguments at the hearing must serve and file a response to petition (a “response”) no later than November 28, 2014 and satisfy the other requirements of the court, as directed in the interim order and the notice of hearing of petition for final order appended hereto as Annex E and Annex F, respectively, and as the court may direct in the future. The court will consider, among other things, the fairness and reasonableness of the arrangement and the rights of every person affected. The court may approve the arrangement in any manner the court may direct, subject to compliance with such terms and conditions, if any, as the court deems fit. The court has further been advised that the final order granted by the court will constitute the basis for the exemption from the registration requirements of the U.S. Securities Act of 1933 (“Securities Act”) provided by Section 3(a)(10) thereof with respect to the Whiting common stock, RSUs, options and restricted stock awards to be issued pursuant to the arrangement.

Although Kodiak’s objective is to complete the arrangement as soon as possible after the Kodiak special meeting, the completion could be delayed for a number of reasons, including, but not limited to, an objection before the court at the hearing of the application for the final order or any delay in obtaining any required approvals. Whiting and Kodiak may determine not to complete the arrangement without prior notice to or action on the part of Kodiak securityholders. See “The Arrangement Agreement—Termination of Arrangement Agreement” beginning on page 124.

For a more complete discussion of court approval matters relating to the arrangement, see “The Arrangement—Court Approval of the Arrangement and Completion of the Arrangement” beginning on page 104.

Regulatory Approvals Required for the Arrangement

The arrangement is subject to the requirements of the HSR Act, which prevents Whiting and Kodiak from completing the arrangement until the waiting period under the HSR Act is terminated or expires. On July 25, 2014, Whiting and Kodiak filed the requisite notification and report forms under the HSR Act with the Antitrust Division of the Department of Justice (the “DOJ”) and the Federal Trade Commission (the “FTC”). Early termination of the waiting period under the HSR Act was granted on August 5, 2014.

For a more complete discussion of regulatory matters relating to the arrangement, see “The Arrangement—Regulatory Approvals Required for the Arrangement” beginning on page 105.

Dissenters’ Rights

Registered Kodiak shareholders are entitled to the dissent rights set out in Section 193 of the YBCA and to be paid the fair value of their common stock if such shareholder dissents to the continuance resolution in compliance with the YBCA and the continuance becomes effective.

Registered Kodiak shareholders also have the right to dissent in respect of the arrangement resolution and, if the arrangement becomes effective, to be paid the fair value, in cash, of the shares of Kodiak common stock in respect of which such registered Kodiak shareholder dissents in compliance with Division 2 of Part 8 of the BCBCA, as modified by Article 4.1 of the plan of arrangement, the interim order and the final order.

For a more complete discussion of rights of dissenting Kodiak shareholders, see “The Arrangement—Appraisal / Dissenters’ Rights” beginning on page 106 and “The Arrangement Agreement—Dissenting Shares” beginning on page 113.

Litigation Relating to the Arrangement

In connection with the arrangement, seven purported class action lawsuits (four of which the plaintiffs voluntarily dismissed) have been filed on behalf of Kodiak shareholders in the United States District Court for the District of Colorado and one purported class action lawsuit has been filed on behalf of Kodiak shareholders in Denver District Court, State of Colorado, which was subsequently removed to United States District Court for the District of Colorado. It is possible that other related or amended suits could subsequently be filed. The defendants have filed motions to dismiss with prejudice in the all remaining cases other than one. The allegations in the four remaining lawsuits are similar. They purport to be brought as class actions on behalf of all shareholders of Kodiak. The complaints name as defendants the individual members of the Kodiak board of directors, Whiting and Whiting Canadian Sub and list Kodiak as a nominal party or a defendant. Additionally, one complaint lists James Henderson, Kodiak’s Chief Financial Officer, as a defendant. The complaints allege that the Kodiak board of directors breached its fiduciary duties to Kodiak shareholders by, among other things, failing to engage in a fair sale process before approving the arrangement and to maximize shareholder value in connection with the arrangement. Additionally, one case alleges violations under Sections 14(a) and 20(a) of the Exchange Act and SEC Rule 14a-9 promulgated thereunder. Specifically, the complaints allege that the Kodiak board of directors undervalued Kodiak in connection with the arrangement and that the Kodiak board of directors agreed to certain deal protection mechanisms that precluded Kodiak from obtaining competing offers. The complaints also allege that Whiting and Whiting Canadian Sub aided and abetted the alleged breaches of the fiduciary duties of the Kodiak board of directors. One case alleges additionally that in issuing the preliminary joint proxy statement/circular the Kodiak board of directors violated the cited sections of, and rule promulgated under, the Exchange Act. The complaints seek, among other things, injunctive relief preventing the closing of the arrangement, rescission of the arrangement or an award of rescissory damages to the purported class in the event that the arrangement is consummated, and damages, including counsel fees and expenses. Whiting and Kodiak believe each lawsuit is without merit.

