As filed with the Securities and Exchange Commission on March 3, 2006

Registration No. 333-131867

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Amendment No. 1

to

Form S-4

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

WESTERN ALLIANCE BANCORPORATION

(Exact name of Registrant as specified in its charter)

Western Alliance Bancorporation

2700 West Sahara Avenue

Las Vegas, Nevada 89102

Telephone: (702) 248-4200

(Name, address and telephone of principal executive offices)

Robert Sarver

President, Chief Executive Officer

2700 West Sahara Avenue

Las Vegas, Nevada 89102

Telephone: (702) 248-4200

(Name, address, including zip code and telephone number, including area code, of agent for service)

with copies to:

      Approximate date of commencement of proposed sale of the securities to the public: As soon as practicable after this Registration Statement becomes effective and all other conditions to the consummation of the transaction described herein have been satisfied or waived.

      If the securities being registered on this Form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box.     o

      If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.     o

      If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.     o

      The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

      The Boards of Directors of Western Alliance Bancorporation (“Western Alliance”) and Intermountain First Bancorp (“Intermountain”) have approved an agreement and plan of merger, pursuant to which Intermountain will merge with and into Western Alliance, with Western Alliance surviving (referred to herein as the “merger”).

      If the merger takes place, you may elect to receive either 2.44 shares of Western Alliance common stock or $71.30 in cash, or some combination thereof, for each share of Intermountain common stock you own, unless you exercise your dissenter’s rights. Each outstanding Intermountain stock option will be converted into an option to purchase 2.44 shares of Western Alliance common stock. You will have the opportunity to elect the form of consideration to be received for your shares, subject to proration and allocation procedures set forth in the merger agreement which are intended to ensure that at least 60% of the outstanding shares of Intermountain common stock on a fully diluted basis will be converted into shares of Western Alliance common stock. Therefore, your ability to receive all cash may depend on the elections of other Intermountain shareholders.

      We expect that the merger will generally be tax-free with respect to any Western Alliance common stock that you receive and will generally be taxable with respect to any cash that you receive. Western Alliance’s common stock is traded on the New York Stock Exchange under the symbol “WAL”.

      This is a prospectus of Western Alliance relating to its offering of up to 3,764,120 shares of Western Alliance common stock to Intermountain shareholders in the proposed merger and a proxy statement of Intermountain. This document contains important information about Western Alliance, Intermountain, the merger and the conditions that must be satisfied before the merger can occur. Please give all the information your careful attention.

Important Message for Holders of Intermountain Voting Common Stock

      Your vote is very important. The merger agreement and the merger must be approved by the holders of at least a majority of the outstanding shares of Intermountain’s common stock entitled to vote. To vote your shares, you may use the enclosed proxy card or attend the special shareholders meeting we will hold to allow you to consider and vote on the merger. To approve the merger agreement, you must vote for the proposal by following the instructions on the enclosed proxy card. If you do not vote at all, that will, in effect, count as a vote against the proposal. We urge you to vote FOR this proposal.

William Bullard

Vice President

Intermountain First Bancorp

      Western Alliance’s common stock has not been approved or disapproved by the Securities and Exchange Commission, any state securities commission, or the Federal Deposit Insurance Corporation, nor have any of these institutions passed upon the accuracy or adequacy of this proxy statement/ prospectus. Any representation to the contrary is a criminal offense. The shares of Western Alliance common stock are not savings deposit accounts or other obligations of any bank or savings association, and are not insured by the Federal Deposit Insurance Corporation or any other governmental agency.

       Please see “Risk Factors” beginning on page 7 for a discussion of risks associated with the merger and in owning Western Alliance stock.

The date of this proxy statement/ prospectus is March 3, 2006

and is first being mailed to shareholders on March 7, 2006

      THIS PROSPECTUS INCORPORATES IMPORTANT BUSINESS AND FINANCIAL INFORMATION ABOUT WESTERN ALLIANCE THAT IS NOT INCLUDED IN OR DELIVERED WITH THIS DOCUMENT. THIS INFORMATION IS AVAILABLE WITHOUT CHARGE TO YOU IF YOU CALL OR WRITE TO DALE GIBBONS, WESTERN ALLIANCE BANCORPORATION, 2700 WEST SAHARA AVENUE, LAS VEGAS, NV 89102, TELEPHONE: (702) 248-4200, OR WILLIAM BULLARD, INTERMOUNTAIN FIRST BANCORP, 777 N. RAINBOW BOULEVARD, LAS VEGAS, NEVADA 89107, TELEPHONE: (702) 310-4000, IN ORDER TO OBTAIN TIMELY DELIVERY OF DOCUMENTS YOU SHOULD REQUEST INFORMATION AS SOON AS POSSIBLE, BUT NO LATER THAN MARCH 23, 2006

INTERMOUNTAIN FIRST BANCORP

777 N. Rainbow Boulevard

Las Vegas, Nevada 89107

NOTICE OF SPECIAL MEETING OF

SHAREHOLDERS TO BE HELD ON

March 28, 2006

      A special meeting of shareholders of Intermountain First Bancorp (“Intermountain”) will be held at 10:00 a.m. local time on March 28, 2006, at its principal executive offices at 777 N. Rainbow Boulevard, Las Vegas, Nevada 89107, for the following purposes:

      You are entitled to notice of and to vote at the special meeting or any adjournments or postponements thereof only if you were a holder of record of Intermountain’s voting common stock at the close of business on March 3, 2006.

      Intermountain’s Board of Directors has determined that the merger is advisable and is fair to and in the best interest of Intermountain’s shareholders, has approved the merger agreement and the merger, and recommends that the holders of Intermountain’s voting common stock vote to approve the merger agreement and the merger.

      The affirmative vote of a majority of the shares of Intermountain’s voting common stock outstanding on March 3, 2006 is required to approve the merger agreement and the merger. The required vote of Intermountain’s shareholders is based on the total number of shares of Intermountain’s voting common stock outstanding and not on the number of shares which are actually voted. Not returning a proxy card, or not voting in person at the special meeting or abstaining from voting will have the same effect as voting AGAINST the merger agreement and the merger.

      If you hold Intermountain common stock on the record date, you are entitled to dissent from the merger under Sections 92.A-300 through 92.A-500 of the Nevada Revised Statutes (“NRS”). A copy of these sections is attached to the proxy statement/ prospectus at Appendix B.

      It is very important all shares of Intermountain voting common stock be represented at the special meeting. Whether or not you plan to attend the special meeting, please complete, date and sign the enclosed proxy card and return it as soon as possible in the enclosed postage-paid envelope. A shareholder who executes a proxy may revoke it at any time before it is exercised by giving written notice to the Secretary of Intermountain at the address set forth above, by subsequently filing another proxy or by attending the special meeting and voting in person.

Las Vegas, Nevada

March 3, 2006

      If you hold Intermountain voting common stock, your vote is important. Please complete, sign, date and return your proxy card.

TABLE OF CONTENTS

QUESTIONS AND ANSWERS ABOUT THE MERGER

	•	are a tax-exempt organization;
	•	are a mutual fund;
	•	are a dealer in securities or foreign currencies;
	•	are a bank or other financial institution;
	•	are an insurance company;
	•	are a non-United States person;
	•	are subject to the alternative minimum tax;
	•	are a trader in securities who elects to apply a mark-to-market method of accounting;
	•	acquired your shares of Intermountain’s common stock from the exercise of options or otherwise as compensation or through a qualified retirement plan;
	•	hold shares of Intermountain’s common stock as part of a straddle, hedge, constructive sale or conversion transaction; or
	•	do not hold shares of Intermountain’s common stock as capital assets.

	Tax matters are very complicated. You should consult your tax advisor for a full explanation of the tax consequences of the merger to you.

	•	to vote on the merger agreement, the merger and the other transactions contemplated by the merger agreement; and
	•	to address any other matters that properly come before the special meeting, or any adjournments or postponements of the meeting, including a motion to adjourn the special meeting to another time and/or place to solicit additional proxies in favor of the merger agreement and the merger or otherwise.

