Athlon Energy (ATHL) 8-K/A Financial Statements and Exhibits

Exhibit 99.3

ATHLON ENERGY INC.

UNAUDITED PRO FORMA FINANCIAL STATEMENTS

INTRODUCTION

Athlon Energy Inc. (“Athlon”), a Delaware corporation incorporated on April 1, 2013, is an independent exploration and production company focused on the acquisition, development, and exploitation of unconventional oil and liquids-rich natural gas reserves in the Permian Basin.  On June 2, 2014, Athlon acquired certain oil and natural gas properties and related assets in the Midland Basin from Hibernia Holdings, LLC (“Hibernia”) for approximately $394.0 million in cash (the “Hibernia Acquisition”).  On June 3, 2014, Athlon acquired certain oil and natural gas properties and related assets in the Midland Basin from and Piedra Energy II, LLC (“Piedra”) for approximately $292.8 million in cash (the “Piedra Acquisition”).  On August 28, 2014, Athlon acquired certain oil and natural gas properties and related assets in the Midland Basin from Summit West Resources LP and Summit Group (“Summit”) for approximately $202.5 million in cash (the “Summit Acquisition” and together with the Hibernia Acquisition and the Piedra Acquisition, the “Acquisitions”).

The accompanying unaudited pro forma financial statements give effect to the Acquisitions, including related financing transactions.  The unaudited pro forma balance sheet assumes that the Summit Acquisition and related financing transactions occurred on June 30, 2014.  The Hibernia Acquisition and the Piedra Acquisition are already reflected in Athlon’s historical consolidated balance sheet as of June 30, 2014.  The unaudited pro forma statements of operations assume that the Acquisitions and related financing transactions occurred on January 1, 2013.

The accompanying unaudited pro forma financial statements should be read together with:

·Athlon’s unaudited consolidated financial statements included in its Quarterly Report on Form 10-Q for the quarter ended June 30, 2014, filed with the SEC on August 14, 2014;

·Athlon’s audited consolidated financial statements included in its Annual Report on Form 10-K for the year ended December 31, 2013, filed with the SEC on March 3, 2014;

·Hibernia Energy LLC’s audited consolidated financial statements as of and for the year ended December 31, 2013 included as Exhibit 99.3 to Amendment No. 1 to Athlon’s Current Report on Form 8-K/A filed with the SEC on June 16, 2014;

·Piedra’s audited Statements of Direct Operating Revenues and Direct Operating Expenses of Certain Oil and Natural Gas Properties for the year ended December 31, 2013 included as Exhibit 99.3 to Athlon’s Current Report on Form 8-K filed with the SEC on April 9, 2014;

·Summit’s unaudited Statements of Direct Operating Revenues and Direct Operating Expenses of Certain Oil and Natural Gas Properties for the three and six months ended June 30, 2014 and 2013 included as Exhibit 99.1 to this Current Report on Form 8-K/A; and

·Summit’s audited Schedule of Direct Operating Revenues and Direct Operating Expenses of Certain Oil and Natural Gas Properties for the year ended December 31, 2013 included as Exhibit 99.2 to this Current Report on Form 8-K/A.

The accompanying unaudited pro forma financial statements were derived by making certain adjustments to Athlon’s historical consolidated financial statements.  The adjustments are based on currently available information and certain estimates and assumptions.  Therefore, the actual adjustments may differ from the pro forma adjustments.  However, management believes that the assumptions provide a reasonable basis for presenting the significant effects of the transactions as contemplated and that the pro forma adjustments give appropriate effect to those assumptions and are properly applied in the unaudited pro forma financial statements.

