Rex Energy 8-K Unaudited Pro Forma Consolidated Financial Statements

Exhibit 99.1

REX ENERGY CORPORATION

UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS

FOR THE YEAR ENDED DECEMBER 31, 2009 AND

SIX MONTHS ENDED JUNE 30, 2010

Introduction

On June 30, 2010, Rex Energy Corporation (the “Company”), through its wholly owned subsidiary, Rex Energy Rockies, LLC, a Delaware limited liability company (“Rex Rockies”), entered into a Purchase and Sale Agreement (the “Purchase Agreement”) with Duncan Oil Partners, LLC, a Colorado limited liability company (“Duncan”), pursuant to which Rex Rockies agreed to purchase from Duncan all of its right, title and interest in and to certain oil and gas leases covering approximately 26,900 gross (18,700 net) acres located in the Denver-Julesburg Basin in Laramie County, State of Wyoming. Under the terms of the Purchase Agreement, Rex Rockies agreed to pay Duncan a purchase price equal to $1,000 per net leasehold acre conveyed at closing, for a total purchase price of approximately $18.7 million. The Purchase Agreement provided that at closing the purchase price may be adjusted upwards or downwards based upon the final number of net leasehold acres being conveyed by Duncan to Rex Rockies following Rex Rockies’ title review of the oil and gas leases and related assets. Pursuant to the Purchase Agreement, Rex Rockies agreed to pay Duncan approximately $1.9 million to serve as a deposit to be credited toward payment of the purchase price at the closing, which was paid by Rex Rockies concurrently with the execution of the Purchase Agreement.

On July 30, 2010, following its review of title to the oil and gas leases, Rex Rockies purchased Duncan’s oil and gas interests in approximately 18,375 net acres for a total purchase price of approximately $18.4 million, less the deposit previously paid to Duncan. Under the terms of the Purchase Agreement, Rex Rockies may purchase Duncan’s oil and gas interests in an additional 320 net acres in the event that certain title defects relating to the acreage are cured by Duncan within a period of 90 days from the closing date.

The adjustments presented in the unaudited pro forma Consolidated Balance Sheet are based on currently available information and certain estimates and assumptions. Therefore, actual results may differ from the pro forma adjustments. However, management believes that the estimates and assumptions used provide a reasonable basis for presenting the significant effects of the acquisition of this acreage. Management also believes the pro forma adjustments give appropriate effect to the estimates and assumptions and are applied in conformity with U.S. generally accepted accounting principles. Pro Forma Consolidated Statements of Operations for the six months ended June 30, 2010 and the year ended December 31, 2009, have not been provided because the transaction would not have had a material impact.

REX ENERGY CORPORATION

UNAUDITED PRO FORMA CONSOLIDATED BALANCE SHEET

($ in Thousands, Except Per Share Data)

	June 30, 2010
	Rex Energy Corporation Historical			Pro Forma Adjustments			Rex Energy Corporation Pro Forma
ASSETS
Current Assets
Cash and Cash Equivalents	$	13,378		$	(3,476	) (a)	$	9,902
Accounts Receivable		8,068			—			8,068
Short-Term Derivative Instruments		3,943			—			3,943
Deferred Taxes		—			—			—
Inventory, Prepaid Expenses and Other		1,553			—			1,553
Total Current Assets		26,942			(3,476	)		23,466
Property and Equipment (Successful Efforts Method)
Evaluated Oil and Gas Properties		226,235			—			226,235
Unevaluated Oil and Gas Properties		112,876			18,375	(b)		131,251
Other Property and Equipment		41,441			—			41,441
Wells and Facilities in Progress		42,280			—			42,280
Pipelines		5,162			—			5,162
Total Property and Equipment		427,994			18,375			446,369
Less: Accumulated Depreciation, Depletion and Amortization		(84,884	)		—			(84,884	)
Net Property and Equipment		343,110			18,375			361,485
Other Assets – Net		1,975			(1,869	) (c)		106
Intangible Assets – Net		993			—			993
Investment in RW Gathering		4,108			—			4,108
Long-Term Derivative Instruments		3,179			—			3,179
Total Assets	$	380,307		$	13,030		$	393,337
LIABILITIES AND EQUITY
Current Liabilities
Accounts Payable	$	10,287		$	—		$	10,287
Accrued Expenses		9,460			—			9,460
Short-Term Derivative Instruments		2,108			—			2,108
Current Deferred Tax Liability		345			—			345
Total Current Liabilities		22,200			—			22,200
Senior Secured Line of Credit and Long-Term Debt		15,035			13,030	(d)		28,065
Long-Term Derivative Instruments		—			—			—
Long-Term Deferred Tax Liability		5,146			—			5,146
Other Deposits and Liabilities		4,504			—			4,504
Future Abandonment Cost		16,639			—			16,639
Total Liabilities		63,524			13,030			76,554
Owners’ Equity
Common Stock, $.001 par value per share, 100,000,000 and 44,049,533 shares issued and outstanding on June 30, 2010.		44			—			44
Additional Paid-In Capital		373,520			—			373,520
Accumulated Deficit		(72,632	)		—			(72,632	)
Rex Energy Owners’ Equity		300,932			—			300,932
Noncontrolling Interests		15,851			—			15,851
Total Owners’ Equity		316,783			—			316,783
Total Liabilities and Owners’ Equity	$	380,307		$	13,030		$	393,337

REX ENERGY CORPORATION

NOTES TO THE UNAUDITED PRO FORMA BALANCE SHEET

1. Basis of Presentation

The historical Consolidated Balance Sheet as of June 30, 2010 is derived from and should be read in conjunction with the Company’s unaudited Consolidated Balance Sheet in our June 30, 2010 Form 10-Q, which was filed with the Securities and Exchange Commission on August 4, 2010.

The pro forma adjustments in the accompanying Consolidated Balance Sheet have been prepared as if the purchase of the Duncan acreage was completed on June 30, 2010. The pro forma Balance Sheet does not contend to be indicative of the financial position or results of the Company’s operations as of such date or for such periods, nor is it necessarily indicative of future results.

2. Pro Forma Adjustments and Assumptions

The unaudited pro forma Consolidated Balance Sheet gives pro forma effect to the following:

(a) Reflects the estimated Cash and Cash Equivalents available towards the purchase price of the acreage.

(b) Reflects the increase to Unevaluated Oil and Gas Properties for the full purchase price of the acreage.

(c) Reflects the deposit paid to Duncan in June 2010, which at the time of purchase was reclassified to Unevaluated Oil and Gas Properties.

(d) Reflects the estimated amount to be used towards the purchase from our Senior Credit Facility.