		Last Reported Sale Price of
		Western Alliance’s				Implied Value
Date		Common Stock				per Share
December 29, 2005		$	29.40			$	71.74
March 1, 2006		$	36.01			$	87.86

		At
		December 31,
		2005
Book value per share:
Western Alliance historical		$	10.71
Intermountain historical			21.32
Combined — 60% stock election			12.35
Combined — 100% stock election			13.30
Intermountain pro forma equivalent — 60% stock election			30.15
Intermountain pro forma equivalent — 100% stock election			32.45
Tangible book value per share:
Western Alliance historical		$	10.48
Intermountain historical			21.32
Combined — 60% stock election			9.06
Combined — 100% stock election			10.19
Intermountain pro forma equivalent— 60% stock election			22.10
Intermountain pro forma equivalent— 100% stock election			24.86

		Year ended
		December 31,
		2005
Basic earnings per share:
Western Alliance historical		$	1.36
Intermountain historical			3.30
Combined — 60% stock election			1.37
Combined — 100% stock election			1.32
Intermountain pro forma equivalent — 60% stock election			3.34
Intermountain pro forma equivalent — 100% stock election			3.21
Diluted earnings per share:
Western Alliance historical		$	1.24
Intermountain historical			3.18
Combined — 60% stock election			1.25
Combined — 100% stock election			1.20
Intermountain pro forma equivalent — 60% stock election			3.05
Intermountain pro forma equivalent — 100% stock election			2.94

	•	changes in general economic conditions, either nationally or locally in the areas in which we conduct or will conduct our business;
	•	inflation, interest rate, market and monetary fluctuations;
	•	the inability to obtain the regulatory approvals for the merger on acceptable terms, on the anticipated schedule or at all;
	•	lower revenues following the merger than we expect;
	•	changes in gaming or tourism in our primary market area;
	•	risks associated with our growth and expansion strategy and related costs;
	•	increased lending risks associated with our high concentration of commercial real estate, construction and land development and commercial, industrial loans;
	•	increases in competitive pressures among financial institutions and businesses offering similar products and services;
	•	higher defaults on our loan portfolio than we expect;
	•	changes in management’s estimate of the adequacy of the allowance for loan losses;
	•	legislative or regulatory changes or changes in accounting principles, policies or guidelines;
	•	management’s estimates and projections of interest rates and interest rate policy;
	•	the execution of our business plan; and
	•	other factors affecting the financial services industry generally or the banking industry in particular.

RISK FACTORS

      In addition to the other information included in this proxy statement/ prospectus (including the matters addressed in “Cautionary Note Concerning Forward-Looking Statements”), you should carefully consider the matters described below in determining whether to approve the merger agreement and whether to make a cash or stock election. Any of these risks could have an adverse effect on Western Alliance’s business, financial condition, results of operations or prospects, which could in turn affect the price of its shares.

Risks Related to the Merger

The integration of the companies will present significant challenges that may result in the combined business not operating as effectively as expected or in the failure to achieve some or all of the anticipated benefits of the transaction.

      The benefits and synergies expected to result from the proposed transaction will depend in part on whether the operations of Intermountain can be integrated in a timely and efficient manner with those of Western Alliance. Western Alliance will face challenges in consolidating its functions with those of Intermountain, and integrating the organizations, procedures and operations of the two businesses. The integration of Western Alliance and Intermountain will be complex and time-consuming, and the management of both companies will have to dedicate substantial time and resources to it. These efforts could divert management’s focus and resources from other strategic opportunities and from day-to-day operational matters during the integration process. Failure to successfully integrate the operations of Western Alliance and Intermountain could result in the failure to achieve some of the anticipated benefits from the transaction, including cost savings and other operating efficiencies, and could have an adverse effect on the business, results of operations, financial condition or prospects of Western Alliance after the transaction.

The price of Western Alliance common stock will fluctuate before and after the merger, which could increase or decrease the value of the merger consideration received by Intermountain shareholders receiving Western Alliance common stock.

      On December 29, 2005, the day before the merger agreement was executed, the closing price of a share of Western Alliance common stock was $29.40. On March 1, 2006, the most recent practicable date before the mailing of this proxy statement/ prospectus, the closing price was $36.01. Based on these closing prices and the 2.44 exchange ratio, the implied value of the merger consideration consisting of Western Alliance common stock was $71.74 on December 29, 2005 and $87.86 on March 1, 2006. The price of Western Alliance common stock may increase or decrease before and after completion of the merger. Therefore, the market value of Western Alliance common stock received by an Intermountain shareholder in connection with the merger could be lower than the market value of Western Alliance stock on December 29, 2005, March 1, 2006 or the closing date of the merger, and the market value of the stock consideration could be less than the $71.30 cash consideration received by shareholders receiving the cash consideration. The market value of Western Alliance common stock received by an Intermountain shareholder in connection with the merger could also be higher than those trading prices, and shareholders receiving the cash consideration could receive cash worth less than the market value of the stock consideration. The market price of Western Alliance stock fluctuates based upon general market economic conditions, Western Alliance’s business and prospects and other factors.

Shareholders may receive a form of consideration different from what they elect.

      While each Intermountain shareholder may elect to receive cash or Western Alliance common stock in the merger, at least 60% of the Intermountain common stock outstanding at the completion of the merger will be converted into Western Alliance common stock. Therefore, if Intermountain shareholders elect more cash than is available under the merger agreement, their elections will be prorated to permit at least 60% of the Intermountain common stock outstanding at the completion of the merger to be converted into Western Alliance

common stock. As a result, if a cash election proves to be more popular among Intermountain shareholders, and you choose the cash election, you might receive a portion of your consideration in the form of stock.

If you tender shares of Intermountain common stock to make an election, you will not be able to transfer those shares until after the merger, unless you revoke your election prior to the election deadline.

      To make a cash or stock election, you must deliver your stock certificate(s) to the exchange agent. The deadline for doing this is 5:00 p.m. New York City time, on March 27, 2006, the day before the special meeting of shareholders. You will not be able to sell any shares of Intermountain common stock that you have delivered, unless you revoke your election before the deadline by providing written notice to the exchange agent. If you do not revoke your election, you will not be able to liquidate your investment in Intermountain common stock for any reason until you receive cash or Western Alliance common stock, or both, in the merger. During the period between delivery of your shares and the closing of the merger, the trading price of Western Alliance common stock may decrease.

      The date that you will receive your merger consideration depends on the completion date of the merger, which is expected to occur in the second quarter of 2006. The completion date of the merger might be later than expected due to unforeseen events, such as delays in obtaining regulatory approvals.

The merger agreement limits Intermountain’s ability to pursue alternatives to the merger.

      The merger agreement contains terms and conditions that make it more difficult for Intermountain to sell its business to a party other than Western Alliance. These “no shop” provisions impose restrictions on Intermountain that, subject to certain exceptions, limit Intermountain’s ability to discuss or facilitate competing third-party proposals to acquire all or a significant part of Intermountain.

      In addition, the board of directors of Intermountain has agreed that it will not, directly or indirectly, facilitate or recommend a competing acquisition proposal, subject to limited exceptions. While the board of directors could take such actions if it determined that the failure to do so would violate its fiduciary duties, doing so would entitle Western Alliance to terminate the merger agreement and may entitle it to receive a termination fee. Intermountain will also be required to pay the termination fee if a competing acquisition proposal has been made known to Intermountain or its shareholders and the merger agreement is subsequently terminated for a variety of reasons (including because Intermountain shareholders fail to approve the merger or because Intermountain willfully breaches the merger agreement), and Intermountain completes, or enters into an agreement for, an alternative acquisition transaction during the 12 months after the termination of the merger agreement.

      Western Alliance required Intermountain to agree to these provisions as a condition to Western Alliance’s willingness to enter into the merger agreement. However, these provisions might discourage a third party that might have an interest in acquiring all or a significant part of Intermountain from considering or proposing that acquisition even if it were prepared to pay consideration with a higher per share market price than the current proposed merger consideration, and the termination fee might result in a potential competing acquirer proposing to pay a lower per share price to acquire Intermountain than it might otherwise have proposed to pay.

Intermountain’s executive officers and directors have interests in the merger that are different from your interest as an Intermountain shareholder.

      Intermountain executive officers negotiated the merger agreement with Western Alliance, and the board of directors approved the agreement and is recommending that Intermountain shareholders who are entitled to vote, vote for the agreement. In considering these facts and the other information contained in this proxy statement/ prospectus, you should be aware that Intermountain’s executive officers and directors have interests in the merger in addition to the interests that they share with you as an Intermountain shareholder. As described in detail under the heading “Interests of Intermountain Directors and Executive Officers in the Merger That are Different Than Yours,” there are substantial interests to be conveyed to each director and executive officer of Intermountain as a result of the accelerated vesting or additional issuance of stock options, as well as other considerations. Following the completion of the merger, the board of directors of Western

Alliance will appoint to its board of directors a representative of Intermountain who shall have been, immediately prior to the effective time, either a member of Intermountain’s board of directors or a holder of at least 5% of the capital stock of Intermountain. Also, following the bank merger, BankWest of Nevada will invite all of the members of Nevada First’s board of directors to join the board of directors of BankWest of Nevada.

