#1WA Western Alliance Bancorporation® INVESTOR UPDATE 2Q 2023#2Forward-Looking Statements This presentation contains forward-looking statements that relate to expectations, beliefs, projections, future plans and strategies, anticipated events or trends and similar expressions concerning matters that are not historical facts. Examples of forward-looking statements include, among others, statements we make regarding our expectations with regard to our business, financial and operating results, future economic performance and dividends. The forward-looking statements contained herein reflect our current views about future events and financial performance and are subject to risks, uncertainties, assumptions and changes in circumstances that may cause our actual results to differ significantly from historical results and those expressed in any forward-looking statement. Some factors that could cause actual results to differ materially from historical or expected results include, among others: the risk factors discussed in the Company's Annual Report on Form 10-K for the year ended December 31, 2022 and the Company's subsequent Quarterly Reports on Form 10-Q, each as filed with the Securities and Exchange Commission; adverse developments in the financial services industry generally such as the recent bank failures and any related impact on depositor behavior; risks related to the sufficiency of liquidity; the potential adverse effects of unusual and infrequently occurring events such as the COVID-19 pandemic and any governmental or societal responses thereto; changes in general economic conditions, either nationally or locally in the areas in which we conduct or will conduct our business; the impact on financial markets from geopolitical conflicts such as the war between Russia and Ukraine; inflation, interest rate, market and monetary fluctuations; 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 credit losses; legislative or regulatory changes or changes in accounting principles, policies or guidelines; supervisory actions by regulatory agencies which may limit our ability to pursue certain growth opportunities, including expansion through acquisitions; additional regulatory requirements resulting from our continued growth; 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. Any forward-looking statement made by us in this presentation is based only on information currently available to us and speaks only as of the date on which it is made. We do not intend and disclaim any duty or obligation to update or revise any industry information or forward-looking statements, whether written or oral, that may be made from time to time, set forth in this press release to reflect new information, future events or otherwise. Non-GAAP Financial Measures This presentation contains both financial measures based on GAAP and non-GAAP based financial measures, which are used where management believes them to be helpful in understanding the Company's results of operations or financial position. Where non-GAAP financial measures are used, the comparable GAAP financial measure, as well as the reconciliation to the comparable GAAP financial measure, can be found in the Company's press release as of and for the quarter ended March 31, 2023. These disclosures should not be viewed as a substitute for operating results determined in accordance with GAAP, nor are they necessarily comparable to non-GAAP performance measures that may be presented by other companies. WA Western Alliance BancorporationⓇ 2#3Quarter-to-Date Financial Update (as of May 12, 2023) Leading national commercial bank with unique combination of sustained profitability, dependable earnings, controlled high-quality growth, and protected by consistent asset quality standards 1 Stable Deposits -WAL's deposit balances stabilized by March 20 and resumed growth trajectory QTD deposit growth exceeded $2 billion as of May 12, up from $47.6 billion as of March 31 2 3 Insured Deposit Strength - >79% as of May 12, up from 68% as of March 31 Balance Sheet Repositioning On Track - Imminent completion of ~50% in sales of the $6 billion of loans reclassified to HFS in 1Q23 4 HFI Loan / Deposit Ratio Improvement - 94% as of May 12, compared to ~98% as of March 31 LO Enhanced Capital Base - Q2 asset sales have boosted CET1 to 9.7% & TCE/TA to 6.7% as of April 30 6 Strong Asset Quality - Supported by conservative underwriting standards & loan covenants WA Western Alliance BancorporationⓇ | 3#4Priorities and Goals Safe and Sound Growth, Emphasizing Capital, Liquidity, and Holistic Customer Relationships 1 Reduce reliance on non-core funding - Lower FHLB borrowings to more normal level & repay BTFP 2 Loan/Deposit ratio to the mid-80s through increased focus on cultivating full banking relationships 3 Organic balance sheet repositioning & surgical asset sales poised to lift CET1 above 10% by June 30 4 Maintain high insured deposit mix through reciprocal products LO Prioritize