SUMMARY

This summary highlights selected information contained in this document and may not contain all of the information that is important to you. For a more complete description of the merger agreement and the merger, and for other relevant information, you should carefully read this entire document and the other documents to which we have referred you. See “Where You Can Find More Information” beginning on page [—]. We include page references to direct you to a more complete description of the topics presented in this summary.

The Companies

Duke Energy Corporation (see page [—])

526 South Church Street

Charlotte, North Carolina 28202

(704) 594-6200

Duke Energy, together with its subsidiaries, is a diversified energy company with both regulated and unregulated utility operations. Duke Energy supplies, delivers and processes energy for customers in the United States and selected international markets. Duke Energy’s regulated utility operations consist of its U.S. franchised electric and gas segment, which owns approximately 27,000 megawatts of generating capacity and serves approximately four million customers located in five states in the southeast and midwest regions of the United States, representing a population of approximately 12 million people. Duke Energy’s commercial power and international business segments own and operate diverse power generation assets in North America and Latin America, including a portfolio of renewable energy assets in the United States.

For the year ended December 31, 2010, Duke Energy had total revenues of $14.3 billion and net income of $1.3 billion. Duke Energy’s consolidated assets as of December 31, 2010 were $59.1 billion. Duke Energy’s common stock is listed and trades on the NYSE under the symbol “DUK.”

Progress Energy, Inc. (see page [—])

410 South Wilmington Street

Raleigh, North Carolina 27601

(919) 546-6111

Progress Energy is a public utility holding company primarily engaged in the regulated electric utility business. Progress Energy owns, directly or indirectly, all of the outstanding common stock of its utility subsidiaries, Carolina Power & Light Company d/b/a Progress Energy Carolinas, Inc., or Progress Energy Carolinas, and Florida Power Corporation d/b/a Progress Energy Florida, Inc., or Progress Energy Florida. Progress Energy’s utility business has more than 22,000 megawatts of regulated electric generating capacity and serves approximately 3.1 million retail electric customers as well as other load-serving entities.

For the year ended December 31, 2010, Progress Energy had total revenues of $10.2 billion and net income of $863 million. Progress Energy’s consolidated assets as of December 31, 2010 were $33.1 billion. Progress Energy’s common stock is listed and trades on the NYSE under the symbol “PGN.”

Diamond Acquisition Corporation (see page [—])

Diamond Acquisition Corporation is a North Carolina corporation and a wholly-owned subsidiary of Duke Energy. Diamond Acquisition Corporation was formed on January 6, 2011, for the purpose of effecting the merger. Diamond Acquisition Corporation has not conducted any activities other than those incidental to its formation and the matters contemplated in the merger agreement.

Risk Factors

Before deciding whether to vote for the proposals presented in this document, you should carefully consider all of the information contained in or incorporated by reference into this document, as well as the specific factors under the heading “Risk Factors” beginning on page [—].

The Merger (see page [—])

Upon completion of the merger, Diamond Acquisition Corporation will merge with and into Progress Energy. Progress Energy will be the surviving corporation in the merger and will thereby become a wholly-owned subsidiary of Duke Energy.

In the merger, each outstanding share of Progress Energy common stock (other than certain shares owned by Progress Energy, Duke Energy, or Diamond Acquisition Corporation, which will be cancelled) will be converted into the right to receive shares of Duke Energy common stock, with cash to be paid in lieu of fractional shares (other than in respect of shares held in the Progress Energy dividend reinvestment plan). The merger agreement provides for an exchange ratio of 0.87083 of a share of Duke Energy common stock for each share of Progress Energy common stock, after giving effect to a 1-for-3 reverse stock split with respect to the Duke Energy common stock that Duke Energy plans to implement before the merger. Duke Energy shareholders will continue to own their existing shares of Duke Energy common stock, after adjustment for the reverse stock split.

Based on the number of shares of Duke Energy common stock and Progress Energy common stock outstanding on [    —    ], 2011, the record date for the two companies’ special meetings of shareholders, existing Duke Energy shareholders would own approximately [—]% of the common stock of Duke Energy and former Progress Energy shareholders would own approximately [—]% of the common stock of Duke Energy upon the completion of the merger.

