Net interest income after provision for loan losses decreased $577,000, or 10.9%, to $4.7 million for the nine months ended September 30, 2020 compared to $5.3 million for the nine months ended September 30, 2019 due primarily to a decrease in the interest rate spread.
Total interest income decreased $401,000, or 6.7%, to $5.6 million for the nine months ended September 30, 2020 compared to $6.0 million for the nine months ended September 30, 2019. The decrease resulted from a decrease in the yield earned on interest-bearing assets partially offset by an increase in the average balance of interest-earning assets. The average tax equivalent yield on interest-earning assets declined to 3.78% for the nine months ended September 30, 2020 from 4.22% for the for the same period in 2019, due primarily to a decrease in market interest rates. The average balance of interest-earning assets increased to $204.7 million for the nine months ended September 30, 2020 from $193.3 million for the nine months ended September 30, 2019, due primarily to increases in cash and cash equivalents and investment securities, partially offset by a decline in loans receivable.
Total interest expense increased $80,000, or 12.2%, to $738,000 for the nine months ended September 30, 2020 compared to $658,000 for the nine months ended September 30, 2019 due to an increase in both the average balance and cost of interest-bearing liabilities. The average balance of interest-bearing liabilities increased to $142.1 million for the nine months ended September 30, 2020 from $133.5 million for the same period in 2019, due primarily to increases in both the average balance of Federal Home Loan Bank borrowings and the average balance of savings and interest-bearing demand deposit accounts, partially offset by a decrease in the average balance of time deposits. The average cost of interest-bearing liabilities increased to 0.69% for the nine months ended September 30, 2020 from 0.66% for the same period in 2019. The average cost of deposits declined slightly to 0.61% for the nine months ended September 30, 2020 from 0.63% for the same period in 2019. As a result of the changes in interest-earning assets and interest-bearing liabilities, the interest rate spread decreased to 3.09% from 3.56% and the net interest margin decreased to 3.29% from 3.77% for the nine months ended September 30, 2020 and 2019, respectively. Because the length of the COVID-19 pandemic and the efficacy of the extraordinary measures being put in place to address its economic consequences are unknown, until the pandemic subsides, the Company expects its net interest income and net interest margin will be adversely affected in 2020 and possibly longer.
Provision for Loan Losses. Non-performing loans increased to $1.4 million, at September 30, 2020 compared to $1.2 million at December 31, 2019, or 1.2% and 0.9% of total loans, respectively. At September 30, 2020, $1.1 million or 74.8% of nonperforming loans were current on their loan payments. Based on an analysis of the factors described in "Summary of Significant Accounting Policies – Allowance for Loan Losses,” and due primarily to forecasted probable loan losses reflecting the worsening impact of the COVID-19 pandemic on the economy, the Company recorded a $30,000 provision for loan losses for the three months ended September 30, 2020, compared to a $6,000 provision for loan losses for the same period of 2019. For the nine months ended September 30, 2020, the Company recorded a $102,000 provision for loan losses, compared to a $6,000 provision for loan losses for the same period of 2019. We believe the provision for loan losses could increase in future periods based on the possibility of increased loan delinquencies and defaults as a result of the COVID-19 pandemic.
Noninterest Income. Noninterest income decreased $13,000, or 6.0%, for the quarter ended September 30, 2020 as compared to the same period in 2019, due primarily to a decrease of $41,000 deposit account service charges, partially offset by increases of $8,000 and $21,000 in ATM and debit card fee income and other income, respectively.
Noninterest income increased $26,000, or 4.1%, for the nine months ended September 30, 2020 as compared to the same period in 2019, due primarily to increases of $97,000 in net gains on sales of securities available for sale, $23,000 in ATM and debit card fee income and $35,000 in other income, partially offset by a $126,000 decrease in deposit account service charges.
Noninterest Expense. Noninterest expense decreased $362,000, or 19.2%, for the quarter ended September 30, 2020 as compared to the same period in 2019. This decrease was due primarily to decreases in data processing expenses of $334,000, decreases in impairment loss on real estate held for sale of $67,000 and decreases in other expenses of $54,000, partially offset by an increase of $89,000 in compensation and benefits expense. Data processing expenses decreased due primarily to lower data processing fees of $129,000 and $193,000 of contract termination expenses recognized in the third quarter of last year related to the Bank’s core processing system conversion which was completed