Note 4 - Income Taxes

Income tax expense (benefit) for the three and nine months ended September 30, 2015, and 2014, differs from the amount that would be provided by applying the statutory United States federal income tax rate to income before income taxes primarily due to the effect of state income taxes, changes in valuation allowances, percentage depletion, research and development (“R&D”) credits, and other permanent differences. The quarterly rate can also be impacted by the proportional effects of forecasted net income or loss as of each period end presented.

The provision for income taxes consists of the following:



	For the Three Months Ended September 30,						For the Nine Months Ended September 30,
	2015			2014			2015			2014
	(in thousands)
Current portion of income tax expense (benefit):
Federal	$	—		$	—		$	—		$	—
State	(8,308		)	479			2,092			1,480
Deferred portion of income tax expense (benefit)	4,168			124,269			(80,388		)	198,180
Total income tax expense (benefit)	$	(4,140	)	$	124,748		$	(78,296	)	$	199,660
	403.5		%	37.4		%	42.2		%	37.4		%

On a year-to-date basis, a change in the Company’s effective tax rate between reported periods will generally reflect differences in its estimated highest marginal state tax rate due to changes in the composition of income from Company activities among various state tax jurisdictions. Cumulative effects of state rate changes are reflected in the period legislation is enacted. The cumulative effects of Texas and North Dakota enacted rate changes are reflected in the year-to-date deferred portion of income tax expense (benefit). During the nine months ended September 30, 2015, the Company determined certain Oklahoma properties sold in the quarter ended June 30, 2015, qualified for the Oklahoma capital gain deduction which resulted in additional state tax benefit.

The Company is generally no longer subject to United States federal or state income tax examinations by tax authorities for years before 2007. During the first quarter of 2015, as a result of its R&D credit settlement with the IRS Appeals Office in late 2014, the Company recorded an additional $2.0 million net R&D credit from a claim filed on an amended return. No R&D credit was recorded in 2014. During the quarter ended September 30, 2015, the IRS initiated an audit of the SM-Mitsui Tax Partnership for 2013. The Company has a significant investment in the underlying assets of the tax partnership.