Note K – Income Taxes

The Company’s effective income tax rate is calculated as the amount of income tax expense (benefit) divided by income from continuing operations before income taxes. For the three-month periods ended March 31, 2019 and 2018, the Company’s effective income tax rates were as follows:


	2019	2018
Three months ended March 31	32.1%	530.2%

The effective tax rates for most periods where earnings are generated, generally exceed the U.S. statutory tax rate due to several factors, including: the effects of income generated in foreign tax jurisdictions, certain of which have income tax rates that are higher than the U.S. Federal rate; U.S. state tax expense; and certain expenses, including exploration and other expenses in certain foreign jurisdictions, for which no income tax benefits are available or are not presently being recorded due to a lack of reasonable certainty of adequate future revenue against which to utilize these expenses as deductions. Conversely, the effective tax rates for most periods where losses are incurred generally are lower than U.S. statutory tax rate of 21% due to similar reasons.

The effective tax rate for the three-month period ended March 31, 2019 was above the U.S. statutory tax rate of 21% primarily due to exploration expenses in certain foreign jurisdictions in which no income tax benefit is available. These impacts were partially offset by no tax applied to the pre-tax income of the noncontrolling interest in MP GOM.

The effective tax rate for the three-month period ended March 31, 2018 was above the statutory tax rate primarily due to the impact of the IRS’s April 2, 2018 guidance allowing for the preservation of 2017 operating loss carryforwards under the 2017 Tax Act’s taxation of unrepatriated foreign earnings. The preservation of the tax loss carryforward reduced the deferred tax expense by $156 million and resulted in a $36 million charge to taxes payable for a net $120 million tax benefit.

The Company’s tax returns in multiple jurisdictions are subject to audit by taxing authorities. These audits often take multiple years to complete and settle. Although the Company believes that recorded liabilities for unsettled issues are adequate, additional gains or losses could occur in future years from resolution of outstanding unsettled matters. As of March 31, 2019, the earliest years remaining open for audit and/or settlement in our major taxing jurisdictions are as follows: United States – 2015; Canada – 2013; Malaysia – 2012; and United Kingdom – 2017.