Zions Bancorporation Completes Acquisition of Amegy

December 3, 2005

SALT LAKE CITY, Dec. 3 /PRNewswire-FirstCall/ -- Zions Bancorporation (Nasdaq: ZION) ("Zions") today announced that it has today completed its acquisition of Amegy Bancorporation, Inc., ("Amegy") as a result of which Amegy Bank N.A. has become a subsidiary of Zions Bancorporation. Amegy Bank N.A. retains its charter, name, board and management team, and becomes the third largest bank of Zions' eight community banking companies.

"We are excited to have Amegy as part of our collection of great banks," said Harris H. Simmons, chairman and chief executive officer of Zions. "This transaction adds one of the largest and fastest-growing markets in the country to our already outstanding footprint," added Mr. Simmons. "Amegy's customers will continue to deal with what we believe is the best team of bankers in Texas, backed up by the strength of our $40 billion company. We welcome Amegy's customers and employees to the Zions organization."

"The results of the third quarter -- the highest new loan commitments in the history of the bank and the largest deposit growth linked quarter -- clearly indicate that the market's reception of this transaction has been very positive," said Paul B. Murphy Jr., chief executive officer of Amegy Bank. "I truly believe this affiliation will be great for our customers, our employees -- and for the state of Texas."

Shareholder Consideration

Based on the average closing price of Zions common stock of $76.1550 for the ten trading days immediately prior to the closing date of December 3, 2005, former Amegy shareholders will receive, for each Amegy common share, either $23.88 in cash or 0.3136 of a share of Zions stock, depending on the election made by that shareholder and the proration and adjustment procedures described in the merger agreement.

According to the Federal Reserve, the completion of this transaction makes Zions the 38th largest depository organization in the United States, with total consolidated assets of approximately $41.7 billion based on data as of September 30, 2005.

Forward-Looking Statements

Statements contained in this filing which are not historical facts are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, statements about the benefits of the merger between Zions Bancorporation and Amegy Bancorporation, Inc., including future financial and operating results and performance; statements about Zions Bancorporation's plans, objectives, expectations and intentions with respect to future operations, products and services; and other statements identified by words such as "expects," "anticipates," "intends," "plans," "believes," "seeks," "estimates," "will," "should," "may" or words of similar meaning. These forward-looking statements are based upon the current beliefs and expectations of the management of Zions Bancorporation and are inherently subject to significant business, economic and competitive uncertainties and contingencies, many of which are difficult to predict and generally beyond the control of Zions Bancorporation. In addition, these forward-looking statements are subject to assumptions with respect to future business strategies and decisions that are subject to change. Actual results may differ materially from the anticipated results discussed in these forward-looking statements.

The following factors, among others, could cause actual results to differ materially from the anticipated results or other expectations expressed in the forward-looking statements: (1) the businesses of Zions Bancorporation and Amegy may not be combined successfully, or such combination may take longer, be more difficult, time-consuming or costly to accomplish than expected; (2) the expected growth opportunities and cost savings from the merger may not be fully realized or may take longer to realize than expected; (3) operating costs, customer losses and business disruption following the merger, including adverse effects on relationships with employees, may be greater than expected; (4) adverse governmental or regulatory policies may be enacted; (5) competition from other financial services companies; (6) economic conditions, either nationally or locally in areas in which Zions Bancorporation and its subsidiaries conduct their operations, being less favorable than expected; (7) changes in the interest rate environment reducing expected interest margins; and (8) legislation or regulatory changes, which adversely affect the ability of Zions Bancorporation or its subsidiaries to conduct the businesses in which they are engaged. Additional factors that could cause actual results to differ materially from those expressed in the forward-looking statements are discussed in the 2004 Annual Reports on Form 10-K of Zions Bancorporation and Amegy Bancorporation, Inc. filed with the Securities and Exchange Commission and available at the SEC's Internet site (http://www.sec.gov). Zions Bancorporation does not undertake any obligation to update any forward-looking statements to reflect circumstances or events that occur after the date on which such statements were made.

About Zions Bancorporation

Zions Bancorporation is one of the nation's premier financial services companies, consisting of a collection of great banks in select high growth markets. Zions operates its banking businesses under local management teams and community identities through over 450 offices and 500 ATMs in nine Western states: Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Texas, Utah, and Washington. The company is a national leader in Small Business Administration lending and public finance advisory services. In addition, Zions is included in the S&P 500 and NASDAQ Financial 100 indices. Investor information and links to subsidiary banks can be accessed at

SOURCE  Zions Bancorporation
    -0-                             12/03/2005
    /CONTACT:  Clark Hinckley of Zions Bancorporation, +1-801-524-4787/
    /Web site:  http://www.zionsbancorporation.com /
    (ZION ABNK)

CO:  Zions Bancorporation; Amegy Bancorporation, Inc.
ST:  Utah
IN:  FIN
SU:  TNM SBS

DH
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