Note 4 - Income Taxes

The income tax (expense) benefit recorded for the three months ended March 31, 2019, and 2018, differs from the amounts that would be provided by applying the statutory United States federal income tax rate to income or loss before income taxes primarily due to the effect of state income taxes, excess tax benefits and deficiencies from share-based payment awards, limitations on the compensation of certain covered individuals, changes in valuation allowances, and accumulated impacts of other smaller permanent differences. The quarterly rate can also be affected by the proportional impacts of forecasted net income or loss as of each period end presented.

The provision for income taxes for the three months ended March 31, 2019, and 2018, consisted of the following:



	For the Three Months Ended March 31,
	2019			2018
	(in thousands)
Current portion of income tax (expense) benefit:
Federal	$	—		$	—
State	(965		)	(625		)
Deferred portion of income tax (expense) benefit	47,003			(98,366		)
Income tax (expense) benefit	$	46,038		$	(98,991	)
Effective tax rate	20.6		%	23.8		%

The change in the Company’s effective tax rate for the periods presented in the table above generally reflects differences in its estimated highest marginal state tax rate due to changes in the composition of income or loss from Company activities, including divestitures, among multiple state tax jurisdictions. Future periods are not expected to reflect these differences as the Company’s current activities are occurring predominately in Texas. For years before 2015, the Company is generally no longer subject to United States federal or state income tax examinations by tax authorities.