multi-faceted, integrated customer relationships to foster increased deposit stickiness 6 Accelerate HQLA growth to further enhance liquidity strength 7 8 High-touch customer relationships supported by ongoing education on WAL expertise & strength Augment deposit diversification from Corporate Trust and indirect consumer channel WA Western Alliance BancorporationⓇ 4#5Western Alliance Bancorporation Overview The Bank for All Seasons A national banking platform of specialized financial services paired with attractive regional markets provides complementary, diversified revenue streams and high operating leverage to produce industry-leading financial results Serving a wide range of commercial and consumer related clients nationwide, from corporate and small business to public and non-profit borrowers Summary NYSE Headquarters WAL Phoenix, AZ IPO Market Cap¹ 2005 $3.4bn Offices Employees 57 3,300+ Diversified business model provides flexibility and responsiveness to changing winds and market conditions to provide long-term superior risk- adjusted returns BANK DIRECTOR S&P GLOBAL MI FORBES One of Forbes' "America's Best Banks" Year After Year AMERICAN BANKER #1 Top-Performing Large Bank with Assets $50B and Above, 2022 #1 Best Emerging Regional Bank & Top 10 U.S. Banks for Growth Strategy #2 Best-Performing of the 50 Largest Public U.S. Banks, 2021 INSTITUTIONAL INVESTOR MAG 2022 All-America Executive Team Best CEO & Best CFO Total Assets $71.0bn NPAs/Assets³ 0.17% LTM NCOs/ Avg. Loans 0.05% LTM PPNR Growth 18.4% LTM ROTCE, adjusted² 25.2% TBV per Share 5-Year CAGR 16.1% WA Western Alliance Bancorporation® Note: Financial data as of March 31, 2023 Market data as of May 15, 2023. Refer to slide 2 for further discussion of Non-GAAP financial measures. Nonperforming assets includes nonaccrual loans and repossessed assets. LO 5#61st Quarter 2023 | Financial Highlights Highlights Earnings & Profitability EPS / Adjusted¹ Net Income / Adjusted¹ 1Q23 4Q22 Q1-22 $1.28/$2.30 $2.67 $2.22 Net Income EPS $142.2/$251.9 $293.0 $240.1 Net Revenue / Adjusted¹ $551.9/$712.2 $701.2 $555.8 Pre-Provision Net Revenue¹ $351.6 $367.9 $306.9 $142.2 million $251.9, adjusted $1.28 $2.30, adjusted Net Interest Margin 3.79% 3.98% 3.32% Efficiency Ratio / Adjusted 1 62.1% / 43.2% 46.9% 44.1% ROAA / Adjusted¹ 0.81% 1.43% 1.67% 1.64% ROTCE, Adjusted¹ 21.9% 27.7% 23.9% PPNR1 Q1: $351.6 million 15% YoY ROTCE, adjusted¹ 21.9% Balance Sheet & Capital Total Loans $46,435 $51,862 $41,119 Total Deposits $47,587 $53,644 $52,160 CET1 Ratio 9.4% 9.3% 9.0% TCE Ratio¹ 6.5% 6.5% 6.7% Tangible Book Value per Share¹ $41.56 $40.25 $37.13 Asset Quality Provision for Credit losses $19.4 $3.1 $9.0 Net Loan Charge-Offs $6.0 $1.8 $0.2 Loan Growth Q1: $(5.4) billion 13% YOY Tangible Book Value PER SHARE¹ Deposit Growth Q1: $(6.1) billion (9)% YoY NPAs²/ Total Assets Net Loan Charge-Offs/Avg. Loans 0.05% 0.01% 0.00% Total Loan ACL/Funded HFI Loans³ 0.75% 0.69% 0.73% NPAS²/Total Assets 0.17% 0.14% 0.17% $41.56 12% YoY 0.17% Dollars in millions, except EPS WA Western Alliance Bancorporation® Refer to slide 2 for further discussion of Non-GAAP financial measures. 2) Nonperforming assets includes nonaccrual loans and repossessed assets. Ratio includes an allowance for credit losses of $20.8 million as of March 31, 2023 related to a pool of loans covered under 4 separate credit linked notes. CO 6#7Diversified Business Model Provides Flexibility Across Economic Cycles WAL actively adapts business and capital allocation in response to changing external environment Growth trajectory maintained with prudent credit risk management Regional Banking Divisions CRE Technology & Innovation National Business Lines Geographic Growth Diversification Trajectory Residential Mortgages Ample growth potential Organic Growth Superior total Dividends shareholder returns Capital Allocation WA WA Western Alliance BancorporationⓇ Share Repurchases M&A Lot Banking Risk- Adjusted Yields Hotel Franchise Finance Deep segment & product expertise supports cyclical business lines Risk Operating Management Leverage Pristine asset quality Municipal & Nonprofit HOA Warehouse Mortgage Banking Lending Capital Corporate Call Lines Finance Highly efficient lending & deposit platforms Note: Illustrative as business objectives are not mutually exclusive and image does not represent full suite of WAL divisions, products and services. 