Risk Factors Related to an Investment in Western Alliance

Our current primary market area is substantially dependent on gaming and tourism revenue, and a downturn in gaming or tourism could hurt our business and our prospects.

      Our business is currently concentrated in the Las Vegas metropolitan area. The economy of the Las Vegas metropolitan area is unique in the United States for its level of dependence on services and industries related to gaming and tourism. Any event that negatively impacts the gaming or tourism industry will adversely impact the Las Vegas economy.

      Gaming and tourism revenue (whether or not such tourism is directly related to gaming) is vulnerable to fluctuations in the national economy. A prolonged downturn in the national economy could have a significant adverse effect on the economy of the Las Vegas area. Virtually any development or event that could dissuade travel or spending related to gaming and tourism, whether inside or outside of Las Vegas, could adversely affect the Las Vegas economy. In this regard, the Las Vegas economy is more susceptible than the economies of other cities to issues such as higher gasoline and other fuel prices, increased airfares, unemployment levels, recession, rising interest rates, and other economic conditions, whether domestic or foreign. Gaming and tourism are also susceptible to certain political conditions or events, such as military hostilities and acts of terrorism, whether domestic or foreign. A terrorist act, or the mere threat of a terrorist act, may adversely affect gaming and tourism and the Las Vegas economy and may cause substantial harm to our business.

      In addition, Las Vegas competes with other areas of the country for gaming revenue, and it is possible that the expansion of gaming operations in other states, such as California, as a result of changes in laws or otherwise, could significantly reduce gaming revenue in the Las Vegas area.

      Although we have no substantial customer relationships in the gaming and tourism industries, a downturn in the Las Vegas economy, generally, could have an adverse effect on our customers and result in an increase in loan delinquencies and foreclosures, a reduction in the demand for our products and services and a reduction of the value of our collateral for loans which could result in the reduction of a customer’s borrowing power, any of which could adversely affect our business, financial condition, results of operations and prospects.

We may not be able to continue our growth at the rate we have in the past several years.

      We have grown substantially, from having one chartered bank with $443.7 million in total assets and $410.2 million in total deposits as of December 31, 2000, to three chartered banks with $2.7 billion in total assets and $2.3 billion in total deposits as of September 30, 2005. If we are unable to effectively execute on our strategy, we may not be able to continue to grow at our historical rates. In particular, Alliance Bank of Arizona and Torrey Pines Bank have achieved unusually high annual rates of growth as compared to other recently opened de novo banks. We do not expect this high level of growth at Alliance Bank of Arizona and Torrey Pines Bank to continue in the future.

Our growth and expansion strategy may not prove to be successful and our market value and profitability may suffer.

      Growth through acquisitions of banks or the organization of new banks in high-growth markets, especially in markets outside of our current markets, represents an important component of our business strategy. In addition to our agreement to acquire Intermountain, we recently entered into an agreement to acquire Bank of Nevada. For more information regarding this acquisition, see “Recent Developments”. Both of these

acquisitions, as well as any future acquisitions, will be accompanied by the risks commonly encountered in acquisitions. These risks include, among other things:

      We expect that competition for suitable acquisition candidates may be significant. We may compete with other banks or financial service companies with similar acquisition strategies, many of which are larger and have greater financial and other resources. We cannot assure you that we will be able to successfully identify and acquire suitable acquisition targets on acceptable terms and conditions.

      In addition to the acquisition of existing financial institutions, we may consider the organization of new banks in new market areas. We do not have any current plan to organize a new bank. Any acquisition or organization of a new bank carries with it numerous risks, including the following:

      We cannot assure you that we will be successful in overcoming these risks or any other problems encountered in connection with acquisitions and the organization of new banks. Our inability to overcome these risks could have an adverse effect on our ability to achieve our business strategy and maintain our market value and profitability growth.

The combined company’s status as a holding company makes it dependent on dividends from its subsidiaries to meet its obligations.

      After the merger, Western Alliance will continue to be a holding company that conducts almost all of its operations through its subsidiaries. The combined company will not have significant assets other than the stock of its subsidiaries. Accordingly, the combined company will depend on dividends from its subsidiaries to meet its obligations. The combined company’s right to participate in any distribution of earnings or assets of its subsidiaries is subject to the prior claims of creditors of such subsidiaries. Under federal and state law, a subsidiary is limited in the amount of dividends it may pay to its parent without prior regulatory approval. Also, bank regulators have the authority to prohibit a subsidiary from paying dividends if the bank regulators determine that such subsidiary is in an unsafe or unsound condition or that the payment would be an unsafe and unsound bank practice.

If we continue to grow rapidly as planned, we may not be able to control costs and maintain our asset quality.

      We expect to continue to grow our assets and deposits, the products and services which we offer and the scale of our operations, generally, both internally and through acquisitions. Our ability to manage our growth successfully will depend on our ability to maintain cost controls and asset quality while attracting additional loans and deposits on favorable terms. If we grow too quickly and are not able to control costs and maintain asset quality, this rapid growth could materially adversely affect our financial performance.

We may have difficulty managing our growth, which may divert resources and limit our ability to successfully expand our operations.

      Our rapid growth has placed, and it may continue to place, significant demands on our operations and management. Our future success will depend on the ability of our officers and other key employees to continue to implement and improve our operational, credit, financial, management and other internal risk controls and processes and our reporting systems and procedures, and to manage a growing number of client relationships. We may not successfully implement improvements to our management information and control systems and control procedures and processes in an efficient or timely manner and may discover deficiencies in existing systems and controls. In particular, our controls and procedures must be able to accommodate an increase in expected loan volume and the infrastructure that comes with new branches and banks. Thus, our growth strategy may divert management from our existing businesses and may require us to incur additional expenditures to expand our administrative and operational infrastructure. If we are unable to manage future expansion in our operations, we may experience compliance and operational problems, have to slow the pace of growth, or have to incur additional expenditures beyond current projections to support such growth, any one of which could adversely affect our business.

Our future growth is dependent upon our ability to recruit additional, qualified employees, especially seasoned relationship bankers.

      Our market areas are experiencing a period of rapid growth, placing a premium on highly qualified employees in a number of industries, including the financial services industry. Our business plan includes, and is dependent upon, hiring and retaining highly qualified and motivated executives and employees at every level. In particular, our success has been partly the result of our management’s ability to seek and retain highly qualified relationship bankers that have long-standing relationships in their communities. These professionals bring with them valuable customer relationships, and have been an integral part of our ability to attract deposits and to expand rapidly in our market areas. We expect to experience substantial competition in our endeavor to identify, hire and retain the top-quality employees that we believe are key to our future success. If we are unable to hire and retain qualified employees, we may not be able to grow our franchise and successfully execute our business strategy.

We are highly dependent on real estate and events that negatively impact the real estate market could hurt our business.

      A significant portion of our loan portfolio is dependent on real estate. As of September 30, 2005, real estate related loans accounted for approximately 80% of total loans. Our financial condition may be adversely affected by a decline in the value of the real estate securing our loans. In addition, acts of nature, including earthquakes, fires and floods, which may cause uninsured damage and other loss of value to real estate that secures these loans, may also negatively impact our financial condition.

      In addition, as of September 30, 2005, 18.2% of our total deposits consisted of non-interest bearing demand deposits maintained by title insurance companies. A slowdown in real estate activity, particularly commercial real estate activity, in the markets we serve may cause a decline in our deposit growth and may negatively impact our financial condition.

Our high concentration of commercial real estate, construction and land development and commercial, industrial loans expose us to increased lending risks.

      As of September 30, 2005, the composition of our loan portfolio was as follows:

      Commercial real estate, construction and land development and commercial and industrial loans, which comprised 83.9% of our total loan portfolio as of September 30, 2005, expose us to a greater risk of loss than our residential real estate and consumer loans, which comprised 16.1% of our total loan portfolio as of September 30, 2005. Commercial real estate and land development loans typically involve larger loan balances to single borrowers or groups of related borrowers compared to residential loans. Consequently, an adverse development with respect to one commercial loan or one credit relationship may expose us to a significantly greater risk of loss compared to an adverse development with respect to one residential mortgage loan.