Upon completion of the merger, Mr. Rogers, the current chairman, president and chief executive officer of Duke Energy, will serve as the executive chairman of the board of directors of Duke Energy, and Mr. Johnson, the current chairman, president and chief executive officer of Progress Energy, will serve as the president and chief executive officer of Duke Energy, subject to their ability and willingness to serve. Both Mr. Rogers and Mr. Johnson would serve on the board of directors of Duke Energy upon completion of the merger, which at that time will be comprised of 18 members, with 11 members designated by Duke Energy and seven members designated by Progress Energy.

The combined company will maintain Duke Energy’s current headquarters in Charlotte, North Carolina, following the completion of the merger. Duke Energy will also maintain substantial operations in Raleigh, North Carolina. Until the merger has received all necessary approvals and is completed, Duke Energy and Progress Energy will continue operating as separate entities. The companies are targeting to complete the merger by the end of 2011, subject to receipt of the necessary shareholder and regulatory approvals, although we cannot assure completion by any particular date.

Recommendation of the Board of Directors of Duke Energy (see page [—])

The Duke Energy board of directors unanimously recommends that the holders of Duke Energy common stock vote “FOR” the reverse stock split proposal, the share issuance proposal and the Duke Energy adjournment proposal.

For a more complete description of Duke Energy’s reasons for the merger and the recommendation of the Duke Energy board of directors, see “The Merger—Duke Energy’s Reasons for the Merger and Recommendation of Duke Energy’s Board of Directors” beginning on page [—].

Recommendation of the Board of Directors of Progress Energy (see page [—])

The Progress Energy board of directors unanimously recommends that the holders of Progress Energy common stock vote “FOR” the merger proposal and the Progress Energy adjournment proposal.

For a more complete description of Progress Energy’s reasons for the merger and the recommendation of the Progress Energy board of directors, see “The Merger—Progress Energy’s Reasons for the Merger and Recommendation of Progress Energy’s Board of Directors” beginning on page [—].

Opinions of Financial Advisors

Opinions of Financial Advisors to Duke Energy (see page [—])

Opinion of J.P. Morgan Securities LLC. In connection with the execution of the merger agreement, the Duke Energy board of directors received an opinion, dated January 8, 2011, from Duke Energy’s financial advisor, J.P. Morgan Securities LLC, or J.P. Morgan, as to the fairness, from a financial point of view and as of such date, to Duke Energy of the exchange ratio provided for in the merger agreement. For purposes of J.P. Morgan’s opinion, the exchange ratio refers to the 2.6125 exchange ratio provided for in the merger agreement before adjustment for the Duke Energy reverse stock split that Duke Energy plans to effect prior to the completion of the merger as to which reverse stock split J.P. Morgan expressed no opinion. The full text of the written opinion of J.P. Morgan dated January 8, 2011, which sets forth, among other things, the assumptions made, procedures followed, matters considered, and qualifications and limitations on the opinion and the review undertaken by J.P. Morgan in connection with rendering its opinion, is included as Annex B to this document and is incorporated by reference herein in its entirety. You are encouraged to read the opinion and the description beginning on page [—] carefully in their entirety. This summary and the description of the opinion beginning on page [—] are qualified in their entirety by reference to the full text of the opinion. J.P. Morgan provided its written opinion to the Duke Energy board of directors (in its capacity as such) in connection with and for purposes of its evaluation of the exchange ratio. J.P. Morgan’s opinion was limited to the fairness, from a financial point of view, to Duke Energy of the exchange ratio in the merger agreement and J.P. Morgan expressed no opinion as to any other matter. The opinion does not constitute a recommendation to any shareholder as to how any shareholder should vote with respect to the merger or any other matter.

