UnitedHealth Group (UNH)

Important Merger Information

In connection with the proposed transactions, UnitedHealth Group and PacifiCare have filed relevant materials with the Securities and Exchange Commission (SEC), including a registration statement on Form S-4 that contains a prospectus and proxy statement. Because those documents contain important information, holders of PacifiCare common stock are urged to read them. The registration statement, including the prospectus and proxy statement are available for free (along with any other documents and reports filed by UnitedHealth Group and PacifiCare with the SEC) at the SEC’s Web site, www.sec.gov. In addition, PacifiCare stockholders may obtain free copies of the documents filed with the SEC by PacifiCare by directing a written request to PacifiCare Health Systems Inc., 5995 Plaza Drive, Cypress, CA 90630, Attention: Investor Relations.

UnitedHealth Group and its directors and executive officers may be deemed to be participants in the solicitation of proxies from the holders of PacifiCare common stock in connection with the proposed transactions. Information about the directors and executive officers of UnitedHealth Group is set forth in the proxy statement for UnitedHealth Group’s 2005 Annual Meeting of Stockholders, which was filed with the SEC on April 7, 2005. Investors may obtain additional information regarding the interests of such participants by reading the prospectus and proxy solicitation statement dated October 12, 2005.

PacifiCare and its directors and executive officers may be deemed to be participants in the solicitation of proxies from the holders of PacifiCare common stock in connection with the proposed transaction. Information about the directors and executive officers of PacifiCare and their ownership of PacifiCare common stock is set forth in the proxy statement for PacifiCare’s 2005 Annual Meeting of Stockholders, which was filed with the SEC on April 13, 2005. Investors may obtain additional information regarding the interests of such participants by reading the prospectus and proxy solicitation statement if and when it becomes available.

This communication shall not constitute an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offering of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.