If we lost a significant portion of our low-cost deposits, it would negatively impact our profitability.

      Our profitability depends in part on our success in attracting and retaining a stable base of low-cost deposits. As of September 30, 2005, our deposit base was comprised of 44.7% non-interest bearing deposits, of which 40.7% consisted of title company deposits, 54.5% consisted of other business deposits and 4.8% consisted of consumer deposits. If we lost a significant portion of these low-cost deposits, it would negatively impact our profitability. We consider these deposits to be core deposits. While we generally do not believe these deposits are sensitive to interest-rate fluctuations, the competition for these deposits in our markets is strong and if we lost a significant portion of these low-cost deposits, it would negatively affect our profitability.

Many of our loans have been made recently, and in certain circumstances there is limited repayment history against which we can fully assess the adequacy of our allowance for loan losses. If our allowance for loan losses is not adequate to cover actual loan losses, our earnings will decrease.

      The risk of nonpayment of loans is inherent in all lending activities, and nonpayment, if it occurs, may negatively impact our earnings and overall financial condition, as well as the value of our common stock. Also, many of our loans have been made over the last three years and in certain circumstances there is limited repayment history against which we can fully assess the adequacy of our allowance for loan losses. We make various assumptions and judgments about the collectibility of our loan portfolio and provide an allowance for probable losses based on several factors. If our assumptions are wrong, our allowance for loan losses may not be sufficient to cover our losses, which would have an adverse effect on our operating results. Additions to our allowance for loan losses decrease our net income. While we have not experienced any significant charge-offs or had large numbers of nonperforming loans, due to the significant increase in loans originated during this period, we cannot assure you that we will not experience an increase in delinquencies and losses as these loans continue to mature. The actual amount of future provisions for loan losses cannot be determined at this time and may exceed the amounts of past provisions.

Our future success will depend on our ability to compete effectively in a highly competitive market.

      We face substantial competition in all phases of our operations from a variety of different competitors. Our competitors, including commercial banks, community banks, savings and loan associations, mutual savings banks, credit unions, consumer finance companies, insurance companies, securities dealers, brokers, mortgage bankers, investment advisors, money market mutual funds and other financial institutions, compete with lending and deposit-gathering services offered by us. Increased competition in our markets may result in reduced loans and deposits.

      There is very strong competition for financial services in the market areas in which we conduct our businesses from many local commercial banks as well as numerous regionally based commercial banks. Many of these competing institutions have much greater financial and marketing resources than we have. Due to their size, many competitors can achieve larger economies of scale and may offer a broader range of products and services than us. If we are unable to offer competitive products and services, our earnings may be negatively affected.

      Some of the financial services organizations with which we compete are not subject to the same degree of regulation as is imposed on bank holding companies and federally insured financial institutions. As a result, these nonbank competitors have certain advantages over us in accessing funding and in providing various services. The banking business in our primary market areas is very competitive, and the level of competition

facing us may increase further, which may limit our asset growth and profitability. For more information on the competition we have in our markets, see “Information About Western Alliance — Business Strategy.”

Our business would be harmed if we lost the services of any of our senior management team or senior relationship bankers.

      We believe that our success to date has been substantially dependent on our senior management team, which includes Robert Sarver, our Chairman, President and Chief Executive Officer and Chief Executive Officer of Torrey Pines Bank, Dale Gibbons, our Chief Financial Officer, Larry Woodrum, President and Chief Executive Officer of BankWest of Nevada and James Lundy, President and Chief Executive Officer of Alliance Bank of Arizona, and certain of our senior relationship bankers. We also believe that our prospects for success in the future are dependent on retaining our senior management team and senior relationship bankers. In addition to their skills and experience as bankers, these persons provide us with extensive community ties upon which our competitive strategy is based. Our ability to retain these persons may be hindered by the fact that we have not entered into employment agreements with any of them. The loss of the services of any of these persons, particularly Mr. Sarver, could have an adverse effect on our business if we can’t replace them with equally qualified persons who are also familiar with our market areas.

Mr. Sarver’s involvement in outside business interests requires substantial time and attention and may adversely affect our ability to achieve our strategic plan and maintain our current growth.

      Mr. Sarver joined us in December of 2002 and has been an integral part of our recent growth. He has substantial business interests that are unrelated to us, including his ownership interest in the Phoenix Suns NBA franchise. Mr. Sarver’s other business interests demand substantial time commitments, and may reduce the amount of time he has available to devote to our business. A significant reduction in the amount of time Mr. Sarver devotes to our business may adversely affect our ability to achieve our strategic plan and maintain our current growth.

Adverse publicity or circumstances similar to that experienced following the arrest and subsequent acquittal of our Chief Financial Officer could generate negative publicity for us, cause reputational harm and cause our stock price to decline.

      In June 2002, after a jury trial, Dale Gibbons was acquitted of charges of possession of a controlled substance, dealing in harmful material to a minor and endangerment of a child. Following his acquittal, Mr. Gibbons filed a civil rights lawsuit against numerous parties. In early 2005, the defendants were granted summary judgment on substantially all of Mr. Gibbons’ claims, and, subsequently, the parties resolved the lawsuit and an order of dismissal was entered by the U.S. District Court. There was extensive media coverage of all of the events surrounding Mr. Gibbons’ arrest and his subsequent resignation as the Chief Financial Officer of his then employer, Zions Bancorporation. Before hiring Mr. Gibbons as our Chief Financial Officer, our Audit Committee engaged special legal counsel and an investigator to assist in considering Mr. Gibbons’ prospective employment with Western Alliance. We evaluated Mr. Gibbons’ extensive banking background, reviewed the legal and investigatory descriptions of the facts and circumstances surrounding his arrest and consulted with the Federal Deposit Insurance Corporation and the Federal Reserve Bank of San Francisco. Our Board of Directors determined that Mr. Gibbons was suitable to serve as our Chief Financial Officer. Subsequent to his hiring, our Board was updated on the claims and information alleged against Mr. Gibbons in the civil rights lawsuit. Also, in July 2005, we completed our initial public offering and listed our common stock on the NYSE. Mr. Gibbons was an integral part of that effort. Our Board continues to believe Mr. Gibbons is suitable to serve as our Chief Financial Officer. However, adverse publicity or circumstances, similar to that which surrounded Mr. Gibbons’ arrest and trial in 2001 and 2002, could materially damage the public’s perception of us, and impair the reputations of Mr. Gibbons and Western Alliance, and adverse public sentiment could affect the market price of our common stock and our business.

A deterioration in economic conditions generally could adversely affect our business, financial condition, results of operations and prospects.

      A deterioration in economic conditions generally could adversely affect our business, financial condition, results of operations and prospects. Such a deterioration could result in a variety of adverse consequences to us, including a reduction in net income and the following:

Economic conditions either nationally or locally in areas in which our operations are concentrated may be less favorable than expected.

      Deterioration in local, regional, national or global economic conditions could result in, among other things, an increase in loan delinquencies, a decrease in property values, a change in housing turnover rate or a reduction in the level of bank deposits. Particularly, a weakening of the real estate or employment market in our primary market areas of Las Vegas, San Diego, Tucson and Phoenix could result in an increase in the number of borrowers who default on their loans and a reduction in the value of the collateral securing their loans, which in turn could have an adverse effect on our profitability and asset quality.

Terrorist attacks and threats of war or actual war may impact all aspects of our operations, revenues, costs and stock price in unpredictable ways.

      Terrorist attacks in the United States, as well as future events occurring in response or in connection to them including, without limitation, future terrorist attacks against United States targets, rumors or threats of war, actual conflicts involving the United States or its allies or military or trade disruptions, may impact our operations. Any of these events could cause consumer confidence and savings to decrease or result in increased volatility in the United States and worldwide financial markets and economy. Any of these occurrences could have an adverse impact on our operating results, revenues and costs and may result in the volatility of the market price for our common stock and impair its future price.

      We do not anticipate paying any dividends on our common stock. As a result, capital appreciation, if any, of our common stock may be your sole source of gains in the future.

      We have never paid a cash dividend, and do not anticipate paying a cash dividend in the foreseeable future. As a result, you may only receive a return on your investment in the common stock if the market price of the common stock increases.

We may underestimate the impact of new reporting company requirements.