7#8HFI Reclassification Surgically selected loan reclassifications from Held-For-Investment to Held- For-Sale portfolio 1 Balance Sheet Repositioning Plan Balance sheet repositioning, which included surgical sale of assets and Loan HFS reclassifications, resulted in net non- operating charges of $110 million, but will have an immediate accretive impact to regulatory capital and allow us to prioritize core client relationships with holistic lending, deposit and treasury management needs Select Asset Dispositions Significant progress in executing surgical asset sales to expeditiously improve capital and liquidity, and reduce wholesale borrowings 2 Reclassified $6.0 billion of HFI loans to HFS at an average mark of ~2% ➤ One-time Loan FV Charge: $123mm (After-Tax: $92mm) A • ~$1.74 billion asset sales completed in Q1 CET1 Benefit 1. EFR & SNC loan sales ~$920mm loan sales CET1 Impact: -12 bps Prioritizing core client relationships with holistic lending, deposit, and treasury management needs $110mm Net Non-Operating Loss Breakdown ($mm) 1Q23 P&L Impact Completed (1Q23) 2. Other loan sales 3. MSR sales $360mm MSR sales 4. Select security sales (Primarily CLOS) $460mm securities +17 bps sales - Non-Core C&I Unwind of Inefficient CLNS 1. MWL $242mm 2. EFR $25mm - Syndicated Shared National Credits (SNCs) - Capital Call & Subscription Lines (EFR) Select Residential RE - Early Buyout Resi. (EBOS) Equipment Finance leases Non-Core CRE Other $5.2 $12.7 ■Loans Sold B HFI Reclass Sec Sold & Debt Exting $92.2 -$0.5 Marks for future contracted and planned loan sales are already included in Q1 HFI reclassification fair value adjustment Note: Balance sheet information as of 3/31/23 WA Western Alliance BancorporationⓇ Contracted (2Q23) $3.0bn loans contracted for sale in Q2 ~$2.3bn in loan dispositions QTD Unwind of inefficient CLNS $275mm EFR CLN repaid QTD Remaining C ~$3.0bn HFS loans remaining (2023) +33 bps 8#9Highlights QTD Capital Update & Projected Build by June 30 CET1 Ratio 9.32% 0.23% -0.06% 0.12% -0.10% 9.38% Achieved 9.7% CET1 at 4/30 0.51% -0.18% ☐ Additional 2Q23 Capital Generation 2023 Target CET1 >10% • Strong organic capital generation drove net CET1 increase in 1Q23 and allowed us to raise liquidity through other B/S actions HFS reclassification in 1Q23 optimizes RWA and positions for stronger capital build going forward through asset sales (with a material amount under contract) -0.12% Net 17 bps increase Net 2 bps increase Net 33 bps increase Locked-in CET1 Build 9.71% 4Q22 HFI Reclass. to HFS Asset Sales CLN (WH) Unwind Organic B/S Capital Growth Generation 1Q23 Asset Sales CLN (EFR) Unwind 1 2 A Dollars in billions, unless otherwise indicated WA Western Alliance Bancorporation® HFS Loan Sales (Planned) & RWA Release Organic Capital Generation + B/S Growth 2 B 2 C 2Q23 Target • . HFS loan sales provide capital benefit through RWA release Loan marks taken on reclassified HFS loans provide confidence of expected capital benefit from planned sales 1H23 completed and planned actions and organic capital generation accelerate attainment of >10% capital goal by 2Q23 9#10ROAA (1Q23 4 Quarter Average) Strong Earnings & Capital Less Unrealized Sec. Marks ROAA vs. Adj. CET1 (Incl. of AOCI and HTM Unrealized Securities Marks) for Top 50 Banks by Assets 6.50 2.30 2.10 1.90 1.70 • OZK • FCNC.A Highlights 1Q23 Adjusted ROAA of 1.43% vs. 1.67% for 4Q22 and 1.64% ROAA for 1Q22 WAL is top decile in ROAA • 1Q23 CET1 of 9.4% and ~9.7% as of April 30th Adj. CET1 (inclusive of AOCI and HTM unrealized marks) increased to ~8.1% in 1Q23 from ~7.9% in 4Q22 WAL is at median for Adj. CET1 ● EWBC • WALT CBSH 1.50 • СМА ● HWC RF • BPOP PNFP • РВ 1.30 • HBAN SNV ONB WBS BOKF ● UBSI FNB CFR ABCB ⚫ FITB FHN UCBI TFC 1.10 ● PNC WTFC FHB FULT MTB SSB UMBF ASB OVLY GBCI JPM TCBI ZION ● USB KEY ● PACW¹ CFG 0.90 BAC FIBK SFNC CADE ● WFC ⚫ BKU • COLB 0.70 C 0.50 4.0% 5.0% 6.0% 7.0% WA 8.0% 9.0% 10.0% 11.0% 12.0% CET1 Adj. for AOCI & HTM (1Q23) 1) 1Q23 ROAA adjusted Western Alliance Bancorporation® | 10#11Insured Deposits* Focused Efforts to Drive Increased Deposit Liquidity Deposit-led growth driving loan-to-deposit ratio to mid-80s Insured Deposits vs. Loan / Deposit Ratio for Top 50 Banks by Assets 85% 80% WAL¹ WBS ASB FNB 75% SFNC UCBI RF SNV GBCI FIBK PACW CADE PB WTFC ONB VLY 70% FULT HBAN CFG CBSH UBSI OZK PNFP NYCB COLB KEY HWC 65% TFC SSB BKU FITB 60% ABCB FHB FHN EWBC MTB UMBF ZION BOKF PNC 55% FCNC.A CMA TCBI WFC 50% USB BAC CFR BPOP JPM 45% 100% 90% 80% 70% 60% 50% 40% Loan-to-Deposit Ratio WA Western Alliance Bancorporation® Highlights WAL prioritizes core client relationships to fulfill customers' holistic banking needs • Controlling growth by emphasizing deposit relationships has lowered the HFI • Loan/Deposit ratio from ~98% as of March 31 to 94% as of May 12 WAL has the highest insured deposit percentage among the top-50 largest U.S. banks ⚫WAL has successfully retained deep- rooted relationships and those for which we offer proprietary, integrated treasury management technology • Of depositors, ~85% have multiple products (deposits, TM, loans) 1) Insured Deposit % as of March 31, 2023, except for WAL, which is as of May 12, 2023. Deposit insurance includes direct, collateralized, pass-through, and insured networks WAL Loan-to-Deposit % uses HFI Loans Source: S&P Global Market Intelligence, 1Q23 company earnings presentations, and 1Q23 Call Reports | 11#12Specialized, High Quality Loan Portfolio Diversified by product, client-type and geography emphasizing underwriting