Concentration Risk, Credit Risk, Policy [Policy Text Block]

Concentrations. The Bank was incorporated in California and started its business from California. Therefore, loans originated, and deposits solicited were mainly from California. As of December 31, 2023, gross loans were primarily comprised of 49.8% of commercial real estate loans, 29.9% of residential mortgage loans, and 16.9% of commercial loans. As of December 31, 2023, approximately 50.5% of the Bank’s residential mortgages were for properties located in California.

Allowance for Credit Losses on Available for Sale Debt Securities [Policy Text Block]

Allowance for Credit Losses on Available for Sale Securities. For AFS debt securities in an unrealized loss position, the Company first assesses whether it intends to sell, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If an entity intends to sell the debt security, or more likely than not will be required to sell the security before recovery of its amortized cost basis, any allowance for credit losses shall be written off and the amortized cost basis shall be written down to the debt security's fair value at the reporting date with any incremental impairment reported in earnings. For AFS debt securities that do not meet the aforementioned criteria, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, management considers the extent to which fair value is less than amortized cost, the payment structure of the security, failure of the issuer of the security to make scheduled interest or principal payments, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. Any fair value changes that have not been recorded through an allowance for credit losses is recognized in other comprehensive income.

Changes in the allowance for credit losses are recorded as provision for credit loss expense. Losses are charged against the allowance when management believes the uncollectability of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell is met.

The amortized cost of the Company’s AFS debt securities exclude accrued interest, which is included in “accrued interest receivable” on the Consolidated Balance Sheets. The Company has made an accounting policy election not to measure an allowance for credit losses for accrued interest receivables on AFS debt securities since the Company timely reverses any previously accrued interest when the debt security remains in default for an extended period. As each AFS debt security has a unique security structure, where the accrual status is clearly determined when certain criteria listed in the terms are met, the Company assesses the default status of each security as defined by the debt security’s specific security structure.

Trading securities are reported at fair value, with unrealized gains or losses included in income.

Financing Receivable, Held-for-Investment [Policy Text Block]

Loans Held for Investment. Loans receivable that the Company has the intent and ability to hold for the foreseeable future or until maturity are stated at their outstanding principal, reduced by an allowance for loan losses and net of deferred loan fees or costs on originated loans and unamortized premiums or discounts on purchased loans. Nonrefundable fees and direct costs associated with the origination or purchase of loans are deferred and netted against outstanding loan balances. The deferred net loan fees and costs are recognized in interest income as an adjustment to yield over the loan term using the effective interest method or straight-line method. Discounts or premiums on purchased loans are accreted or amortized to interest income using the effective interest method or straight-line method over the remaining period to contractual maturity. Interest on loans is calculated using the simple-interest method on daily balances of the principal amounts outstanding based on an actual or 360-day basis.

Generally, loans are placed on nonaccrual status when they become 90 days past due. Loans are considered past due when contractually required principal or interest payments have not been made on the due dates. Loans are also placed on nonaccrual status when management believes, after considering economic and business conditions and collection efforts, that the borrower’s financial condition is such that full collection of principal or interest becomes uncertain, regardless of the length of past due status. Once a loan is placed on nonaccrual status, interest accrual is discontinued, and all unpaid accrued interest is reversed against interest income. As a result, accrued interest receivable does not carry a credit loss reserve. Interest payments received on nonaccrual loans are reflected as a reduction of principal and not as interest income. A loan is returned to accrual status when the borrower has demonstrated a satisfactory payment trend subject to management’s assessment of the borrower’s ability to repay the loan.

Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block]

Allowance for Credit Losses (“ACL”) on Loans Held for Investment. The Company adopted ASU 2016-13, Financial Instruments – Credit Losses (Topic 326) on January 1, 2021 which introduced a new current expected credit loss (“CECL”) approach for financial instruments measured at amortized cost and other commitments to extend credit. CECL requires the immediate recognition of estimated credit losses expected to occur over the estimated remaining life of the asset. The forward-looking concept of CECL requires loss estimates to consider historical experience, GDP, unemployment rates, CRE and home price indexes, and reasonable and supportable economic forecasts of future events and circumstances.

The ACL is the combination of the allowance for loan losses and the reserve for unfunded loan commitments. The allowance for loan losses is reported as a reduction of the amortized cost basis of loans, while the reserve for unfunded loan commitments is included within "other liabilities" on the Consolidated Balance Sheets. The amortized cost basis of loans does not include accrued interest receivable, which is included in "accrued interest receivable" on the Consolidated Balance Sheets. The "Provision for credit losses" on the Consolidated Statements of Operations and Comprehensive Income is a combination of the provision for loan losses and the provision for unfunded loan commitments.