      We recently became a reporting company as a result of our initial public offering in June, 2005. As a public company, we have and will continue to incur significant accounting, legal and other expenses that we did not incur as a private company. In addition, the Sarbanes Oxley Act of 2002, as well as new rules implemented by the SEC and the NYSE, have required changes to corporate governance practices of public companies. For example, Section 404 of Sarbanes Oxley will require us to evaluate and report on our internal controls over financial reporting and have our independent auditors attest to our evaluation, beginning with our annual report on Form 10-K for the fiscal year ending December 31, 2005. If we underestimate the expense and resources spent by management involved in complying with these regulations, our financial performance may be adversely affected.

We have limited rights to use the “BankWest of Nevada” mark.

      Pursuant to a previous settlement agreement, we have agreed to use the word “BankWest” only within the name and service mark “BankWest of Nevada.” The settlement agreement only covers our use of the mark in Clark and Nye counties, Nevada. Our use of the mark “BankWest of Nevada” outside of Clark or Nye counties could result in:

      Nevada First Bank, a wholly owned subsidiary of Intermountain, has a branch located in Reno, which is outside of Clark and Nye counties. Following consummation of the Bank of Nevada transaction, we intend to change the name of BankWest of Nevada to Bank of Nevada. See “Recent Developments of Western Alliance” for more information about the Bank of Nevada transaction. If our use of the “BankWest of Nevada” mark or any other similar mark is limited or prohibited, or we are required to pay an additional license fee for such use, our business, financial condition and results of operations could be materially and adversely affected.

Risks Related to the Banking Industry

We operate in a highly regulated environment; changes in laws and regulations and accounting principles may adversely affect us.

      We are subject to extensive regulation, supervision, and legislation which govern almost all aspects of our operations. See “Supervision and Regulation.” The laws and regulations applicable to the banking industry could change at any time and are primarily intended for the protection of customers, depositors and the deposit insurance funds. Any changes to these laws or any applicable accounting principles could make it more difficult and expensive for us to comply and could affect the way that we conduct business, which may negatively impact our results of operations and financial condition. While we cannot predict what effect any presently contemplated or future changes in the laws or regulations or their interpretations would have on us, these changes could be materially adverse to our investors and stockholders.

Changes in interest rates could adversely affect our profitability, business and prospects.

      Increases or decreases in prevailing interest rates could have an adverse effect on our business, asset quality and prospects. Our operating income and net income depend to a great extent on our net interest margin. Net interest margin is the difference between the interest yields we receive on loans, securities and other interest earning assets and the interest rates we pay on interest bearing deposits and other liabilities. These rates are highly sensitive to many factors beyond our control, including competition, general economic conditions and monetary and fiscal policies of various governmental and regulatory authorities, including the Board of Governors of the Federal Reserve System, referred to as the FRB. If the rate of interest we pay on our interest bearing deposits and other liabilities increases more than the rate of interest we receive on loans, securities and other interest earning assets, our net interest income, and therefore our earnings, could be adversely affected. Our earnings could also be adversely affected if the rates on our loans and other investments fall more quickly than those on our deposits and other liabilities.

      In addition, loan volumes are affected by market interest rates on loans; rising interest rates generally are associated with a lower volume of loan originations while lower interest rates are usually associated with higher loan originations. Conversely, in rising interest rate environments, loan repayment rates will decline and in falling interest rate environments, loan repayment rates will increase. We cannot assure you that we will be able to minimize our interest rate risk. In addition, an increase in the general level of interest rates may adversely affect the ability of certain borrowers to pay the interest on and principal of their obligations.

      Interest rates also affect how much money we can lend. When interest rates rise, the cost of borrowing increases. Accordingly, changes in market interest rates could materially and adversely affect our net interest spread, asset quality, loan origination volume, business, financial condition, results of operations and cash flows.

We are required to maintain an allowance for loan losses. This allowance for loan losses may have to be adjusted in the future. Any adjustment to the allowance for loan losses, whether due to regulatory changes, economic changes or other factors, may affect our financial condition and earnings.

      We maintain an allowance for loan losses. The allowance is established through a provision for loan losses based on our management’s evaluation of the risks inherent in our loan portfolio and the general economy. The allowance is based upon a number of factors, including the size of the loan portfolio, asset classifications, economic trends, industry experience and trends, industry and geographic concentrations, estimated collateral values, management’s assessment of the credit risk inherent in the portfolio, historical loan loss experience and loan underwriting policies. In addition, we evaluate all loans identified as problem loans and augment the allowance based upon the perceived risks associated with those problem loans.

      The federal regulators, in reviewing our loan portfolio as part of a regulatory examination, may request us to increase our allowance for loan losses, thereby negatively affecting our financial condition and earnings at that time. Moreover, additions to the allowance may be necessary based on changes in economic and real estate market conditions, new information regarding existing loans, identification of additional problem loans and other factors, both within and outside of our management’s control.

We are exposed to risk of environmental liabilities with respect to properties to which we take title.

      About 80% of our outstanding loan portfolio as of September 30, 2005 was secured by real estate. In the course of our business, we may foreclose and take title to real estate, and could be subject to environmental liabilities with respect to these properties. We may be held liable to a governmental entity or to third parties for property damage, personal injury, investigation and clean-up costs incurred by these parties in connection with environmental contamination, or may be required to investigate or clean up hazardous or toxic substances, or chemical releases at a property. The costs associated with investigation or remediation activities could be substantial. In addition, if we are the owner or former owner of a contaminated site, we may be subject to common law claims by third parties based on damages and costs resulting from environmental contamination emanating from the property. These costs and claims could adversely affect our business and prospects.

SHAREHOLDER MEETING

Matters to be Considered at the Special Meeting

      We are first mailing this document to the holders of Intermountain’s common stock on or about March 7, 2006. It is accompanied by a proxy card furnished in connection with the solicitation of proxies by the Intermountain Board of Directors for use at the special meeting of Intermountain’s shareholders at 10.00 a.m. local time on Tuesday, March 28, 2006, at its principal executive offices at 777 N. Rainbow Boulevard, Las Vegas, Nevada 89107. At the special meeting, the holders of Intermountain’s voting common stock will consider and vote on:

Eligible Votes

      Intermountain has four series of common stock:

      The voting common stock and the Series A voting common stock comprise Intermountain’s voting common stock. Therefore, if you hold shares of either non-voting common stock or Series A non-voting common stock, you are not entitled to vote those shares at the special meeting of shareholders.

Record Date and Voting

      The Intermountain Board of Directors has fixed the close of business on March 3, 2006 as the record date for determining the Intermountain shareholders entitled to receive notice of and to vote at the special meeting. Only holders of record of Intermountain’s voting common stock at the close of business on that day will be entitled to vote at the special meeting or at any adjournment or postponement of the meeting. At the close of business on March 3, 2006, there were 1,304,761 shares of Intermountain’s common stock outstanding and entitled to vote at the special meeting, held by approximately 98 shareholders of record.

      Each holder of Intermountain’s voting common stock on March 3, 2006 will be entitled to one vote for each share held of record on each matter that is properly submitted at the special meeting or any adjournment or postponement of the meeting. The presence, in person or by proxy, of the holders of a majority of Intermountain’s common stock issued and outstanding and entitled to vote at the special meeting is necessary to constitute a quorum. Abstentions with respect to shares of Intermountain voting common stock will be included in the calculation of the number of shares represented at the special meeting in order to determine whether a quorum has been achieved. Since approval of the merger agreement requires the affirmative vote of the holders of at least a majority of the shares of Intermountain’s voting common stock issued and outstanding, abstentions with respect to shares of Intermountain voting common stock will have the same effect as a vote against the merger agreement.

      If a quorum is not obtained, or if fewer shares of Intermountain’s voting common stock are voted in favor of the proposal for approval of the merger agreement than the number required for approval, it is expected that the special meeting will be adjourned to allow additional time for obtaining additional proxies. In that event,

proxies will be voted to approve an adjournment, except for proxies as to which instructions have been given to vote against the merger agreement.

      If you hold shares of Intermountain voting common stock and your proxy card is properly executed and received by Intermountain in time to be voted at the special meeting, the shares represented by the proxy card will be voted in accordance with the instructions marked on the proxy card. Executed proxies with respect to shares of Intermountain voting common stock with no instructions indicated on the proxy card will be voted FOR the merger agreement and the merger.

      The Intermountain board of directors is not aware of any other matters that may properly come before the special meeting. If any other matters properly come before the special meeting, the persons named in the accompanying proxy will vote the shares represented by all properly executed proxies on those matters as determined by a majority of the Intermountain board of directors.

