deposits grew $ 167.8 million , or 7 % , to $ 2.504 billion at december 31 , 2020 , compared to $ 2.336 billion at december 31 , 2019. non-interest bearing deposits grew by $ 225.8 million in 2020 , or 20 % , and made up 54 % of total deposits at year-end . cost of deposits remained low at 0.11 % in 2020 , compared to 0.20 % in 2019. net interest income totaled $ 96.7 million and $ 95.7 million in 2020 and 2019 , respectively . the $ 1.0 million increase in 2020 was primarily due to sba ppp loans and lower rates on interest-bearing deposits , largely offset by lower yields on earning-assets . the tax-equivalent net interest margin decreased to 3.55 % in 2020 , compared to 3.98 % in 2019. the 43 basis point decrease was primarily due to lower yields across interest-earning asset categories , partially offset by lower rates on interest-bearing deposits . the efficiency ratio was 57.06 % in 2020 , up from 55.33 % in 2019. contributing to this increase was the decrease in net interest margin , higher provision for credit losses on unfunded loan commitments , and lower income from s ervice charges on deposit accounts and atm fees in 2020. for the year ended december 31 , 2020 , return on assets and return on equity were 1.04 % and 8.60 % , respectively , compared to 1.34 % and 10.49 % in the prior year . all capital ratios exceeded regulatory requirements . the total risk-based capital ratio for bancorp was 16.0 % at december 31 , 2020 up from 15.1 % at december 31 , 2019. tangible common equity to tangible assets was 11.3 % at both december 31 , 2020 and december 31 , 2019 ( see footnote 8 , item 6 , selected financial data , for the definition of this non-gaap financial measure ) . the total risk-based capital ratio for the bank was 15.8 % at december 31 , 2020 and 14.6 % at december 31 , 2019. the board of directors declared a cash dividend of $ 0.23 per share on january 22 , 2021. this was the 63 rd consecutive quarterly dividend paid by bank of marin bancorp . the cash dividend was paid on february 12 , 2021 to shareholders of record at the close of business on february 5 , 2021. our strong capital and liquidity position afforded us the opportunity to eliminate a high cost funding source . on march 15 , 2021 we redeemed the $ 2.8 million subordinated debenture , which carried a rate of 5.68 % in 2020. the redemption consisted of $ 4.1 million principal balance , quarterly interest due , and $ 1.3 million in accelerated accretion of purchase discount . the contractual interest rate on the subordinated debenture was 3-month libor plus 1.40 % , or 1.62 % as of december 31 , 2020. covid-19 pandemic-related response update - we have remained open and responded to customer needs throughout 2020. we more than doubled our charitable contributions to non-profit organizations in our community to over $ 1.0 million in 2020. in march 2020 , we began waiving all atm and overdraft fees and cancelling early withdrawal penalties for time certificate of deposits when allowed by law . we accommodated loan payment relief requests for borrowers with financial hardships and lowered interest rate floors on commercial prime rate loans . under the provisions of the coronavirus aid , relief and economic security act ( `` cares act `` ) of 2020 , bank of marin originated over 1,800 ppp loans to small businesses , reaching nearly 28,000 employees in our markets . in 2021 , we are once again diligently working with our customers to accommodate requests for round two of ppp 26 loans under the economic aid to hard-hit small businesses , nonprofits , and venues act ( `` economic aid act `` ) , which became law in december of 2020. paycheck protection program - while the ppp affords us an opportunity to assist our customers and community and requires a large of amount of human resources , the ppp loans do not pose a significant amount of risk of loss to the bank as they are 100 % guaranteed by the sba . as of december 31 , 2020 , there were 1,777 ppp loans outstanding totaling $ 291.6 million , net of $ 5.4 million in unearned fees . during the fourth quarter bank of marin opened a secure ppp loan forgiveness application portal and gave all ppp borrowers access to apply . as of december 31 , 2020 we received sba loan forgiveness payments totaling $ 10.9 million for 35 loans that were forgiven . of the total ppp loans rem aining , 74 % ( 1,309 loans ) totaling $ 58.7 million are less than or equal to $ 150 thousand and have access to streamlined forgiveness processing . on january 19 , 2021 , the bank launched the application process and began accepting loan requests for the second round of ppp , as revised by the economic aid act . as of march 11 , 2021 , we have received 974 loan applications totaling $ 131.6 million . payment relief - during 2020 , in accordance with section 4013 of the cares act , subsequently amended by the economic aid act , we elected to apply the temporary