Under the Company’s CECL approach, management estimates the ACL using relevant available information from internal and external sources, relating to past events, current conditions, and reasonable and supportable economic forecasts that vary by loan portfolio. We use economic forecasts from Moody’s Analytics in this process. The economic forecast is updated monthly; therefore, the one used for each quarter-end calculation is generally based on a one-month lag based on the timing of when the forecast is released. The Company does not consider a one-month lag to create a material difference but considers any subsequent material changes to our estimated loss forecasts as deemed appropriate. Historical credit loss experience provides the basis for the estimation of expected credit losses. Adjustments to historical loss information are made for differences in current loan-specific risk characteristics such as differences in underwriting standards, portfolio mix, delinquency level, or term as well as for changes in environmental conditions, such as changes in gross domestic product (or “GDP”), unemployment rates, property values, or other relevant factors.

Under the CECL methodology, quantitative and qualitative loss factors are applied to our population of loans on a collective pool basis when similar risk characteristics exist. The Company evaluates loans for expected credit losses on an individual basis if, based on current information and events, the loan does not share similar credit risk characteristics with other loans. The Company may choose to measure expected credit losses on an individual loan basis by using one of the following methods: (1) the present value of the expected future cash flows of the loan discounted at the loan’s original effective interest rate, or (2) if the loan is collateral dependent, the fair value of the collateral less costs to sell. For loans that are not collateral-dependent, the Company uses the present value of future cash flows.

Under the Company’s CECL methodology, nine portfolio segments with similar risk characteristics are evaluated for expected loss. Six portfolios are modeled using econometric models and three smaller portfolios are evaluated using a simplified loss-rate method that calculates lifetime expected credit losses for the respective pools (simplified approach). The six portfolios subject to econometric modeling include residential mortgages; commercial and industrial loans (“C&I”); construction loans; commercial real estate (“CRE”) for multifamily loans; CRE for owner-occupied loans; and other CRE loans. We estimate the probability of default during the reasonable and supportable forecast period using separate econometric regression models developed to correlate macroeconomic variables, (GDP, unemployment, CRE prices and residential mortgage prices) to historical credit performance for each of the six loan portfolios from the fourth quarter of 2007 to the fourth quarter of 2022. Loss given default rates are computed based on the net charge-offs recognized divided by the exposure at default of defaulted loans starting with the fourth quarter of 2007 through the fourth quarter of 2022. The probability of default and the loss given default rates are applied to the expected amount at default at the loan level based on contractual scheduled payments and estimated prepayments. The amounts so calculated comprise the quantitative portion of the allowance for credit losses.

The Company’s CECL methodology utilizes an eight-quarter reasonable and supportable (“R&S”) forecast period, and a four-quarter reversion period. Management relies on multiple forecasts, blending them into a single loss estimate. Generally speaking, the blended scenario approach would include the Baseline, the Alternative Scenario 1 – Upside – 10th Percentile and the Alternative Scenario 3 – Downside – 90th Percentile forecasts. After the R&S period, the Company reverts linearly for the four-quarter reversion period to the long-term loss rates for each of the six portfolios of loans.

The Company’s CECL methodology estimates expected credit losses over the contractual term of the loans, adjusted for expected prepayments when appropriate. The contractual term excludes expected extensions, renewals, and modifications unless the extension or renewal options are included in the original or modified contract at the reporting date and are not unconditionally cancellable by the Company.

The simplified approach portfolios include Small Business Administration (“SBA”) loans, Home Equity Lines of Credit (“HELOCs”) and cash-secured loans, which are not modelled econometrically due to the low loss history for these three pools of loans. The forecasted loss rate is based on the forecasted GDP and unemployment rates during the first eight quarters of the portfolio’s contractual life, reversion loss rates for the next four quarters of the portfolio’s contractual life on a linear declining rate, and the long-term loss rate projected over the remainder of the portfolio’s contractual life.

Under the Company’s CECL methodology, the qualitative portion of the reserve on pooled loans represents management’s judgment of additional considerations to account for internal and external risk factors that are not adequately measured in the quantitative reserve. The qualitative loss factors consider idiosyncratic risk factors, conditions that may not be reflected in quantitatively derived results, or other relevant factors to seek to ensure the allowance for credit losses reflects our best estimate of current expected credit losses. The qualitative reserves include reserves for policy exceptions, experience of management and staff, level of competition in the lending environment, weak risk identification, lack of historical loss experience with residential mortgage loans made to non-U.S. residents, oil & gas, the higher risk characteristics of purchased syndicated loans, model uncertainty, and loans with potential risk of loss given the current environment, including CRE and Office loans, but have not degraded to the point of qualifying for a specific reserve. Current and forecasted economic trends and underlying market values for collateral dependent loans also are considered within the econometric models described above.