      If you hold shares of Intermountain voting common stock, you are requested to complete, date and sign the accompanying proxy form and to return it promptly in the enclosed postage-paid envelope. The enclosed proxy card is different from the election form that you can use to elect to receive cash or stock in the merger. Do not return your proxy card with the election form. For information about the election form, see “The Merger-Election Procedures; Surrender of Stock Certificates”. To vote on the merger agreement, you need to hold shares of Intermountain voting common stock and complete the proxy card properly and return it in the enclosed envelope or attend the special meeting and vote in person.

      You should not forward any stock certificates with your proxy card. If you complete an election form, you should forward your Intermountain stock certificates to the exchange agent with the election form. If you do not complete an election form, if the merger takes place, Intermountain stock certificates should be delivered in accordance with instructions that will be sent to you by Western Alliance’s exchange agent promptly after the effective time of the merger.

Required Vote; Revocability of Proxies

      In order to approve and adopt the merger agreement, the merger of Intermountain and Western Alliance and the other transactions contemplated by the merger agreement, the holders of at least a majority of the shares of Intermountain’s voting common stock issued and outstanding on March 3, 2006, must affirmatively vote FOR the merger agreement and the merger.

      The required vote of Intermountain’s shareholders is based on the total number of outstanding shares of Intermountain’s common stock entitled to vote and not on the number of shares which are actually voted. Not returning a proxy card, not voting in person at the special meeting or abstaining from voting all will have the same effect as voting AGAINST the merger agreement and the merger.

      The directors and executive officers and certain major shareholders of Intermountain beneficially owned as of December 31, 2005, a total of 885,132 shares of Intermountain’s voting common stock (excluding all options to purchase shares of Intermountain’s common stock), which was approximately 67.8% of the outstanding shares of Intermountain’s voting common stock on that date. The directors and executive officers and certain major shareholders have agreed to vote their shares in favor of the merger agreement and the merger and against competing proposals.

      If you submit a proxy card, attending the special meeting will not automatically revoke your proxy. However, you may revoke a proxy at any time before it is voted by:

RECENT DEVELOPMENTS OF WESTERN ALLIANCE

Unaudited Consolidated Financial Results for 2005 and the Fourth Quarter of 2005

      On January 17, 2006, Western Alliance announced its unaudited consolidated financial results for 2005 and the fourth quarter of 2005.

      Total assets were $2.86 billion at December 31, 2005, an increase of 31.3% from $2.18 billion at December 31, 2004. Loans were $1.79 billion at December 31, 2005, an increase of $605 million from December 31, 2004. Deposits were $2.39 billion at December 31, 2005, an increase of $638 million from December 31, 2004. Stockholders’ equity increased $111 million from December 31, 2004 to $244 million at December 31, 2005, due primarily to Western Alliance’s initial public offering in July 2005. Western Alliance had 537 full-time equivalent employees and 16 full-service banking offices on December 31, 2005, compared to 424 full-time equivalent employees and 13 offices on December 31, 2004.

      Net Income. Net income was $28.1 million, or $1.24 per diluted share, for 2005, compared with $20.1 million, or $1.09 per diluted share, for 2004. For the fourth quarter of 2005, net income was $8.4 million, up 31.3% from $6.4 million for the fourth quarter of 2004. Diluted earnings per share were $0.34 for the fourth quarter of 2005, compared to $0.33 for the same period in 2004. Western Alliance closed its initial public offering of 4.2 million shares on July 6, 2005, which increased average shares outstanding in 2005 and resulted in net proceeds of $85.1 million.

      Net Interest Income. Net interest income increased 35.4% to $28.6 million in the fourth quarter of 2005 from $21.1 million in the fourth quarter of 2004. The interest margin was 4.43% in the fourth quarter of 2005, compared to 4.20% in the fourth quarter of 2004.

      Provision for Loan Losses. The provision for loan losses was $2.0 million for the fourth quarter of 2005, compared to $0.8 million for the fourth quarter of 2004.

      Non-interest income. Non-interest income was $3.4 million for the fourth quarter of 2005, up 33.3% from $2.6 million for the same period in 2004.

      Non-interest expense. Non-interest expense was $17.1 million for the fourth quarter of 2005, up 32.4% from $12.9 million for the same period in 2004.

      The following tables contain selected consolidated financial and other data of Western Alliance at the dates and for the periods indicated. You should read this information in conjunction with the consolidated financial statements included in this document. The information at and for the three months and year ended December 31, 2005 is unaudited. However, in the opinion of management, all adjustments (consisting only of normal recurring adjustments) which are necessary to fairly present the results for the periods included have been made.

Acquisition of Bank of Nevada

      On January 16, 2006, Western Alliance and Bank of Nevada, a Nevada-chartered bank, entered into a definitive merger agreement, pursuant to which Bank of Nevada will merge with and into BankWest of Nevada, a wholly owned subsidiary of Western Alliance. Under the terms of the agreement, Bank of Nevada shareholders will receive $80.187 in cash for each share of Bank of Nevada common stock. Following completion of the merger, BankWest of Nevada will be renamed Bank of Nevada. The transaction is valued at approximately $74 million. As of September 30, 2005, Bank of Nevada had total assets of approximately $281 million, total loans of approximately $214 million, total deposits of approximately $253 million and stockholders’ equity was approximately $24 million. The transaction, which is subject to customary closing conditions, including approval from the shareholders of Bank of Nevada and banking regulators, is expected to be completed in the second quarter of 2006.

Acquisition of Office Building

      On December 30, 2005, BankWest of Nevada acquired an office building located at 2700 West Sahara Avenue, Las Vegas, Nevada, for a purchase price of $16,300,000. The property, which had previously been leased by BankWest of Nevada, serves as the corporate headquarters for Western Alliance and BankWest of Nevada.

RECENT DEVELOPMENTS OF INTERMOUNTAIN

Unaudited Consolidated Financial Results for 2005 (Compared to 2004)

      Total assets were $459.4 million at December 31, 2005, an increase of 31.1% from $350.4 million at December 31, 2004. Loans were $374.2 million at December 31, 2005, an increase of $87 million from December 31, 2004. Deposits were $395.5 million at December 31, 2005, an increase of $90 million from December 31, 2004. Stockholders’ equity increased $7.1 million from December 31, 2004 to $31.7 million at December 31, 2005, due primarily to the earnings of Nevada First Bank, a wholly owned subsidiary. Intermountain had 96 full-time equivalent employees and five full-service banking offices on December 31, 2005, compared to 75 full-time equivalent employees and four offices on December 31, 2004.

      Net Income. Net income was $4.9 million, or $3.18 per diluted share, for 2005, compared with $3.7 million, or $2.54 per diluted share, for 2004. The increase in net income is primarily attributed to an increase in interest earning assets in 2005.

      The following tables contain selected consolidated financial and other data of Intermountain at the dates and for the periods indicated. The information at and for the year ended December 31, 2005 is unaudited. However, in the opinion of management, all adjustments (consisting only of normal recurring adjustments) which are necessary to fairly present the results for the periods included have been made.

Corrective Bonus Payments and Option Rescission

      Intermountain has agreed to pay a “bonus” to certain individuals who exercised options in 2005, which options were originally issued as incentive stock options but were subsequently disqualified. This bonus is intended to compensate these individuals for certain tax-related costs of exercising non-incentive stock options. Intermountain will also pay interest and penalties as a result of not making these tax payments at the time these options were exercised. Intermountain has also rescinded all unexercised stock option agreements entered into in 2005 between Intermountain and its option holders which were disqualified from being treated as incentive stock options. The total amount of expense accrued in 2005 as a result of these modifications and bonus payments was approximately $656,000.

SELECTED CONSOLIDATED FINANCIAL AND OTHER DATA

      Set forth below are highlights from Western Alliance’s consolidated financial data of and for the years ended December 31, 2000 through 2004 and Western Alliance’s unaudited consolidated financial data as of and for the nine months ended September 30, 2004 and 2005. The results of operations for the nine months ended September 30, 2005 are not necessarily indicative of the results of operations of Western Alliance for the full year. Western Alliance’s management prepared the unaudited information on the same basis as it prepared Western Alliance audited consolidated financial statements. In the opinion of Western Alliance’s management, this information reflects all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of this data for these periods. You should read this information in conjunction with Western Alliance’s consolidated financial statements and related notes for the years ended December 31, 2002 through 2004 and for the nine months ended September 30, 2005 and 2004 that are included in this joint proxy statement/ prospectus and from which this information is derived. See also “Where You Can Find More Information” on page 138.

MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND

RESULTS OF OPERATIONS OF WESTERN ALLIANCE

      The following discussion and analysis of our financial condition and results of operations should be read in conjunction with “Selected Consolidated Financial and Other Data” and our consolidated financial statements and related notes included elsewhere in this prospectus. This discussion and analysis contains forward-looking statements that involve risks, uncertainties and assumptions. Certain risks, uncertainties and other factors, including but not limited to those set forth under “Cautionary Note Concerning Forward-Looking Statements,” “Risk Factors” and elsewhere in this proxy statement/ prospectus, may cause actual results to differ materially from those projected in the forward-looking statements.

Overview and History

      We are a bank holding company headquartered in Las Vegas, Nevada. We provide a full range of banking and related services to locally owned businesses, professional firms, real estate developers and investors, local nonprofit organizations, high net worth individuals and consumers through our subsidiary banks and financial services companies located in Nevada, Arizona and California. In addition to traditional lending and deposit gathering capabilities, we also offer a broad array of financial products and services aimed at satisfying the needs of small to mid-sized businesses and their proprietors, including cash management, trust administration and estate planning, custody and investments and equipment leasing.

      We generate the majority of our revenue from interest on loans, service charges on customer accounts and income from investment securities. This revenue is offset by interest expense paid on deposits and other borrowings and non-interest expense such as administrative and occupancy expenses. Net interest income is the difference between interest income on interest-earning assets such as loans and securities and interest expense on interest-bearing liabilities such as customer deposits and other borrowings which are used to fund those assets. Net interest income is our largest source of net income. Interest rate fluctuations, as well as changes in the amount and type of earning assets and liabilities, combine to affect net interest income.

      We provide a variety of loans to our customers, including commercial and residential real estate loans, construction and land development loans, commercial and industrial loans, and to a lesser extent, consumer loans. We rely primarily on locally generated deposits to provide us with funds for making loans. We intend to continue expanding our lending activities and have recently begun offering Small Business Administration, or SBA, loans.

      In addition to these traditional commercial banking capabilities, we also provide our customers with cash management, trust administration and estate planning, equipment leasing, and custody and investment services, resulting in revenue generated from non-interest income. We receive fees from our deposit customers in the form of service fees, checking fees and other fees. Other services such as safe deposit and wire transfers provide additional fee income. We may also generate income from time to time from the sale of investment securities. The fees collected by us and any gains on sales of securities are found in our Consolidated Statements of Income under “non-interest income.” Offsetting these earnings are operating expenses referred to as “non-interest expense.” Because banking is a very people intensive industry, our largest operating expense is employee compensation and related expenses.

Primary Factors in Evaluating Financial Condition and Results of Operations

      As a bank holding company, we focus on several factors in evaluating our financial condition and results of operations, including:

      Return on Average Equity. For the nine months ended September 30, 2005, net income increased 44.0% to $19.6 million compared to $13.6 million for the same period on 2004. The increase in net income was due primarily to an increase in net interest income of $23.7 million and an increase in non-interest income of $2.6 million, offset by an increase of $1.1 million to the provision for loan losses, and an increase of $15.8 million in other expenses. Basic earnings per share increased to $0.99 per share for the nine months ended September 30, 2005 compared to $0.81 per share for the same period in 2004. Diluted earnings per share increased to $0.90 per share for the nine months ended September 30, 2005 compared to $0.76 per share for the same period last year. The increase in net income offset by the increase in equity resulted in an ROE of 14.82% for the nine months ended September 30, 2005 compared to 16.84% for the nine months ended September 30, 2004.

      Our net income for the year ended December 31, 2004 increased 130.8% to $20.1 million compared to $8.7 million for the year ended December 31, 2003. The increase in net income was due primarily to an increase in net interest income of $30.1 million and a decrease of $1.2 million to the provision for loan losses, partially offset by an increase of $17.6 million in other expenses. Basic earnings per share increased to $1.17 per share for the year ended December 31, 2004, compared to $0.61 per share for the same period in 2003. Diluted earnings per share increased to $1.09 per share for the year ended December 31, 2004, compared to $0.59 per share for the same period last year. The increase in net income resulted in an ROE of 17.5% for the year ended December 31, 2004, compared to 12.2% for the year ended December 31, 2003.

      Return on Average Assets. Our ROA for the nine months ended September 30, 2005 increased to 1.09% compared to 1.00% for the same period in 2004. The increases in ROA are primarily due to the increases in net income as discussed above.

      Asset Quality. For all banks and bank holding companies, asset quality plays a significant role in the overall financial condition of the institution and results of operations. We measure asset quality in terms of nonperforming loans and assets as a percentage of gross loans and assets, and net charge-offs as a percentage of average loans. Nonperforming loans include loans past due 90 days or more and still accruing, non-accrual loans and restructured loans. Net charge-offs are calculated as the difference between charged-off loans and recovery payments received on previously charged-off loans. As of September 30, 2005, non-accrual loans were $175,000 compared to $1.6 million at December 31, 2004 and $275,000 at December 31, 2003. Nonperforming loans as a percentage of gross loans were 0.01% as of September 30, 2005, compared to 0.13% as of December 31, 2004 and 0.04% as of December 31, 2003. At September 30, 2005 and December 31, 2004 and 2003, our nonperforming assets were exclusively comprised of nonperforming loans. For the nine months ended September 30, 2005, net charge-offs as a percentage of average loans were 0.02%, compared to net charge-offs of less than 0.01% and 0.17% for the years ended December 31, 2004 and 2003.

      Asset Growth. The ability to produce loans and generate deposits is fundamental to our asset growth. Our assets and liabilities are comprised primarily of loans and deposits, respectively. Total assets increased 29.1% to $2.7 billion as of September 30, 2005 from $2.2 billion as of December 31, 2004 and $1.6 billion as of December 31, 2003. Gross loans grew 49.0% to $1.6 billion as of September 30, 2005 from $1.2 billion as of December 31, 2004 and $733.1 million as of December 31, 2003. Total deposits increased 38.9% to $2.3 billion as of September 30, 2005 from $1.8 billion as of December 31, 2004 and $1.1 billion as of December 31, 2003.

      Operating Efficiency. Operating efficiency is measured in terms of how efficiently income before income taxes is generated as a percentage of revenue. Our efficiency ratio (non-interest expenses divided by the sum of net interest income and non interest income) was 58.0% for the nine months ended September 30, 2005 from 57.1% for the same period in 2004. Our efficiency ratios for the years ended December 31, 2004 and 2003 were 56.3% and 60.3%, respectively.

Critical Accounting Policies

      The Notes to Consolidated Financial Statements contain a summary of our significant accounting policies, including discussions on recently issued accounting pronouncements, our adoption of them and the related impact of their adoption. We believe that certain of these policies, along with various estimates that we are required to make in recording our financial transactions, are important to have a complete picture of our financial position. In addition, these estimates require us to make complex and subjective judgments, many of which include matters with a high degree of uncertainty. The following is a discussion of these critical accounting policies and significant estimates. Additional information about these policies can be found in Note 1 of the Consolidated Financial Statements.

      Allowance for Loan Losses. The allowance for loan losses is a valuation allowance for probable losses incurred in the loan portfolio. Our allowance for loan loss methodology incorporates a variety of risk considerations in establishing an allowance for loan loss that we believe is adequate to absorb losses in the existing portfolio. Such analysis addresses our historical loss experience, delinquency and charge-off trends, collateral values, changes in nonperforming loans, economic conditions, peer group experience and other considerations. This information is then analyzed to determine “estimated loss factors” which, in turn, is assigned to each loan category. These factors also incorporate known information about individual loans, including the borrowers’ sensitivity to interest rate movements. Changes in the factors themselves are driven by perceived risk in pools of homogenous loans classified by collateral type, purpose and term. Management monitors local trends to anticipate future delinquency potential on a quarterly basis. In addition to ongoing internal loan reviews and risk assessment, management utilizes an independent loan review firm to provide advice on the appropriateness of the allowance for loan losses.

      The allowance for loan losses is increased by the provision for loan losses charged to expense and reduced by loans charged off, net of recoveries. Provisions for loan losses are provided on both a specific and general basis. Specific allowances are provided for watch, criticized, and impaired credits for which the expected/anticipated loss may be measurable. General valuation allowances are based on a portfolio segmentation based on collateral type, purpose and risk grading, with a further evaluation of various factors noted above.