For a more complete discussion of litigation relating to the arrangement, see “The Arrangement—Litigation Relating to the Arrangement” beginning on page 110.

Conditions to Completion of the Arrangement

The respective obligations of Kodiak and Whiting to complete the arrangement are subject to the satisfaction of the following conditions:

The obligation of Whiting to complete the arrangement is further subject to the satisfaction or waiver of the following conditions:

The obligation of Kodiak to complete the arrangement is further subject to the satisfaction or waiver of the following condition:

Other than the receipt of an opinion from Foley & Lardner LLP by Whiting noted above, the conditions set forth in the arrangement agreement may be waived by Whiting or Kodiak. For a more complete discussion of the conditions to the arrangement, see “The Arrangement Agreement—Conditions” beginning on page 114.

Timing of the Arrangement

The arrangement is expected to be completed in the fourth quarter of 2014. However, it is possible that factors outside of each company’s control could require them to complete the arrangement at a later time or not to complete it at all.

No Solicitation of Other Offers

In the arrangement agreement, subject to certain exceptions, each of Whiting and Kodiak has agreed that it will not, directly or indirectly:

The arrangement agreement includes customary exceptions such that, prior to obtaining shareholder approval, the parties may engage in negotiations regarding and, subject to complying with certain specified procedures and, in certain circumstances, a payment of a termination fee and/or reimbursement of expenses as described below, the applicable party’s board of directors may change its recommendation of the transaction in light of, or terminate the arrangement agreement to enter into an agreement for, an unsolicited takeover proposal that is determined to be a “superior proposal,” in each case, to the extent necessary to do so to comply with applicable fiduciary duties.

For a discussion of the limitations on solicitation of takeover proposals from third parties, see “The Arrangement Agreement—Covenants—No Solicitation of Other Offers” beginning on page 117.

Termination of the Arrangement Agreement and Termination Fees

The arrangement agreement may be terminated in any of the following ways:

The arrangement agreement provides that, upon a termination of the arrangement agreement under specified circumstances, Kodiak is required to pay a termination fee equal to $130.0 million to Whiting plus reimbursement of up to $10.0 million of Whiting’s expenses and, alternatively, Whiting is required to pay a termination fee equal to $130.0 million to Kodiak plus reimbursement of up to $10.0 million of Kodiak’s expenses. If the arrangement agreement is terminated due to the failure to obtain the Whiting stockholder approval of the share issuance proposal, Whiting would be required to reimburse up to $10.0 million of Kodiak’s expenses; and if the arrangement agreement is terminated due to the failure to obtain the Kodiak shareholder approval of the continuation resolution or Kodiak securityholder approval of the arrangement resolution, Kodiak would be required to reimburse up to $10.0 million of Whiting’s expenses.

For a more detailed discussion of each party’s termination rights and the related termination fee, see “The Arrangement Agreement—Termination of Arrangement Agreement” beginning on page 124.

Matters to be Considered at the Special Meetings

Whiting

At the Whiting special meeting, Whiting stockholders will be asked to consider and vote upon:

Whiting stockholder approval of the share issuance proposal is required to complete the arrangement.

Approval of the share issuance proposal requires the affirmative vote of the holders of a majority of the voting power of the shares of Whiting common stock represented in person or by proxy.

Approval of the Whiting adjournment proposal requires the affirmative vote of the holders of a majority of the voting power of the shares of Whiting common stock represented in person or by proxy.

The Whiting board of directors recommends that Whiting stockholders vote “FOR” all of the proposals set forth above, as more fully described under “Whiting Proposals” beginning on page 134.

Kodiak

At the Kodiak special meeting, Kodiak shareholders and securityholders will be asked to consider and vote upon:

Kodiak shareholder approval of the continuance resolution and Kodiak securityholder approval of the arrangement resolution is required to complete the arrangement.

Approval of the continuance resolution requires the affirmative vote of holders of at least two-thirds of the votes cast on the continuance resolution by those holders of Kodiak common stock present in person or represented by proxy.

