UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 8-K/A

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): June 30, 2014

Atlas Energy, L.P.

(Exact name of registrant as specified in its chapter)

Registrant’s telephone number, including area code: 412-489-0006

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Explanatory Note

On July 2, 2014, Atlas Energy, L.P. (“ATLS”) filed a Current Report on Form 8-K (the “Original 8-K”) to report the completion by ARP Rangely Production, LLC, a wholly-owned subsidiary of Atlas Resource Partners, L.P. (“ARP”), whose general partner is a wholly-owned subsidiary of ATLS, of the previously announced acquisition (the “Rangely Acquisition”) of certain oil and gas related interests in the Rangely Field assets in northwest Colorado from Merit Management Partners I, L.P., Merit Energy Partners III, L.P. and Merit Energy Company, LLC (“Merit Energy”) for $420.0 million in cash (the “Acquired Assets”). This Current Report on Form 8-K/A amends Item 9.01 of the Original 8-K to present certain financial statements for Merit Energy and to present certain unaudited pro forma financial information in connection with the Rangely Acquisition.

The unaudited pro forma consolidated balance sheet of ATLS as of March 31, 2014, and the related pro forma consolidated statements of operations for the three months ended March 31, 2014 and the year ended December 31, 2013, are filed as Exhibit 99.2 to this Current Report on Form 8-K/A and are incorporated herein by reference.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

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EXHIBIT INDEX

4

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the registration statements on Form S-8 (No. 333-138589, No. 333-173082 and No. 333-180568) of Atlas Energy, L.P. of our report dated June 30, 2014, with respect to the Statement of Revenues and Direct Operating Expenses of the Oil and Gas Properties under Contract for Purchase by ARP Rangely Production, LLC from Merit Energy for the year ended December 31, 2013 which report appears in the Current Report on Form 8-K/A of Atlas Energy, L.P. filed on August 7, 2014.

/s/ KPMG LLP

Dallas, Texas

August 7, 2014

Exhibit 99.1

STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES

OF THE OIL AND GAS PROPERTIES UNDER CONTRACT FOR PURCHASE BY

ARP RANGELY PRODUCTION, LLC FROM MERIT ENERGY

THREE MONTHS ENDED MARCH 31, 2014 AND 2013 (UNAUDITED)

AND THE YEAR ENDED DECEMBER 31, 2013

CONTENTS

		KPMG LLP
		Suite 3100
		717 North Harwood Street
		Dallas, TX 75201-6585

Independent Auditors’ Report

The Members

Merit Energy Company, LLC:

We have audited the accompanying statements of revenues and direct operating expenses of Merit Energy Company’s oil and gas properties under contract for purchase by ARP Rangely Production, LLC (the Properties) for the year ended December 31, 2013.

Management’s Responsibility for the Schedule

Management is responsible for the preparation and fair presentation of these financial statements in accordance with U.S. generally accepted accounting principles; this includes the design, implementation, and maintenance of internal control relevant to the preparation and fair presentation of financial statements that are free from material misstatement, whether due to fraud or error.

Auditors’ Responsibility

Our responsibility is to express an opinion on these financial statements based on our audit. We conducted our audit in accordance with auditing standards generally accepted in the United States of America. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free from material misstatement.

An audit involves performing procedures to obtain audit evidence about the amounts and disclosures in the financial statements. The procedures selected depend on the auditors’ judgment, including the assessment of the risks of material misstatement of the financial statements, whether due to fraud or error. In making those risk assessments, the auditor considers internal control relevant to the entity’s preparation and fair presentation of the financial statements in order to design audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the entity’s internal control. Accordingly, we express no such opinion. An audit also includes evaluating the appropriateness of accounting policies used and the reasonableness of significant accounting estimates made by management, as well as evaluating the overall presentation of the financial statements.

We believe that the audit evidence we have obtained is sufficient and appropriate to provide a basis for our audit opinion.

Opinion

In our opinion, the financial statements referred to above present fairly, in all material respects, the revenues and direct expenses of Merit Energy Company’s oil and gas properties under contract for purchase by ARP Rangely Production, LLC for the year ended December 31, 2013, in accordance with U.S. generally accepted accounting principles.

Dallas, Texas

June 30, 2014

KPMG LLP is a Delaware limited liability partnership,

the U.S. member firm of KPMG International Cooperative

(“KPMG International”), a Swiss entity.

STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES

OF THE OIL AND GAS PROPERTIES UNDER CONTRACT FOR PURCHASE BY

ARP RANGELY PRODUCTION, LLC FROM MERIT ENERGY

(In thousands)

See accompanying Notes to Statements of Revenues and Direct Operating Expenses

NOTES TO STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES

OF THE OIL AND GAS PROPERTIES UNDER CONTRACT FOR PURCHASE BY

ARP RANGELY PRODUCTION, LLC FROM MERIT ENERGY

THREE MONTHS ENDED MARCH 31, 2014 AND 2013 (UNAUDITED)

AND THE YEAR ENDED DECEMBER 31, 2013

NOTE 1 – BASIS OF PRESENTATION

On May 6, 2014, ARP Rangely Production, LLC (“ARP”) entered into a Purchase and Sale agreement (“PSA”) with Merit Energy Company and certain of its affiliates (“Merit Energy”) to purchase oil and gas properties and related facilities located in the Iles, Hiawatha West, and Rangely fields in Colorado as further defined in the PSA (the “Properties”) for approximately $420 million, subject to normal closing adjustments, with an effective date of April 1, 2014. The accompanying statements of revenues and direct operating expenses relate only to the Properties.

Historical financial statements prepared in accordance with accounting principles generally accepted in the United States of America have never been prepared for the Properties. During the periods presented, the Properties were not accounted for or operated as a consolidated entity or as a separate division by Merit Energy. The accompanying statements of revenues and direct operating expenses related to the Properties were prepared from the historical accounting records of Merit Energy.

Certain indirect expenses, as further described in Note 4, were not allocated to the Properties and have been excluded from the accompanying statements. Any attempt to allocate these expenses would require significant and judgmental allocations, which would be arbitrary and may not be indicative of the performance of the properties on a stand-alone basis.

These statements of revenues and direct operating expenses do not represent a complete set of financial statements reflecting the financial position, results of operations, stakeholder’s equity and cash flows of the Properties and are not necessarily indicative of the results of operations for the Properties going forward.

The accompanying statements of revenues and direct operating expenses for the three months ended March 31, 2014 and 2013 are unaudited but, in the opinion of management, include all adjustments (consisting of normal recurring adjustments) that are necessary for a fair presentation of the revenues and direct operating expenses of the Properties for those periods.

Note 2 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Revenue Recognition

Merit Energy utilizes the sales method of accounting for oil and natural gas liquids revenues whereby revenues, net of royalties, are recognized based on the actual volumes of oil and natural gas liquids production sold to purchasers. The amount of natural gas liquids sold may differ from the amount to which Merit Energy is entitled based on its revenue interests in the properties.

Direct Operating Expenses

Direct operating expenses, which are recognized on an accrual basis, relate to the direct expenses of operating the Properties. The direct operating expenses include lease operating, ad valorem tax and production tax expense. Lease operating expenses include lifting costs, well repair expenses, surface repair expenses, well workover costs and other field expenses. Lease operating expenses also include expenses directly associated with support personnel, support services, equipment and facilities directly related to oil and natural gas production activities.

NOTES TO STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES

OF THE OIL AND GAS PROPERTIES UNDER CONTRACT FOR PURCHASE BY

ARP RANGELY PRODUCTION, LLC FROM MERIT ENERGY

THREE MONTHS ENDED MARCH 31, 2014 AND 2013 (UNAUDITED)

AND THE YEAR ENDED DECEMBER 31, 2013

Note 3 – CONTINGENCIES

The activities of the Properties are subject to potential claims and litigation in the normal course of operations. Merit Energy management does not believe that any liability resulting from any pending or threatened litigation will have a material adverse effect on the operations or financial results of the Properties.

Note 4 – EXCLUDED EXPENSES

The Properties are part of a much larger enterprise prior to their sale by Merit Energy to ARP. Indirect general and administrative expenses, interest, income taxes, and other indirect expenses were not allocated to the Properties and have been excluded from the accompanying statements. In addition, any allocation of such indirect expenses may not be indicative of costs which would have been incurred by the Properties on a stand-alone basis.

Depreciation, depletion, and amortization have been excluded from the accompanying statements of revenues and direct operating expenses as such amounts would not necessarily be indicative of the depletion calculated on the Properties on a stand-alone basis.