accounting relief provisions for loan modifications that met certain criteria , which would otherwise be designated as tdrs under existing gaap . of the 269 loans totaling $ 402.9 million granted payment relief since the onset of the pandemic , 222 loans or $ 324.2 million have resumed normal payments and 18 loans or $ 7.7 million paid off . as of december 31 , 2020 , 21 borrowing relationships with 29 loans totaling $ 71.0 million had requested additional payment relief . story_separator_special_tag the decrease was primarily due to $ 1.0 million in consulting expenses related to core processing contract negotiations in 2018 , lower data processing expenses in 2019 as a result of the renegotiation of the bank 's core systems contract , and lower federal deposit insurance corporation ( `` fdic `` ) deposit insurance expenses due to the fdic deposit insurance fund reserve exceeding its billing threshold in 2019. the decreases in non-interest expense were partially offset by $ 918 thousand higher salaries and related benefits as a result of annual merit increases , three additional full-time equivalent employees ( on average ) , and personnel severance , as well as higher recruiting fees recorded in other expenses . provision for income taxes income tax provisions reflect accruals for taxes at the applicable rates for federal income tax and california franchise tax based upon reported pre-tax income . provisions also reflect permanent differences between income for tax and financial reporting purposes ( such as earnings on tax exempt loans and municipal securities , boli , low-income housing tax credits , and stock-based compensation from the exercise of stock options , disqualifying dispositions of incentive stock options and vesting of restricted stock awards ) . the provision for income taxes totaled $ 10.3 million at an effective tax rate of 25.5 % in 2020 , compared to $ 11.7 million at an effective tax rate of 25.4 % in 2019 and $ 10.8 million at an effective tax rate of 24.9 % in 2018. the decrease in the provision in 2020 compared to 2019 reflected lower pre-tax income and higher tax-exempt interest income on municipal securities . the slight increase in the effective tax rate in 2020 as compared to 2019 was due to a favorable deferred tax liability true-up recognized in 2019 and a lower tax benefit from boli income in 2020. the increase in the effective tax rate in 2019 compared to 2018 was due to a higher level of tax benefits in 2018 from the exercise of non-qualified stock options and disqualifying dispositions of incentive stock options by former employees of bank of napa post-acquisition . we file a consolidated return in the u.s. federal tax jurisdiction and a combined return in the state of california tax jurisdiction . there were no ongoing federal or state income tax examinations at the issuance of this report . at december 31 , 2020 and 2019 , neither the bank nor bancorp had accruals for interest or penalties related to unrecognized tax benefits . financial condition our assets increased $ 204.6 million from december 31 , 2019 to december 31 , 2020 , mainly due to loan growth of $ 245.3 million , primarily driven by ppp loan originations , which were offset by a $ 68.3 million decrease in investment security balances . investment securities we maintain an investment securities portfolio to provide liquidity and to generate earnings on funds that have not been loaned to customers . management determines the maturities and types of securities to be purchased based on liquidity and interest rate risk position , and the desire to attain a reasonable investment yield balanced with risk exposure . table 5 shows the composition of the debt securities portfolio by expected maturity at december 31 , 2020 and 2019. expected maturities differ from contractual maturities because the issuers of the securities may have the right to call or prepay obligations with or without call or prepayment penalties . we estimate and update expected maturity dates regularly based on current and historical prepayment speeds . the weighted average life of the investment portfolio at december 31 , 2020 and 2019 was approximately five and six years , respectively . 32 table 5 investment securities replace_table_token_5_th 1 book value reflects cost , adjusted for accumulated amortization and accretion . 2 weighted average calculation is based on amortized cost of securities . 