Basis of Presentation - (Policies)	3 Months Ended
Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The consolidated financial statements include the accounts of Bank of Marin Bancorp (“Bancorp”), a bank holding company, and its wholly-owned bank subsidiary, Bank of Marin (the “Bank”), a California state-chartered commercial bank. References to “we,” “our,” “us” mean Bancorp and the Bank that are consolidated for financial reporting purposes. The accompanying unaudited consolidated interim financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). Certain information and note disclosures normally included in annual financial statements prepared in accordance with U.S. generally accepted accounting principles ("GAAP") have been condensed or omitted pursuant to those rules and regulations. Certain items in prior financial statements have been reclassified to conform to the current presentation. Although we believe that the disclosures are adequate and the information presented is not misleading, we suggest that these interim financial statements be read in conjunction with the annual financial statements and the notes thereto included in our 2020 Annual Report on Form 10-K. In the opinion of management, the unaudited consolidated financial statements reflect all adjustments, which are necessary for a fair presentation of the consolidated financial position, the results of operations, changes in comprehensive income, changes in stockholders’ equity, and cash flows for the periods presented. All material intercompany transactions have been eliminated. The results of these interim periods may not be indicative of the results for the full year or for any other period. The NorCal Community Bancorp Trust II (the "Trust") was formed for the sole purpose of issuing trust preferred securities. Bancorp is not considered the primary beneficiary of the Trust (a variable interest entity), therefore the Trust is not consolidated in our consolidated financial statements, but rather the subordinated debenture is shown as a liability on our consolidated statements of condition. Bancorp's investment in the securities of the Trust is accounted for under the equity method and is included in interest receivable and other assets on the consolidated statements of condition. Refer to Note 6, Borrowings, for additional information on the subordinated debenture due to NorCal Community Bancorp Trust II and the early redemption that occurred on March 15, 2021.
Earnings Per Share	Basic earnings per share (“EPS”) are calculated by dividing net income by the weighted average number of common shares outstanding during each period, excluding unvested restricted stock awards. Diluted EPS are calculated using the weighted average number of potentially dilutive common shares. The number of potentially dilutive common shares included in the quarterly diluted EPS is computed using the average market prices during the three months included in the reporting period under the treasury stock method. The number of potentially dilutive common shares included in year-to-date diluted EPS is a year-to-date weighted average of potentially dilutive common shares included in each quarterly diluted EPS computation. In computing diluted EPS, we exclude anti-dilutive shares such as options whose exercise prices exceed the current common stock price, as they would not reduce EPS under the treasury method. We have two forms of outstanding common stock: common stock and unvested restricted stock awards. Holders of unvested restricted stock awards receive non-forfeitable dividends at the same rate as common shareholders and they both share equally in undistributed earnings. Under the two-class method, the difference in EPS is nominal for these participating securities.
Recently Adopted and Issued Accounting Standards	Accounting Standards Adopted in 2021 In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (ASC Topic 740): Simplifying the Accounting for Income Taxes. This ASU is intended to reduce the cost and complexity related to accounting for income taxes by removing certain exceptions to the guidance in ASC 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and simplifying aspects of the accounting for franchise taxes and enacted changes in tax laws or rates. We adopted this ASU prospectively on January 1, 2021, which did not have a material impact on our financial condition or results of operations. In January 2020, the FASB issued ASU No. 2020-01, Investments - Equity Securities (ASC Topic 321), Investments - Equity Method and Joint Ventures (ASC Topic 323), and Derivatives and Hedging (ASC Topic 815) - Clarifying the Interactions between ASC 321, ASC 323, and ASC 815. Among other things, this ASU clarifies that a company should consider observable transactions that require a company to either apply or discontinue the equity method of accounting under ASC 323, for the purposes of applying the measurement alternative in accordance with ASC 321. We adopted this ASU prospectively on January 1, 2021, which did not have a material impact on our financial condition or results of operations. In October 2020, the FASB issued ASU No. 2020-08, Codification Improvements to Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs. This ASU was issued as part of the Board's ongoing project to improve codification or correct unintended application. This ASU adds clarification to ASU 2017-08, which the Bank early-adopted in 2017, and delineates whether an entity with callable debt securities that have multiple call dates should amortize the amount above that which is repayable, to the next call date. We adopted this ASU prospectively on