jurisdictions in which we operate and the tax laws and regulations in effect. Our income tax expense for periods beginning in 2018 is based on the U.S. federal corporate income tax rate of 21%.
Key Metrics
We discuss certain key metrics, described below, which provide useful information about our business and the operational factors underlying our financial performance.
Net income is the amount of profit or loss remaining after deducting all incurred expenses, including income taxes, from the total earned revenues for an accounting period.
Underwriting (loss) income is calculated by subtracting losses and LAE and underwriting, acquisition and insurance expenses from net earned premiums.
Adjusted operating income is net income excluding net realized investment gains and losses, expenses relating to various transactions that we consider to be unique and non-recurring in nature (net of estimated tax impact).
Loss and LAE ratio, expressed as a percentage, is the ratio of losses and LAE, allocated and unallocated, to net earned premiums, net of the effects of reinsurance.
Loss and LAE ratio, excluding catastrophe, is the ratio of losses and LAE, allocated and unallocated, excluding those losses categorized as catastrophe losses, to net earned premiums, net of the effects of reinsurance, excluding the impact of reinsurance premiums related to catastrophe losses.
Expense ratio, expressed as a percentage, is the ratio of underwriting, acquisition and insurance expenses to net earned premiums.
Combined ratio is the sum of the loss and LAE ratio and the expense ratio. A combined ratio under 100% indicates an underwriting profit. A combined ratio over 100% indicates an underwriting loss.
Combined ratio, excluding catastrophe losses and related items, is the sum of the loss and LAE ratio, excluding catastrophe losses and related items and the expense ratio.
Adjusted loss and LAE ratio is the loss and LAE ratio excluding the effects of the whole account quota share reinsurance agreement (“WAQS”) (as defined below).
Adjusted Loss and LAE ratio, excluding catastrophe, is the ratio of losses and LAE, allocated and unallocated, excluding the effects of the WAQS, and excluding those losses categorized as catastrophe losses, to net earned premiums, net of the effects of reinsurance, excluding the impact of reinsurance premiums related to catastrophe losses.
Adjusted expense ratio is the expense ratio excluding the effects of the WAQS.
Adjusted combined ratio is the combined ratio excluding the effects of the WAQS.
Return on equity is net income expressed on an annualized basis as a percentage of average beginning and ending stockholders’ equity during the period.
Adjusted operating return on equity is adjusted operating income expressed on an annualized basis as a percentage of average beginning and ending stockholders’ equity during the period.
Net retention ratio is the ratio of net written premiums to GWP.
Underwriting (loss) income, adjusted operating income, adjusted loss and LAE ratio, adjusted expense ratio, adjusted combined ratio and adjusted operating return on equity are non-generally accepted accounting principles (“GAAP”) financial measures. See “Reconciliation of Non-GAAP Financial Measures” for a reconciliation of net income