Opinion of BofA Merrill Lynch. In connection with the execution of the merger agreement, Merrill Lynch, Pierce, Fenner & Smith Incorporated, or BofA Merrill Lynch, financial advisor to the Duke Energy board of directors, delivered to the Duke Energy board of directors at its meeting on January 8, 2011, an opinion as to the fairness, from a financial point of view and as of the date of the opinion, to Duke Energy of the exchange ratio provided for in the merger agreement. For purposes of BofA Merrill Lynch’s opinion, the exchange ratio refers to the 2.6125 exchange ratio provided for in the merger agreement before adjustment for the Duke Energy reverse stock split that Duke Energy plans to effect prior to the completion of the merger, as to which reverse stock split BofA Merrill Lynch expressed no opinion. The full text of the written opinion of BofA Merrill Lynch, which describes, among other things, the assumptions made, procedures followed, factors considered and limitations on the review undertaken by BofA Merrill Lynch, is attached as Annex C to this document and is incorporated by reference herein in its entirety. You are encouraged to read the opinion and the description beginning on page [—] carefully in their entirety. This summary and the description of the opinion beginning on page [—] are qualified in their entirety by reference to the full text of the opinion. BofA Merrill Lynch provided its opinion to the Duke Energy board of directors (in its capacity as such) for the benefit and use of the Duke Energy board of directors in connection with and for purposes of its evaluation of the exchange ratio from a financial point of view. BofA Merrill Lynch’s opinion does not address any other aspect of the merger and does not constitute a recommendation to any shareholder as to how to vote or act in connection with the merger or any other matter.

Opinions of Financial Advisors to Progress Energy (see page [—])

Opinion of Lazard Frères & Co. LLC. In connection with the execution of the merger agreement, on January 8, 2011, Lazard Frères & Co. LLC, or Lazard, delivered its opinion to the Progress Energy board of directors that, as of such date, and based upon and subject to the assumptions, procedures, factors, qualifications and limitations set forth therein, the exchange ratio was fair, from a financial point of view, to holders of Progress Energy common stock. For purposes of Lazard’s opinion, the exchange ratio refers to the 2.6125 exchange ratio provided for in the merger agreement before adjustment for the Duke Energy reverse stock split that Duke Energy plans to effect prior to the completion of the merger, as to which reverse stock split Lazard expressed no opinion. The full text of Lazard’s written opinion, dated January 8, 2011, which sets forth the assumptions made, procedures followed, factors considered and qualifications and limitations on the review undertaken by Lazard in connection with its opinion, is attached to this document as Annex D and is incorporated by reference herein in its entirety. You are encouraged to read Lazard’s opinion and the description beginning on page [—] carefully and in their entirety. This summary and the description of the opinion beginning on page [—] are qualified in their entirety by reference to the full text of the opinion. Lazard’s opinion was directed to the Progress Energy board of directors for the information and assistance of the Progress Energy board of directors in connection with its evaluation of the merger and addressed only the fairness as of the date of the opinion, from a financial point of view, of the exchange ratio to holders of Progress Energy common stock. Lazard’s opinion was not intended to, and does not, constitute a recommendation to any shareholder as to how such shareholder should vote or act with respect to the merger or any matter relating thereto.

Opinion of Barclays Capital Inc. In connection with the execution of the merger agreement, on January 8, 2011, Barclays Capital Inc., or Barclays Capital, rendered its oral opinion (which Barclays Capital subsequently confirmed in writing) to the Progress Energy board of directors that, as of such date and based upon and subject to the qualifications, limitations and assumptions stated in its opinion, from a financial point of view, the exchange ratio was fair to shareholders of Progress Energy. The full text of Barclays Capital’s written opinion, dated as of January 8, 2011, is attached as Annex E to this document and is incorporated by reference herein in its entirety. Barclays Capital’s written opinion sets forth, among other things, the assumptions made, procedures followed, factors considered and limitations upon the review undertaken by Barclays Capital in rendering its opinion. You are encouraged to read the opinion and the description beginning on page [—] carefully and in their entirety. This summary and the description of the opinion beginning on page [—] are qualified in their entirety by reference to the full text of the opinion. Barclays Capital’s opinion, the issuance of which was approved by Barclays Capital’s fairness opinion committee, is addressed to the Progress Energy board of directors, addresses only the fairness, from a financial point of view, of the exchange ratio to the Progress Energy shareholders and does not constitute a recommendation to any shareholder of Progress Energy as to how such shareholder should vote with respect to the merger or any other matter.

Interests of Directors and Executive Officers in the Merger (see page [—])

Duke Energy

Some of Duke Energy’s directors and executive officers have financial interests in the merger that may be different from, or in addition to, the interests of Duke Energy shareholders generally. The Duke Energy board of directors was aware of and considered these potential interests, among other matters, in evaluating and negotiating the merger agreement and the merger, in approving the merger agreement and in recommending the approval of the reverse stock split proposal, the share issuance proposal and the Duke Energy adjournment proposal.