January 1, 2021. Because this ASU was narrow in scope and for clarification purposes, it did not have a material impact on our financial condition and results of operations. Accounting Standards Not Yet Effective In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848). The amendments in this ASU are elective and provide optional guidance for a limited period of time to ease the potential burden of accounting for, or recognizing the effects of reference rate reform. The amendments in this ASU provide optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. The amendments in this ASU may be elected as of March 12, 2020 through December 31, 2022. An entity may choose to elect the amendments in this update at an interim period subsequent to March 12, 2020 with adoption methods varying based on transaction type. We have not elected to apply amendments at this time, however, will assess the applicability of this ASU to us as we continue to monitor guidance for reference rate reform from FASB and its impact on our financial condition and results of operations. In January 2021, the FASB issued ASU No. 2021-01, Reference Rate Reform (Topic 848). The main amendments in this ASU are intended to clarify certain optional expedients and scope of derivative instruments. The amendments are elective and effective immediately upon issuance of this ASU. Amendments may be elected through December 31, 2022. We have not elected to apply amendments at this time, however, will assess the applicability of this ASU to us as we continue to monitor guidance for reference rate reform from FASB and its impact on our financial condition and results of operations.
Fair Value Hierarchy and Fair Value Measurement	We group our assets and liabilities that are measured at fair value in three levels within the fair value hierarchy, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are: Level 1: Valuations are based on unadjusted quoted prices in active markets for identical assets or liabilities. Level 2: Valuations are based on quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuations for which all significant assumptions are observable or can be corroborated by observable market data. Level 3: Valuations are based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Values are determined using pricing models and discounted cash flow models and may include significant management judgment and estimation. Available-for-sale securities are recorded at fair value on a recurring basis. When available, quoted market prices (Level 1) are used to determine the fair value of available-for-sale securities. If quoted market prices are not available, we obtain pricing information from a reputable third-party service provider, who may utilize valuation techniques that use current market-based or independently sourced parameters, such as bid/ask prices, dealer-quoted prices, interest rates, benchmark yield curves, prepayment speeds, probability of default, loss severity and credit spreads (Level 2). Level 2 securities include obligations of state and political subdivisions, U.S. agencies or government-sponsored agencies' debt securities, mortgage-backed securities, government agency-issued, privately-issued collateralized mortgage obligations, and corporate bonds.Held-to-maturity securities may be written down to fair value as a result of impairment through a provision for credit losses in investments securities. We On a recurring basis, derivative financial instruments are recorded at fair value, which is based on the income approach using observable Level 2 market inputs, reflecting market expectations of future interest rates as of the measurement date. Standard valuation techniques are used to calculate the present value of the future expected cash flows assuming an orderly transaction. Valuation adjustments may be made to reflect both our own credit risk and the counterparties’ credit risk in determining the fair value of the derivatives. Level 2 inputs for the valuations are limited to observable market prices for London Interbank Offered Rate ("LIBOR") and Overnight Index Swap ("OIS") rates (for the very short term), quoted prices for LIBOR futures contracts, observable market prices for LIBOR and OIS swap rates, and one-month and three-month LIBOR basis spreads at commonly quoted intervals. Mid-market pricing of the inputs is used as a practical expedient in the fair value measurements. We project spot rates at reset days specified by each swap contract to determine future cash flows, then discount to present value using OIS curves as of the measurement date. When the value of any collateral placed with counterparties is less than the interest rate derivative liability, a credit valuation adjustment ("CVA") is applied to reflect the credit risk we pose to counterparties. We have used the spread between the Standard & Poor's BBB rated U.S. Bank Composite rate and LIBOR for the closest maturity term corresponding to the duration of the swaps to derive the CVA. A similar credit risk adjustment, correlated to the credit standing of the counterparty, is made when collateral posted by the counterparty does not fully cover their liability to us. For further discussion on our methodology in valuing our derivative financial instruments, refer to Note 9, Derivative Financial Instruments and Hedging Activities.Certain financial assets may be measured at fair value on a non-recurring basis. These assets are subject to fair value adjustments that result from the application of the lower of cost or fair value accounting or write-downs of individual assets, such as impaired loans that are collateral dependent and other real