Finance and Other Service Income. Finance and other service income includes revenues from premium installment charges, which we recognize when earned, and other miscellaneous income and fees. Finance and other service income for the three months ended March 31, 2022 decreased by $655, or 16.5%, to $3,317 from $3,972 for the comparable 2021 period. The decrease is primarily driven by a change in our late fee assessment policy.
Loss and Loss Adjustment Expenses. Loss and loss adjustment expenses incurred for the three months ended March 31, 2022 increased by $11,671, or 10.5%, to $123,166 from $111,495 for the comparable 2021 period. The increase in losses is due to a return of pre-pandemic frequency in our private passenger automobile line of business and current market conditions including inflation and supply chain delays.
Our GAAP loss ratio for the three months ended March 31, 2022 increased to 65.8% from 57.8% for the comparable 2021 period. Our GAAP loss ratio excluding loss adjustment expenses for the three months ended March 31, 2022 was 55.2% compared to 44.7% for the comparable 2021 period. Total prior year favorable development included in the pre-tax results for the three months ended March 31, 2022 was $12,412 compared to $12,459 for the comparable 2021 period.
Underwriting, Operating and Related Expenses. Underwriting, operating and related expenses for the three months ended March 31, 2022 decreased by $3,430, or 5.3%, to $61,594 from $65,024 for the comparable 2021 period. Our GAAP expense ratio for the three months ended March 31, 2022 decreased to 32.9% from 33.7% for the comparable 2021 period. The decrease is driven by a decrease in contingent commission expenses offset by expense incurred related to an activist investor.
Interest Expense. Interest expense was $129 for the three months ended March 31, 2022 and 2021. The credit facility commitment fee included in interest expense was $19 for the three months ended March 31, 2022 and 2021.
Income Tax Expense. Our effective tax rate was 22.5% and 20.1% for the quarters ended March 31, 2022 and 2021, respectively. The effective tax rate for the quarter ended March 31, 2022 was higher than the statutory rate primarily due to the effects of the change in unrealized gains on equity securities and the impact of stock-based compensation. The effective tax rate for the quarter ended March 31, 2021 was lower than the statutory rate primarily due to the effects of tax-exempt investment income and the impact of stock-based compensation.
Net Income. Net income for the three months ended March 31, 2022 was $7,838 compared to $36,174 for the comparable 2021 period.
Non-GAAP Operating Income. Non-GAAP operating income as defined above was $14,809 for the three months ended March 31, 2022 compared to $28,856 for the comparable 2021 period. The decrease in Non-GAAP operating income was primarily the result of an increase in loss and loss adjustment expenses compared to the prior period.
Liquidity and Capital Resources
As a holding company, Safety’s assets consist primarily of the stock of our direct and indirect subsidiaries. Our principal source of funds to meet our obligations and pay dividends to shareholders, therefore, is dividends and other permitted payments from our subsidiaries, principally Safety Insurance. Safety is the borrower under our credit facility.
Safety Insurance’s sources of funds primarily include premiums received, investment income, and proceeds from sales and redemptions of investments. Safety Insurance’s principal uses of cash are the payment of claims, operating expenses and taxes, the purchase of investments, and the payment of dividends to Safety.
Net cash used for operating activities was $15,276 during the three months ended March 31, 2022 compared to net cash provided by operating activities of $12,523 during the three months ended March 31, 2021. Our operations