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Filed by Cinergy Corp.
Commission File No. 1-11377
Pursuant to Rule 425 under the Securities Act of 1933
And Deemed Filed Pursuant to Rule 14a-12
Under the Securities Exchange Act of 1934
  
Subject Company: Cinergy Corp.
Commission File No. 1-11377

ARTICLE FOR MAY EDITION OF "ENERGY ADVISOR" (5/16/05):

CINERGY AND DUKE ENERGY AGREE TO MERGE;
CREATES ENERGY COMPANY WITH $36 BILLION MARKET CAPITALIZATION

        On Monday, May 9^th, Cinergy and Duke Energy announced a merger, creating a $36 billion energy company with 5.4 million retail customers and over 54,000 megawatts of electric generation, domestically and internationally. This transaction will create North America's largest diversified utility and gas company and is expected to be completed in 2006.

        The combined organization, to be called Duke Energy, will continue to focus on excellence in operational performance, customer satisfaction and financial strength. Cinergy's commercial businesses will continue to be an important element of the business strategy, building upon its track record of value creation for customers.

        Cinergy is dedicated to serving customer needs and this transaction further strengthens its capability to do so. During the transition period and beyond, customers can expect the same level of commitment and service they have become accustomed to from Cinergy.

        Please be assured that Cinergy, as always, is committed to its commercial businesses and to its customers. If you have questions or would like to discuss this exciting news further, please don't hesitate to call your Cinergy contact.

        For more information, please refer to the news release and fact sheet, which provide additional insight for your review.

Forward-Looking Statement

        This document includes statements that do not directly or exclusively relate to historical facts. Such statements are "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These forward-looking statements include statements regarding benefits of the proposed mergers and Restructuring Transactions, integration plans and expected synergies, anticipated future financial operating performance and results, including estimates of growth. These statements are based on the current expectations of management of Duke Energy and Cinergy. There are a number of risks and uncertainties that could cause actual results to differ materially from the forward-looking statements included in this document. For example, (1) the companies may be unable to obtain shareholder approvals required for the transaction; (2) the companies may be unable to obtain regulatory approvals required for the transaction, or required regulatory approvals may delay the transaction or result in the imposition of conditions that could have a material adverse effect on the combined company or cause the companies to abandon the transaction; (3) conditions to the closing of the mergers and the restructuring transactions may not be satisfied; (4) problems may arise in successfully integrating the businesses of the companies, which may result in the combined company not operating as effectively and efficiently as expected; (5) the combined company may be unable to achieve cost-cutting synergies or it may take longer than expected to achieve those synergies; (6) the transaction may involve unexpected costs or unexpected liabilities, or the effects of purchase accounting may be different from the companies' expectations; (7) the credit ratings of the combined company or its subsidiaries may be different from what the companies expect; (8) the businesses of the companies may suffer as a result of uncertainty surrounding the transaction; (9) the industry may be subject to future regulatory or legislative actions that could adversely affect the companies; and (10) the companies may be adversely affected by other economic, business, and/or competitive factors. Additional factors that may affect the future results of Duke Energy and Cinergy are set forth in their respective filings with the Securities and Exchange Commission ("SEC"), which are available at www.duke-energy.com/investors and www.cinergy.com/investors, respectively. Duke Energy and Cinergy undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Additional Information and Where to Find It

        In connection with the proposed transaction, a registration statement of Deer Holding Corp., which will include a joint proxy statement of Duke Energy and Cinergy, and other materials, will be filed with SEC. WE URGE INVESTORS TO READ THE REGISTRATION STATEMENT AND PROXY STATEMENT AND THESE OTHER MATERIALS CAREFULLY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT DUKE ENERGY, CINERGY, DEER HOLDING CORP., AND THE PROPOSED TRANSACTION. Investors will be able to obtain free copies of the registration statement and proxy statement (when available) as well as other filed documents containing information about Duke Energy and Cinergy at http://www.sec.gov, SEC's Web site. Free copies of Duke Energy's SEC filings are also available on Duke Energy's Web site at www.duke-energy.com/investors and free copies of Cinergy's SEC filings are also available on Cinergy's Web site at www.cinergy.com/investors.

Participants in the Solicitation

        Duke Energy, Cinergy and their respective executive officers and directors may be deemed, under SEC rules, to be participants in the solicitation of proxies from Duke Energy's or Cinergy's stockholders with respect to the proposed transaction. Information regarding the officers and directors of Duke Energy is included in its definitive proxy statement for its 2005 annual meeting filed with SEC on March 31, 2005. Information regarding the officers and directors of Cinergy is included in its definitive proxy statement for its 2005 annual meeting filed with SEC on March 28, 2005. More detailed information regarding the identity of potential participants, and their direct or indirect interests, by securities, holdings or otherwise, will be set forth in the registration statement and proxy statement and other materials to be filed with SEC in connection with the proposed transaction.

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CINERGY AND DUKE ENERGY AGREE TO MERGE; CREATES ENERGY COMPANY WITH $36 BILLION MARKET CAPITALIZATION