We investigate how firms use differences in state income tax regimes to lower their state tax burdens. We develop a model that predicts that firms’ state effective tax rates first decrease then increase as a function of the number of states in which they file returns. Using firm-level data, we find evidence consistent with the model's predictions and we estimate that such rates are minimized at 24 states. Consistent with predictions from prior literature, our evidence also suggests that firms use sales factor apportionment to reduce state tax burdens.

We investigate factors that explain firms' decisions to disclose and record contingent tax liabilities. Our findings are based on confidential Internal Revenue Service audit data and financial statement footnotes for 100 large industrial firms from 1987 to 1995. Descriptive statistics indicate that these firms often fail to disclose IRS claims for tax deficiencies that exceed a 5-percent-of-income rule of thumb. We find that the probability of disclosure increases in the relative amount of the claim or the expected loss, although the largest claims drive this result. Our evidence is consistent with firms using a stable measure of size, such as assets or normal income, to gauge materiality, rather than relying only on current period reported income. We also find that the amount accrued for the contingent liability increases in the amount of the expected loss. However, our inferences may not generalize beyond a population of large, frequently audited firms.