Approval of the arrangement resolution requires the (i) affirmative vote of the holders of at least two-thirds of the votes cast on the arrangement resolution by those holders of Kodiak common stock present in person or represented by proxy, voting as one class, and (ii) affirmative vote of at least two-thirds of the votes cast on the arrangement resolution by those holders of Kodiak common stock and holders of Kodiak RSUs, options and restricted stock awards present in person or represented by proxy together voting as another class, with each Kodiak RSU, option and restricted stock award entitling the holder thereof to that number of votes equal to the number of shares of Kodiak common stock issuable upon the valid exercise of an option, or the valid settlement of an RSU or restricted stock award, as applicable.

Approval of the arrangement-related compensation proposal requires that the votes cast in favor of such proposal exceed the votes cast against such proposal.

Approval of the Kodiak adjournment proposal requires that the votes cast in favor of such proposal exceed the votes cast against such proposal.

The Kodiak board of directors recommends that Kodiak stockholders vote “FOR” all of the proposals set forth above and that the Kodiak securityholders vote “FOR” the arrangement resolution, as more fully described under “Kodiak Proposals” beginning on page 141.

Risk Factors

You should also carefully consider the risks that are described in the section entitled “Risk Factors” beginning on page 30.

Whiting Selected Historical Financial Data

Whiting’s consolidated statements of income and statements of cash flows information for the years ended December 31, 2011, 2012 and 2013 and Whiting’s consolidated balance sheet information at December 31, 2012 and 2013 are derived from Whiting’s audited consolidated financial statements incorporated by reference into this joint proxy statement/circular. Whiting’s consolidated statements of income and statements of cash flows information for the years ended December 31, 2009 and 2010 and Whiting’s consolidated balance sheet information at December 31, 2009, 2010 and 2011 are derived from Whiting’s audited consolidated financial statements that are not included or incorporated by reference into this joint proxy statement/circular. Whiting’s consolidated statements of income and statements of cash flows information for the six months ended June 30, 2013 and 2014 and the consolidated balance sheet information at June 30, 2014 have been derived from Whiting’s unaudited consolidated financial statements incorporated by reference into this joint proxy statement/circular. Whiting’s historical results include the results from Whiting’s proved property acquisitions beginning on the following dates: properties in North Dakota and Montana, September 20, 2013; properties in Colorado, September 1, 2010; and additional interests in properties in North Ward Estes, November 1, 2009 and October 1, 2009. In addition, Whiting’s historical results also include the effects of Whiting’s proved property divestitures beginning on the following dates: properties in the Postle field, April 1, 2013; and properties in Texas, October 1, 2013. This information is only a summary and you should read it in conjunction with Whiting’s consolidated financial statements and related notes incorporated by reference in this joint proxy statement/circular. The consolidated financial data may not be indicative of future performance.

Whiting Historical Operating and Reserve Data

The following table presents summary information regarding Whiting’s historical operating data for the years ended December 31, 2009, 2010, 2011, 2012 and 2013 and the six month periods ended June 30, 2013 and 2014 and Whiting’s estimated net proved oil and natural gas reserves as of December 31, 2009, 2010, 2011, 2012 and 2013. The reserve estimates presented in the table below are based on reports prepared by Cawley Gillespie & Associates, Inc., independent reserve engineers.

Kodiak Selected Historical Financial Data

Kodiak’s consolidated statements of income and statements of cash flows information for the years ended December 31, 2011, 2012 and 2013 and Kodiak’s consolidated balance sheet information at December 31, 2012 and 2013 are derived from Kodiak’s audited consolidated financial statements incorporated by reference into this joint proxy statement/circular. Kodiak’s consolidated statements of income and statements of cash flows information for the years ended December 31, 2009 and 2010 and Kodiak’s consolidated balance sheet information at December 31, 2009, 2010 and 2011 are derived from Kodiak’s audited consolidated financial statements that are not included or incorporated by reference into this joint proxy statement/circular. Kodiak’s consolidated statements of income and statements of cash flows information for the six months ended June 30, 2013 and 2014 and the consolidated balance sheet information at June 30, 2014 have been derived from Kodiak’s unaudited consolidated financial statements incorporated by reference into this joint proxy statement/circular. This information is only a summary and you should read it in conjunction with Kodiak’s consolidated financial statements and related notes incorporated by reference in this joint proxy statement/circular. The consolidated financial data may not be indicative of future performance.