discipline 1Q23 Loans HFI by Product Type 1Q23 Loans HFI by Borrower Type . C&D Equity Fund 9% Other; Warehouse 1% Lending 10% Resources 2% ■Residential Municipal & Nonprofit 3% Tech & Innovation 5% C&D 33% 33% CRE, NOO 4% 9% ■CRE, OO ■C&I Residential 32% 21% $46.4 billion • Other C&I 13% CRE, 00 4% Hotel Franchise Finance 9% CRE, NOO 12% Accelerated growth in NBLs and Residential has contributed to loan diversification and evolution of strategy into low-to-no-loss loan categories ~66% of 3-year growth in low-to-no-loss categories Loans HFI and Yields 6.28% 5.43% 5.23% 5.18% 5.40% 5.62% 5.82% 5.83% Spot Rate 6.45% 4.79% 4.74% 4.32% $51.9 $46.4 $6.8 $27.1 $39.1 $8.4 $11.1 $13.2 $15.1 $17.7 $21.1 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 1Q23 Dollars in billions WA Western Alliance Bancorporation® Highlights • . Diverse mix of regionally-focused commercial banking divisions & nationally-oriented specialized businesses Leverages deep segment expertise to provide specialized banking services to niche markets across the country Segment-focused model supports superior client value and company risk management National reach enables selective relationships with highest asset quality and profitability 1Q23 Loans HFS (ex-AMH Resi) Composition ■ Other C&I 2% 8% 18% 23% Equity Fund Resources ■Syndications ■Mtg. WH 44% 6% CRE, NOO ■Residential Yields Average Spot Loans HFI 6.28% 6.45% Loans HFS N/A 7.34% HFS - AMH Resi 5.90% 6.33% | 12#13Highlights Demonstrated Conservative Credit Culture Classified Loans / Loans • Non-Accrual Loans / Loans 2.99% 1.11% 0.81% 0.77% 2.56% 2.10%2.10% 2.03% 0.73% 0.74% 1.77% 1.62% 0.55% 0.50% 1.37%1.39% 1.40% 1.87% 1.23%1.23% 0.44% 0.56% °0.40% 1.50% 0.33% 0.34% 0.27% 0.44% 1.14% 1.14%1.18% 0.43% 0.70% 0.82% 0.74% 0.70% 0.93% 0.31% 0.29% 0.27% 0.23% 0.16% 0.19%0.16% 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 MRQ¹ 0.25% 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 MRQ' Net Charge-Offs / Average Loans 0.19% 0.18% 0.16%0 0.15%0.15% 0.14% 0.13% 0.12% . • • A decade of business transformation has resulted in consistent relative outperformance in asset quality and credit metrics Asset quality remained strong during height of the pandemic Improvement / stabilization in non- accruals reflects timely identification and resolution of problem loans before realizing losses Credit mitigation expertise is critical with a weaker macro backdrop A quarter of the loan portfolio is credit protected, consisting of government guaranteed, Credit Linked Notes-protected, and cash secured assets² WA Western Alliance Bancorporation® 0.10% 9.06%0.06% 0.02% 0.06% 0.06% 0.05% 0.01% 0.02% 0.02% 0.00% -0.07% -0.06% 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 MRQ' WAL Peers --Top Quartile Note: Peers consist of 34 publicly traded banks headquartered in the U.S. with total assets between $25B and $150B as of March 31, 2023 Source: S&P Global Market Intelligence 1) MRQ is 1Q23 for WAL and some peers and 4Q22 for the remainder 2) As of March 31, 2023, CLNs cover a substantial portion of Residential ($9.5 billion) loans outstanding | 13#140.60% 0.30% 0.00% WAL SSB ONB GBCI FCNC.A WTFC · EWBC CADE UCBI COLB FNB VLY WBS PNFP Note: Peers consist of 34 publicly traded banks headquartered in the U.S. with total assets between $25B and $150B as of March 31, 2023 Source: S&P Global Market Intelligence ◉ CBSH NYCB A Max Average NOIZ FHN UBSI ☐ FIBK ASB PB Peer Group 5.25% Maximum of Peers Avg of Peers Minimum of Peers 1.20% Amount Bank Amount Amount Bank Average 37 bps HWC 15 bps 1 bp WAL 0.90% Maximum 525 bps HWC 70 bps 13 bps WAL BOKF ABCB CMA SNV BKU PACW Demonstrated Conservative Credit Culture Deliberate business transformation, emphasizing underwriting specialization and diversification strategy, has produced sustained superior asset quality with reduced dispersion in realized credit losses Annualized Net Charge-Offs 1Q14 - 1Q23 FULT CFR SFNC TCBI ◉ OZK UMBF HWC WA Western Alliance BancorporationⓇ ||14#15Highlights Substantial Reserve Levels Reserve levels enhanced by credit protection and low loss loan categories Adjusted Total Loan ACL / Funded Loans: 1Q23 1.15% 0.06% EBOS³ 0.95% 0.97% 0.02% 0.12% Resi 0.20% 0.75% Total Loan ACL / Funded Loans 1,2 1 1.36% 0.21% WAL remains appropriately reserved, especially when considering credit protection from Credit Linked Notes (CLNs) and historically low loss loan categories Total Loan ACL / Funded Loans increased to 0.75% in Q1 as a result of heightened economic uncertainty • Total Loan ACL / Funded Loans less loans covered by CLNs is 0.95% Total Loan ACL / Funded Loans less loans covered by CLNs and select no-to- low-loss loan categories (EFR, Residential, and Mortgage Warehouse) is 1.36% • > 7x historical maximum annual loss rate4 Reserves are a multiple of average losses times portfolio duration • Estimated weighted average duration of the loan portfolio is < 4 years - Loans Covered by CLNs EFR Loans - Residential Loans - Mortgage