estate owned ("OREO"). Fair value of loans is based on exit price techniques and obtained from an independent third-party that uses its proprietary valuation model and methodology and may not reflect actual or prospective market valuations. The discounted cash flow valuation approach reflects key inputs and assumptions such as loan probability of default, loss given default, prepayment speed, and market discount rates. Fair value of fixed-rate time deposits is estimated by discounting future contractual cash flows using discount rates that reflect the current market rates offered for time deposits of similar remaining maturities. Fair value of the subordinated debenture is estimated using a discounted cash flow approach based on current interest rates for similar financial instruments adjusted for credit and liquidity spreads. The value of unrecognized financial instruments is estimated based on the fee income associated with the commitments which, in the absence of credit exposure, is considered to approximate their settlement value.
Finance, Loan and Lease Receivables, Held-for-investment, Allowance and Nonperforming Loans	Commercial and Industrial Loans - Commercial loans are generally made to established small and mid-sized businesses to provide financing for their growth and working capital needs, equipment purchases and acquisitions. Management examines historical, current, and projected cash flows to determine the ability of the borrower to repay obligations as agreed. Commercial loans are made based primarily on the identified cash flows of the borrower and secondarily on the underlying collateral and guarantor support. The cash flows of borrowers, however, may not occur as expected, and the collateral securing these loans may fluctuate in value. Most commercial and industrial loans are secured by the assets being financed, such as accounts receivable and inventory, and typically include personal guarantees. We target stable businesses with guarantors who provide additional sources of repayment and have proven to be resilient in periods of economic stress. A weakened economy, and resultant decreased consumer and/or business spending, may have an effect on the credit quality of commercial loans. In April 2020, the Bank began participating in the Small Business Administration's ("SBA") Paycheck Protection Program ("PPP"). As of March 31, 2021, there were 2,513 PPP loans outstanding. PPP loans totaling $365.0 million (net of $8.0 million in unrecognized fees and costs) and $291.6 million (net of $5.4 million in unrecognized fees and costs) as of March 31, 2021 and December 31, 2020, respectively, were included in commercial and industrial loan balances. Of the PPP loans outstanding as of March 31, 2021, 841 loans totaling $119.5 million funded during the first quarter of 2021 under the second round of the PPP stimulus plan. PPP loans have terms of two to five years and earn interest at 1%. In addition, the SBA paid the Bank a fee of 1%-5% depending on the loan amount, which was netted with loan origination costs and accreted/amortized into interest income using the effective yield method over the contractual life of each loan. The recognition of fees and costs is accelerated when the SBA forgives the loan and/or the loan is paid off prior to maturity. PPP loans are fully guaranteed by the SBA and have virtually no risk of loss. We expect the vast majority of the PPP loans to be fully forgiven by the SBA. Commercial Real Estate Loans - Commercial real estate loans, which include income producing investment properties and owner-occupied real estate used for business purposes, are subject to underwriting standards and processes similar to commercial loans discussed above. We underwrite these loans to be repaid from cash flow and to be supported by real property collateral. Underwriting standards for commercial real estate loans include, but are not limited to, debt coverage and loan-to-value ratios. Furthermore, a large majority of our loans are guaranteed by the owners of the properties. Conditions in the real estate markets or downturn in the general economy may adversely affect our commercial real estate loans. In the event of a vacancy, we expect guarantors to carry the loans until they find a replacement tenant. The owner's substantial equity investment provides a strong economic incentive to continue to support the commercial real estate projects. As such, we have generally experienced a relatively low level of loss and delinquencies in this portfolio. Construction Loans - Construction loans are generally made to developers and builders to finance construction, renovation and occasionally land acquisitions in anticipation of near-term development. Construction loans include interest reserves that are used for the payment of interest during the development and marketing periods and are capitalized as part of the loan balance. When a construction loan is placed on nonaccrual status before the depletion of the interest reserve, we apply the interest funded by the interest reserve against the loan's principal balance. These loans are underwritten after evaluation of the borrower's financial strength, reputation, prior track record, and independent appraisals. We monitor all construction projects to determine whether they are on schedule, completed as planned and in accordance with the approved construction budgets. Significant events can affect the construction industry, including: the inherent volatility of real estate markets and vulnerability to delays due to weather, change orders, inability to obtain construction permits, labor or material shortages, and price changes. Estimates