The Company’s CECL methodology requires a significant amount of management judgment in determining the appropriate allowance for credit losses. Several of the steps in the methodology involve judgment and are subjective in nature including, among other things: segmenting the loan portfolio; determining the period over which loss history to consider; selecting predictive econometric regression models that use appropriate macroeconomic variables; determining the methodology to forecast prepayments; selecting the most appropriate economic forecast scenario; determining the length of the R&S forecast and reversion periods; estimating expected utilization rates on unfunded loan commitments; and assessing relevant and appropriate qualitative factors. In addition, the CECL methodology is dependent on economic forecasts that are inherently imprecise and will change from period to period. Although the allowance for credit losses is considered by management to be appropriate, there can be no assurance that it will be sufficient to absorb future losses.

Management believes the allowance for credit losses is appropriate for the current expected credit losses in our loan portfolio and associated unfunded commitments, and the risk ratings and inherent loss rates currently assigned are reasonable and appropriate as of the reporting date. It is possible that others, given the same information, may at any point in time reach different conclusions that could result in a significant impact to the Company’s financial statements.

Individually Evaluated Loans. Loans that do not share similar risk characteristics with other financial assets are individually evaluated for impairment and excluded from loan pools used within the collective evaluation of estimated credit losses. We defined the following criteria for what constitutes a “default”, which results in a loan no longer sharing similar risk characteristics with other loans, and therefore requires an individual evaluation for expected credit losses. The criteria for default may include any one of the following: on nonaccrual status, modifications to borrowers experiencing financial difficulty, or payment delinquency of 90 days or more.

The Company has adopted ASU 2022-02, “Financial Instruments – Troubled Debt Restructurings and Vintage Disclosures” effective January 1, 2023. As part of the adoption, the Company has elected to apply the pending content prospectively and the practical expedient to exclude the accrued interest receivable balance from the disclosed amortized cost basis of loan modifications to debtors experiencing financial difficulty, consistent with our ACL approach discussed further below in this footnote.

Under the new guidance on loan modifications made to borrowers experiencing financial difficulty, when a loan held for investment is modified and is considered to be a continuation of the original loan, the Company uses the post-modification contractual rate to derive the effective interest rate when using a discounted cash flow method to determine the allowance for credit loss.

The amendments in this new guidance eliminate the previous TDR recognition and measurement guidance and, instead, require that an entity evaluate whether the modification represents a new loan or a continuation of an existing loan.

Under the prior TDR guidance, a TDR is a formal modification of the terms of a loan when the lender, for economic or legal reasons related to the borrower’s financial difficulties, grants a concession to the borrower. The concessions may be granted in various forms, including a change in the stated interest rate, a reduction in the loan balance or accrued interest, or an extension of the maturity date. Although these loan modifications were considered TDRs, TDR loans that had, pursuant to the Bank’s policy, performed under the restructured terms and had demonstrated sustained performance under the modified terms for six months were returned to accrual status. The sustained performance considered by management pursuant to its policy included the periods prior to the modification if the prior performance met or exceeded the modified terms. This would include cash paid by the borrower prior to the restructuring to set up interest reserves. Loans classified as TDRs were reported as individually evaluated loans.

The allowance for credit loss on a TDR was measured using the same method as all other loans held for investment, except when the value of a concession cannot be measured using a method other than the discounted cash flow method. Under the prior guidance when the value of a concession was measured using the discounted cash flow method, the allowance for credit loss was determined by discounting the expected future cash flows at the original interest rate of the loan.

Letter of Credit Fees [Policy Text Block]

Letter of Credit Fees. Issuance and commitment fees received for the issuance of commercial or standby letters of credit are recognized over the term of the instruments.

