Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2018
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	(2) Summary of Significant Accounting Policies (a) Basis of Presentation These unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) applicable to interim financial information. The accompanying unaudited condensed consolidated financial statements of AMGP have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and, accordingly, do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. In the opinion of management, the accompanying unaudited condensed consolidated financial statements include all adjustments (consisting of normal and recurring accruals) considered necessary to fairly present AMGP’s financial position as of December 31, 2017 and September 30, 2018, and its results of operations for the three and nine months ended September 30, 2017 and 2018 and its cash flows for nine months ended September 30, 2017 and 2018. AMGP has no items of other comprehensive income (loss); therefore, its net income (loss) is identical to its comprehensive income (loss). Operating results for the period ended September 30, 2018 are not necessarily indicative of the results that may be expected for the full year. As of the date these unaudited condensed consolidated financial statements were filed with the SEC, the Partnership completed its evaluation of potential subsequent events for disclosure and no items requiring disclosure were identified other than as disclosed in Note 9 – Subsequent Events. (b) Principles of Consolidation The unaudited condensed consolidated financial statements include the accounts of AMGP, AMP GP (its wholly-owned subsidiary), and IDR LLC. (c) Investment in Antero Midstream AMGP has determined that Antero Midstream is a variable interest entity (“VIE”) for which we are not the primary beneficiary and therefore, do not consolidate. We have concluded that Antero Resources is the primary beneficiary of Antero Midstream and Antero Resources should consolidate Antero Midstream’s financial results. Antero Resources is the primary beneficiary based on its power to direct the activities that most significantly impact Antero Midstream’s economic performance and its obligations to absorb losses or receive benefits of Antero Midstream that could be significant to Antero Midstream. Antero Resources owns approximately 52.9% of the outstanding limited partner interests in Antero Midstream and its officers and management group also act as management of Antero Midstream. Antero Midstream was formed to own, operate, and develop midstream energy assets to service Antero Resources’ production under long term contracts as described herein. We do not own any limited partnership interests in Antero Midstream and have no capital interests in Antero Midstream. We have not provided and do not anticipate providing financial support to Antero Midstream. Antero Resources and Antero Midstream have contracts with 20-year initial terms and automatic renewal provisions, whereby Antero Resources has dedicated the rights for gathering and compression, and water handling and treatment services to Antero Midstream on a fixed-fee basis. Such dedications cover a substantial portion of Antero Resources’ current acreage and future acquired acreage, in each case, except for acreage that was already dedicated to other parties prior to entering into the service contracts or that was acquired subject to a pre-existing dedication. The contracts call for Antero Resources to present, in advance, drilling and completion plans in order for Antero Midstream to put in place gathering and compression, water handling, and gas processing assets to service Antero Resources’ assets. The drilling and completion capital investment decisions made by Antero Resources control the development and operation of all of Antero Midstream’s assets. Antero Resources therefore controls the activities that most significantly impact Antero Midstream’s economic performance. Because of these contractual obligations and the capital requirements related to these obligations, Antero Midstream has devoted and, for the foreseeable future, will devote substantially all of its resources to servicing Antero Resources’ operations. Additionally, revenues from Antero Resources will provide substantially all of Antero Midstream’s financial support and therefore, its ability to finance its operations. Because of the long term contractual commitment to support Antero Resources’ substantial growth plans, Antero Midstream will be practically and physically constrained from providing any substantive amount of services to other parties. AMGP’s ownership of the non-economic general partner interest in Antero Midstream provides it with significant influence over Antero Midstream, but not control over the decisions that most significantly impact the economic performance of Antero Midstream. AMGP’s indirect ownership of the IDRs of Antero Midstream entitles it to receive cash distributions from Antero Midstream when distributions exceed certain target amounts. Our ownership of these interests does not require us to provide financial support to Antero Midstream. We obtained these interests upon its formation for no consideration. Therefore, they have no cost basis and are classified as long term investments. Our share of Antero Midstream’s earnings as a result of our ownership of the IDRs is accounted for using the equity method of accounting. AMGP recognizes distributions earned from Antero Midstream as “Equity in earnings of Antero Midstream Partners LP” on its statement of operations in the period in which they are earned and are allocated to its capital account. Our long term interest in the IDRs on the balance sheet is recorded in “Investment in Antero Midstream Partners LP.” The ownership of the general partner interests and IDRs do not provide AMGP with any claim to the assets of Antero Midstream other than the balance in its Antero Midstream capital account. Income related to the IDRs is recognized as earned and increases AMGP’s capital account and equity investment. When these distributions are paid to us, they reduce our capital account and our equity investment in Antero Midstream. See Note 5—Distributions from Antero Midstream. (d) Use of Estimates The preparation of the unaudited condensed consolidated financial statements and notes in conformity with GAAP requires that management