Warehouse Loans • 2 3 4 5 Adj. total ACL covers > 20x historical average annual loss rate 4 x duration WA Western Alliance Bancorporation® Total Loan ACL includes allowance for unfunded commitments 2) Ratio includes an allowance for credit losses of $20.8 million as of March 31, 2023 related to a pool of loans covered under 4 separate credit linked notes 3) Early Buyout Loans are government guaranteed See slide 14 | 15#16Scalable, Differentiated Deposit Franchise Diversified funding channels provide secular growth trends and reflect long- term relationships 1Q23 Deposit Base 1Q23 Deposit Composition 22% 14% ■Nonint. Bearing DDA ■MMDA & Savings ■Regions 1% 12% 35% Interest Bearing DDA ■CDs ■Mtg WH 7% Tech & Innov. THOA ~48% of NIB DDAS are ECR-related 15% Sttlmt Svcs ■Bus. Escrow Svcs 29% Other 10% 20% $47.6 billion Deposits, Borrowings, and Cost of Funds 35% • Highlights • $47.6 billion in total deposits as of 3/31 typically tied to lending relationships • • > $2 billion of Q2 QTD deposit growth WAL benefits from holding customer's primary relationship Scalable national funding channels, such as HOA, Settlement Services, Business Escrow Services, and Tech & Innovation Core deposits fund balance sheet growth 98% Loan-to-Deposit ratio as of 3/31 • 94% Loan-to-Deposit ratio as of 5/12 35% of total deposits are noninterest- bearing (~48% Earnings Credit Rate-related) ECR-related deposit balances of $13.4 bn 2.27% 0.39% 0.36% 0.30% 0.31% 0.37% 0.64% 0.86% 0.34% 0.25% 0.80% Spot Rate 2.76% · $7.2 $2.4 $16.7 24.3% • $19.7 $1.0 $16.5 CAGR $21.3 $0.4 $0.8 $0.9 $13.4 $0.5 $0.5 $0.4 $0.4 $8.5 $22 $23 $4.1 $5.6 $7.4 $7.5 $33.9 $26.3 $31.1 $6.6 $7.9 $8.9 $9.5 $11.7 $14.3 $18.5 20.3% CAGR $5.6 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 1Q23 Non-Interest Bearing Deposits Total Borrowings Cost of Funds Interest Bearing Deposits Dollars in billions WA Western Alliance Bancorporation® · ~59% associated with non-interest bearing accounts Note: Borrowings include customer repurchase agreements; Cost of Funds defined as total expense paid on interest bearing liabilities divided by the sum of average interest- bearing liabilities and average non-interest bearing demand deposits. | 16#17$60 $55 $50 $45 Historical Deposit Seasonality Trends Daily Deposit Trends (1/4/21 - 2/28/23) (Dollars in billions) Mar-21 End of Month Deposit Trends (1/4/21 - 2/28/23) Apr-21 May-21 Jun-21 $40 $35 $30 Dec-20 www Jan-21 Feb-21 wwwwww Jul-21 Aug-21 Sep-21 Oct-21 Nov-21 Dec-21 Jan-22 Feb-22 Mar-22 $60 $55 $50 $45 $40 $35 $30 Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 WA Western Alliance Bancorporation® Jun-21 Jul-21 Aug-21 Sep-21 Oct-21 Nov-21 Dec-21 Jan-22 Feb-22 Mar-22 Apr-22 wwwwwww Apr-22 May-22 Jun-22 Jul-22 Aug-22 Sep-22 Oct-22 Nov-22 Jun-22 May-22 Aug-22 Jul-22 Sep-22 Oct-22 Nov-22 Dec-22 Jan-23 Feb-23 Dec-22 Jan-23 Feb-23 Highlights Intra-month deposit trends reflect typical cyclicality in escrow deposit flows and mortgage warehouse disbursements (principal & interest and tax & insurance payments) Prioritizing growth in tax & insurance accounts in Mortgage Warehouse to dampen intra-month cyclicality On average, deposits have grown ~2.0% per month, inclusive of normal monthly cyclicality | 17#18Highlights Leading Efficiency Produces Strong Op. Leverage Track record of simultaneously driving industry-leading growth and efficiency Efficiency Ratio Breakdown of Non-Interest Expenses Salaries & Employee Benefits 63.2% 62.9% 62.1% 60.6% 60.6% 58.9% Other Operating Expenses 56.4% 55.9% 57.7% 57.1% Deposit Costs 53.5% 53.7% 53.3% $347.9 $333.4 53.2% 47.8% 47.0% 45.0% 44.9% $305.8 $86.9 47.6% 41.4% 43.3% 42.6% 42.9% 43.2% 46.9% $82.2 44.7% 38.8% 42.2% 40.7% 41.0% 42.0% 41.1% $248.6 $9.3 $268.9 $18.1 $56.2 37.9% 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 1Q23² WAL WAL Adjusted Peers $125.7 $139.0 $136.5 $148.9 $138.3 • Continued focus on expense management, while investing in growth initiatives and scalable infrastructure to become a leading nationwide banking platform Efficiency ratio¹ increased to 62.1% year-to- date compared to 2022 • Higher efficiency ratio was driven primarily by non-recurring charges and normal Q1 seasonality Adjusted efficiency ratio¹ was 43.2%², compared to 41.1% in 2022 Deposit costs increased $4.7 million in Q1 from the prior quarter, primarily related to higher earnings credit rates Dollars in millions WA Western Alliance Bancorporation® $101.0 $111.8 $113.1 $125.5 $112.1 1Q22 2Q22 3Q22 4Q22 1Q23 Note: Efficiency ratio for WAL and Peers as calculated and reported by S&P Global Market Intelligence. Peers consist of 34 publicly traded banks headquartered in the U.S. with total assets between $25B and $150B as of March 31, 2023; Source: S&P Global Market Intelligence. Refer to slide 2 for further discussion of Non-GAAP financial measures. 