3 yields on tax-exempt municipal bonds are presented on a taxable equivalent basis , using federal tax rate of 21 % . the amortized cost of our investment securities portfolio decreased $ 79.3 million or 14 % during 2020. we purchased $ 97.5 million in securities in 2020 designated as available-for-sale to provide flexibility for liquidity and interest rate risk management . these purchases were offset by $ 143.1 million of paydowns , calls and maturities , and $ 32.8 million of sales during 2020. during 2020 , we purchased $ 57.6 million in obligations of state and political subdivisions , $ 31.0 million in collateralized mortgage obligations ( `` cmos `` ) and $ 9.0 million in debentures of government sponsored agencies . we consider agency debentures and cmos issued by u.s. government sponsored entities to have low credit risk as they carry the credit support of the u.s. federal government . the debentures , cmos and mbs issued by u.s. government sponsored agencies , state and municipal securities , and sba-backed securities made up 70.1 % , 22.1 % and 7.8 % of the portfolio at december 31 , 2020 , compared to 79.6 % , 12.4 % and 7.8 % , respectively at december 31 , 2019. see the discussion in the section captioned “ securities may lose value due to credit quality of the issuers ” in item 1a risk factors above . 33 at december 31 , 2020 , distribution of our investment in obligations of state and political subdivisions was as follows : replace_table_token_6_th the portion of the portfolio outside the state of california is distributed among 10 states . the largest concentrations outside california are in texas ( 55.3 % ) , washington ( 9.3 % ) , and maryland ( 6.4 % ) . during march 2020 , we strategically increased our credit exposure to obligations issued by high credit quality issuers in texas that are either guaranteed by the aaa-rated texas permanent school fund ( `` psf `` ) or backed by revenue sources from essential services such as

liquidity the goal of liquidity management is to provide adequate funds to meet loan demand and to fund operating activities and deposit withdrawals . we accomplish this goal by maintaining an appropriate level of liquid assets and formal lines of credit with the fhlb , frbsf and correspondent banks that enable us to borrow funds as discussed in note 7 to the consolidated financial statement in item 8 of this report . our asset liability management committee ( `` alco '' ) , which is comprised of independent bank directors and the bank 's chief executive officer , is responsible for approving and monitoring our liquidity targets and strategies . alco has adopted a contingency funding plan that provides early detection of potential liquidity issues in the market or the bank and institutes prompt responses that may prevent or alleviate a potential liquidity crisis . management monitors liquidity daily and regularly adjusts our position based on current and future liquidity needs . we also have relationships with third-party deposit networks and can adjust the placement of our deposits via reciprocal or one-way sales as part of our cash management strategy , as discussed in note 6 to the consolidated financial statements in item 8 of this report . we obtain funds from the repayment and maturity of loans , deposit inflows , investment security maturities and paydowns , federal funds purchases , fhlb advances , other borrowings , and cash flow from operations . our primary uses of funds are the origination of loans , the purchase of investment securities , withdrawals of deposits , maturity of certificates of deposit , repayment of borrowings , and dividends to common stockholders .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```liquidity the goal of liquidity management is to provide adequate funds to meet loan demand and to fund operating activities and deposit withdrawals . we accomplish this goal by maintaining an appropriate level of liquid assets and formal lines of credit with the fhlb , frbsf and correspondent banks that enable us to borrow funds as discussed in note 7 to the consolidated financial statement in item 8 of this report . our asset liability management committee ( `` alco '' ) , which is comprised of independent bank directors and the bank 's chief executive officer , is responsible for approving and monitoring our liquidity targets and strategies . alco has adopted a contingency funding plan that provides early detection of potential liquidity issues in the market or the bank and institutes prompt responses that may prevent or alleviate a potential liquidity crisis . management monitors liquidity daily and regularly adjusts our position based on current and future liquidity needs . we also have relationships with third-party deposit networks and can adjust the placement of our deposits via reciprocal or one-way sales as part of our cash management strategy , as discussed in note 6 to the consolidated financial statements in item 8 of this report . we obtain funds from the repayment and maturity of loans , deposit inflows , investment security maturities and paydowns , federal funds purchases , fhlb advances , other borrowings , and cash flow from operations . our primary uses of funds are the origination of loans , the purchase of investment securities , withdrawals of deposits , maturity of certificates of deposit , repayment of borrowings , and dividends to common stockholders .