As provided in the merger agreement, at the completion of the merger, the Duke Energy board of directors will include 11 directors designated by Duke Energy and seven directors designated by Progress Energy.

Mr. Rogers, the current chairman, president and chief executive officer of Duke Energy, will serve as the executive chairman of the Duke Energy board of directors upon the completion of the merger, subject to his ability and willingness to serve. The merger agreement also provides that certain executive officers of Duke Energy at the time the parties signed the merger agreement may continue to be executive officers of Duke Energy at the time the merger is completed. The continuing management of Duke Energy following completion of the merger is described under the heading “The Merger—Continuing Board and Management Positions,” beginning on page [—].

Please see “The Merger—Interests of Directors and Executive Officers in the Merger—Interests of Directors and Executive Officers of Duke Energy in the Merger” beginning on page [—] for additional information about these interests.

Progress Energy

Progress Energy’s directors and executive officers have financial interests in the merger that may be different from, or in addition to, the interests of Progress Energy’s shareholders generally. The board of directors of Progress Energy was aware of and considered these potential interests, among other matters, in evaluating and negotiating the merger agreement and the merger, in adopting the merger agreement and in recommending the approval of the merger proposal and the Progress Energy adjournment proposal.

As provided in the merger agreement, at the completion of the merger, the Duke Energy board of directors will include seven directors designated by Progress Energy (after consultation with Duke Energy). Mr. Johnson, the current chairman, president and chief executive officer of Progress Energy, will serve as the president and chief executive officer of Duke Energy upon the completion of the merger, subject to his ability and willingness to serve. See “The Merger—Continuing Board and Management Positions” beginning on page [—]. In connection with the execution of the merger agreement, Duke Energy, Diamond Acquisition Corporation and Mr. Johnson executed a term sheet in which the parties agreed to enter into a new employment agreement.

Executive officers of Progress Energy will not receive any compensation solely on account of the completion of the merger. Outstanding options to purchase shares of Progress Energy common stock and outstanding awards of restricted stock, restricted stock units and performance shares will be converted into Duke Energy common stock options and other awards that will remain subject to the original vesting requirements under the applicable Progress Energy plan, i.e., the vesting of the options and other awards will not be accelerated on account of the completion of the merger. The outstanding annual incentive awards of executive officers of Progress Energy also will remain subject to the original vesting requirements and will remain subject to performance criteria. As soon as practicable after the completion of the merger, the compensation committee of the Duke Energy board of directors will adjust the original performance criteria for such awards as it determines is appropriate and equitable to reflect the merger, Progress Energy’s performance prior to completion of the merger and the performance criteria of awards made to similarly situated Duke Energy employees.

Additionally, although each of Messrs. Johnson, Yates, Lyash, McArthur and Mulhern will be entitled to severance benefits under the Progress Energy Management Change-in-Control Plan, or the Progress Energy CIC Plan, if their employment is terminated without “cause” or they resign with “good reason” within 24 months after completion of the merger, certain provisions of Mr. Johnson’s term sheet and letter agreement waivers executed by each of Messrs. Yates, Lyash, McArthur and Mulhern, among other things, limit the executives’ eligibility to receive those benefits. In addition, Mr. Johnson’s term sheet provides for the waiver of his right to receive the excise tax gross-up otherwise payable under the Progress Energy CIC Plan on any severance payment he receives.

A member of the board of directors of Progress Energy is an employee of J.P. Morgan, which firm acted as financial advisor to Duke Energy with respect to the merger. Such member has informed the board of directors of

Progress Energy that he did not have any involvement in J.P. Morgan’s engagement with Duke Energy in connection with the merger, and that his compensation would not be directly related to that engagement.

Please see “The Merger—Interests of Directors and Executive Officers in the Merger—Interests of Directors and Executive Officers of Progress Energy in the Merger” beginning on page [—] for additional information about these interests.

The Management of Duke Energy Following the Completion of the Merger (see page [—])

The merger agreement provides that William D. Johnson will serve as the president and chief executive officer of Duke Energy and James E. Rogers will serve as the executive chairman of the board of directors of Duke Energy, in each case as of the completion of the merger and subject to such individual’s ability and willingness to serve.