1Q23 is adjusted to exclude $147.6 million of pre-tax net non-operating charges for WAL | 18#19Significant Access to Liquidity & Funding Capacity Source In-Use Remaining Capacity Total Available Liquidity As of 5/12/23 1. Cash $0 + $2.6B = $2.6B 2. FHLB $7.9B + $3.7B = $11.6B • 3. Fed Discount Window $0 + $16.2B = $16.2B 4. Fed BTFP $1.3B + $0.05B = $1.35B Total $9.2B + $22.6B = $31.8B Significant Available Liquidity $3.7 $2.6 $9.2 $16.2 $0.1 $31.8 1Q23 Investment Portfolio 13% Low Inc. Housing Spot Rate 4.60% 15% Private MBS 20% Agency MBS 9% Muni 27% CLOS 16% Other Outstanding Borrowings Cash FHLB Fed Discount Window Other Capacity Total Liquidity Available $9.1 billion Dollars in billions, unless otherwise indicated WA Western Alliance Bancorporation® Highlights • • • Repaid all borrowings from Federal Reserve discount window by 3/31 . Higher advance rates at FRB's discount window available, if necessary Ample access to contingent liquidity (as of 5/12) On-Balance Sheet Cash: $2.6 billion • • • . Total Unused Borrowing Capacity: $20.0 billion Total Unused Funding Capacity: $22.6 billion Total Available Liquidity: $31.8 billion Continue to evaluate additional opportunities to establish secured borrowing facilities Proceeds from contracted and planned asset sales will be used to pay down BTFP borrowings to $0 and reduce FHLB borrowings to normalized levels of ~$5B New deposit growth will be used to reduce wholesale funding costs and build HQLA investment balance || 19#20Industry-Leading Profitability ROAA Pre-Provision Net Revenue Highlights WAL Peers 2.05% 2.00% 1.83% 1.72% 1.50% 1.56% 1.61% 1.61% 1.62% 1.43% 1.35% 1.28% 1.22% 1.19% 1.10% 1-20% 0.97% 0.92% 0.94% 0.97% 0.95% 0.91% 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 1Q23¹ CAGR: 27% $746 $624 $533 $469 $369 $159 $202 $262 $1,102 $1,384 $1,429 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 LTM2,3 ROATCE Net Interest Income WAL Peers 4.39% 4.42% 4.51% 4.58% 4.65% 4.68% 4.52% $2,377 $2,216 26.2% 25.4% 21.9% 18.3% 18.5% 17.8% 17.7% 18.3% 20.6% 19.6% 17.7% 15.4% 15.9% 16.7% 15.1% 14.6% 11.7% 11.1% 10.8% 11.6% 11.4% 11.5% 3.97% 3.79% 3.67% 3.41% $1,549 $1,167 $1,040 $916 $785 $657 $493 $333 $385 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 1Q23¹ 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 LTM² • • • · Outstanding performance compared to peers with ROAA and ROATCE among highest in industry Net Interest Income continues to rise through strong earning asset growth Net Interest Income increased $161 million, or 7.3%, from 2022 due to the rising rate environment and loan repricing ⚫ NIM increased 12 bps, driven by higher. yields on interest earning assets • PPNR increased $45 million, or 3.3%, from 2022 Nominally asset sensitive • In +/- 100bps shock IRR sensitivity scenarios, net interest income varies less than 1% Dollars in millions NII NIM Note: Peers consist of 34 publicly traded banks headquartered in the U.S. with total assets between $25B and $150B as of March 31, 2023 Source: S&P Global Market Intelligence. WA Western Alliance 1) Bancorporation® 2) Assumes four quarter average; WAL 1Q23 is adjusted to exclude $109.7 million of net non-operating charges, after tax LTM is as of 1Q23 3) 1Q23 adjusted to exclude $147.6 million of pre-tax net non-operating charges 20 20#21Shareholder-Focused Capital Management WAL consistently generates more capital than needed to support organic growth Robust Capital Levels 11.4% 11.4% 11.1% 11.2% 11.5% 11.1% 11.0% 10.9% 11.2% 10.5% 10.4% 9.7% 10.0% 10.4% 10.6% 10.7% 9.9% 9.3% 9.3% 8.8% 9.6% 10.2% 10.3% 9.1% 9.4% 8.6% 9.4% 8.6% 0.2% - 7.9% 8.3% 8.6% 9.0% 8.8% 8.9% 8.3% 8.5% 8.2% 7.1% 7.2% 7.4% 7.3% 6.5% 6.5% 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 MRQ¹ CET1 Peer CET11 TCE/TA Peer TCE/TA¹ Long Term Growth in TBV per Share WAL WAL with Dividends Added Back Peer Avg Peer Avg with Dividends Added Back Highlights Common Equity Tier 1 • CET1 remains healthy at 9.4% as of 3/31 . CET1 was ~9.7% as of 4/30 482% 427% Tangible Common Equity / Tangible Assets² • TCE / TA decreased 20 bps from 2022 to 6.5%, primarily due to AOCI loss impact TBV² Growth and Total Shareholder Return • Long-term shareholder returns driven by TBV accretion ● . • TBVPS increased 11.9% from 2022 19.7% TBVPS CAGR since year end 2013 TBVPS has increased more than 4x that of peers Strong returns bolster capital appreciation above peers • WAL produced 10 bps of CET1 during 1Q through strong, organic capital generation and HFS loan sales 135% 102% 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 MRQ WA Western Alliance Bancorporation® Note: Peers consist of 34 publicly traded banks headquartered in the U.S. with total assets between $25B and $150B as of March 31, 2023 Source: S&P Global Market Intelligence. MRQ is 1Q23 for WAL and most peers and 4Q22 for the remainder Refer to slide 2 for further discussion of Non-GAAP financial measures 21#22WA Western Alliance Bancorporation® Appendix#23Top 50 Banks by Assets - CET1 & ROAA • • WAL ranks No. 25 of the top 50 banks on Adjusted CET1, inclusive of AOCI and HTM unrealized marks WAL is at the top