Comparison of Operating Results for the Three Months Ended June 30, 2021 and 2020
General. Net income decreased by $233,000 or 5.4%, to $4.1 million for the three months ended June 30, 2021 from $4.3 million for the three months ended June 30, 2020. The decrease in net income was primarily due to a $1.7 million decrease in net interest income and a $641,000 increase in non-interest expense. These decreases to net income was partially offset by a $1.8 million decrease in loan loss provisions and a $266,000 increase in non-interest income.
Net Interest Income. Net interest income decreased by $1.7 million, or 11.4%, to $13.1 million for the three months ended June 30, 2021 from $14.8 million for the three months ended June 30, 2020. Interest income decreased by $3.2 million, or 18.0%, primarily due to a 72 basis point decrease in the average yield on average interest-earning assets, which was partially offset by a $50.5 million increase in the average balance of interest-earning assets. Interest expense decreased by $1.6 million, or 48.4%, due to a 37 basis point decrease in the cost of average interest-bearing liabilities, which was partially offset by a $34.7 million increase in the average balance of interest-bearing liabilities. The interest rate spread and net interest margin were 2.49% and 2.54%, respectively, for the three months ended June 30, 2021, compared to 2.84% and 2.94%, respectively, for the three months ended June 30, 2020. The decrease in the interest rate spread and in the net interest margin are attributable to a 72 basis point decrease in the yield of average interest-bearing assets that was partially offset by a 37 basis point decrease in the cost of average interest-earning liabilities.
Interest Income. Interest income decreased by $3.2 million, or 18.0%, to $14.8 million for the three months ended June 30, 2021 from $18.0 million for the three months ended June 30, 2020. Interest income on loans decreased by $3.1 million, or 20.3%, to $12.1 million for the three months ended June 30, 2021 from $15.2 million for the three months ended June 30, 2020. The decrease in interest income on loans occurred because of a $228.8 million, or 14.7%, decrease in the average balance of loans and a 26 basis point decrease in the average loan yield. The decrease in the average balance of loans occurred as loan repayments and loan sales exceeded new loan originations. The decrease in the average loan yield occurred as higher yielding loans were paid off and new loans with lower interest rates were added to the loan portfolio. Interest income on securities decreased by $216,000, or 8.3%, to $2.4 million for the three months ended June 30, 2021 from $2.6 million for the three months ended June 30, 2020. The decrease in interest income on securities occurred because of a 61 basis point decline in the average securities yield, which occurred as higher yielding securities were paid off or sold and securities with lower interest rates were purchased. The average balance of securities increased by $55.3 million, or 15.6%, to $409.1 million for the three months ended June 30, 2021 from $353.8 million for the three months ended June 30, 2020. The increase in the average balance of securities occurred as purchases exceeded the principal repayments and sales of securities.
Interest Expense. Interest expense decreased by $1.6 million, or 48.4%, to $1.7 million for the three months ended June 30, 2021 from $3.2 million for the three months ended June 30, 2020. The decrease in interest expense occurred because interest expense on interest-bearing deposits decreased by $1.3 million, or 53.9%, to $1.1 million for the three months ended June 30, 2021 from $2.4 million for the three months ended June 30, 2020. The decrease in interest expense on interest-bearing deposits was due to a 33 basis point decrease in the average rate on interest-bearing deposits, which was partially offset by a $36.9 million, or 2.3%, increase in the average interest-bearing deposit balance. The average rate paid on interest-bearing deposits decreased to 0.27% for the three months ended June 30, 2021 compared to 0.60% for the three months ended June 30, 2020. The decrease in the average rate paid on interest-bearing deposits was primarily due to lower interest rates offered on savings accounts and certificates of deposit. The average rate paid on savings accounts decreased to 0.11% for the three months ended June 30, 2021 from 0.23% for the three months ended June 30, 2020. The average rate paid on certificates of deposit decreased to 1.11% for the three months ended June 30, 2021 from 1.66% for the three months ended June 30, 2020. Interest expense on FHLB advances decreased by $292,000 or 35.2% to $537,000 for the three months ended June 30, 2021 from $829,000 for the three months ended June 30, 2020. The decrease in interest expense on FHLB advances occurred because of an 80 basis point decrease in the average cost of advances, which was augmented by a $2.2 million decrease in the average FHLB advance balance. The decrease in the average cost of advances occurred as we restructured $102.0 million of FHLB advances at lower interest rates. The decrease in FHLB advance balance occurred as maturing advances were paid off.
Provision for Loan Losses. We recorded a $372,000 reversal of loan loss provisions for the three months ended June 30, 2021 and $1.4 million of loan loss provisions for the three months ended June 30, 2020. The reversal of loan loss provisions occurred primarily due to decreases in the amount of loans in our loan payment deferral program,