The merger agreement also provides that, subject to such individuals’ ability and willingness to serve, the following individuals will be the senior officers of Duke Energy upon completion of the merger:

The Merger Agreement (see page [—])

We include the merger agreement as Annex A to this document. We encourage you to read carefully the merger agreement in its entirety. It is the principal document governing the merger and the other related transactions.

Conditions to the Completion of the Merger (see page [—])

We expect to complete the merger after all of the conditions to the merger in the merger agreement are satisfied or waived, including after Duke Energy and Progress Energy receive shareholder approvals at their respective special meetings of shareholders and receive all required regulatory approvals.

The obligation of each of Duke Energy and Progress Energy to complete the merger is subject to the satisfaction or waiver of a number of customary conditions, including the following:

Termination of the Merger Agreement (see page [—])

Generally, the merger agreement may be terminated at any time prior to the completion of the merger, whether before or (unless otherwise noted below) after the receipt of the necessary shareholder approvals, under the following circumstances:

Either party may also terminate the merger agreement prior to the shareholder approval of the other party being obtained, if the board of directors of the other party:

Termination Fees; Reimbursement of Expenses (see page [—])

Under certain circumstances involving a third-party acquisition proposal, a change in a board of directors’ recommendation of the proposals contained in this document or a termination of the merger agreement by the other party due to a breach of the merger agreement, Duke Energy or Progress Energy may be required, subject to certain conditions, to (i) reimburse the other party for its fees and expenses in an amount not to exceed $30 million and/or (ii) pay a termination fee of $675 million, in the case of a termination fee payable by Duke Energy to Progress Energy, or a termination fee of $400 million, in the case of a termination fee payable by Progress Energy to Duke Energy, provided that any termination fee payable will be reduced by the amount of any fees and expenses previously reimbursed by such party.

No Solicitation; Board Recommendation (see page [—])

The merger agreement restricts the ability of either Duke Energy or Progress Energy to directly or indirectly, solicit, initiate, knowingly encourage or engage in discussions with a third-party regarding a third-party takeover proposal of Duke Energy or Progress Energy, respectively. If, however, either party, as applicable, receives an unsolicited takeover proposal from a third-party that, prior to receipt of its respective shareholder approvals required to complete the merger, such party’s board of directors determines in good faith, after

consultation with such party’s legal and financial advisors, constitutes a superior proposal or is reasonably likely to result in a superior proposal, that party may furnish information to the third-party and engage in discussions or negotiations regarding a takeover proposal with the third-party, subject to specified conditions. The board of directors of either Duke Energy or Progress Energy may also withdraw its approval or recommendation of the proposals described in this document, subject to certain conditions, if such board first determines in good faith, after consulting with outside counsel, that the failure to take such action would be reasonably likely to result in a breach of the board of directors’ fiduciary duties under applicable law.

Accounting Treatment (see page [—])

Duke Energy prepares its financial statements in accordance with accounting principles generally accepted in the United States, which we refer to as GAAP. The merger will be accounted for by applying the acquisition method with Duke Energy treated as the acquiror.

Material U.S. Federal Income Tax Consequences of the Reverse Stock Split (see page [—])

Duke Energy intends for the reverse stock split to qualify as a “recapitalization” within the meaning of Section 368(a) of the Code for U.S. federal income tax purposes. On the basis that the reverse stock split so qualifies, Duke Energy shareholders whose pre-reverse stock split shares of Duke Energy common stock are exchanged in the reverse stock split will not recognize gain or loss for U.S. federal income tax purposes, except to the extent of cash, if any, received in lieu of a fractional share of Duke Energy common stock (which fractional share will be treated as received and then exchanged for such cash).

The discussion of material U.S. federal income tax consequences of the reverse stock split contained in this document 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 reverse stock split. 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.

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

For additional information, please see “Proposals Submitted to Duke Energy’s Shareholders—The Reverse Stock Split Proposal—Material U.S. Federal Income Tax Consequences of the Reverse Stock Split” beginning on page [—].

