7. Income Taxes

Our effective tax rate is generally higher than the statutory rate due to the geographic mix of profit among the foreign and domestic jurisdictions in which we operate. For the three months ended December 31, 2021 and 2020, we recorded income tax expense of $0.2 million and $0.1 million, respectively. Tax expense for the three months ended December 31, 2020, includes a benefit of approximately $0.3 million related to the reversal of previously recorded uncertain tax positions. The quarterly income tax provision is calculated using an estimated annual effective tax rate, based upon expected annual income, permanent items, statutory rates and planned tax strategies in the various jurisdictions in which we operate. However, losses in certain jurisdictions and discrete items are treated separately.

Generally accepted accounting principles require that a valuation allowance be established when it is “more likely than not” that all or a portion of deferred tax assets will not be realized. A review of all available positive and negative evidence needs to be considered, including a company’s performance, the market environment in which the company operates and the length of carryback and carryforward periods. According to those principles, it is difficult to conclude that a valuation allowance is not needed when the negative evidence includes cumulative losses in recent years. We have concluded that we will maintain a full valuation allowance for all net deferred tax assets related to the

carryforwards of U.S. net operating losses and foreign tax credits. We will continue to monitor our cumulative income and loss positions in the U.S. and foreign jurisdictions to determine whether full valuation allowances on net deferred tax assets are appropriate. We expect to pay minimal U.S federal cash taxes for the foreseeable future as a result of our U.S. net operating losses.

We classify all of our uncertain tax positions as income taxes payable long-term. At December 31, 2021 and September 30, 2021, the total amount of unrecognized tax benefits was approximately $1.0 million and $0.9 million, respectively. Income taxes payable long-term includes other items, primarily withholding taxes, that are not due until the related intercompany service fees are paid.

We classify interest and penalties related to unrecognized tax benefits as income tax expense. As of December 31, 2021 and September 30, 2021, we had an accrual for potential interest and penalties of approximately $0.7 million and $0.6 million, respectively, classified with income taxes payable long-term.

Amtech and one or more of its subsidiaries file income tax returns in China and other foreign jurisdictions, as well as in the U.S. and various states in the U.S. We have not signed any agreements with the Internal Revenue Service, any state or foreign jurisdiction to extend the statute of limitations for any fiscal year. As such, the number of open years is the number of years dictated by statute in each of the respective taxing jurisdictions, which generally is from 3 to 5 years.