decile on average ROAA CET1 Adj. CET1 Adj. for AOCI & Avg. for AOCI & Avg. Rank Name HTM CET1 ROAA Rank Name HTM CET1 ROAA 1 JPMorgan Chase & Co. 2 First Citizens Bancshares, Inc. 11.4% 13.8% 1.11% 26 Valley National Bancorp 8.0% 9.0% 1.06% 11.3% 12.5% 6.64% 27 Fulton Financial Corporation 7.6% 9.8% 1.11% 45678 3 United Bankshares, Inc. East West Bancorp, Inc. Bank OZK 11.3% 12.5% 1.36% 28 Citizens Financial Group, Inc. 7.6% 10.0% 0.97% 10.9% 13.1% 1.90% 29 First Interstate BancSystem, Inc. 7.6% 10.5% 0.91% 30 10.8% 11.2% 2.25% Associated Banc-Corp 7.6% 9.5% 1.05% 31 Prosperity Bancshares, Inc. 10.7% 15.6% 1.40% Regions Financial Corporation 7.6% 9.9% 1.47% 32 Texas Capital Bancshares, Inc. 10.6% 12.4% 1.08% Wells Fargo & Company 7.5% 10.8% 0.76% 33 Wintrust Financial Corporation 7.4% 9.2% 1.10% Commerce Bancshares, Inc. 10.5% 14.5% 1.54% 34 Cadence Bank 7.3% 10.1% 0.89% 9 Popular, Inc. 10.1% 16.7% 1.47% 35 Citigroup Inc. 7.3% 12.3% 0.63% 10 Columbia Banking System, Inc. 10.0% 8.9% 0.76% 36 Synovus Financial Corp. 7.3% 9.8% 1.35% 11 BOK Financial Corporation 9.9% 12.2% 1.35% 37 Simmons First National Corporation 7.3% 11.9% 0.87% 12 Ameris Bancorp 9.9% 10.1% 1.36% 38 UMB Financial Corporation 7.2% 10.6% 1.12% 13 Bank United, Inc. 9.4% 10.8% 0.74% 39 Old National Bancorp 7.2% 10.0% 1.30% 14 M&T Bank Corporation 9.2% 10.2% 1.16% 40 Fifth Third Bancorp 6.8% 9.3% 1.22% 15 Cullen/Frost Bankers, Inc. 9.0% 13.2% 1.27% 41 PacWest Bancorp 6.7% 9.2% -2.05% 16 United Community Banks, Inc. 9.0% 12.1% 1.20% 42 Huntington Bancshares Incorporated 6.5% 9.6% 1.32% 17 Pinnacle Financial Partners, Inc. 9.0% 9.9% 1.39% 43 The PNC Financial Services Group, Inc. 6.5% 9.2% 1.15% 18 Glacier Bancorp, Inc. 8.9% 12.7% 1.12% 44 Comerica Incorporated 6.2% 10.1% 1.50% 19 Hancock Whitney Corporation 8.7% 11.6% 1.51% 45 First Hawaiian, Inc. 6.1% 12.0% 1.11% 222222 20 New York Community Bancorp, Inc. 8.5% 9.3% 2.88% 46 Zions Bancorporation, National Association 5.8% 9.9% 1.02% 21 First Horizon Corporation 8.4% 10.4% 1.19% 47 KeyCorp 5.5% 9.1% 0.95% F.N.B. Corporation 8.4% 10.0% 1.25% 48 Bank of America Corporation 5.4% 11.4% 0.92% 23 SouthState Corporation 8.4% 11.1% 1.20% 49 U.S. Bancorp 4.9% 8.5% 0.98% 24 Webster Financial Corporation 8.3% 10.4% 1.28% 50 Truist Financial Corporation 4.6% 9.1% 1.16% 25 Western Alliance Bancorporation 8.1% 9.4% 1.57% Median 8.1% 10.3% 1.18% WA Western Alliance Bancorporation® 23 23#24Focused Efforts to Drive Increased Deposit Liquidity Deposit-led growth driving loan-to-deposit ratio to mid-80s poised to lift WAL from top-quintile for largest banks to top-10 Rank Name Insured Deposit % Loan / I Insured / Deposit % L/D Rank Name Insured Deposit % Loan / Deposit % ! Insured/ L/D 1 Cullen/Frost Bankers, Inc. 49% 41% 1.18x 26 Associated Banc-Corp 76% 96% 0.79x| 2 Bank of America Corporation 61% 55% 1.12x 27 PacWest Bancorp 71% 91% 0.78x 3 Simmons First National Corporation 77% 74% 1.04x 28 Truist Financial Corporation 63% 81% 0.78x 4 Commerce Bancshares, Inc. 68% 67% 1.02x 29 South State Corporation 65% 84% 0.77x 5 JPMorgan Chase & Co. 48% 47% 1.01x | 30 Old National Bancorp 70% 91% 0.77x 6 Regions Financial Corporation 75% 76% 0.98x 31 Citizens Financial Group, Inc. 68% 90% 0.76x 7 Prosperity Bancshares, Inc. 70% 72% 0.98x 32 Wintrust Financial Corporation 70% 93% 0.76x 8 United Community Banks, Inc. 76% 78% 0.98x 33 The PNC Financial Services Group, Inc. 55% 75% 0.74x 9 Glacier Bancorp, Inc. 74% 77% 0.96x 34 United Bankshares, Inc. 67% 92% 0.72x 10 First Interstate BancSystem, Inc. 72% 76% 0.95x 35 Columbia Banking System, Inc. 64% 89% 0.72x 11 Popular, Inc. 48% 53% 0.90x 36 Fulton Financial Corporation 69% 97% 0.71x1 12 Cadence Bank 70% 79% 0.89x 37 Bank OZK 67% 99% 0.68x 13 First Hawaiian, Inc. 58% 67% 0.87x 38 New York Community Bancorp, Inc. 66% 97% 0.68x 14 F.N.B. Corporation 76% 90% 0.85x 39 Zions Bancorporation, National Association 55% 81% 0.68x 15 Western Alliance Bancorporation 79% 94% 0.84x 40 Valley National Bancorp 69% 102% 0.67x 16 UMB Financial Corporation 57% 68% 0.83x || 41 M&T Bank Corporation 55% 83% 0.67x 17 Webster Financial Corporation 77% 92% 0.83x 42 U.S. Bancorp 51% 77% 0.66x 18 Synovus Financial Corp. 73% 88% 0.83x 43 BankUnited, Inc. 62% 97% 0.64x 19 Huntington Bancshares Incorporated 69% 83% 0.83x 44 East West Bancorp, Inc. 56% 89% 0.63x 20 Hancock Whitney Corporation 64% 79% 0.81x 45 Comerica Incorporated 53% 85% 0.62x 21 BOK Financial Corporation 56% 70% 0.80x 46 Texas Capital Bancshares, Inc. 55% 91% 0.61x 2222 Pinnacle Financial Partners, Inc. 67% 84% 0.80x 47 First Horizon Corporation 56% 96% 0.59x | 23 Fifth Third Bancorp 60% 75% 0.80x 48 Ameris Bancorp 58% 101% 0.58x 24 Wells Fargo & Company 55% 70% 0.80x 49 Citigroup Inc. 27% 49% 0.56x 25 KeyCorp 66% 83% 0.79x 50 First Citizens BancShares, Inc. Median 53% 99% 0.54x 66% 83% 0.79x WA Western Alliance Bancorporation® Note: Deposit % as of March 31, 2023, except for WAL, which is as of May 12, 2023. Deposit insurance