In March 2012, Atlas Resource Partners, L.P. (NYSE: ARP) acquired the exploration and production business from ATLS. ATLS owns 100% of the general partner Class A units and incentive distribution rights, and an approximate 64% limited partner interest in ARP.

Distributable cash flow, a non-GAAP measure, of $13.6 million, or $0.26 per common unit⁽¹⁾ for the first quarter 2012;

ATLS declared a cash distribution of $0.25 per limited partner unit for the first quarter 2012 at a distribution coverage ratio of approximately 1.1x. The first quarter 2012 distribution represents a $0.14 per unit increase over the prior year comparable quarter and a $0.01 increase from fourth quarter 2011; and,

On a GAAP basis, net loss was $15.1 million for the first quarter 2012 compared to net income of $241.6 million for the prior year comparable period. The loss for the first quarter 2012 was caused primarily by an ARP non-cash asset impairment of approximately $7 million related to a legacy contract initiated prior to the acquisition from Chevron Corp. in February 2011 and expenses related to the ARP spinoff. The net income in the prior year was primarily attributable to Atlas Pipeline Partner, L.P.’s (NYSE: APL; “APL”) gain on sale of its ownership interest in the Laurel Mountain gathering system. Please see the reconciliation of GAAP net income (loss) to Adjusted EBITDA and distributable cash flow in the financial tables of this release for further information.

On April 17, 2012, ARP declared its initial quarterly cash distribution of $0.12 per unit, which was prorated for the partial first quarter 2012. The distribution is payable Tuesday, May 15, 2012 to ARP unitholders of record as of Friday, April 27, 2012. ATLS earned approximately $2.6 million of cash distributions based upon ARP’s recently announced first quarter 2012 distribution.

ARP’s average net daily production for the first quarter 2012 was 39.4 million cubic feet equivalents per day (“Mmcfed”), an increase of approximately 4.2 Mmcfed, or 12%, compared with the fourth quarter 2011. The increase was primarily due to additional Marcellus Shale wells connected in southwestern Pennsylvania during the quarter.

Drilled 60 net wells within ARP’s investment partnerships during the first quarter 2012 compared with 20 net wells for the prior year comparable period, a 300% increase. At March 31, 2012, ARP had $28.0 million of funds raised from its investment partnerships that had not been applied to the completion of wells at period end, and thus at quarter end had not yet been recognized as well construction and completion revenue on its consolidated combined statements of operations. ARP expects to recognize this amount as revenue during the remainder of 2012.

ATLS owns a 100% of the general partner Class A units and the incentive distribution rights, and a 64% common limited partner interest in ARP. ATLS’ financial results are presented on a consolidated basis with those of ARP. Non-controlling interests in ARP are reflected as income (expense) in ATLS’ consolidated combined statements of operations and as a component of partners’ capital on its consolidated combined balance sheets. A consolidating combined statement of operations and balance sheet have also been provided in the financial tables to this release for the comparable periods presented.

On April 25, 2012, APL declared a distribution for the first quarter of 2012 of $0.56 per common limited partner unit to holders of record on May 8, 2012, which will be paid on May 15, 2012. ATLS earned approximately $5.4 million of cash distributions based upon APL’s recently announced first quarter 2012 distribution.

During the first quarter 2012, APL operated at or above nameplate capacity on all of its gathering and processing systems in the Mid Continent. APL processed approximately 633 million cubic feet per day (“Mmcfd”) of natural gas in the first quarter 2012 amongst its WestOK, WestTX and Velma systems, a 31% increase over the prior year comparable quarter’s volumes. Record high volumes of approximately 60,800 bbl per day of gross natural gas liquids were generated from APL’s three processing systems in Oklahoma and Texas.

ATLS owns a 2.0% general partner interest, all of the incentive distribution rights, and a 10.7% common limited partner interest in APL. ATLS’ financial results are presented on a consolidated basis with those of APL. Non-controlling interests in APL are reflected as income (expense) in ATLS’ consolidated combined statements of operations and as a component of partners’ capital on its consolidated combined balance sheets. A consolidating combined statement of operations and balance sheet have also been provided in the financial tables to this release for the comparable periods presented.