The unaudited pro forma financial statements and related notes are presented for illustrative purposes only.  If the Acquisitions and related financing transactions had occurred in the past, Athlon’s operating results might have been materially different from those presented in the unaudited pro forma financial statements.  The unaudited pro forma financial statements should not be relied upon as an indication of operating results that Athlon would have achieved if the Acquisitions and related financing transactions had taken place on the specified date.  In addition, future results may vary significantly from the results reflected in the unaudited pro forma statements of operations and should not be relied on as an indication of the future results Athlon will have after the completion of the Acquisitions and related financing transactions.

1

ATHLON ENERGY INC.

UNAUDITED PRO FORMA BALANCE SHEET

June 30, 2014

(in thousands)

	Athlon Historical			Pro Forma Adjustments			Pro Forma as Adjusted
ASSETS
Current assets:
Cash and cash equivalents	$	243,302		$	(202,505	)(a)	$	40,530
				(267		)(b)
Accounts receivable	81,463			—			81,463
Inventory	1,176			132		(a)	1,308
Deferred taxes	2,670			—			2,670
Other	510			—			510
Total current assets	329,121			(202,640		)	126,481
Oil and natural gas properties and equipment, at cost - full cost method:
Evaluated properties, including wells and related equipment	2,070,655			93,899		(a)	2,164,554
Unevaluated properties	555,905			109,570		(a)	665,475
Accumulated depletion, depreciation, and amortization	(227,195		)	—			(227,195		)
	2,399,365			203,469			2,602,834
Derivatives, at fair value	318			—			318
Debt issuance costs	25,908			—			25,908
Other	2,097			—			2,097
Total assets	$	2,756,809		$	829		$	2,757,638
LIABILITIES AND EQUITY
Current liabilities:
Trade accounts payable	$	9,861		$	—		$	9,861
Accrued liabilities:
Lease operating	9,208			—			9,208
Production, severance, and ad valorem taxes	6,949			—			6,949
Development capital	120,523			—			120,523
Interest	14,293			—			14,293
Derivatives, at fair value	33,542			—			33,542
Revenue payable	32,827			—			32,827
Other	11,199			659		(a)	11,858
Total current liabilities	238,402			659			239,061
Asset retirement obligations, net of current portion	10,496			437		(a)	10,933
Long-term debt	1,150,000			—			1,150,000
Deferred taxes	109,748			—			109,748
Derivatives, at fair value	3,320			—			3,320
Other	140			—			140
Total liabilities	1,512,106			1,096			1,513,202
Commitments and contingencies
Equity:
Preferred stock	—			—			—
Common stock	969			—			969
Additional paid-in capital	1,173,053			—			1,173,053
Retained earnings	58,951			(267		)(b)	58,684
Total stockholders’ equity	1,232,973			(267		)	1,232,706
Noncontrolling interest	11,730			—			11,730
Total equity	1,244,703			(267		)	1,244,436
Total liabilities and equity	$	2,756,809		$	829		$	2,757,638

The accompanying notes are an integral part of these unaudited pro forma financial statements.

2

ATHLON ENERGY INC.

UNAUDITED PRO FORMA STATEMENT OF OPERATIONS

For the Six Months Ended June 30, 2014

(in thousands, except per share amounts)

