Investor Presentaiton

Highlights Substantial Reserve Levels Reserve levels enhanced by credit protection and low loss loan categories Adjusted Total Loan ACL / Funded Loans: 4Q22 1.34% 1.13% 0.21% 0.06% EBOS³ 0.89% 0.94% 0.05% 0.13% Resi 0.20% 0.69% 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 0.69% in Q4 as a result of heightened economic uncertainty • Total Loan ACL / Funded Loans less loans covered by CLNs is 0.89% Total Loan ACL / Funded Loans less loans covered by CLNs and select no-to- low-loss loan categories (EFR, Residential, and Mortgage Warehouse) is 1.34% . > 7.5x 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 Total Loan ACL / Funded Loans 1,2 - Loans Covered by CLNs - EFR Loans Residential Loans - Mortgage Warehouse Loans • 1 2 3 4 5 Adj. total ACL covers > 25x of historical average annual loss rate4x duration WA Western Alliance Bancorporation® 1) Total Loan ACL includes allowance for unfunded commitments. 2) Ratio includes an allowance for credit losses of $21.9 million as of December 31, 2022 related to a $12.0 billion pool of loans covered under 5 separate credit linked notes. 3) Early Buyout Loans are government guaranteed. 4) Historical weighted average loss rates from the period of Q1 2014 - Q4 2022, per slide 13. 14

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