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 Suspicious Activity Report : deposits grew $ 167.8 million , or 7 % , to $ 2.504 billion at december 31 , 2020 , compared to $ 2.336 billion at december 31 , 2019. non-interest bearing deposits grew by $ 225.8 million in 2020 , or 20 % , and made up 54 % of total deposits at year-end . cost of deposits remained low at 0.11 % in 2020 , compared to 0.20 % in 2019. net interest income totaled $ 96.7 million and $ 95.7 million in 2020 and 2019 , respectively . the $ 1.0 million increase in 2020 was primarily due to sba ppp loans and lower rates on interest-bearing deposits , largely offset by lower yields on earning-assets . the tax-equivalent net interest margin decreased to 3.55 % in 2020 , compared to 3.98 % in 2019. the 43 basis point decrease was primarily due to lower yields across interest-earning asset categories , partially offset by lower rates on interest-bearing deposits . the efficiency ratio was 57.06 % in 2020 , up from 55.33 % in 2019. contributing to this increase was the decrease in net interest margin , higher provision for credit losses on unfunded loan commitments , and lower income from s ervice charges on deposit accounts and atm fees in 2020. for the year ended december 31 , 2020 , return on assets and return on equity were 1.04 % and 8.60 % , respectively , compared to 1.34 % and 10.49 % in the prior year . all capital ratios exceeded regulatory requirements . the total risk-based capital ratio for bancorp was 16.0 % at december 31 , 2020 up from 15.1 % at december 31 , 2019. tangible common equity to tangible assets was 11.3 % at both december 31 , 2020 and december 31 , 2019 ( see footnote 8 , item 6 , selected financial data , for the definition of this non-gaap financial measure ) . the total risk-based capital ratio for the bank was 15.8 % at december 31 , 2020 and 14.6 % at december 31 , 2019. the board of directors declared a cash dividend of $ 0.23 per share on january 22 , 2021. this was the 63 rd consecutive quarterly dividend paid by bank of marin bancorp . the cash dividend was paid on february 12 , 2021 to shareholders of record at the close of business on february 5 , 2021. our strong capital and liquidity position afforded us the opportunity to eliminate a high cost funding source . on march 15 , 2021 we redeemed the $ 2.8 million subordinated debenture , which carried a rate of 5.68 % in 2020. the redemption consisted of $ 4.1 million principal balance , quarterly interest due , and $ 1.3 million in accelerated accretion of purchase discount . the contractual interest rate on the subordinated debenture was 3-month libor plus 1.40 % , or 1.62 % as of december 31 , 2020. covid-19 pandemic-related response update - we have remained open and responded to customer needs throughout 2020. we more than doubled our charitable contributions to non-profit organizations in our community to over $ 1.0 million in 2020. in march 2020 , we began waiving all atm and overdraft fees and cancelling early withdrawal penalties for time certificate of deposits when allowed by law . we accommodated loan payment relief requests for borrowers with financial hardships and lowered interest rate floors on commercial prime rate loans . under the provisions of the coronavirus aid , relief and economic security act ( `` cares act `` ) of 2020 , bank of marin originated over 1,800 ppp loans to small businesses , reaching nearly 28,000 employees in our markets . in 2021 , we are once again diligently working with our customers to accommodate requests for round two of ppp 26 loans under the economic aid to hard-hit small businesses , nonprofits , and venues act ( `` economic aid act `` ) , which became law in december of 2020. paycheck protection program - while the ppp affords us an opportunity to assist our customers and community and requires a large of amount of human resources , the ppp loans do not pose a significant amount of risk of loss to the bank as they are 100 % guaranteed by the sba . as of december 31 , 2020 , there were 1,777 ppp loans outstanding totaling $ 291.6 million , net of $ 5.4 million in unearned fees . during the fourth quarter bank of marin opened a secure ppp loan forgiveness application portal and gave all ppp borrowers access to apply . as of december 31 , 2020 we received sba loan forgiveness payments totaling $ 10.9 million for 35 loans that were forgiven . of the total ppp loans rem aining , 74 % ( 1,309 loans ) totaling $ 58.7 million are less than or equal to $ 150 thousand and have access to streamlined forgiveness processing . on january 19 , 2021 , the bank launched the application process and began accepting loan requests for the second round of ppp , as revised by the economic aid act . as of march 11 , 2021 , we have received 974 loan applications totaling $ 131.6 million . payment relief - during 2020 , in accordance with section 4013 of the cares act , subsequently amended by the economic aid act , we elected to apply the temporary accounting relief provisions for loan modifications that met certain criteria , which would otherwise be designated as tdrs under existing gaap . of the 269 loans totaling $ 402.9 million granted payment relief since the onset of the pandemic , 222 loans or $ 324.2 million have resumed normal payments and 18 loans or $ 7.7 million paid off . as of december 31 , 2020 , 21 borrowing relationships with 29 loans totaling $ 71.0 million had requested additional payment relief . story_separator_special_tag the decrease was primarily due to $ 1.0 million in consulting expenses related to core processing contract negotiations in 2018 , lower data processing expenses in 2019 as a result of the