	Athlon Historical			Hibernia Energy LLC Historical			Piedra Historical		Summit Historical		Stock Offering Pro Forma Adjustments			Notes Offering Pro Forma Adjustments			Pro Forma Adjustments			Pro Forma as Adjusted
Oil and natural gas revenues	$	242,179		$	21,436		$	14,743	$	21,731	$	—		$	—		$	—		$	300,089
Expenses:
Production	40,862			2,349			2,468		3,956		—			—			—			49,635
Depletion, depreciation, and amortization	66,546			4,830			—		—		—			—			9,758		(d)	81,134
General and administrative	23,408			1,710			—		—		—			—			—			25,118
Acquisition costs	1,825			—			—		—		—			—			(1,168		)(e)	657
Derivative fair value loss	43,577			3,697			—		—		—			—			—			47,274
Accretion of discount on asset retierment obligations	417			10			—		—		—			—			60		(f)	487
Total expenses	176,635			12,596			2,468		3,956		—			—			8,650			204,305
Operating income	65,544			8,840			12,275		17,775		—			—			(8,650		)	95,784
Other income (expenses):
Interest expense	(22,706		)	(820		)	—		—		—			(13,448		)(b)	(422		)(g)	(37,396		)
Other	26			1			—		—		—			—			—			27
Total other expenses	(22,680		)	(819		)	—		—		—			(13,448		)	(422		)	(37,369		)
Income (loss) before income taxes	42,864			8,021			12,275		17,775		—			(13,448		)	(9,072		)	58,415
Income tax provision	15,254			—			—		—		—			—			5,534		(h)	20,788
Consolidated net income (loss)	27,610			8,021			12,275		17,775		—			(13,448		)	(14,606		)	37,627
Less: net income attributable to noncontrolling interest	942			—			—		—		—			—			168		(i)	1,110
Net income (loss) attributable to stockholders	$	26,668		$	8,021		$	12,275	$	17,775	$	—		$	(13,448	)	$	(14,774	)	$	36,517
Net income per common share:
Basic	$	0.30																		$	0.37
Diluted	$	0.30																		$	0.37
Weighted average common shares outstanding:
Basic	87,773										9,162		(a)							96,935
Diluted	87,773										9,162		(a)							96,935

The accompanying notes are an integral part of these unaudited pro forma financial statements.

3

ATHLON ENERGY INC.

UNAUDITED PRO FORMA STATEMENT OF OPERATIONS

For the Year Ended December 31, 2013

(in thousands, except per share amounts)

	Athlon Historical			Hibernia Energy LLC Historical			Piedra Historical		Summit Historical		Stock Offering Pro Forma Adjustments			Notes Offering Pro Forma Adjustments			Pro Forma Adjustments			Pro Forma as Adjusted
Oil and natural gas revenues	$	299,373		$	17,595		$	28,862	$	45,048	$	—		$	—		$	2,006	(c)	$	392,884
Expenses:
Production	53,046			2,564			5,640		6,964		—			—			692		(c)	68,906
Depletion, depreciation, and amortization	87,171			3,417			—		—		—			—			19,011		(d)	109,599
General and administrative	21,331			3,340			—		—		—			—			—			24,671
Contract termination fee	2,408			—			—		—		—			—			—			2,408
Acquisition costs	421			—			—		—		—			—			1,435		(e)	1,856
Derivative fair value loss	18,115			1,821			—		—		—			—			—			19,936
Accretion of discount on asset retierment obligations	675			19			—		—		—			—			130		(f)	824
Total expenses	183,167			11,161			5,640		6,964		—			—			21,268			228,200
Operating income	116,206			6,434			23,222		38,084		—			—			(19,262		)	164,684
Other income (expenses):
Interest expense	(36,669		)	(1,160		)	—		—		—			(40,904		)(b)	(58		)(g)	(78,791		)
Other	35			160			—		—		—			—			—			195
Total other expenses	(36,634		)	(1,000		)	—		—		—			(40,904		)	(58		)	(78,596		)
Income (loss) before income taxes	79,572			5,434			23,222		38,084		—			(40,904		)	(19,320		)	86,088
Income tax provision	19,150			—			—		—		—			—			1,568		(h)	20,718
Consolidated net income (loss)	60,422			5,434			23,222		38,084		—			(40,904		)	(20,888		)	65,370
Less: net income attributable to noncontrolling interest	1,359			—			—		—		—			—			184		(i)	1,543
Net income (loss) attributable to stockholders	$	59,063		$	5,434		$	23,222	$	38,084	$	—		$	(40,904	)	$	(21,072	)	$	63,827
Net income per common share:
Basic	$	0.80																		$	0.72
Diluted	$	0.80																		$	0.72
Weighted average common shares outstanding:
Basic	72,915										14,806		(a)							87,721
Diluted	74,771										14,806		(a)							87,721

The accompanying notes are an integral part of these unaudited pro forma financial statements.

