Investor Presentaiton

Transaction Assumptions Earnings Consensus earnings estimates for both companies • ~$6.1 million, or 35.0% of AMRB's standalone noninterest expense base Cost Savings • 25% phase-in during 2021, 90% phase-in during 2022, and 100% thereafter Transaction Expenses $9.5 million after-tax or 7.1% of aggregate deal value • Total gross credit mark of $6.6 million, or 1.56% of AMRB's loan portfolio (excl. PPP) Fair Market Value Adjustments - $0.3 million, or 4.7% of total gross credit mark associated with purchase credit deteriorated ("PCD") loans, recorded into ACL (5.00% of estimated PCD loans) - $6.3 million, or 95.3% of gross loan credit mark associated with non-PCD loans, recorded as a discount to loan value; amortized into earnings over 4 years (1.52% of non-PCD loans) Provision expense of $6.3 million to be taken immediately after close, included in pro forma tangible book value Positive loan interest rate mark of $5.2 million or 1.25% of AMRB's loan portfolio (excl. PPP); amortized from earnings straight-line over 4 years • AOCI netted for fair market value reduction of $1.5 million pretax; amortized into earnings straight line over 4 years Fixed asset write-up $1.3 million on AMRB's Healdsburg branch; 50% depreciated straight-line over 25 years Core Deposit Intangibles Bank of Marin Bancorp American River Bankshares • ~$3.4 million, or 0.50% of AMRB's non-time deposits Amortized sum-of-the-year digits over 10 years 7

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