Investments In Affordable Housing [Policy Text Block]

Investments in Affordable Housing Partnerships and Other Tax Credit Investments. The Company is a limited partner in limited partnerships that invest in low-income housing projects that are intended to qualify for Federal and/or State income tax credits and limited partnerships that invests in alternative energy systems that are intended to qualify for alternative energy tax credits. As further discussed in Note 6 to the Consolidated Financial Statements, the partnership interests are accounted for utilizing the equity method of accounting. As of December 31, 2023, eleven of the limited partnerships in which the Company has an equity interest were determined to be variable interest entities for which the Company is the primary beneficiary. The Company therefore consolidated the financial statements of these ten limited partnerships into the Consolidated Financial Statements. The tax credits from these partnerships are recognized in the consolidated financial statements to the extent they are utilized on the Company’s income tax returns. The investments are reviewed for impairment on an annual basis or on an interim basis if an event occurred that would trigger potential impairment.

Property, Plant and Equipment, Policy [Policy Text Block]

Premises and Equipment. Premises and equipment are carried at cost, less accumulated depreciation. Depreciation is computed on the straight-line method based on the following estimated useful lives of the assets:

Type		Estimated Useful Life (years)
Buildings		15 to 45
Building improvements		5 to 20
Furniture, fixtures, and equipment		3 to 25
Leasehold improvements		Shorter of useful lives or the terms of the leases

Improvements are capitalized and amortized to occupancy expense based on the above table. Construction in process is carried at cost and includes land acquisition cost, architectural fees, general contractor fees, capitalized interest and other costs related directly to the construction of a property.

Intangible Assets, Finite-Lived, Policy [Policy Text Block]

Other intangible assets. Other intangible assets are mainly comprised of core deposit intangible, which represents the purchase price over the fair value of the deposits acquired from other financial institutions, is amortized over its estimated useful life to its residual value in proportion to the economic benefits consumed. If a pattern of consumption cannot be reliably determined, straight-line amortization is used. The Company assesses the recoverability of this intangible asset by determining whether the amortization of the premium balance over its remaining life can be recovered through the remaining deposit portfolio and amortizes core deposit premium over its estimated useful life.

Share-Based Payment Arrangement [Policy Text Block]

Stock-Based Compensation. Stock option compensation expense is calculated based on the fair value of the award at the grant date for those options expected to vest and is recognized as an expense over the vesting period of the grant using the straight-line method. The Company uses the Black-Scholes option pricing model to estimate the value of granted options. This model takes into account the option exercise price, the expected life, the current price of the underlying stock, the expected volatility of the Company’s stock, expected dividends on the stock and a risk-free interest rate. The Company estimates the expected volatility based on the Company’s historical stock prices for the period corresponding to the expected life of the stock options. Restricted stock units are valued at the closing price of the Company’s stock on the date of the grant.

Foreign Exchanged Forwards and Foreign Currency Option Contracts [Policy Text Block]

Foreign Exchange Forwards and Foreign Currency Option Contracts. We enter into foreign exchange forward contracts and foreign currency option contracts with correspondent banks to mitigate the risk of fluctuations in foreign currency exchange rates for foreign currency certificates of deposit, foreign exchange contracts or foreign currency option contracts entered into with our clients. These contracts are not designated as hedging instruments and are recorded at fair value in our Consolidated Balance Sheets. Changes in the fair value of these contracts as well as the related foreign currency certificates of deposit, foreign exchange contracts or foreign currency option contracts, are recognized immediately in net income as a component of non-interest income. Period end gross positive fair values are recorded in other assets and gross negative fair values are recorded in other liabilities.

Comprehensive Income, Policy [Policy Text Block]

Comprehensive Income/(loss). Comprehensive income/(loss) is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources. Comprehensive income/(loss) generally includes net income/(loss), unrealized gains and losses on investments in securities available-for-sale, and cash flow hedges. Comprehensive income/(loss) and its components are reported and displayed in the Company’s Consolidated Statements of Operations and Comprehensive Income.

Foreign Currency Transactions and Translations Policy [Policy Text Block]

Foreign Currency Translation. The Company considers the functional currency of its foreign operations to be the United States dollar. Accordingly, the Company remeasures monetary assets and liabilities at year-end exchange rates, while nonmonetary items are remeasured at historical rates. Income and expense accounts are remeasured at the average rates in effect during the year, except for depreciation, which is remeasured at historical rates. Foreign currency transaction gains and losses are recognized in income in the period of occurrence.

Segment Reporting, Policy [Policy Text Block]

Segment Reporting. Through our branch network and lending units, we provide a broad range of financial services to individuals and companies. These services include demand, time and savings deposits; and commercial and industrial, real estate and consumer lending. While our chief decision makers monitor the revenue streams of our various products and services, operations are managed, and financial performance is evaluated on a company-wide basis. Accordingly, we consider all of our operations to be aggregated in one reportable operating segment.