Material U.S. Federal Income Tax Consequences of the Merger (see page [—])

Assuming the merger qualifies as a reorganization under Section 368(a) of the Code for U.S. federal income tax purposes, as Duke Energy and Progress Energy anticipate, holders of Progress Energy common stock whose shares of Progress Energy common stock are exchanged in the merger for shares of Duke Energy common stock will not recognize gain or loss, except to the extent of cash, if any, received in lieu of a fractional share of Duke Energy common stock.

The discussion of material U.S. federal income tax consequences of the merger contained in this document 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 merger. 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.

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

For additional information, please see “The Merger—Material U.S. Federal Income Tax Consequences of the Merger” beginning on page [—].

Regulatory Matters (see page [—])

To complete the merger, Duke Energy and Progress Energy must obtain approvals or consents from, or make filings with, a number of United States federal and state public utility, antitrust and other regulatory authorities. The material United States federal and state approvals, consents and filings include the following:

Duke Energy and Progress Energy will also provide information regarding the merger to their other state regulators as applicable and as requested. Finally, the transfer of indirect control over certain Federal Communications Commission, or FCC, licenses for private internal communications held by certain subsidiaries of Progress Energy will require the approval of the FCC.

Duke Energy and Progress Energy intend to make various filings and submissions for the above-mentioned authorizations and approvals. Duke Energy and Progress Energy will seek to complete the merger by the end of 2011. Although Duke Energy and Progress Energy believe that they will receive the required consents and approvals described above to complete the merger, we cannot give any assurance as to the timing of these consents and approvals or as to Duke Energy’s and Progress Energy’s ultimate ability to obtain such consents or approvals (or any additional consents or approvals which may otherwise become necessary). We also cannot ensure that we will obtain such consents or approvals on terms and subject to conditions satisfactory to Duke Energy and Progress Energy. Please see “Regulatory Matters,” beginning on page [—], for additional information about these matters.

Effect on Awards Outstanding Under Progress Energy Stock Plans (see page [—])

At the effective time of the merger, each option to purchase shares of Progress Energy common stock that was granted under the Progress Energy employee stock option plans and that is outstanding immediately prior to the effective time of the merger will be converted into an option to acquire a number of shares of Duke Energy common stock equal to the number of shares of Progress Energy common stock subject to the Progress Energy stock option immediately prior to the effective time of the merger multiplied by the exchange ratio, as adjusted to

reflect the reverse stock split, rounded down to the nearest whole share of Duke Energy common stock, with an exercise price per share of Duke Energy common stock equal to the exercise price per share under such Progress Energy stock option divided by the exchange ratio, as adjusted to reflect the reverse stock split, rounded up to the nearest cent. Also upon completion of the merger, each Progress Energy restricted share, Progress Energy restricted stock unit, Progress Energy performance share or other Progress Energy equity award will be converted into an award in respect of a number of shares of Duke Energy common stock equal to the number of shares of Progress Energy common stock represented by such award multiplied by the exchange ratio, as adjusted to reflect the reverse stock split.

Except as set forth above, each converted Progress Energy stock option, Progress Energy restricted share, Progress Energy restricted stock unit, Progress Energy performance share or other Progress Energy equity award will be subject to the same terms and conditions, including vesting, as were applicable to the corresponding Progress Energy stock option, Progress Energy restricted share, Progress Energy restricted stock unit, Progress Energy performance share or other Progress Energy equity award immediately prior to the effective time of the merger. However, the compensation committee of the Duke Energy board of directors will as soon as practicable after the effective time of the merger adjust the performance measures applicable to performance shares as it determines is appropriate and equitable to reflect the performance of Progress Energy during the performance measurement period prior to the effective time of the merger, the transactions undertaken pursuant to the merger agreement and the performance measures under awards made to similarly situated Duke Energy employees for the same or comparable performance cycle.

Legal Proceedings Related to the Merger (see page [—])

Duke Energy and Progress Energy are aware of eleven purported class action lawsuits that plaintiffs had filed against Progress Energy, each member of Progress Energy’s board of directors, Duke Energy and Diamond Acquisition Corporation in connection with the merger. Among other things, the lawsuits seek injunctive relief that would prevent completion of the merger in accordance with the terms of the merger agreement. Both Duke Energy and Progress Energy believe the lawsuits are without merit. The plaintiffs brought ten of the cases in the North Carolina state courts and one in the U.S. District Court for the Eastern District of North Carolina.