Cash general and administrative expense, excluding amounts attributable to APL and ARP, was $2.5 million for the first quarter 2012, a $2.0 million increase from the prior year first quarter. In February 2011, ATLS completed its acquisition of the exploration and production operations from Chevron Corp, which assumed the majority of Atlas’ expenses in the prior year first quarter. Please refer to the consolidating combined statements of operations provided in the financial tables of this release.

Cash interest expense, excluding amounts attributable to APL and ARP, was $0.1 million for the first quarter 2012.

ARP recognized a $7.0 million loss on asset disposal during the first quarter 2012 pertaining to its decision to terminate a farm out agreement with a third party for well drilling in the South Knox area of the New Albany Shale that was originally entered into in 2010. The farm out agreement, which was a legacy contract initiated prior to the acquisition from Chevron Corp. in February 2011, contained certain well drilling targets for ARP to maintain ownership of the South Knox processing plant, which ARP’s management decided in 2012 to not pursue due to the current natural gas price environment. As a result, ARP yielded ownership of the processing plant and recorded a loss related to the net book values of those assets as of March 31, 2012.

Revenues:

Gas and oil production

Well construction and completion

Gathering and processing

Administration and oversight

Well services

Loss on mark-to-market derivatives⁽²⁾

Other, net

Total revenues

Costs and expenses:

Gas and oil production

Well construction and completion

Gathering and processing

Well services

General and administrative⁽¹⁾

Depreciation, depletion and amortization

Total costs and expenses

Operating income

Gain (loss) on asset disposal

Interest expense⁽¹⁾

Income (loss) from continuing operations

Loss from discontinued operations

Net income (loss)

Income attributable to non-controlling interests

Net income (loss) after non-controlling interests

Income not attributable to common limited partners (results of operations of the Transferred Business as of and prior to February 17, 2011, the date of acquisition)⁽¹⁾

Net income (loss) attributable to common limited partners

Net income (loss) attributable to common limited partners per unit – basic and diluted:

Income (loss) from continuing operations attributable to common limited partners

Loss from discontinued operations attributable to common limited partners

Net income (loss) attributable to common limited partners

Weighted average common limited partner units outstanding:

Basic

Diluted

Net income (loss) attributable to common limited partners:

Income (loss) from continuing operations

Loss from discontinued operations

Net income (loss) attributable to common limited partners

In accordance with prevailing accounting literature, ATLS has adjusted its historical financial statements to present them combined with the historical financial results of the exploration and production business acquired from Chevron Corp (the “Transferred Business”) for all periods prior to its acquisition date of February 17, 2011. However, since the results of operations of the Transferred Business prior to its acquisition date are not attributable to the common limited partners of ATLS, these amounts have been deducted to obtain net income (loss) attributable to common limited partners for the respective

Consists principally of hydrocarbon derivative gains / (losses) that relate to the operating activities of ATLS’s consolidated subsidiary, APL. The underlying hydrocarbon derivatives do not represent present or potential future obligations of ATLS.

Current assets:

Cash and cash equivalents

Accounts receivable

Current portion of derivative asset

Prepaid expenses and other

Total current assets

Property, plant and equipment, net

Intangible assets, net

Investment in joint venture

Goodwill, net

Long-term derivative asset

Other assets, net

Current liabilities:

Current portion of long-term debt

Accounts payable

Liabilities associated with drilling contracts

Accrued producer liabilities

Current portion of derivative liability

Current portion of derivative payable to Drilling Partnerships

Accrued interest

Accrued well drilling and completion costs

Accrued liabilities

Total current liabilities

Long-term debt, less current portion

Long-term derivative payable to Drilling Partnerships

Asset retirement obligation and other

Commitments and contingencies

Partners’ Capital:

Common limited partners’ interests

Accumulated other comprehensive income

Non-controlling interests

Total partners’ capital

Net income (loss) attributable to common limited partners per unit – basic

Distributable cash flow per unit⁽²⁾⁽³⁾

Cash distributions paid per unit⁽⁴⁾

ATLAS RESOURCE:

Production volume:⁽⁵⁾⁽⁶⁾

Natural gas (Mcfd)

Oil (Bpd)

Natural gas liquids (Bpd)

Total (Mcfed)

Average sales prices:⁽⁶⁾

Natural gas (per Mcf) ⁽⁷⁾

Oil (per Bbl)⁽⁸⁾

Natural gas liquids (per gallon)

