on both an excess of loss and quota share basis. Both our commercial and residential quota shares will apply to this event from the first dollar of loss, and as such we do not expect to incur material losses from the storm.”
Underwriting Results
Gross written premiums increased 31.0% to $96.1 million compared to $73.3 million in the fourth quarter of 2019, while net earned premiums increased 25.6% compared to the prior year’s fourth quarter. Losses and loss adjustment expenses for the fourth quarter were $17.2 million including $14.5 million of catastrophe losses and $2.7 million of non-catastrophe attritional losses. The loss ratio for the quarter was 44.2%, comprised of a catastrophe loss ratio of 37.2%(1) and an attritional loss ratio of 7.0%, compared to a loss ratio of 7.1% during the same period last year comprised entirely of attritional losses. The fourth quarter losses include $0.1 million of favorable prior year development. In addition to catastrophe losses, the Company’s fourth quarter 2020 results were impacted by a reinsurance expense acceleration charge of $4.1 million and reinstatement premium of $0.8 million on backup reinsurance purchased. Underwriting loss(1) was $5.0 million resulting in a combined ratio of 112.8% compared to underwriting income of $11.4 million and a combined ratio of 63.1% during the same period last year. The fourth quarter of 2020 results include certain expenses related to stock-based compensation and catastrophe losses. The fourth quarter of 2019 results include certain expenses related to the Company’s stock offering and stock-based compensation. Without these items, the Company’s adjusted combined ratio excluding catastrophe losses(1) was 73.8% in the fourth quarter compared to 60.7% during the same period last year. This increase was significantly due to the reinsurance acceleration charge and reinstatement premium incurred in the fourth quarter of 2020.
Investment Results
Net investment income increased by 29.0% to $2.3 million compared to $1.8 million in the prior year’s fourth quarter. The year over year increase was primarily due to a higher average balance of investments held during the three months ended December 31, 2020 due to cash generated from operations as well as proceeds from the Company’s January and June 2020 stock offerings, offset by lower yields on invested assets. Funds are generally invested conservatively in high quality securities, including government agency, asset and mortgage-backed securities, municipal and corporate bonds with an average credit quality of "A2/A". The weighted average duration of the fixed-maturity investment portfolio, including cash equivalents, was 3.96 years at December 31, 2020. Cash and invested assets totaled $456.1 million at December 31, 2020. During the fourth quarter, the Company recognized realized and unrealized gains of $245 thousand related to its investment portfolio as compared to a $1.2 million gain in last year’s fourth quarter.
Tax Rate
The effective tax rate for the three months ended December 31, 2020 was 23.1% compared to 24.6% for the three months ended December 31, 2019. For the current quarter, the Company’s income tax rate differed from the statutory rate due to the tax impact of the permanent component of employee stock option exercises. The 2019 fourth quarter tax rate includes an adjustment from prior periods of $0.4 million, or approximately 3 points of the effective tax rate for the fourth quarter.
Stockholders’ Equity and Returns
Stockholders' equity was $363.7 million at December 31, 2020, compared to $218.6 million at December 31, 2019. For the three months ended December 31, 2020, the Company’s annualized return on equity was (2.0%) compared to 20.4% for the same period last year.
Full Year 2021 Outlook
For the full year 2021, the Company expects to achieve adjusted net income of $62 million to $67 million. This adjusted net income guidance considers the impact of Winter Storm Uri in Texas.
Conference Call
As previously announced, Palomar will host a conference call February 25, 2021, to discuss its fourth quarter and full year 2020 results at 12:00 p.m. (Eastern Time). The conference call can be accessed by dialing 1-877-423-9813 (domestic) or 1-201-689-8573 (international) and asking for the Palomar Fourth Quarter and Full Year 2020 Earnings Call. A telephonic replay will be available approximately two hours after the call and can be accessed by dialing 1-844-512-2921, or for international callers 1-412-317-6671 and providing the access code 13716031. The telephonic replay will be available until 11:59 pm (Eastern Time) on March 4, 2021.
Interested investors and other parties may also listen to a simultaneous webcast of the conference call by logging onto the investor relations section of the Company’s website at http://ir.palomarspecialty.com/. The online replay will remain available for a limited time beginning immediately following the call.
About Palomar Holdings, Inc.
Palomar Holdings, Inc. is the holding company of subsidiaries Palomar Specialty Insurance Company, Palomar Specialty Reinsurance Company Bermuda Ltd., Palomar Insurance Agency, Inc. and Palomar Excess and Surplus Insurance Company. Palomar is an innovative insurer that focuses on the provision of specialty insurance for residential and commercial clients. Palomar’s underwriting and analytical expertise allow it to concentrate on certain markets that it believes are underserved by other insurance companies, such as the markets for earthquake, hurricane and flood insurance. Palomar’s principal insurance subsidiary, Palomar Specialty Insurance Company, is an admitted carrier in 32 states and has an A.M. Best financial strength rating of “A-” (Excellent).
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