We compute and apply to ordinary income an estimated annual effective tax rate on a quarterly basis based on current and forecasted business levels and activities, including the mix of domestic and foreign results and enacted tax laws. The estimated annual effective tax rate is updated quarterly based on actual results and updated operating forecasts. Ordinary income refers to income (loss) before income tax expense excluding significant, unusual or infrequently occurring items. The tax effect of an unusual or infrequently occurring item is recorded in the interim period in which it occurs as a discrete item of tax.


	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2021			2020			2021			2020
	(Dollars in thousands)
Tax expense	$	7,765		$	19,788		$	24,022		$	43,734
Pretax income	35,930			112,564			150,986			258,778
Effective tax rates	21.6		%	17.6		%	15.9		%	16.9		%

The effective tax rate for the three months ended June 30, 2021 was 21.6%. This rate differs from the U.S. statutory rate of 21% primarily due to worldwide earnings from various countries taxed at different rates, which is partially offset by the net combined impact related to the U.S. taxation of global intangible low taxed income ("GILTI"), and Foreign Tax Credits ("FTCs"). A portion of the one-time Change in Control charges recorded in the three months ended June 30, 2021 was not deductible and contributed to the increase in the effective rate. We expect the full year effective tax rate to be approximately 16% to 17%.

The effective tax rate for the three months ended June 30, 2020 was 17.6%. This rate differs from the U.S. statutory rate of 21% primarily due to worldwide earnings from various countries taxed at different rates.

The tax expense decreased from $19.8 million for the three months ended June 30, 2020 to $7.8 million for the three months June 30, 2021. This change is primarily related to a reduction in pretax income, worldwide earnings from various countries taxed at different rates and U.S. taxation of GILTI.

For the six months ended June 30, 2021, the effective tax rate of 15.9% differs from the U.S. statutory rate of 21% primarily due to worldwide earnings from various countries taxed at different rates which is partially offset by the net combined impact related to the U.S. taxation of GILTI and FTCs.

For the six months ended June 30, 2020, the effective tax rate of 16.9% differs from the U.S. statutory rate of 21% primarily due to worldwide earnings from various countries taxed at different rates.

The tax expense decreased from $43.7 million for the six months ended June 30, 2020 to $24.0 million for the six months ended June 30, 2021. This change is primarily related to the reduction in pretax income, worldwide earnings from various countries taxed at different rates and the U.S. taxation of GILTI.

As of June 30, 2021, we had unrecognized tax benefits of $0.1 million, which, if recognized, would have a favorable impact on our effective tax rate.

We file income tax returns in the U.S. federal jurisdiction, and various state and foreign jurisdictions. U.S. federal tax years prior to 2017 are generally closed by statute or have been audited and settled with the applicable domestic tax authorities. Other jurisdictions are still open to examination beginning after 2014.

We continue to assess the realization of our deferred tax assets based on determinations of whether it is more likely than not that deferred tax benefits will be realized through the generation of future taxable income. Appropriate consideration is given to all available evidence, both positive and negative, in assessing the need for a valuation allowance. Examples of positive evidence would include a strong earnings history, an event or events that would increase our taxable income through a continued reduction of expenses, and tax planning strategies that would indicate an ability to realize deferred tax assets. In