The Boston-based insurer also declared Fourth Quarter 2021 Dividend
Net income for the quarter ended September 30, 2021 was $24.8 million, or $1.64 per diluted share, compared to net income of $44.7 million, or $2.96 per diluted share, for the comparable 2020 period. Net income for the nine months ended September 30, 2021 was $98.7 million, or $6.58 per diluted share, compared to net income of $85.2 million, or $5.58 per diluted share, for the comparable 2020 period. Non-generally accepted accounting principles (“non-GAAP”) operating income, as defined below, for the quarter ended September 30, 2021 was $1.70 per diluted share, compared to $2.53 per diluted share, for the comparable 2020 period. Non[1]GAAP operating income for the nine months ended September 30, 2021 was $5.51 per diluted share, compared to $6.02 per diluted share, for the comparable 2020 period.
Safety’s book value per share increased to $61.94 at September 30, 2021 from $59.40 at December 31, 2020. Safety paid $0.90 per share in dividends to investors during the quarters ended September 30, 2021 and 2020, respectively. Safety paid $3.60 per share in dividends to investors during the year ended December 31, 2020.
Direct written premiums for the quarter ended September 30, 2021 decreased by $2.3 million, or 1.1%, to $211.1 million from $213.4 million for the comparable 2020 period. Direct written premiums for the nine months ended September 30, 2021 increased by $4.5 million, or 0.7% to $620.6 million from $616.1 million for the comparable 2020 period. The nine months ended September 30, 2020 direct written premium reflects the Safety Personal Auto Relief Credit, a 15% policyholder credit that was applied to personal auto policies for the months of April, May and June 2020 and was booked as an adjustment to premiums during the second quarter of 2020.
Net written premiums for the quarter ended September 30, 2021 decreased by $3.1 million, or 1.5%, to $202.6 million from $205.7 million for the comparable 2020 period. Net written premiums for the nine months ended September 30, 2021 increased by $1.1 million, or 0.2%, to $593.6 million from $592.5 million for the comparable 2020 period. Net earned premiums for the quarter ended September 30, 2021 decreased by $0.4 million, or 0.2%, to $194.4 million from $194.8 million for the comparable 2020 period. Net earned premiums for the nine months ended September 30, 2021 increased by $6.9 million, or 1.2%, to $581.5 million from $574.6 million for the comparable 2020 period. The changes in both periods are a result of the changes in direct written premiums as described above.
For the quarter ended September 30, 2021, losses and loss adjustment expenses incurred increased by $22.0 million, or 22.7%, to $119.1 million from $97.1 million for the comparable 2020 period. For the nine months ended September 30, 2021, losses and loss adjustment expenses incurred increased by $32.0 million, or 10.4%, to $340.8 million from $308.8 million for the comparable 2020 period. The 2020 losses and loss adjustment expenses in both periods reflect a decrease in frequency, primarily in our private passenger automobile line of business as a result of the COVID-19 pandemic.
Total prior year favorable development included in the pre-tax results for the quarter ended September 30, 2021 was $15.4 million compared to $15.3 million for the comparable 2020 period. Total prior year favorable development included in the pre-tax results for the nine months ended September 30, 2021 was $41.2 million compared to $34.6 million for the comparable 2020 period.
Loss, expense, and combined ratios calculated under U.S. generally accepted accounting principles for the quarter ended September 30, 2021 were 61.3%, 32.6%, and 93.9%, respectively, compared to 49.8%, 35.2%, and 85.0%, respectively, for the comparable 2020 period. Loss, expense, and combined ratios calculated under U.S. generally accepted accounting principles for the nine months ended September 30, 2021 were 58.6%, 33.3%, and 91.9%, respectively, compared to 53.7%, 34.0%, and 87.7%, respectively, for the comparable 2020 period.
Net investment income for the quarter ended September 30, 2021 increased by $1.4 million, or 14.3%, to $11.1 million from $9.7 million for the comparable 2020 period. Net investment income for the nine months ended September 30, 2021 increased by $2.1 million, or 6.8%, to $32.4 million from $30.3 million for the comparable 2020 period. The increase in both periods is a result of an increase in the average invested asset balance and an increase in the equity in earnings of other invested assets compared to the prior year. Net effective annualized yield on the investment portfolio for the quarter ended September 30, 2021 was 3.1% compared to 2.8% for the comparable 2020 period. Net effective annualized yield on the investment portfolio for the nine months ended September 30, 2021 was 3.0% compared to 2.9% for the comparable 2020 period. Our duration on fixed maturities was 3.5 years at September 30, 2021 compared to 3.2 years at December 31, 2020, respectively. Today, our Board of Directors approved a $0.90 per share quarterly cash dividend on its issued and outstanding common stock payable on December 15, 2021 to shareholders of record at the close of business on December 1, 2021.
Non-GAAP Measures
Management has included certain non-GAAP financial measures in presenting the Company’s results. Management believes that these non-GAAP measures better explain the Company’s results of operations and allow for a more complete understanding of the underlying trends in the Company’s business. These measures should not be viewed as a substitute for those determined in accordance with generally accepted accounting principles (“GAAP”). In addition, our definitions of these items may not be comparable to the definitions used by other companies.
Non-GAAP operating income and non-GAAP operating income per diluted share consist of our GAAP net income adjusted by the net realized gains (losses) on investments, change in net unrealized gains on equity securities, credit loss (expense) benefit and taxes related thereto. For the three months ended September 30, 2021, a decrease of $3.4 million for the change in unrealized gains on equity securities was recognized within income before income taxes, compared to an increase of $7.5 million recognized in the comparable 2020 period. For the nine months ended September 30, 2021, an increase of $11.4 million for the change in unrealized gains on equity securities was recognized in income before income taxes, compared to a decrease of $5.6 million recognized in the comparable 2020 period. Net income and earnings per diluted share are the GAAP financial measures that are most directly comparable to non-GAAP operating income and non-GAAP operating income per diluted share, respectively. A reconciliation of the GAAP financial measures to these non-GAAP measures is included in the financial highlights below.