of construction costs and value associated with the completed project may be inaccurate. Repayment of construction loans is largely dependent on the ultimate success of the project. Consumer Loans - Consumer loans primarily consist of home equity lines of credit, other residential loans and floating homes along with a small number of installment loans. Our other residential loans include tenancy-in-common fractional interest loans ("TIC") located almost entirely in San Francisco County. We originate consumer loans utilizing credit score information, debt-to-income ratio and loan-to-value ratio analysis. Diversification among consumer loan types, coupled with relatively small loan amounts that are spread across many individual borrowers, mitigates risk. We do not originate sub-prime residential mortgage loans, nor is it our practice to underwrite loans commonly referred to as "Alt-A mortgages," the characteristics of which are reduced documentation, borrowers with low FICO scores or collateral with high loan-to-value ratios. Credit Quality Indicators We use a risk rating system to evaluate asset quality, and to identify and monitor credit risk in individual loans, and in the loan portfolio. Our definitions of “Special Mention” risk graded loans, or worse, are consistent with those used by the Federal Deposit Insurance Corporation ("FDIC"). Our internally assigned grades are as follows: Pass and Watch - Loans to borrowers of acceptable or better credit quality. Borrowers in this category demonstrate fundamentally sound financial positions, repayment capacity, credit history and management expertise. Loans in this category must have an identifiable and stable source of repayment and meet the Bank’s policy regarding debt-service-coverage ratios. These borrowers are capable of sustaining normal economic, market or operational setbacks without significant financial consequences. Negative external industry factors are generally not present. The loan may be secured, unsecured or supported by non-real estate collateral for which the value is more difficult to determine and/or marketability is more uncertain. This category also includes “Watch” loans, where the primary source of repayment has been delayed. “Watch” is intended to be a transitional grade, with either an upgrade or downgrade within a reasonable period. Special Mention - Potential weaknesses that deserve close attention. If left uncorrected, those potential weaknesses may result in deterioration of the payment prospects for the asset. Special Mention assets do not present sufficient risk to warrant adverse classification. Substandard - Inadequately protected by either the current sound worth and paying capacity of the obligor or the collateral pledged, if any. A Substandard asset has a well-defined weakness or weaknesses that jeopardize(s) the liquidation of the debt. Substandard assets are characterized by the distinct possibility that we will sustain some loss if such weaknesses or deficiencies are not corrected. Well-defined weaknesses include adverse trends or developments of the borrower’s financial condition, managerial weaknesses and/or significant collateral deficiencies. Doubtful - Critical weaknesses that make collection or liquidation in full improbable. There may be specific pending events that work to strengthen the asset; however, the amount or timing of the loss may not be determinable. Pending events generally occur within one year of the asset being classified as Doubtful. Examples include: merger, acquisition, or liquidation; capital injection; guarantee; perfecting liens on additional collateral; and refinancing. Such loans are placed on non-accrual status and usually are collateral-dependent. We regularly review our credits for accuracy of risk grades whenever we receive new information. Borrowers are generally required to submit financial information at regular intervals. Typically, commercial borrowers with lines of credit are required to submit financial information with reporting intervals ranging from monthly to annually depending on credit size, risk and complexity. In addition, investor commercial real estate borrowers with loans exceeding a certain dollar threshold are usually required to submit rent rolls or property income statements annually. We monitor construction loans monthly. We review home equity and other consumer loans based on delinquency. We also review loans graded “Watch” or worse, regardless of loan type, no less than quarterly.
Troubled Debt Restructuring	Our loan portfolio includes certain loans modified in a troubled debt restructuring (“TDR”), where we have granted economic concessions to borrowers experiencing financial difficulties. These concessions typically result from our loss mitigation activities and could include reductions in the interest rate, payment extensions, forgiveness of principal, forbearance or other actions. TDRs on non-accrual status at the time of restructure may be returned to accruing status after management considers the borrower’s sustained repayment performance for a reasonable period, generally nine months, and obtains reasonable assurance of repayment and performance. We may remove a loan from TDR designation if it meets all of the following conditions: •The loan is subsequently refinanced or restructured at current market interest rates and the new terms are consistent with the treatment of creditworthy borrowers under regular underwriting standards; •The borrower is no longer considered to be in financial difficulty; •Performance on the loan is reasonably assured; and •Existing loan did not have any forgiveness of principal or interest.