Production costs:⁽⁶⁾⁽⁹⁾

Lease operating expenses per Mcfe⁽¹⁰⁾

Production taxes per Mcfe

Total production costs per Mcfe⁽¹⁰⁾

ATLAS PIPELINE:

Production volume:⁽⁶⁾

Gathered gas volume(Mcfd)

Processed gas volume (Mcfd)

Residue gas volume (Mcfd)

Processed NGL volume (Bpd)

Condensate volume (Bpd)

Average sales prices:⁽⁶⁾

Natural gas (per Mcf)

Condensate (per Bbl)

Natural gas liquids (per gallon)

In accordance with prevailing accounting literature, ATLS has adjusted its historical financial statements to present them combined with the historical financial results of the Transferred Business for all periods prior to its acquisition date of February 17, 2011. However, since the results of operations of the Transferred Business prior to its acquisition date are not attributable to the common limited partners of ATLS, these amounts have been deducted to obtain net income (loss) attributable to common limited partners for the respective period. Also, the historical results of the Transferred Business prior to the acquisition date do not reflect general and administrative expenses and interest expense as ATLS was unable to identify and allocate such amounts to the Transferred Business for the respective periods.

A reconciliation from net income to distributable cash flow is provided in the financial tables of this release.

Calculation consists of distributable cash flow divided by the weighted average common limited partner units outstanding of 51,294,000 for the three months ended March 31, 2012. For the three months ended March 31, 2011, the weighted average common limited partner units outstanding utilized for the calculation is the weighted average common limited partner units outstanding for the period subsequent to February 17, 2011, the date of acquisition for the Transferred Business, which includes the 23.4 million common limited partner units issued as partial consideration for the acquisition.

Represents the cash distributions declared per limited partner unit for the respective period and paid by ATLS within 50 days after the end of each quarter, based upon the distributable cash flow generated during the respective quarter. The cash distribution declared of $0.11 per limited partner unit for the 1^st quarter 2011 reflects a prorated cash distribution for the period from February 17, 2011, the date of acquisition for the Transferred Business, to March 31, 2011.

Production quantities consist of the sum of (i) ARP’s proportionate share of production from wells in which it has a direct interest, based on ARP’s proportionate net revenue interest in such wells, and (ii) ARP’s proportionate share of production from wells owned by the investment partnerships in which ARP has an interest, based on its equity interest in each such partnership and based on each partnership’s proportionate net revenue interest in these wells.

“Mcf” and “Mcfd” represent thousand cubic feet and thousand cubic feet per day; “Mcfe” and “Mcfed” represent thousand cubic feet equivalents and thousand cubic feet equivalents per day, and “Bbl” and “Bpd” represent barrels and barrels per day. Barrels are converted to Mcfe using the ratio of six Mcf’s to one barrel.

ARP’s average sales price for natural gas before the effects of financial hedging was $2.88 per Mcf and $4.47 per Mcf for the three months ended March 31, 2012 and 2011, respectively. These amounts exclude the impact of subordination of production revenues to investor partners within the investor partnerships. Including the effects of subordination, average natural gas sales prices were $3.98 per Mcf ($2.53 per Mcf before the effects of financial hedging) and $4.67 per Mcf ($3.68 per Mcf before the effects of financial hedging) for the three months ended March 31, 2012 and 2011, respectively.

ARP’s average sales price for oil before the effects of financial hedging was $100.41 per barrel and $87.39 per barrel for the three months ended March 31, 2012 and 2011, respectively.

Production costs include labor to operate the wells and related equipment, repairs and maintenance, materials and supplies, property taxes, severance taxes, insurance and production overhead. These amounts exclude the effects of ARP’s proportionate share of lease operating expenses associated with subordination of production revenue to investor partners within ARP’s investor partnerships. Including the effects of these costs, lease operating expenses per Mcfe were $0.84 per Mcfe ($0.95 per Mcfe for total production costs) and $0.69 per Mcfe ($0.80 per Mcfe for total production costs) for the three months ended March 31, 2012 and 2011, respectively.

First quarter 2011 amount was adjusted to reflect current period classification resulting from the misclassification of amounts lease operating production expenses and transportation production expenses.

