WESTERN ALLIANCE BANCORPORATION

Report of Independent Registered Public Accounting Firm

To the Stockholders and Board of Directors of Western Alliance Bancorporation

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Western Alliance Bancorporation and subsidiaries (the Company) as of December 31, 2025 and 2024, the related consolidated statements of income, comprehensive income, stockholders’ equity and cash flows for each of the three years in the period ended December 31, 2025, and the related notes to the consolidated financial statements (collectively, the financial statements).

In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2025, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company’s internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control — Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission in 2013, and our report dated February 20, 2026 expressed an unqualified opinion on the effectiveness of the Company’s internal control over financial reporting.

Basis for Opinion

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matters

The critical audit matters communicated below are matters arising from the current period audit of the financial statements that were communicated or required to be communicated to the audit committee and that: (1) relate to accounts or disclosures that are material to the financial statements, and (2) involved our especially challenging, subjective or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matters below, providing separate opinions on the critical audit matters or on the accounts or disclosures to which they relate.

Allowance for Credit Losses–Loans Held for Investment

As described in Notes 1 and 4 to the financial statements, the Company’s allowance for credit losses for loans held for investment and unfunded loan commitments totaled $460.6 million and $49.6 million as of December 31, 2025, respectively. The allowance for credit losses on loans held for investment and unfunded loan commitments is calculated under the expected credit loss model and is an estimate of life-of-loan losses for the Company’s loans held for investment and unfunded loan commitments.

The allowance for credit losses for loans held for investment consists of an asset-specific component for estimating credit losses for individual loans that do not share risk characteristics with other loans and a pooled component for estimating credit losses for pools of loans that share similar risk characteristics. The allowance for credit losses on unfunded loan commitments consists of a pooled component for estimating credit losses for pools of unfunded loan commitments that share similar risk characteristics and includes consideration of the likelihood that estimated funding levels will occur. The allowance for the pooled component for the allowance for credit losses on loans held for investment and the allowance for credit losses on unfunded loan commitments is derived from an estimate of expected credit losses primarily using an expected loss methodology that incorporates risk parameters (probability of default, loss given default and exposure at default) which are derived from various vendor models, internally developed statistical models or nonstatistical estimation approaches.

The quantitative estimates of expected credit losses on loans held for investment and unfunded loan commitments derived from the probability of default, loss given default and exposure at default are adjusted by management to incorporate consideration of different probability weighted economic scenarios, current trends and conditions that are not captured in the quantitative credit loss estimates through the use of qualitative and/or environmental factors, which requires management to apply a significant amount of judgment and involves a high degree of estimation.

We identified management’s adjustments to quantitative estimates of expected credit losses on loans held for investment and unfunded loan commitments related to the incorporation of different probability weighted economic scenarios, current trends and conditions as a critical audit matter because auditing management’s judgments involved a high degree of complexity and auditor judgment given the high degree of subjectivity exercised by management in developing the adjustments.

Our audit procedures related to management’s adjustments to quantitative estimates of expected credit losses on loans held for investment and unfunded loan commitments related to the incorporation of different probability weighted economic scenarios, current trends and conditions included the following, among others:

•We obtained an understanding of the relevant controls related to management’s adjustments to quantitative estimates of expected credit losses on loans held for investment and unfunded loan commitments related to the incorporation of different probability weighted economic scenarios, current trends and conditions and tested such controls for design and operating effectiveness.

•We evaluated the appropriateness of management’s adjustments to quantitative estimates of expected credit losses on loans held for investment and unfunded loan commitments related to the incorporation of different probability weighted economic scenarios, current trends and conditions by performing the following procedures:

◦We tested the completeness and accuracy of the data used by management to determine management’s adjustments to quantitative estimates of expected credit losses on loans held for investment and unfunded loan commitments related to the incorporation of different probability weighted economic scenarios, current trends and conditions.

◦We evaluated management’s considerations of data utilized as a basis for management’s adjustments to quantitative estimates of expected credit losses on loans held for investment and unfunded loan commitments related to the incorporation of different probability weighted economic scenarios, current trends and conditions.

◦We evaluated management’s support of adjustments to quantitative estimates of expected credit losses on loans held for investment and unfunded loan commitments related to the incorporation of different probability weighted economic scenarios, current trends and conditions.

◦We agreed management’s adjustments to quantitative estimates of expected credit losses on loans held for investment and unfunded loan commitments related to the incorporation of different probability weighted economic scenarios, current trends and conditions to the allowance for credit losses on loans held for investment and unfunded loan commitments calculations.

Valuation of Mortgage Servicing Rights

As described in Notes 1 and 5 to the financial statements, the Company’s mortgage servicing rights totaled $1,494 million as of December 31, 2025. When the Company sells mortgage loans in the secondary market and retains the right to service these loans, a servicing right asset is capitalized at the time of sale when the benefits of servicing are deemed to be greater than adequate compensation for performing the servicing activities. Mortgage servicing rights represent the then-current fair value of future net cash flows expected to be realized from performing servicing activities. The Company has elected to subsequently measure mortgage servicing rights at fair value. The Company estimates the fair value of mortgage servicing rights using a discounted cash flow model that incorporates assumptions that market participants would use in estimating the fair value of servicing rights, including, but not limited to, option adjusted spread, conditional prepayment rate and cost to service.

We identified the option adjusted spread and conditional prepayment rate assumptions used in the valuation of mortgage servicing rights as a critical audit matter due to the significant judgment required by management in determining these assumptions. Auditing these assumptions involved a high degree of auditor judgment and increased audit effort as there was limited observable market information and the calculated fair value of the mortgage servicing rights is sensitive to changes in these key assumptions.

Our audit procedures related to the valuation of mortgage servicing rights as of December 31, 2025 included, among others, testing management’s process for determining the fair value, including:

•We obtained an understanding of the relevant controls related to the establishment of the option adjusted spread and conditional prepayment assumptions used in the valuation of mortgage servicing rights and tested such controls for design and operating effectiveness.

•We evaluated the appropriateness of the valuation model and methodology.

•We tested the completeness and accuracy of the data used in the model.

•We utilized internal valuation specialists to assist with evaluating the reasonableness of the option adjusted spread and conditional prepayment rate assumptions by considering the consistency with available external market and industry data.

/s/RSM US LLP

We have served as the Company’s auditor since 1994.

Austin, Texas

February 20, 2026