Basis of Presentation - (Policies)

3 Months Ended

Mar. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The consolidated financial statements include the accounts of Bank of Marin Bancorp (“Bancorp”), a bank holding company, and its wholly-owned bank subsidiary, Bank of Marin (the “Bank”), a California state-chartered commercial bank. References to “we,” “our,” “us” mean Bancorp and the Bank that are consolidated for financial reporting purposes. The accompanying unaudited consolidated interim financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). Certain information and note disclosures normally included in annual financial statements prepared in accordance with U.S. generally accepted accounting principles ("GAAP") have been condensed or omitted pursuant to those rules and regulations. Certain items in prior financial statements have been reclassified to conform to the current presentation. Although we believe that the disclosures are adequate and the information presented is not misleading, we suggest that these interim financial statements be read in conjunction with the annual financial statements and the notes thereto included in our 2020 Annual Report on Form 10-K. In the opinion of management, the unaudited consolidated financial statements reflect all adjustments, which are necessary for a fair presentation of the consolidated financial position, the results of operations, changes in comprehensive income, changes in stockholders’ equity, and cash flows for the periods presented. All material intercompany transactions have been eliminated. The results of these interim periods may not be indicative of the results for the full year or for any other period.

The NorCal Community Bancorp Trust II (the "Trust") was formed for the sole purpose of issuing trust preferred securities. Bancorp is not considered the primary beneficiary of the Trust (a variable interest entity), therefore the Trust is not consolidated in our consolidated financial statements, but rather the subordinated debenture is shown as a liability on our consolidated statements of condition. Bancorp's investment in the securities of the Trust is accounted for under the equity method and is included in interest receivable and other assets on the consolidated statements of condition. Refer to Note 6, Borrowings, for additional information on the subordinated debenture due to NorCal Community Bancorp Trust II and the early redemption that occurred on March 15, 2021.

Earnings Per Share

Basic earnings per share (“EPS”) are calculated by dividing net income by the weighted average number of common shares outstanding during each period, excluding unvested restricted stock awards. Diluted EPS are calculated using the weighted average number of potentially dilutive common shares. The number of potentially dilutive common shares included in the quarterly diluted EPS is computed using the average market prices during the three months included in the reporting period under the treasury stock method. The number of potentially dilutive common shares included in year-to-date diluted EPS is a year-to-date weighted average of potentially dilutive common shares included in each quarterly diluted EPS computation. In computing diluted EPS, we exclude anti-dilutive shares such as options whose exercise prices exceed the current common stock price, as they would not reduce EPS under the treasury method. We have two forms of outstanding common stock: common stock and unvested restricted stock awards. Holders of unvested restricted stock awards receive non-forfeitable dividends at the same rate as common shareholders and they both share equally in undistributed earnings. Under the two-class method, the difference in EPS is nominal for these participating securities.

Recently Adopted and Issued Accounting Standards

Accounting Standards Adopted in 2021

In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (ASC Topic 740): Simplifying the Accounting for Income Taxes. This ASU is intended to reduce the cost and complexity related to accounting for income taxes by removing certain exceptions to the guidance in ASC 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and simplifying aspects of the accounting for franchise taxes and enacted changes in tax laws or rates. We adopted this ASU prospectively on January 1, 2021, which did not have a material impact on our financial condition or results of operations.

In January 2020, the FASB issued ASU No. 2020-01, Investments - Equity Securities (ASC Topic 321), Investments - Equity Method and Joint Ventures (ASC Topic 323), and Derivatives and Hedging (ASC Topic 815) - Clarifying the Interactions between ASC 321, ASC 323, and ASC 815. Among other things, this ASU clarifies that a company should consider observable transactions that require a company to either apply or discontinue the equity method of accounting under ASC 323, for the purposes of applying the measurement alternative in accordance with ASC 321. We adopted this ASU prospectively on January 1, 2021, which did not have a material impact on our financial condition or results of operations.

In October 2020, the FASB issued ASU No. 2020-08, Codification Improvements to Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs. This ASU was issued as part of the Board's ongoing project to improve codification or correct unintended application. This ASU adds clarification to ASU 2017-08, which the Bank early-adopted in 2017, and delineates whether an entity with callable debt securities that have multiple call dates should amortize the amount above that which is repayable, to the next call date. We adopted this ASU prospectively on January 1, 2021. Because this ASU was narrow in scope and for clarification purposes, it did not have a material impact on our financial condition and results of operations.

