Amegy Bank Fully Operational after Hurricane Rita; ISS Recommends Merger Transaction to Its Clients.

HOUSTON -- Amegy Bank announced that it is fully operational today following Hurricane Rita. Information technology systems -- and the products and services dependent on those -- were fully operational. Although only two of the Bank's 80 banking centers were closed today, all of them will be open tomorrow.

"I continue to be amazed and gratified by the way our employees have responded to this storm which could have been a significant challenge," said Paul Murphy, CEO. "Our business continuity plan worked as it is supposed to which means that throughout the last week, we were prepared to handle emergencies and then to resume operations as soon as possible. Our employees realize the importance of helping their neighbors, customers and communities return to normalcy and conduct business quickly in the aftermath of any disruptions. Furthermore, based on a preliminary assessment, the Bank anticipates no material impact to its credit risk profile."

He noted that Amegy had just assisted the City of Houston by providing an emergency branch for two weeks for Hurricane Katrina victims at one of the City's evacuation sites.

Related to the proposed merger transaction between Amegy Bancorporation (Nasdaq:ABNK) and Zions Bancorporation (Nasdaq:ZION), Institutional Shareholder Services (ISS) has informed its clients that it recommends the merger transaction. The Amegy shareholder meeting concerning the proposed merger will be held on October 11, 2005, with the legal closing anticipated later in the fourth quarter.

Amegy Bancorporation, Inc., the parent company of Amegy Bank N.A., is the largest independent bank holding company headquartered in Houston, Texas. The Company focuses on commercial lending, treasury management and investment services for businesses, private financial management and trust services for families and individuals, and retail and mortgage banking services. The Company, with $7.74 billion in assets, has 80 full-service branches located throughout the Houston and Dallas metropolitan areas.

Additional Information and Where to Find it

Zions Bancorporation has filed a registration statement on Form S-4 (File No. 333-127636), which includes a proxy statement of Amegy Bancorporation, Inc.; both companies may also file other relevant documents concerning the proposed merger transaction with the Securities and Exchange Commission (SEC). INVESTORS ARE URGED TO READ THE FORM S-4 (INCLUDING ALL AMENDMENTS AND SUPPLEMENTS TO IT) AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC BECAUSE THEY CONTAIN IMPORTANT INFORMATION. You may obtain the documents free of charge at the website maintained by the SEC at www.sec.gov. In addition, you may obtain documents filed with the SEC by Zions free of charge by contacting: Investor Relations, Zions Bancorporation, One South Main Street, Suite 1134, Salt Lake City, Utah 84111, 801-524-4787. You may obtain documents filed with the SEC by Amegy free of charge by contacting: Controller, Amegy Bancorporation, Inc., 4400 Post Oak Parkway, Houston, Texas 77027, 713-235-8800.

Participants in Solicitation

Zions Bancorporation, Amegy Bancorporation, Inc., and their respective directors and executive officers, may be deemed to be participants in the solicitation of proxies from Amegy's shareholders in connection with the merger. Information about the directors and executive officers of Zions and their ownership of Zions stock is set forth in the proxy statement for Zions' 2005 Annual Meeting of Shareholders. Information about the directors and executive officers of Amegy and their ownership of Amegy stock is set forth in the proxy statement for Amegy's 2005 Annual Meeting of Shareholders. Investors may obtain additional information regarding the interests of such participants by reading the Form S-4 and proxy statement for the merger when they become available.

Investors should read the Form S-4 carefully before making any voting or investment decisions.