We provide additional information on legal proceedings related to the merger beginning on page [—].

Comparison of Shareholder Rights (see page [—])

Progress Energy is a North Carolina corporation. Duke Energy is a Delaware corporation. The shares of Duke Energy common stock that Progress Energy shareholders will receive in the merger will be shares of a Delaware corporation. Progress Energy shareholder rights under North Carolina law and Duke Energy shareholder rights under Delaware law are different. In addition, Duke Energy’s amended and restated certificate of incorporation and its amended and restated by-laws contain provisions that are different from Progress Energy’s amended and restated articles of incorporation and by-laws, each as amended.

For a summary of certain differences between the rights of Duke Energy shareholders and Progress Energy shareholders, see “Comparison of Shareholder Rights,” beginning on page [—].

SELECTED HISTORICAL FINANCIAL DATA OF DUKE ENERGY

The following table sets forth selected consolidated financial information for Duke Energy. Duke Energy derived the selected statement of operations data for each of the years in the five year period ended December 31, 2010 and the selected balance sheet data as of December 31 for each of the five years in the period ended December 31, 2010 from Duke Energy’s consolidated audited financial statements. The following information is only a summary and is not necessarily indicative of the results of future operations of Duke Energy or the combined company, and you should read the information together with Duke Energy’s consolidated financial statements, the notes related thereto and management’s related reports on Duke Energy’s financial condition and performance, all of which are contained in Duke Energy’s reports filed with the SEC and incorporated herein by reference. See “Where You Can Find More Information” beginning on page [—] of this document.

SELECTED HISTORICAL FINANCIAL DATA OF PROGRESS ENERGY

The following table sets forth selected consolidated financial information for Progress Energy. Progress Energy derived the selected statement of operations data for each of the years in the five year period ended December 31, 2010 and the selected balance sheet data as of December 31 for each of the five years in the period ended December 31, 2010 from Progress Energy’s consolidated audited financial statements. The following information is only a summary and is not necessarily indicative of the results of future operations of Duke Energy and Progress Energy or the combined company, and you should read the information together with Progress Energy’s consolidated financial statements, the notes related thereto and management’s related reports on Progress Energy’s financial condition and performance, all of which are contained in Progress Energy’s reports filed with the SEC and incorporated herein by reference. See “Where You Can Find More Information” beginning on page [—] of this document.

SELECTED UNAUDITED PRO FORMA CONDENSED COMBINED CONSOLIDATED FINANCIAL DATA

The unaudited pro forma condensed combined consolidated statement of operations information for the year ended December 31, 2010 gives effect to the merger as if it had occurred on January 1, 2010. The unaudited pro forma condensed combined consolidated balance sheet information as of December 31, 2010 gives effect to the merger as if it had occurred on December 31, 2010.

We present the unaudited pro forma condensed combined consolidated financial statements for illustrative purposes only, and they are not necessarily indicative of the results of operations and financial position that would have been achieved had the pro forma events taken place on the dates indicated, or the future consolidated results of operations or financial position of the combined company. Future results may vary significantly from the results reflected because of various factors, including those discussed in this document under the heading “Risk Factors” beginning on page [—]. You should read the following selected unaudited pro forma condensed combined consolidated financial information in conjunction with the “Unaudited Pro Forma Condensed Combined Consolidated Financial Information” and related notes included in this document beginning on page [—].

COMPARATIVE HISTORICAL AND UNAUDITED PRO FORMA PER SHARE FINANCIAL DATA

The following table presents: (1) historical per share information for Duke Energy; (2) pro forma per share information of the combined company after giving effect to the merger; and (3) historical and equivalent pro forma per share information for Progress Energy.

We derived the combined company pro forma per share information primarily by combining information from the historical consolidated financial statements of Duke Energy and Progress Energy. You should read this table together with the historical consolidated financial statements of Duke Energy and Progress Energy that are filed with the SEC and incorporated by reference into this document. You should not rely on the pro forma per share information as being necessarily indicative of actual results had the merger occurred on January 1, 2010 for statement of operations purposes or December 31, 2010 for book value per share data.