includes direct, collateralized, pass-through, and insured networks WAL Loan-to-Deposit % uses HFI Loans Source: S&P Global Market Intelligence, 1Q23 company earnings presentations, and 1Q23 Call Reports 24#25WAL's Thoughtful Evolution Deliberate evolution from a Nevada-focused community bank to a national commercial bank New Business Lines Key Corporate Events Total Assets ($Bn) 4Q02 $0.9 2Q05 $2.6 1994 Founded as Bank West of Nevada Dec-2002 WAL investors acquire to expand regionally 2005 IPO 4Q09 $5.8 BANK OF NEVADA FIRST INDEPENDENT BANK 2015 Acquisition of Bridge Bank Nevada Community Bank (1994 - 2002) Nascent Regional Bank (2003 - 2009) Alliance Bank WA Western Alliance Bancorporation® OF ARIZONA Alliance Association BankⓇ TORREY PINES BANK 2003 Opened de novo Alliance Bank of AZ 2003 Opened de novo Torrey Pines Bank in SoCal HOA Services ('08) 2014 $10.0 4Q17 2019 3Q21 1023 $20.3 $25.3 $52.8 $71.0 2016 2021 Acquisition Crossed of GE Hotel Finance Portfolio $50B in assets 2021 Acquisition of AmeriHome Mortgage BridgeBank Regional Bank with a National Reach (2010 - 2017) National Business Lines Specialized Mortgage Services ('10) Municipal / Public Finance ('11) Resort Finance ('12) Technology & Innovation ('15) Hotel Franchise Finance ('16) National Commercial Bank (2018 - Present) Gaming ('19) Settlement Services ('19) Business Escrow Services ('20) Digital Asset Banking ('21) Entertainment & Media ('21) Restaurant Franchise Finance ('21) 2021 Partnership with TassatPay to offer blockchain payments 25 25#26Geography Composition Characteristics Highlights Business Transformation Deliberate business transformation emphasizes underwriting specialization and diversification strategy, which sustains superior asset quality Loan Portfolio: 2010 Community banking focused Nevada concentrated Local business C&I and HNW developers Other 4% • Loan Portfolio: 1Q23 National, specialized commercial bank Regional footprint Specialized C&l and institutional sponsor-backed developers C&D 10% Other C&I 20% Equity Fund Resources 2% C&D 9% Municipal Other & Nonprofit Tech & 1% 3% Innovation 5% Other C&I 13% Residential Warehouse Lending 11% 1% Hotel 2% $4.2 Bn CRE, Owner Occupied 28% CRE, Non-Owner Occupied 24% NV 40.4% CA 21.9% AZ 17.0% Other 20.7% 25% of Residential 32% Loans Credit Protected $46.4 Bn Warehouse Lending 10% Hotel Franchise Finance 9% CA 38.8% AZ 9.4% NV 6.0% Other 45.8% CRE, Owner Occupied 4% CRE, Non- Owner Occupied 12% • • • Deliberate, decade-long business transformation strategy • Nearly 70% of GFC losses from 4Q09 to 4Q12 came from categories comprising 44% of portfolio at 4Q09, which today makes up <6% of loans • Losses concentrated in Nevada and consumer lending during GFC Since year-end 2013, cumulative NCOs of $35mm vs total ACL of $350mm today • No quarterly NCO >$8.2mm (13bps) Diverse mix of regionally-focused commercial banking divisions and nationally-oriented, specialized businesses • • • National reach and deep segment expertise enables selective relationships with strong counterparties, leading profitability and superior company risk management Nevada loan concentration reduction: 40% to 6% National lending diversification: 21% to 46% CRE loan concentration reduction: 54% to 25% 50% of loans in low-to-no-loss categories today WA Western Alliance Bancorporation® 26 26#27Branch-Lite, National Commercial Bank A national banking platform of specialized financial services, paired with attractive regional markets, provides complementary, diversified revenue streams and high operating leverage to produce superior financial returns WAL's branch network represented by major MSAs Physical office location of business development employees Remote locations of business development employees WA Western Alliance BancorporationⓇ National Business Line Growth Business development offices primarily driven by loan and deposit initiatives for: - Bridge Bank / Tech & Innovation - Warehouse Lending - National CRE Settlement Services - Business Escrow Services - HOA Services | 27#28Commercial Real Estate Statistics CRE ($11.2 Billion; 25% of Total Loans) 29% 15% 21% 35% ■ Hotel ■ Office Other CRE - Investor Other CRE - OO Asset Quality ($B) 3/31/23 Special Mention % Sub-Std % Office ($2.5 Billion; 5% of Total Loans) . . • Primarily shorter-term bridge loans for repositioning or redevelopment projects Strong sponsorship from institutional equity and large regional and national developers • All direct relationships generated by WAL Significant up-front cash equity required from. sponsors Conservative loan-to-cost underwriting Average LTV < 55%; Average LTC ~62% No junior debt/mezzanine Largely suburban exposure in "Work From Home" MSAs • <15% in San Fran. / Bay Area, Seattle, and NYC Limited exposure to Downtown / Central Business Districts (CBDs) Hotel $4.3 ($3.9 - CRE Inv.) 0.2% 4.9% Office $2.5 (~$2.4 - CRE Inv.) 2.6% 1.5% WA Western Alliance BancorporationⓇ 28 28#29WA Western Alliance Bancorporation®