Adjusted EBITDA and Distributable Cash Flow Summary:

Atlas Resource Cash Distributions Earned⁽²⁾:

Limited Partner Units

Class A Units (2%)

Incentive Distribution Rights

Total Atlas Resource Cash Distributions Earned⁽²⁾

per limited partner unit

Atlas Pipeline Cash Distributions Earned⁽²⁾:

Limited Partner Units

General Partner 2% Interest

Incentive Distribution Rights

Total Atlas Pipeline Cash Distributions Earned⁽²⁾

per limited partner unit

Total Cash Distributions Earned

E&P Operations Adjusted EBITDA prior to spinoff on March 5, 2012⁽³⁾

Cash general and administrative expenses⁽⁴⁾

Other, net

Adjusted EBITDA⁽⁵⁾

Cash interest expense⁽⁶⁾

Maintenance capital expenditures⁽³⁾

Distributable Cash Flow⁽⁵⁾

Distributions Paid⁽⁷⁾

per limited partner unit

Distribution coverage ratio

Reconciliation of non-GAAP measures to net income (loss)⁽⁵⁾:

Distributable cash flow

Distributable cash flow of Transferred Business as of and prior to February 17, 2011 (the date of acquisition)⁽¹⁾

E&P Operations EBITDA prior to spinoff on March 5, 2012⁽³⁾

Atlas Resource net loss attributable to common limited partners

Atlas Resource cash distributions earned⁽²⁾

Atlas Pipeline net income attributable to common limited partners

Atlas Pipeline cash distributions earned⁽²⁾

Non-recurring spinoff and acquisition costs

Depreciation, depletion and amortization

Amortization of deferred finance costs

Non-cash stock compensation expense

Maintenance capital expenditures⁽³⁾

Other non-cash adjustments

Income attributable to non-controlling interests

Net income (loss)

In accordance with prevailing accounting literature, ATLS has adjusted its historical financial statements to present them combined with the historical financial results of the Transferred Business for all periods prior to its acquisition date of February 17, 2011. However, since the results of operations of the Transferred Business prior to its acquisition date are not attributable to the common limited partners of ATLS, these amounts have been deducted to obtain net income (loss) attributable to common limited partners for the respective period. Also, the historical results of the Transferred Business prior to the acquisition date do not reflect general and administrative expenses and interest expense as ATLS was unable to identify and allocate such amounts to the Transferred Business for the respective periods.

Represents the cash distribution paid by ARP and APL within 45 days after the end of each quarter, based upon the distributable cash flow generated during the respective quarter.

Represents the E&P Operations Adjusted EBITDA generated and maintenance capital expenditures incurred by ATLS on a stand-alone basis prior to the transfer of its E&P assets to ARP on March 5, 2012.

Excludes non-cash stock-compensation expense, non-recurring spinoff costs and non-recurring acquisition costs incurred, including amounts in connection with the acquisition of the Transferred Business.

Adjusted EBITDA and distributable cash flow are non-GAAP (generally accepted accounting principles) financial measures under the rules of

Excludes non-cash amortization of deferred financing costs.

Represents the cash distribution paid within 50 days after the end of each quarter, based upon the distributable cash flow generated during the respective quarter.

Total debt

Less: Cash

Total net debt /(cash)

Partners’ capital

Total capitalization

Ratio of net debt to capitalization

Net of eliminated amounts.

Total debt

Less: Cash

Total net debt /(cash)

Partners’ capital

Total capitalization

Ratio of net debt to capitalization

Net of eliminated amounts.

Revenues:

Gas and oil production

Well construction and completion

Gathering and processing

Administration and oversight

Well services

Loss on mark-to-market derivatives

Other, net

Total revenues

Costs and expenses:

Gas and oil production

Well construction and completion

Gathering and processing

Well services

General and administrative

Depreciation, depletion and amortization

Total costs and expenses

Operating income (loss)

Loss on asset disposal

Interest expense

Income (loss) from continuing operations

Discontinued operations

Net income (loss)

Income attributable to non-controlling interests

Net income (loss) attributable to common limited partners

Revenues:

Gas and oil production

Well construction and completion

Gathering and processing

Administration and oversight

Well services

Loss on mark-to-market derivatives

Other, net

Total revenues

Costs and expenses:

Gas and oil production

Well construction and completion

Gathering and processing

Well services

General and administrative

Depreciation, depletion and amortization

Total costs and expenses

Operating income (loss)

Gain on asset disposal

Interest expense

Income (loss) from continuing operations

Discontinued operations

Net income (loss)

Income attributable to non-controlling interests

Net income (loss) after non-controlling interests