Accounting Standards Not Yet Effective

In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848). The amendments in this ASU are elective and provide optional guidance for a limited period of time to ease the potential burden of accounting for, or recognizing the effects of reference rate reform. The amendments in this ASU provide optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. The amendments in this ASU may be elected as of March 12, 2020 through December 31, 2022. An entity may choose to elect the amendments in this update at an interim period subsequent to March 12, 2020 with adoption methods varying based on transaction type. We have not elected to apply amendments at this time, however, will assess the applicability of this ASU to us as we continue to monitor guidance for reference rate reform from FASB and its impact on our financial condition and results of operations.

In January 2021, the FASB issued ASU No. 2021-01, Reference Rate Reform (Topic 848). The main amendments in this ASU are intended to clarify certain optional expedients and scope of derivative instruments. The amendments are elective and effective immediately upon issuance of this ASU. Amendments may be elected through December 31, 2022. We have not elected to apply amendments at this time, however, will assess the applicability of this ASU to us as we continue to monitor guidance for reference rate reform from FASB and its impact on our financial condition and results of operations.

Fair Value Hierarchy and Fair Value Measurement

We group our assets and liabilities that are measured at fair value in three levels within the fair value hierarchy, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are:

Level 1: Valuations are based on unadjusted quoted prices in active markets for identical assets or liabilities.

Level 2: Valuations are based on quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuations for which all significant assumptions are observable or can be corroborated by observable market data.

Level 3: Valuations are based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Values are determined using pricing models and discounted cash flow models and may include significant management judgment and estimation.

Available-for-sale securities are recorded at fair value on a recurring basis. When available, quoted market prices (Level 1) are used to determine the fair value of available-for-sale securities. If quoted market prices are not available, we obtain pricing information from a reputable third-party service provider, who may utilize valuation techniques that use current market-based or independently sourced parameters, such as bid/ask prices, dealer-quoted prices, interest rates, benchmark yield curves, prepayment speeds, probability of default, loss severity and credit spreads (Level 2). Level 2 securities include obligations of state and political subdivisions, U.S. agencies or government-sponsored agencies' debt securities, mortgage-backed securities, government agency-issued, privately-issued collateralized mortgage obligations, and corporate bonds.Held-to-maturity securities may be written down to fair value as a result of impairment through a provision for credit losses in investments securities. We On a recurring basis, derivative financial instruments are recorded at fair value, which is based on the income approach using observable Level 2 market inputs, reflecting market expectations of future interest rates as of the measurement date. Standard valuation techniques are used to calculate the present value of the future expected cash flows assuming an orderly transaction. Valuation adjustments may be made to reflect both our own credit risk and the counterparties’ credit risk in determining the fair value of the derivatives. Level 2 inputs for the valuations are limited to observable market prices for London Interbank Offered Rate ("LIBOR") and Overnight Index Swap ("OIS") rates (for the very short term), quoted prices for LIBOR futures contracts, observable market prices for LIBOR and OIS swap rates, and one-month and three-month LIBOR basis spreads at commonly quoted intervals. Mid-market pricing of the inputs is used as a practical expedient in the fair value measurements. We project spot rates at reset days specified by each swap contract to determine future cash flows, then discount to present value using OIS curves as of the measurement date. When the value of any collateral placed with counterparties is less than the interest rate derivative liability, a credit valuation adjustment ("CVA") is applied to reflect the credit risk we pose to counterparties. We have used the spread between the Standard & Poor's BBB rated U.S. Bank Composite rate and LIBOR for the closest maturity term corresponding to the duration of the swaps to derive the CVA. A similar credit risk adjustment, correlated to the credit standing of the counterparty, is made when collateral posted by the counterparty does not fully cover their liability to us. For further discussion on our methodology in valuing our derivative financial instruments, refer to Note 9, Derivative Financial Instruments and Hedging Activities.Certain financial assets may be measured at fair value on a non-recurring basis. These assets are subject to fair value adjustments that result from the application of the lower of cost or fair value accounting or write-downs of individual assets, such as impaired loans that are collateral dependent and other real estate owned ("OREO").