NOTES TO STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES

OF THE OIL AND GAS PROPERTIES UNDER CONTRACT FOR PURCHASE BY

ARP RANGELY PRODUCTION, LLC FROM MERIT ENERGY

THREE MONTHS ENDED MARCH 31, 2014 AND 2013 (UNAUDITED)

AND THE YEAR ENDED DECEMBER 31, 2013

Note 5 – SUPPLEMENTARY OIL AND GAS INFORMATION (UNAUDITED)

Estimated Net Quantities of Oil and Natural Gas Reserves

The estimates of Proved Oil and Gas Reserves as of December 31, 2013 and 2012 were prepared for Merit Energy utilizing year-end estimates of reserve quantities provided by third-party independent petroleum engineering consultants. The estimated proved net recoverable reserves presented below include only those quantities that were expected to be commercially recoverable at the SEC applicable prices and costs for each year under the then existing regulatory practices and with conventional equipment and operating methods. Proved Developed Reserves represent only those reserves estimated to be recovered through existing wells. Proved Undeveloped Reserves include those reserves that may be recovered from new wells on undrilled acreage or from existing wells on which a relatively major expenditure for recompletion or secondary recovery operation is required. All of the Properties’ Proved Reserves set forth here in are located in Colorado. The estimate of reserves, and the standardized measure of discounted future net cash flows shown below reflect Merit Energy’s development plan for the Properties rather than ARP’s development plan for those Properties.

Discounted future cash flow estimates like those shown below are not intended to represent estimates of the fair value of our oil and natural gas properties. Estimates of fair value should also consider unproved reserves, anticipated future oil and natural gas prices, interest rates, changes in development and production costs and risks associated with future production. Because of these and other considerations, any estimate of fair value is subjective and imprecise.

The following table sets forth estimates of the proved oil and natural gas liquids reserves (net of royalty interests) for the Properties and changes therein, for the periods indicated. The Properties do not contain any natural gas reserves.

NOTES TO STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES

OF THE OIL AND GAS PROPERTIES UNDER CONTRACT FOR PURCHASE BY

ARP RANGELY PRODUCTION, LLC FROM MERIT ENERGY

THREE MONTHS ENDED MARCH 31, 2014 AND 2013 (UNAUDITED)

AND THE YEAR ENDED DECEMBER 31, 2013

Standardized Measure of Discounted Future Net Cash Flows

We have summarized the Standardized Measure related to our proved oil and natural gas liquids reserves. We have based the following summary on a valuation of Proved Reserves using discounted cash flows based on SEC pricing applicable for each year, costs and economic conditions and a 10% discount rate. The additions to Proved Reserves from the purchase of reserves in place and new discoveries and extensions could vary significantly from year to year; additionally, the impact of changes to reflect current prices and costs of reserves proved in prior years could also be significant. Accordingly, you should not view the information presented below as an estimate of the fair value of our oil and natural gas properties, nor should you consider the information indicative of any trends.

Standardized Measure of Oil and Gas

During recent years, prices paid for oil and natural gas have fluctuated significantly. Estimated discounted future net cash flows in the table above for December 31, 2013 were computed using NYMEX prices of $96.90 per barrel of oil and $3.67 per MMBTU of natural gas.

NOTES TO STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES

OF THE OIL AND GAS PROPERTIES UNDER CONTRACT FOR PURCHASE BY

ARP RANGELY PRODUCTION, LLC FROM MERIT ENERGY

THREE MONTHS ENDED MARCH 31, 2014 AND 2013 (UNAUDITED)

AND THE YEAR ENDED DECEMBER 31, 2013

The following table sets forth the changes in standardized measure of discounted future net cash flows relating to proved oil and natural gas liquids reserves for the period indicated.

Changes in Standardized Measure

Exhibit 99.2

UNAUDITED PRO FORMA FINANCIAL INFORMATION

The following unaudited pro forma consolidated financial data reflects Atlas Energy, L.P.’s (NYSE: ATLS; the “Partnership” or “ATLS”) historical results as adjusted on a pro forma basis to give effect to (A) Atlas Resource Partners, L.P.’s (NYSE: ARP; “ARP”) acquisitions of (i) certain oil and gas assets from EP Energy E&P Company, L.P. (“EP Energy”) for $709.6 million in cash (the “EP Energy Acquisition”), and (ii) a 25% non-operated net working interest in oil and natural gas liquids producing assets in the Rangely Field in northwest Colorado from Merit Management Partners I, L.P., Merit Energy Partners III, L.P. and Merit Energy Company, LLC (“Merit Energy”) for $420.0 million in cash (the “Rangely Acquisition”), funded with borrowings under ARP’s revolving credit facility, the issuance of an additional $100.0 million of ARP’s 7.75% senior unsecured notes due on January 15, 2021 (“7.75% ARP Senior Notes”) for net proceeds of approximately $97.3 million, and the issuance of an additional 15.5 million ARP common limited partner units (including approximately 2.0 million units pursuant to an over-allotment option) in a public offering at a price of $19.90 per unit yielding net proceeds of approximately $297.5 million, and (B) (i) Atlas Pipeline Partners, L.P.’s (“APL”) May 7, 2013 acquisition from TEAK Midstream, LLC (“TEAK”) of 100% of the outstanding member and other ownership interests of TEAK for approximately $1.0 billion (the “TEAK Acquisition”). The estimated adjustments to give effect to the acquisitions are described in the notes to the unaudited pro forma financial data.