4

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS

Note 1.Basis of Presentation

Athlon’s historical financial information as of and for the six months ended June 30, 2014 is derived from Athlon’s consolidated financial statements included in its Quarterly Report on Form 10-Q for the quarter ended June 30, 2014.  Athlon’s historical financial information for the year ended December 31, 2013 is derived from Athlon’s consolidated financial statements included in its Annual Report on Form 10-K for the year ended December 31, 2013.

Hibernia Energy LLC’s historical financial information for the year ended December 31, 2013 is derived from its audited consolidated financial statements, which were included as Exhibit 99.3 to Amendment No. 1 to Athlon’s Current Report on Form 8-K/A filed with the SEC on June 16, 2014.

Piedra’s historical financial information for the year ended December 31, 2013 is derived from its audited Schedule of Direct Operating Revenues and Direct Operating Expenses of Certain Oil and Natural Gas Properties, which was included as Exhibit 99.3 to Athlon’s Current Report on Form 8-K filed with the SEC on April 9, 2014.  Piedra’s Schedules of Direct Operating Revenues and Direct Operating Expenses of Certain Oil and Natural Gas Properties are not intended to be a complete presentation of the results of operations of the properties, as they do not include general and administrative expenses, effects of derivative transactions, interest income or expense, depreciation, depletion, and amortization, any provision for income tax expenses, and other income and expense items not directly associated with direct operating revenues from natural gas, natural gas liquids, and crude oil.  As such, they are not indicative of the operating results of the Piedra assets going forward.

Summit’s historical financial information for the six months ended June 30, 2014 is derived from its unaudited Statements of Direct Operating Revenues and Direct Operating Expenses of Certain Oil and Natural Gas Properties, which is included as Exhibit 99.1 to this Current Report on Form 8-K/A.  Summit’s historical financial information for the year ended December 31, 2013 is derived from its audited Statements of Direct Operating Revenues and Direct Operating Expenses of Certain Oil and Natural Gas Properties, which is included as Exhibit 99.2 to this Current Report on Form 8-K.  Summit’s Statements of Direct Operating Revenues and Direct Operating Expenses of Certain Oil and Natural Gas Properties are not intended to be a complete presentation of the results of operations of the properties, as they do not include general and administrative expenses, effects of derivative transactions, interest income or expense, depreciation, depletion, and amortization, any provision for income tax expenses, and other income and expense items not directly associated with direct operating revenues from natural gas, natural gas liquids, and crude oil.  As such, they are not indicative of the operating results of the Summit assets going forward.

For purposes of the unaudited pro forma balance sheet, it is assumed that the Summit Acquisition and related financing transactions occurred on June 30, 2014.  The Hibernia Acquisition and the Piedra Acquisition are already reflected in Athlon’s historical consolidated balance sheet as of June 30, 2014.  For purposes of the unaudited pro forma statements of operations, it is assumed that the Acquisitions and related financing transactions occurred on January 1, 2013.

Note 2.Pro Forma Adjustments and Assumptions

Athlon made the following adjustments and assumptions in the preparation of the unaudited pro forma balance sheet:

(a)To record the Summit Acquisition for $202.5 million in cash and to allocate the purchase price to the assets acquired and liabilities assumed.  The allocation of the purchase price to the assets acquired and liabilities assumed is preliminary and, therefore, subject to change.

The allocation of the purchase price of the Summit Acquisition to the fair value of the assets acquired and liabilities assumed is as follows (in thousands):

Evaluated, including wells and related equipment	$	93,899
Unevaluated	109,570
Inventory	132
Total assets acquired	203,601
Other current liabilities	659
Asset retirement obligations	437
Total liabilities assumed	1,096
Fair value of net assets acquired	$	202,505

5

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS – Continued

(b)Reflects estimated incremental acquisition costs incurred in connection with the consummation of the Acquisitions.  As of June 30, 2014, Athlon had incurred $1.2 million of acquisition costs and expects total acquisition costs to be approximately $1.4 million.

Athlon made the following adjustments and assumptions in the preparation of the unaudited pro forma statements of operations:

(a)Reflects the April 2014 issuance and sale of 14,806,250 shares of common stock.

(b)Reflects estimated incremental interest expense and amortization of debt issuance costs associated with the issuance of the 2022 Notes.

(c)A portion of the assets acquired by Hibernia were acquired by them during May 2013.  Reflects the incremental oil and natural gas revenues and production costs associated with those assets from January 1, 2013 through the date Hibernia acquired them.

(d)Reflects incremental depletion, depreciation, and amortization of oil and natural gas properties associated with the Acquisitions.  Costs associated with evaluated properties are amortized using a unit-of-production basis under the full cost method of accounting for oil and natural gas properties.

(e)Reflects estimated acquisition costs incurred in connection with the consummation of the Acquisitions.  As of June 30, 2014, Athlon had incurred $1.2 million of acquisition costs and expects total acquisition costs to be approximately $1.4 million.

(f)Reflects incremental accretion of discount on asset retirement obligations associated with the Acquisitions.

(g)Reflects an increase in unused commitment fees and amortization of debt issuance costs related to Athlon’s credit agreement, partially offset by the elimination of interest expense associated with a portion of the outstanding borrowings under Athlon’s credit agreement.  On a pro forma basis, there would have been no outstanding borrowings under Athlon’s credit agreement as of January 1, 2013.

A 1/8% change in LIBOR would have no effect on Athlon’s interest expense as there would have been no variable rate debt outstanding during the periods presented on a pro forma basis.

(h)Reflects estimated increase in income tax provision associated with the reduction in operating income from the Acquisitions and the pro forma adjustments using Athlon’s effective tax rate of 35.6% and 24.1% for the six months ended June 30, 2014 and the year ended December 31, 2013, respectively.  This rate is inclusive of federal, state, and local income taxes and differs from the statutory rate as Athlon has only been subject to federal income tax as a subchapter C corporation since the date of its incorporation.

(i)Athlon is the sole managing partner of Athlon Holdings LP and owns less than 100% of the economic interest in Athlon Holdings LP, but has 100% of the voting power and controls the management of Athlon Holdings LP.  Upon consummation of the April 2014 issuance and sale of 14,806,250 shares of common stock, Athlon’s ownership percentage of Athlon Holdings LP increased, resulting in a decrease in the noncontrolling interest from approximately 2.2% to approximately 1.9%.  Reflects estimated increase in net income attributable to noncontrolling interest based on pro forma income before income taxes.

Note 3. Pro Forma Earnings Per Share

The following table reflects the pro forma allocation of net income to Athlon’s common stockholders and earnings per share (“EPS”) computations for the periods indicated:

6

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS – Continued

	Six months ended June 30, 2014			Year ended December 31, 2013
	(in thousands, except per share amounts)
Basic EPS
Numerator:
Undistributed net income attributable to stockholders	$	36,517		$	63,827
Participation rights of unvested stock awards in undistributed earnings	(368		)	(467		)
Basic undistributed net income attributable to stockholders	$	36,149		$	63,360
Denominator:
Basic weighted average shares outstanding	96,935			87,721
Basic EPS attributable to stockholders	$	0.37		$	0.72
Diluted EPS
Numerator:
Undistributed net income attributable to stockholders	$	36,517		$	63,827
Participation rights of unvested stock awards in undistributed earnings	(368		)	(467		)
Effect of conversion of New Holdings Units to shares of Athlon’s common stock (a)	—			—
Diluted undistributed net income attributable to stockholders	$	36,149		$	63,360
Denominator:
Basic weighted average shares outstanding	96,935			87,721
Effect of conversion of New Holdings Units to shares of Athlon’s common stock (a)	—			—
Diluted weighted average shares outstanding	96,935			87,721
Diluted EPS attributable to stockholders	$	0.37		$	0.72

(a)For the six months ended June 30, 2014 and for the year ended December 31, 2013, 1,855,563 New Holdings Units were outstanding but excluded from the pro forma EPS calculations because their effect would have been antidilutive.