Fair value of loans is based on exit price techniques and obtained from an independent third-party that uses its proprietary valuation model and methodology and may not reflect actual or prospective market valuations. The discounted cash flow valuation approach reflects key inputs and assumptions such as loan probability of default, loss given default, prepayment speed, and market discount rates.

Fair value of fixed-rate time deposits is estimated by discounting future contractual cash flows using discount rates that reflect the current market rates offered for time deposits of similar remaining maturities.

Fair value of the subordinated debenture is estimated using a discounted cash flow approach based on current interest rates for similar financial instruments adjusted for credit and liquidity spreads.

The value of unrecognized financial instruments is estimated based on the fee income associated with the commitments which, in the absence of credit exposure, is considered to approximate their settlement value.

Finance, Loan and Lease Receivables, Held-for-investment, Allowance and Nonperforming Loans

Commercial and Industrial Loans - Commercial loans are generally made to established small and mid-sized businesses to provide financing for their growth and working capital needs, equipment purchases and acquisitions. Management examines historical, current, and projected cash flows to determine the ability of the borrower to repay obligations as agreed. Commercial loans are made based primarily on the identified cash flows of the borrower and secondarily on the underlying collateral and guarantor support. The cash flows of borrowers, however, may not occur as expected, and the collateral securing these loans may fluctuate in value. Most commercial and industrial loans are secured by the assets being financed, such as accounts receivable and inventory, and typically include personal guarantees. We target stable businesses with guarantors who provide additional sources of repayment and have proven to be resilient in periods of economic stress. A weakened economy, and resultant decreased consumer and/or business spending, may have an effect on the credit quality of commercial loans.

In April 2020, the Bank began participating in the Small Business Administration's ("SBA") Paycheck Protection Program ("PPP"). As of March 31, 2021, there were 2,513 PPP loans outstanding. PPP loans totaling $365.0 million (net of $8.0 million in unrecognized fees and costs) and $291.6 million (net of $5.4 million in unrecognized fees and costs) as of March 31, 2021 and December 31, 2020, respectively, were included in commercial and industrial loan balances. Of the PPP loans outstanding as of March 31, 2021, 841 loans totaling $119.5 million funded during the first quarter of 2021 under the second round of the PPP stimulus plan. PPP loans have terms of two to five years and earn interest at 1%. In addition, the SBA paid the Bank a fee of 1%-5% depending on the loan amount, which was netted with loan origination costs and accreted/amortized into interest income using the effective yield method over the contractual life of each loan. The recognition of fees and costs is accelerated when the SBA forgives the loan and/or the loan is paid off prior to maturity. PPP loans are fully

guaranteed by the SBA and have virtually no risk of loss. We expect the vast majority of the PPP loans to be fully forgiven by the SBA.

Commercial Real Estate Loans - Commercial real estate loans, which include income producing investment properties and owner-occupied real estate used for business purposes, are subject to underwriting standards and processes similar to commercial loans discussed above. We underwrite these loans to be repaid from cash flow and to be supported by real property collateral. Underwriting standards for commercial real estate loans include, but are not limited to, debt coverage and loan-to-value ratios. Furthermore, a large majority of our loans are guaranteed by the owners of the properties. Conditions in the real estate markets or downturn in the general economy may adversely affect our commercial real estate loans. In the event of a vacancy, we expect guarantors to carry the loans until they find a replacement tenant. The owner's substantial equity investment provides a strong economic incentive to continue to support the commercial real estate projects. As such, we have generally experienced a relatively low level of loss and delinquencies in this portfolio.

Construction Loans - Construction loans are generally made to developers and builders to finance construction, renovation and occasionally land acquisitions in anticipation of near-term development. Construction loans include interest reserves that are used for the payment of interest during the development and marketing periods and are capitalized as part of the loan balance. When a construction loan is placed on nonaccrual status before the depletion of the interest reserve, we apply the interest funded by the interest reserve against the loan's principal balance. These loans are underwritten after evaluation of the borrower's financial strength, reputation, prior track record, and independent appraisals. We monitor all construction projects to determine whether they are on schedule, completed as planned and in accordance with the approved construction budgets. Significant events can affect the construction industry, including: the inherent volatility of real estate markets and vulnerability to delays due to weather, change orders, inability to obtain construction permits, labor or material shortages, and price changes. Estimates of construction costs and value associated with the completed project may be inaccurate. Repayment of construction loans is largely dependent on the ultimate success of the project.