      We incorporate our internal loss history to establish potential risk based on collateral type securing each loan. As an additional comparison, we examine peer group banks to determine the nature and scope of their losses. Finally, we closely examine each credit graded “Watch List/ Special Mention” and below to individually assess the appropriate specific loan loss reserve for such credit.

      At least annually, we review the assumptions and formulae by which additions are made to the specific and general valuation allowances for loan losses in an effort to refine such allowance in light of the current status of the factors described above. The total loan portfolio is thoroughly reviewed at least quarterly for satisfactory levels of general and specific reserves together with impaired loans to determine if write downs are necessary.

      Although we believe the levels of the allowance as of September 30, 2005 and December 31, 2004 and 2003 were adequate to absorb probable losses in the loan portfolio, a decline in local economic or other factors could result in increasing losses that cannot be reasonably estimated at this time.

      Available-for-Sale Securities. Statement of Financial Accounting Standards No. 115, Accounting for Certain Investments in Debt and Equity Securities, requires that available-for-sale securities be carried at fair value. Management utilizes the services of a third party vendor to assist with the determination of estimated fair values. Adjustments to the available-for-sale securities fair value impact the consolidated financial statements by increasing or decreasing assets and stockholders’ equity.

      Stock-Based Compensation. We account for stock-based employee compensation arrangements in accordance with provision of Accounting Principles Board, or APB, Opinion No. 25, “Accounting for Stock Issued to Employees” and comply with the disclosure provisions of Statement of Financial Accounting Standards, or SFAS, No. 123 “Accounting for Stock-Based Compensation.” Therefore, we do not record any compensation expense for stock options we grant to our employees where the exercise price equals the fair market value of the stock on the date of grant and the exercise price, number of shares eligible for issuance under the options and vesting period are fixed. We comply with the disclosure requirements of SFAS No. 123 and SFAS No. 148, which require that we disclose our pro forma net income or loss and net income or loss per common share as if we had expensed the fair value of the options.

      In December 2004, the Financial Accounting Standards Board published FASB Statement No. 123 (revised 2004), Share-Based Payment, or FAS 123(R). FAS 123(R) requires that the compensation cost relating to share-based payment transactions, including grants of employee stock options, be recognized in financial statements. That cost will be measured based on the fair value of the equity or liability instruments issued. FAS 123(R) permits entities to use any option-pricing model that meets the fair value objective in the Statement. Modifications of share-based payments will be treated as replacement awards with the cost of the incremental value recorded in the financial statements.

      The Statement became effective at the beginning of the first quarter of 2006. As of the effective date, we now apply the Statement using a modified version of prospective application. Under that transition method, compensation cost is recognized for (1) all awards granted after the required effective date and to awards modified, cancelled, or repurchased after that date and (2) the portion of awards granted subsequent to completion of an IPO and prior to the effective date for which the requisite service has not yet been rendered, based on the grant-date fair value of those awards calculated for pro forma disclosures under SFAS 123.

      The impact of this Statement on us in 2006 and beyond will depend on various factors including our future compensation strategy.

Trends and Developments Impacting Our Recent Results

      Certain trends emerged and developments have occurred that are important in understanding our recent results and that are potentially significant in assessing future performance.

      Growth in our market areas. Our growth has been fueled in particular by the significant population and economic growth of the greater Las Vegas area where we conduct the majority of our operations. The growth in this area has coincided with significant investments in the gaming and tourism industry. The significant

population increase has resulted in an increase in the acquisition of raw land for residential and commercial development, the construction of residential communities, shopping centers and office buildings, and the development and expansion of the businesses and professions that provide essential goods and services to this expanded population. Similarly, growth in the Phoenix, Tucson and San Diego markets has contributed to our growth.

      Asset sensitivity. Management uses various modeling strategies to manage the repricing characteristics of our assets and liabilities. These models contain a number of assumptions and can not take into account all the various factors that influence the sensitivities of our assets and liabilities. Despite these limitations, most of our models at September 30, 2005 indicated that our balance sheet was asset sensitive. A company is considered to be asset sensitive if the amount of its interest earning assets maturing or repricing within a certain time period exceed the amount of its interest-bearing liabilities also maturing or repricing within the same period. Being asset sensitive means generally that in times of rising interest rates, a company’s net interest income will increase, and in times of falling interest rates, net interest income will decrease.

      Because many of our assets are floating rate loans, which are funded by our relatively large non-interest bearing deposit base, we are asset sensitive. During 2003 and 2004, we mitigated this asset sensitivity and increased earnings by investing in mortgage-backed securities funded by short-term FHLB borrowings. This strategy had the effect of leveraging our excess capital to produce incremental returns without incurring additional credit risk. In light of the rising interest rate environment, beginning in the third quarter of 2004, we discontinued this strategy.

      We expect that if market interest rates continue to rise, our net interest margin and our net interest income will be favorably impacted. See “Quantitative and Qualitative Disclosure about Market Risk.”

      Impact of expansion on non-interest expense. We anticipate that the expansion will result in a significant increase in occupancy and equipment expense. The cost to construct and furnish a new branch is approximately $2.5 million, excluding the cost to lease or purchase the land on which the branch is located. Consistent with our historical growth strategy, as we open new offices and expand both within and outside our current markets, we plan to recruit seasoned relationship bankers, thereby increasing our salary expenses. Initially, this increase in salary expense is expected to be higher than the revenues to be received from the customer relationships brought to us by the new relationship bankers.

      Prior to 2005, Robert Sarver’s management company received an annual fee of $60,000 pursuant to a consulting agreement. The consulting agreement was terminated in 2005 and Mr. Sarver received an annual base salary of $500,000 in 2005. In addition, Mr. Sarver received a discretionary bonus determined by our Compensation Committee, which amount was 100% of his 2005 base salary.

      Impact of service center on non-interest income. We have a service center facility currently under development in the Las Vegas metropolitan area, which we anticipate will become operational in the third quarter of 2006. The anticipated cost to construct and furnish our service center will be between $13.0 and $15.0 million. We expect that this facility, once completed, will increase our capacity to provide courier, cash management and other business services. We anticipate this will have a favorable impact on our non-interest income.

Results of Operations

      Our results of operations depend substantially on net interest income, which is the difference between interest income on interest-earning assets, consisting primarily of loans receivable, securities and other short-term investments, and interest expense on interest-bearing liabilities, consisting primarily of deposits and borrowings. Our results of operations are also dependent upon our generation of non-interest income, consisting of income from trust and investment advisory services and banking service fees. Other factors contributing to our results of operations include our provisions for loan losses, gains or losses on sales of securities and income taxes, as well as the level of our non-interest expenses, such as compensation and benefits, occupancy and equipment and other miscellaneous operating expenses.

      The following table sets forth a summary financial overview for the nine months ended September 30, 2005 and 2004.

      Net income for the nine months ended September 30, 2005 increased 44.0% over the same period in the 2004, which is due to an increase in net interest income of $23.7 million and an increase in non-interest income of $2.6 million, offset by an increase of $1.1 million to the provision for loan losses and $15.8 million in other expenses. The increase in net interest income for the nine month period ended September 30, 2005 over the same period in September 30, 2004 was the result of an increase in the volume of and yield earned on interest-earning assets, primarily loans.

      Net Interest Income and Net Interest Margin. Net interest income for the nine months ended September 30, 2005 increased 47.5% over the same period in 2004. This was due to an increase in interest income of $32.2 million, reflecting the effect of an increase of $543.8 million in average interest-bearing assets which was funded with an increase of $624.8 million in average deposits, of which $252.1 million were non-interest bearing.

      The average yield on our interest-earning assets was 5.71% for the nine months ended September 30, 2005, compared to 5.01% for the same period in 2004. The increase in the yield on our interest-earning assets is a result of an increase in market rates, repricing on our adjustable rate loans, and new loans originated with higher interest rates because of the higher interest rate environment. Also, loans, which typically yield more than our other interest-bearing assets, increased as a percent of total interest-bearing assets from 52.0% for the nine months ended September 30, 2004, to 62.5% for the same period in 2005.

      The cost of our average interest-bearing liabilities increased to 2.14% in the nine months ended September 30, 2005, from 1.63% in the nine months ended September 30, 2004, which is a result of higher rates paid on deposit accounts, borrowings and junior subordinated debt. The increase in the cost of our interest-bearing liabilities was partially offset by lower average balances on our borrowings, which typically carry higher rates than our deposits.