Note 4.Supplementary Information

There are numerous uncertainties inherent in estimating quantities of proved reserves and in projecting future rates of production and timing of development expenditures.  Oil and natural gas reserve engineering is and must be recognized as a subjective process of estimating underground accumulations of oil and natural gas that cannot be measured in any exact way, and estimates of other engineers might differ materially from those included herein.  The accuracy of any reserve estimate is a function of the quality of available data and engineering, and estimates may justify revisions based on the results of drilling, testing, and production activities.  Accordingly, reserve estimates are often materially different from the quantities of oil and natural gas that are ultimately recovered.  Reserve estimates are integral to management’s analysis of impairment of oil and natural gas properties and the calculation of depletion, depreciation, and amortization on these properties.  Natural gas volumes include natural gas liquids.

7

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS – Continued

Athlon’s estimated pro forma net quantities of proved reserves were as follows as of December 31, 2013:

	Athlon Historical	Hibernia Historical	Piedra Historical	Summit Historical	Total Pro Forma
Proved developed reserves:
Oil (MBbls)	26,436	4,159	2,414	2,985	35,994
Natural gas (MMcf)	121,820	10,067	8,242	13,604	153,733
Combined (MBOE)	46,740	5,837	3,787	5,252	61,616
Proved undeveloped reserves:
Oil (MBbls)	44,738	9,695	6,868	—	61,301
Natural gas (MMcf)	214,718	23,012	23,247	—	260,977
Combined (MBOE)	80,524	13,530	10,743	—	104,797
Proved reserves:
Oil (MBbls)	71,174	13,854	9,282	2,985	97,295
Natural gas (MMcf)	336,538	33,079	31,489	13,604	414,710
Combined (MBOE)	127,264	19,367	14,530	5,252	166,413

The changes in Athlon’s pro forma proved reserves were as follows for 2013:

	Athlon Historical						Hibernia Historical						Piedra Historical						Summit Historical						Total Pro Forma
			Natural		Oil				Natural		Oil				Natural		Oil				Natural		Oil				Natural		Oil
	Oil		Gas		Equivalent		Oil		Gas		Equivalent		Oil		Gas		Equivalent		Oil		Gas		Equivalent		Oil		Gas		Equivalent
	(MBbls)		(MMcf)		(MBOE)		(MBbls)		(MMcf)		(MBOE)		(MBbls)		(MMcf)		(MBOE)		(MBbls)		(MMcf)		(MBOE)		(MBbls)		(MMcf)		(MBOE)
Balance, December 31, 2012	49,423		219,333		85,979		3,176		6,991		4,341		9,688		23,624		13,625		3,398		14,472		5,810		65,685		264,420		109,755
Purchases of minerals-in-place	495		2,059		838		8,288		18,262		11,332		—		—		—		—		—		—		8,783		20,321		12,170
Extensions and discoveries	23,895		102,820		41,031		2,248		4,977		3,078		—		—		—		—		—		—		26,143		107,797		44,109
Revisions of previous estimates	43		22,977		3,874		304		3,220		840		(139	)	8,527		1,282		—		—		—		208		34,724		5,996
Production	(2,682	)	(10,651	)	(4,458	)	(162	)	(371	)	(224	)	(267	)	(662	)	(377	)	(413	)	(868	)	(558	)	(3,524	)	(12,552	)	(5,617	)
Balance, December 31, 2013	71,174		336,538		127,264		13,854		33,079		19,367		9,282		31,489		14,530		2,985		13,604		5,252		97,295		414,710		166,413

The following pro forma standardized measure of the discounted net future cash flows and changes applicable to proved reserves reflect the effect of income taxes assuming the Acquisitions had been subject to federal income tax.  The future net cash flows are discounted at 10% per year and assume continuation of existing economic conditions.

