Between June 30, 2021 and September 30, 2021, accrued interest receivable increased $105,000 to $2.0 million, deferred income taxes increased $226,000 to $1.9 million, and other assets increased $783,000 to $1.7 million, while premises and equipment decreased $130,000 to $9.7 million, and foreclosed assets held for sale decreased $68,000 to $191,000. Federal Home Loan Bank (FHLB) stock was $4.2 million at both September 30, 2021 and June 30, 2021. The increase in accrued interest receivable was primarily the result of an increase in the average balance of securities, the increase in deferred income taxes was mostly due to a decrease in unrealized gains on the sale of
securities, and the increase in other assets was due to a fluctuation in items in process. The decrease in premises and equipment was the result of ordinary depreciation, and the decrease in foreclosed assets held for sale was due to the sale of property.
At September 30, 2021, our investment in bank-owned life insurance was $9.1 million, a decrease of $215,000 from $9.3 million at June 30, 2021. We invest in bank-owned life insurance to provide us with a funding source for our benefit plan obligations. Bank-owned life insurance also generally provides us noninterest income that is
non-taxable.
Federal regulations generally limit our investment in bank-owned life insurance to 25% of our Tier 1 capital plus our allowance for loan losses, which totaled $21.8 million at September 30, 2021.
Deposits decreased $30.3 million, or 4.5%, to $637.3 million at September 30, 2021 from $667.6 million at June 30, 2021. Noninterest bearing demand accounts decreased $51.8 million, or 53.4%, to $45.2 million and certificates of deposit, excluding brokered certificates of deposit, decreased $286,000, or 0.1%, to $250.9 million, while savings, NOW, and money market accounts increased $21.7 million, or 7.0%, to $330.5 million. Brokered certificates of deposit were $10.8 million at both September 30, 2021 and June 30, 2021. The large decrease in noninterest bearing demand accounts was due to approximately $55.6 million in deposits from a public entity that collects real estate taxes that were on deposit at June 30, 2021 and withdrawn in the three months ended September 30, 2021, when tax monies were distributed. Repurchase agreements increased $458,000, or 7.3%, to $6.7 million at September 30, 2021 from $6.2 million at June 30, 2021. Borrowings consisted of advances from the Federal Home Loan Bank of Chicago and a line of credit from CIBC Bank USA. The FHLB advances were $25.0 million at both September 30, 2021 and June 30, 2021, while the CIBC line of credit balance was $3.0 million at both September 30, 2021 and June 30, 2021.
Advances from borrowers for taxes and insurance decreased $152,000, or 16.4%, to $776,000 at September 30, 2021 from $928,000 at June 30, 2021, while accrued interest payable decreased $12,000, or 6.0%, to $187,000 at September 30, 2021 from $199,000 at June 30, 2021, and other liabilities decreased $1.0 million, or 17.3%, to $4.9 million at September 30, 2021 from $6.0 million at June 30, 2021. The decrease in advances from borrowers for taxes and insurance was attributable to the timing of the payment of real estate taxes and insurance, while the decrease in accrued interest payable was mostly due to a decrease in average rates on deposits, partially offset by an increase in the average balances of deposits. The decrease in other liabilities was a result of accrued compensation and benefits that were paid out in the three months ended September 30, 2021. Total equity increased $733,000, or 0.9%, to $86.0 million at September 30, 2021 from $85.3 million at June 30, 2021. Equity increased due to net income of $1.9 million, and ESOP and stock equity plan activity of $267,000, partially offset by dividends payable of $568,000 and a decrease of $857,000 in accumulated other comprehensive income, net of tax.
Comparison of Operating Results for the Three Months Ended September 30, 2021 and 2020
Net income increased $560,000 to $1.9 million net income for the three months ended September 30, 2021 from $1.3 million net income for the three months ended September 30, 2020. The increase was primarily due to an increase in net interest income and a decrease in provision for loan losses, partially offset by a decrease in noninterest income and an increase in noninterest expense.
Net interest income increased by $684,000, or 14.0%, to $5.6 million for the three months ended September 30, 2021 from $4.9 million for the three months ended September 30, 2020. The increase was due to a decrease of $698,000 in interest expense, partially offset by a decrease of $14,000 in interest income. A $39.6 million, or 5.7%, increase in the average balance of interest earning assets was partially offset by a $30.1 million, or 5.1%, increase in the average balance of interest bearing liabilities. Our net interest margin increased by 22 basis points to 3.02% for the three months ended September 30, 2021 compared to 2.80% for the three months ended September 30, 2020, while our interest rate spread increased by 29 basis points to 2.95% for the three months ended September 30, 2021 compared to 2.66% for the three months ended September 30, 2020.