Borrowed Funds. Advances from the FHLB decreased $30.5 million, or 60.3%, from $50.7 million at December 31, 2020 to $20.1 million at September 30, 2021, as the Company was able to utilize increased deposits to fund asset growth.
Stockholders’ Equity. Stockholders' equity increased $7.7 million to $124.2 million at September 30, 2021, primarily due to net income of $8.6 million partially offset by a $1.6 million reversal from a net unrealized gain to a net unrealized loss on available for sale securities. At September 30, 2021, the Company’s book value per share was $10.99. At September 30, 2021, the Company’s ratio of stockholders’ equity-to-total assets was 9.84%. Unearned common stock held by the Bank’s employee stock ownership plan was $3.8 million at September 30, 2021.
Comparison of Operating Results for the Three and Nine Months Ended September 30, 2021 and September 30, 2020
Net Income. Net income for the three months ended September 30, 2021 increased $1.5 million, or 133.5%, to $2.7 million, or $0.25 per diluted share, compared to net income of $1.2 million, or $0.10 per diluted share, for the three months ended September 30, 2020. Interest and dividend income increased $185,000, or 1.7%, interest expense decreased $846,000, or 45.8%, the provision for loan losses decreased $3.2 million, or 142.4%, non-interest income decreased $457,000, or 21.8%, while other expenses and taxes increased $2.2 million, or 29.0%, between comparable quarters.
For the nine months ended September 30, 2021, net income was $8.6 million, or $0.79 per diluted share, compared to $3.6 million, or $0.33 per diluted share, for the nine months ended September 30, 2020. Interest and dividend income decreased by $479,000, or 1.5%, interest expense decreased $3.1 million, or 48.0%, and the provision for loan losses decreased $7.9 million, or 138.1%, resulting in a $10.5 million increase, or 51.0%, in net interest income after the provision for loan losses. Non-interest income increased $330,000, or 6.1% while other non-interest and tax expense increased $5.9 million, or 26.1%, during the equivalent nine month timeframes.
Net Interest Income. Net interest income increased $1.0 million, or 11.4%, to $10.1 million for the three months ended September 30, 2021, compared to $9.0 million for the quarter ended September 30, 2020. The ratio of average interest-earning assets to average interest-bearing liabilities improved 1.6% to 145.46% while our net interest margin increased by 2 basis points to 3.42% when comparing the third quarter of 2021 to the same period in 2020.
For the nine months ended September 30, 2021, net interest income increased $2.6 million, or 10.0%, to $29.0 million from $26.3 million for the comparable 2020 period. Overall there was a 3 basis point decrease in the net interest margin to 3.44%, when comparing the respective nine month periods, while the ratio of average interest-earning assets to average interest-bearing liabilities improved 3.4% to 144.42%.
Interest Income. Interest income increased $185,000, or 1.7%, to $11.1 million for the three months ended September 30, 2021 from $10.9 million for the comparable 2020 period. The average yield decreased by 33 basis points to 3.76%, which was offset by an increase in the average balances of interest-earning assets of $110.8 million, or 10.5%, to $1.17 billion.
For the nine months ended September 30, 2021, interest income decreased $479,000, or 1.5%, to $32.3 million from $32.8 million for the nine months ended September 30, 2020. The average yield declined by 49 basis points when comparing the nine-month periods ended September 30, 2021 and 2020 to 3.84% for the nine months ended September 30, 2021, which was offset by an increase in the average balance of interest-earning assets of $113.3 million, or 11.2%, to $1.13 billion. The decrease was mostly driven lower earning asset yields due to lower yielding PPP loans and lower yielding debt securities due to the significant decline in the interest rate environment, partially offset by higher average earning asset balances.
Interest Expense. Interest expense decreased $846,000, or 45.8%, from $1.8 million for the quarter ended September 30, 2020, to $1.0 million for the quarter ended September 30, 2021. Interest rates on interest-bearing liabilities decreased 50 basis points to an average of 0.49% for the quarter ended September 30, 2021, which was offset by an increase in the average balance of total interest-bearing liabilities of $64.5 million, or 8.7%, to $803.2 million as the increase in the average balance of deposits was offset by a decrease in the average balance of FHLB advances.