In management’s opinion, the standardized measure of discounted future net cash flows should be examined with caution.  The basis for this table is the reserve studies prepared by petroleum engineers, which contain imprecise estimates of quantities and rates of production of reserves.  Revisions of previous year estimates can have a significant impact on these results.  Also, exploration costs in one year may lead to significant discoveries in later years and may significantly change previous estimates of proved reserves and their valuation.  Therefore, the standardized measure of discounted future net cash flows is not necessarily indicative of the fair value of Athlon’s evaluated oil and natural gas properties.

The data presented should not be viewed as representing the expected cash flow from or current value of, existing proved reserves since the computations are based on a large number of estimates and arbitrary assumptions.  Reserve quantities cannot be measured with precision and their estimation requires many judgmental determinations and frequent revisions.  Actual future prices and costs are likely to be substantially different from the prices and costs utilized in the computation of reported amounts.

Athlon’s pro forma standardized measure of discounted future net cash flows was as follows as of December 31, 2013:

	Athlon Historical			Hibernia Historical			Piedra Historical			Summit Historical			Pro Forma  Adjustments			Pro Forma as Adjusted
	(in thousands)
Future cash inflows	$	8,053,437		$	1,491,194		$	1,073,809		$	339,909		$	—		$	10,958,349
Future production costs	(2,421,186		)	(326,331		)	(321,907		)	(110,428		)	—			(3,179,852		)
Future development costs	(1,242,817		)	(202,159		)	(160,555		)	—			—			(1,605,531		)
Future income taxes	(1,347,259		)	(10,438		)	(7,517		)	(2,380		)	(304,717		)	(1,672,311		)
Future net cash flows	3,042,175			952,266			583,830			227,101			(304,717		)	4,500,655
10% annual discount	(1,942,501		)	(605,100		)	(369,043		)	(110,592		)	189,840			(2,837,396		)
Standardized measure of discounted estimated future net cash flows	$	1,099,674		$	347,166		$	214,787		$	116,509		$	(114,877	)	$	1,663,259

8

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS – Continued

The changes in Athlon’s pro forma standardized measure of discounted estimated future net cash flows were as follows for 2013:

	Athlon Historical			Hibernia Historical			Piedra Historical			Summit Historical			Pro Forma Adjustments			Pro Forma as Adjusted
	(in thousands)
Net change in prices and production costs	$	250,716		$	40,254		$	1,918		$	13,557		$	—		$	306,445
Purchases of minerals-in-place	11,601			127,844			—			—			—			139,445
Extensions, discoveries, and improved recovery	448,208			60,044			—			—			—			508,252
Revisions of previous quantity estimates	50,202			15,232			19,199			—			—			84,633
Production, net of production costs	(246,327		)	(15,031		)	(23,223		)	(38,084		)	—			(322,665		)
Previously estimated development costs incurred during the period	130,900			6,292			23,238			—			—			160,430
Accretion of discount	86,658			13,315			17,172			13,105			—			130,250
Change in estimated future development costs	(17,389		)	31,100			554			—			—			14,265
Net change in income taxes	(520,162		)	(2,968		)	(343		)	101			(114,877		)	(638,249		)
Change in timing and other	54,353			13,350			6,974			(2,026		)	—			72,651
Net change in standardized measure	248,760			289,432			45,489			(13,347		)	(114,877		)	455,457
Standardized measure, beginning of year	850,914			57,734			169,298			129,856			—			1,207,802
Standardized measure, end of year	$	1,099,674		$	347,166		$	214,787		$	116,509		$	(114,877	)	$	1,663,259

9