Management believes that core and non-core fee income and other expense are useful in assessing our core operating performance and in understanding the primary drivers of our fee income and other expense when comparing periods.
The tax equivalent adjustment to net interest income, net interest margin, tax-exempt interest income and increase in cash surrender value of life insurance recognizes the income tax savings when comparing taxable and tax-exempt assets and assumes a 35% tax rate. Management believes that it is a standard practice in the banking industry to present net interest income and net interest margin on a fully tax equivalent basis, and accordingly believes that providing these measures may be useful for peer comparison purposes. For the same reasons, management believes the tax equivalent adjustments to tax-exempt interest income and increase in cash surrender value of life insurance are useful.
Management also believes that by excluding net gains and losses on investment securities, net gains and losses on sale of other assets, net losses on other real estate owned, net gain on sale of loans held for sale and increase (decrease) in market value of assets held in trust for deferred compensation from the non-interest income components, and excluding prepayment fees on interest bearing liabilities, impairment changes and increase (decrease) in market value of assets held in trust for deferred compensation from the other expense components, of the efficiency ratio and the ratio of annualized net other expense to average assets, these ratios better reflect our core operating performance, as the excluded items do not pertain to our core business operations and their exclusion makes these ratios more meaningful when comparing our operating results from period to period.
In addition, management believes that presenting the ratio of Tier 1 common equity to risk-weighted assets is useful for assessing our capital strength and for peer comparison purposes. The other measures exclude the acquisition-related goodwill and other intangible assets, net of tax benefit, in determining tangible assets, tangible equity, tangible common equity and average tangible common equity and exclude other intangible amortization expense, net of tax benefit, in determining net cash flow available to common stockholders. Management believes the presentation of these other financial measures excluding the impact of such items provides useful supplemental information that is helpful in understanding our financial results, as they provide a method to assess management’s success in utilizing our tangible capital as well as our capital strength. Management also believes that providing measures that exclude balances of acquisition-related goodwill and other intangible assets, which are subjective components of valuation, facilitates the comparison of our performance with the performance of our peers. In addition, management believes that these are standard financial measures used in the banking industry to evaluate performance.