Consumer Loans - Consumer loans primarily consist of home equity lines of credit, other residential loans and floating homes along with a small number of installment loans. Our other residential loans include tenancy-in-common fractional interest loans ("TIC") located almost entirely in San Francisco County. We originate consumer loans utilizing credit score information, debt-to-income ratio and loan-to-value ratio analysis. Diversification among consumer loan types, coupled with relatively small loan amounts that are spread across many individual borrowers, mitigates risk. We do not originate sub-prime residential mortgage loans, nor is it our practice to underwrite loans commonly referred to as "Alt-A mortgages," the characteristics of which are reduced documentation, borrowers with low FICO scores or collateral with high loan-to-value ratios.

Credit Quality Indicators

We use a risk rating system to evaluate asset quality, and to identify and monitor credit risk in individual loans, and in the loan portfolio. Our definitions of “Special Mention” risk graded loans, or worse, are consistent with those used by the Federal Deposit Insurance Corporation ("FDIC"). Our internally assigned grades are as follows:

Pass and Watch - Loans to borrowers of acceptable or better credit quality. Borrowers in this category demonstrate fundamentally sound financial positions, repayment capacity, credit history and management expertise. Loans in this category must have an identifiable and stable source of repayment and meet the Bank’s policy regarding debt-service-coverage ratios. These borrowers are capable of sustaining normal economic, market or operational setbacks without significant financial consequences. Negative external industry factors are generally not present. The loan may be secured, unsecured or supported by non-real estate collateral for which the value is more difficult to determine and/or marketability is more uncertain. This category also includes “Watch” loans, where the primary source of repayment has been delayed. “Watch” is intended to be a transitional grade, with either an upgrade or downgrade within a reasonable period.

Special Mention - Potential weaknesses that deserve close attention. If left uncorrected, those potential weaknesses may result in deterioration of the payment prospects for the asset. Special Mention assets do not present sufficient risk to warrant adverse classification.

Substandard - Inadequately protected by either the current sound worth and paying capacity of the obligor or the collateral pledged, if any. A Substandard asset has a well-defined weakness or weaknesses that jeopardize(s) the liquidation of the debt. Substandard assets are characterized by the distinct possibility that we will sustain some

loss if such weaknesses or deficiencies are not corrected. Well-defined weaknesses include adverse trends or developments of the borrower’s financial condition, managerial weaknesses and/or significant collateral deficiencies.

Doubtful - Critical weaknesses that make collection or liquidation in full improbable. There may be specific pending events that work to strengthen the asset; however, the amount or timing of the loss may not be determinable. Pending events generally occur within one year of the asset being classified as Doubtful. Examples include: merger, acquisition, or liquidation; capital injection; guarantee; perfecting liens on additional collateral; and refinancing. Such loans are placed on non-accrual status and usually are collateral-dependent.

We regularly review our credits for accuracy of risk grades whenever we receive new information. Borrowers are generally required to submit financial information at regular intervals. Typically, commercial borrowers with lines of credit are required to submit financial information with reporting intervals ranging from monthly to annually depending on credit size, risk and complexity. In addition, investor commercial real estate borrowers with loans exceeding a certain dollar threshold are usually required to submit rent rolls or property income statements annually. We monitor construction loans monthly. We review home equity and other consumer loans based on delinquency. We also review loans graded “Watch” or worse, regardless of loan type, no less than quarterly.

Troubled Debt Restructuring

Our loan portfolio includes certain loans modified in a troubled debt restructuring (“TDR”), where we have granted economic concessions to borrowers experiencing financial difficulties. These concessions typically result from our loss mitigation activities and could include reductions in the interest rate, payment extensions, forgiveness of principal, forbearance or other actions. TDRs on non-accrual status at the time of restructure may be returned to

accruing status after management considers the borrower’s sustained repayment performance for a reasonable period, generally nine months, and obtains reasonable assurance of repayment and performance.

We may remove a loan from TDR designation if it meets all of the following conditions:

•The loan is subsequently refinanced or restructured at current market interest rates and the new terms are consistent with the treatment of creditworthy borrowers under regular underwriting standards;

•The borrower is no longer considered to be in financial difficulty;

•Performance on the loan is reasonably assured; and

•Existing loan did not have any forgiveness of principal or interest.