The unaudited pro forma consolidated statements of operations information for the three months ended March 31, 2014 and the year ended December 31, 2013 assume the following transactions had occurred as of January 1, 2013. In addition, the pro forma consolidated balance sheet as of March 31, 2014 reflects the following transactions as if they had occurred on March 31, 2014:

The unaudited pro forma consolidated balance sheet and the unaudited pro forma consolidated statements of operations were derived by adjusting the Partnership’s historical consolidated financial statements. However, management of the Partnership believes that the adjustments provide a reasonable basis for presenting the significant effects of the transactions described above. The unaudited pro forma financial data presented is for informational purposes only and is based upon available information and assumptions that management of the Partnership believes are reasonable under the circumstances. The allocation of the fair value of the assets

acquired and liabilities assumed is based upon their estimated fair values, which are subject to adjustment and could change significantly as the Partnership continues to evaluate the preliminary allocations related to the Rangely Acquisition. This unaudited pro forma financial information is not necessarily indicative of what the financial position or results of operations of the Partnership would have been had the transactions been consummated on the dates assumed, nor are they necessarily indicative of any future operating results or financial position. The Partnership may have performed differently had the transactions actually occurred on the dates assumed.

Consolidated supplemental oil and gas disclosures as of December 31, 2013, which were presented inclusive of the EP Energy Acquisition, were included with the Partnership’s annual filing on Form 10-K for the year ended December 31, 2013 specifically in Item 8: Financial Statements and Supplementary Data – Footnote 21 “Supplemental Oil and Gas Disclosures (Unaudited)”.

In February 2012, the board of directors of the Partnership’s General Partner (“the Board”) approved the formation of ARP as a newly created exploration and production master limited partnership and the related transfer of substantially all of the Partnership’s exploration and production assets to ARP on March 5, 2012. The Board also approved the distribution of approximately 5.2 million ARP common units to the Partnership’s unitholders, which were distributed on March 13, 2012 using a ratio of 0.1021 ARP limited partner units for each of the Partnership’s common units owned on the record date of February 28, 2012.

ATLAS ENERGY, L.P. AND SUBSIDIARIES

PRO FORMA CONSOLIDATED BALANCE SHEET

MARCH 31, 2014

(in thousands)

(Unaudited)

ATLAS ENERGY, L.P. AND SUBSIDIARIES

PRO FORMA CONSOLIDATED STATEMENT OF OPERATIONS

FOR THE THREE MONTHS ENDED MARCH 31, 2014

(in thousands)

(Unaudited)

ATLAS ENERGY, L.P. AND SUBSIDIARIES

PRO FORMA CONSOLIDATED STATEMENT OF OPERATIONS

FOR THE YEAR ENDED DECEMBER 31, 2013

(in thousands, except per unit data)

(Unaudited)

ATLAS ENERGY, L.P. AND SUBSIDIARIES

NOTES TO UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS

Proved Gas and Oil Reserve Quantities

ARP’s pro forma net proved gas and oil reserves and changes in net proved gas and oil reserves attributable to the Rangely Acquisition are summarized below:

Standardized Measure

ARP’s pro forma standardized measure of discounted future net cash flows before income taxes related to the proved gas and oil reserves of the Rangely Acquisition is as follows (in thousands):

FASB requirements for gas and oil reserve estimation and disclosure require that reserve estimates and future cash flows be based on the average market prices for sales of gas and oil on the first calendar day of each month during the year. The average prices used for 2013 under these rules were $3.67 per Mcf of natural gas and $96.78 per barrel of oil.

Changes in Standardized Measure

ARP Pro forma changes in the standardized measure of discounted future net cash flows before income taxes related to the proved gas and oil reserves of the Rangely Acquisition are as follows: