425

Filed by: ACE Limited

Pursuant to Rule 425 under the Securities Act of 1933

and deemed filed pursuant to Rule 14a-12

of the Securities Exchange Act of 1934

Subject Company: The Chubb Corporation

Commission File No. 001-08661

The following message from Combined Insurance President Brad Bennett was sent to Combined Insurance employees on July 8, 2015.

I hope most of you had the opportunity to listen to Evan Greenberg’s call last week announcing the agreement to acquire Chubb Insurance. If you did, you heard his enthusiasm about the transaction and all that it represents for the ACE Group and our collective future. Combining these two great organizations, which share a culture for underwriting discipline with proven long-term track records for world-class results, will reflect a growth organization with size and a strength of balance sheet that will put us into a very elite group of global insurers. When the transaction is complete, the growth and earning power of the two companies together will be greater than the sum of each separately, and will offer even greater prospects given the enhanced product capabilities and domestic and international presence.

What does this mean for Combined? For now, it means we stay focused on our growth goals—nothing changes. As for the future, I can only imagine that the acquisition will offer us an even stronger platform for growth and opportunities. Because the transaction isn’t expected to be completed until early 2016, details of integration will be limited over the next few months. We will answer any questions we can, and ask for your patience when we don’t have answers.

I have been in this industry a long time and have seen many mergers and acquisitions take place. This one further validates for me that our leadership is focused and in pursuit of a vision that we can all be very proud of. I am sure you will agree: it is exciting to be a part of it.

Brad

Forward Looking Statements

All forward-looking statements made in this communication, related to the acquisition of Chubb, potential post-acquisition performance or otherwise, reflect ACE’s current views with respect to future events, business transactions and business performance and are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. In some cases, you can identify forward-looking statements by words such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “predict,” “potential,” “continue,” “could,” “future,” “project” or other words of similar meaning. All forward-looking statements involve risks and uncertainties, which may cause actual results to differ, possibly materially, from those contained in the forward-looking statements.

Forward-looking statements include, but are not limited to, statements about the benefits of the proposed transaction involving ACE and Chubb, including future financial results; ACE’s and Chubb’s plans, objectives, expectations and intentions; the expected timing of completion of the transaction and other statements that are not historical facts. Important factors that could cause actual results to differ, possibly materially, from those indicated by the forward-looking statements include, without limitation, the following: the inability to complete the transaction in a timely manner; the inability to complete the transaction due to the failure of Chubb’s shareholders to adopt the transaction agreement or the failure of ACE shareholders to approve, among other matters, the issuance of ACE common stock in connection with the acquisition; the failure to satisfy other conditions to completion of the merger, including receipt of required regulatory approvals; the failure of the proposed transaction to close for any other reason; the possibility that any of the anticipated benefits of the proposed transaction will not be realized; the risk that integration of Chubb’s operations with those of ACE will be materially delayed or will be more costly or difficult than expected; the challenges of integrating and retaining key employees; the effect of the announcement of the transaction on ACE’s, Chubb’s or the combined company’s respective business relationships, operating results and business generally; the possibility that the anticipated synergies and cost savings of the merger will not be realized, or will not be realized within the expected time period; the possibility that the transaction may be more expensive to complete than anticipated, including as a result of unexpected factors or events; diversion of management’s attention from ongoing business operations and opportunities; general competitive, economic, political and market conditions and fluctuations; and actions taken or conditions imposed by the United States and foreign governments and regulatory authorities. In addition, you should carefully consider the risks and uncertainties and other factors that may affect future results of the combined company described in the section entitled “Risk Factors” in the joint proxy statement/prospectus to be delivered to ACE’s and Chubb’s respective shareholders, and in ACE’s and Chubb’s respective filings with the Securities and Exchange Commission (“SEC”) that are available on the SEC’s website, located at www.sec.gov, including the sections entitled “Risk Factors” in ACE’s Annual Report on Form 10-K for the year ended December 31, 2014, which was filed with the SEC on February 27, 2015, and “Risk Factors” in Chubb’s Annual Report on Form 10-K for the year ended December 31, 2014, which was filed with the SEC on February 26, 2015. You should not place undue reliance on forward-looking statements, which speak only as of the date of this press release. ACE undertakes 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

This press release does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval. This press release may be deemed to be solicitation material in respect of the proposed transaction between ACE and Chubb. In connection with the proposed transaction, ACE intends to file a registration statement on Form S-4, containing a joint proxy statement/prospectus with the SEC. The final joint proxy statement/prospectus will be delivered to the shareholders of ACE and Chubb. This press release is not a substitute for the registration statement, definitive joint proxy statement/prospectus or any other documents that ACE or Chubb may file with the SEC or send to shareholders in connection with the proposed transaction. Shareholders are urged to read all relevant documents filed with the SEC, including the joint proxy because they will contain important information about the proposed transaction. Shareholders will be able to obtain copies of the joint proxy statement/prospectus and other documents filed with the SEC (when available) free of charge at the SEC’s website, http://www.sec.gov. Copies of documents filed with the SEC by ACE will be made available free of charge on ACE’s website at www.acegroup.com. Copies of documents filed with the SEC by Chubb will be made available free of charge on Chubb’s website at www.Chubb.com.


Participants in Solicitation

ACE, Chubb and their respective directors, executive officers and other members of management and employees may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information about the directors and executive officers of ACE is set forth in the proxy statement for ACE’s 2015 Annual General Meeting, which was filed with the SEC on April 8, 2015, and ACE’s Annual Report on Form 10-K for the year ended December 31, 2014, which was filed with the SEC on February 27, 2015. Information about the directors and executive officers of Chubb is set forth in the proxy statement for Chubb’s 2015 Annual Meeting of Shareholders, which was filed with the SEC on March 13, 2015, and Chubb’s Annual Report on Form 10-K for the year ended December 31, 2014, which was filed with the SEC on February 26, 2015. Other information regarding the participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the joint proxy statement/prospectus and other relevant materials filed with the SEC. You may obtain free copies of these documents as described above.