renegotiation of the bank 's core systems contract , and lower federal deposit insurance corporation ( `` fdic `` ) deposit insurance expenses due to the fdic deposit insurance fund reserve exceeding its billing threshold in 2019. the decreases in non-interest expense were partially offset by $ 918 thousand higher salaries and related benefits as a result of annual merit increases , three additional full-time equivalent employees ( on average ) , and personnel severance , as well as higher recruiting fees recorded in other expenses . provision for income taxes income tax provisions reflect accruals for taxes at the applicable rates for federal income tax and california franchise tax based upon reported pre-tax income . provisions also reflect permanent differences between income for tax and financial reporting purposes ( such as earnings on tax exempt loans and municipal securities , boli , low-income housing tax credits , and stock-based compensation from the exercise of stock options , disqualifying dispositions of incentive stock options and vesting of restricted stock awards ) . the provision for income taxes totaled $ 10.3 million at an effective tax rate of 25.5 % in 2020 , compared to $ 11.7 million at an effective tax rate of 25.4 % in 2019 and $ 10.8 million at an effective tax rate of 24.9 % in 2018. the decrease in the provision in 2020 compared to 2019 reflected lower pre-tax income and higher tax-exempt interest income on municipal securities . the slight increase in the effective tax rate in 2020 as compared to 2019 was due to a favorable deferred tax liability true-up recognized in 2019 and a lower tax benefit from boli income in 2020. the increase in the effective tax rate in 2019 compared to 2018 was due to a higher level of tax benefits in 2018 from the exercise of non-qualified stock options and disqualifying dispositions of incentive stock options by former employees of bank of napa post-acquisition . we file a consolidated return in the u.s. federal tax jurisdiction and a combined return in the state of california tax jurisdiction . there were no ongoing federal or state income tax examinations at the issuance of this report . at december 31 , 2020 and 2019 , neither the bank nor bancorp had accruals for interest or penalties related to unrecognized tax benefits . financial condition our assets increased $ 204.6 million from december 31 , 2019 to december 31 , 2020 , mainly due to loan growth of $ 245.3 million , primarily driven by ppp loan originations , which were offset by a $ 68.3 million decrease in investment security balances . investment securities we maintain an investment securities portfolio to provide liquidity and to generate earnings on funds that have not been loaned to customers . management determines the maturities and types of securities to be purchased based on liquidity and interest rate risk position , and the desire to attain a reasonable investment yield balanced with risk exposure . table 5 shows the composition of the debt securities portfolio by expected maturity at december 31 , 2020 and 2019. expected maturities differ from contractual maturities because the issuers of the securities may have the right to call or prepay obligations with or without call or prepayment penalties . we estimate and update expected maturity dates regularly based on current and historical prepayment speeds . the weighted average life of the investment portfolio at december 31 , 2020 and 2019 was approximately five and six years , respectively . 32 table 5 investment securities replace_table_token_5_th 1 book value reflects cost , adjusted for accumulated amortization and accretion . 2 weighted average calculation is based on amortized cost of securities . 3 yields on tax-exempt municipal bonds are presented on a taxable equivalent basis , using federal tax rate of 21 % . the amortized cost of our investment securities portfolio decreased $ 79.3 million or 14 % during 2020. we purchased $ 97.5 million in securities in 2020 designated as available-for-sale to provide flexibility for liquidity and interest rate risk management . these purchases were offset by $ 143.1 million of paydowns , calls and maturities , and $ 32.8 million of sales during 2020. during 2020 , we purchased $ 57.6 million in obligations of state and political subdivisions , $ 31.0 million in collateralized mortgage obligations ( `` cmos `` ) and $ 9.0 million in debentures of government sponsored agencies . we consider agency debentures and cmos issued by u.s. government sponsored entities to have low credit risk as they carry the credit support of the u.s. federal government . the debentures , cmos and mbs issued by u.s. government sponsored agencies , state and municipal securities , and sba-backed securities made up 70.1 % , 22.1 % and 7.8 % of the portfolio at december 31 , 2020 , compared to 79.6 % , 12.4 % and 7.8 % , respectively at december 31 , 2019. see the discussion in the section captioned “ securities may lose value due to credit quality of the issuers ” in item 1a risk factors above . 33 at december 31 , 2020 , distribution of our investment in obligations of state and political subdivisions was as follows : replace_table_token_6_th the portion of the portfolio outside the state of california is distributed among 10 states . the largest concentrations outside california are in texas ( 55.3 % ) , washington ( 9.3 % ) , and maryland ( 6.4 % ) . during march 2020 , we strategically increased our credit exposure to obligations issued by high credit quality issuers in texas that are either guaranteed by the aaa-rated texas permanent school fund ( `` psf `` ) or backed by revenue sources from essential services such as