formulate estimates and assumptions that affect income, expenses, assets, and liabilities. Changes in facts and circumstances or discovery of new information may result in revised estimates, and actual results could differ from those estimates. (e) Income Taxes AMGP regularly reviews its tax positions in each significant taxing jurisdiction during the process of evaluating our tax provision. AMGP makes adjustments to its tax provision when: (i) facts and circumstances regarding a tax position change, causing a change in management’s judgment regarding that tax position; and/or (ii) a tax position is effectively settled with a tax authority at a differing amount. Equity-based compensation expense related to the Series B Units and certain IPO costs that are not deductible for federal income tax purposes. These non-deductible expenses and costs, along with the effect of state taxes, account for the difference between the federal tax rate of 35% and 21% for the three and nine months ended September 30, 2017 and 2018, respectively, and the effective rate of income tax expense for financial reporting purposes. (f) General and Administrative Expenses General and administrative costs incurred pre-IPO in 2017 primarily relate to legal and other costs incurred in connection with our IPO. Post-IPO general and administrative expense consists primarily of management fees paid to Antero Resources, and other legal and administrative expenses. Additionally, in connection with the formation of a conflicts committee of the board of directors of the Partnership’s general partner to consider potential transactions involving us in connection with Antero Resources’ and Antero Midstream’s efforts to explore, review, and evaluate potential measures related to its valuation, the conflicts committee retained an investment advisor and attorneys. The agreement with the investment advisor calls for a $2 million retainer fee, which has been expensed. Attorneys’ fees related to this matter are charged to expense as incurred. (g) Fair Value Measures The Financial Accounting Standards Board (the “FASB”) Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosures, clarifies the definition of fair value, establishes a framework for measuring fair value, and expands disclosures about fair value measurements. This guidance also relates to all nonfinancial assets and liabilities that are not recognized or disclosed on a recurring basis (e.g., the initial recognition of asset retirement obligations and impairments of long‑lived assets). The fair value is the price that we estimate would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A fair value hierarchy is used to prioritize inputs to valuation techniques used to estimate fair value. An asset or liability subject to the fair value requirements is categorized within the hierarchy based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. The highest priority (Level 1) is given to unadjusted quoted market prices in active markets for identical assets or liabilities, and the lowest priority (Level 3) is given to unobservable inputs. Level 2 inputs are data, other than quoted prices included within Level 1, which are observable for the asset or liability, either directly or indirectly. (h) Net Income per Common Share Net income per common share – basic for each period is computed by dividing net income attributable to common shareholders by the basic weighted average number of common shares outstanding during the period. Net income per common share – diluted for each period is computed after giving consideration to the potential dilution from outstanding Series B Units, calculated using the if-converted method. During the periods in which AMGP incurs a net loss, diluted weighted average shares outstanding are equal to basic weighted average common shares outstanding because the effect of all equity awards is anti-dilutive. Based on AMGP’s market capitalization as of September 30, 2018, 4,091,741 AMGP shares would be issuable upon conversion of all outstanding Series B Units. The effect of these awards is anti-dilutive for the three and nine months ended September 30, 2018, and thus, our diluted net income per common share for the three and nine months ended September 30, 2018 is equal to its basic net income per common share. (i) Recently Adopted Accounting Standard On June 20, 2018, the FASB issued Accounting Standards Update (“ASU”) No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting, which aligns the accounting for employee and nonemployee share-based payments. The new standard becomes effective for AMGP on January 1, 2019. Early adoption of the standard is permitted. The standard requires a cumulative-effect adjustment to partners’ capital at the beginning of the fiscal year of adoption. AMGP has elected to adopt the standard as of October 1, 2018. No cumulative-effect adjustment to partners’ capital will be required as the awards were remeasured to fair value as of September 30, 2018. As a result of adopting this standard, AMGP will reclassify its $3 million liability for equity-based compensation to partners’ capital as of September 30, 2018 in the fourth quarter of 2018. See Note 4 – Long-Term Incentive Plans.

(2) Summary of Significant Accounting Policies

(a) Basis of Presentation

These unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) applicable to interim financial information. The accompanying unaudited condensed consolidated financial statements of AMGP have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and, accordingly, do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. In the opinion of management, the accompanying unaudited condensed consolidated financial statements include all adjustments (consisting of normal and recurring accruals) considered necessary to fairly present AMGP’s financial position as of December 31, 2017 and September 30, 2018, and its results of operations for the three and nine months ended September 30, 2017 and 2018 and its cash flows for nine months ended September 30, 2017 and 2018. AMGP has no items of other comprehensive income (loss); therefore, its net income (loss) is identical to its comprehensive income (loss). Operating results for the period ended September 30, 2018 are not necessarily indicative of the results that may be expected for the full year.

As of the date these unaudited condensed consolidated financial statements were filed with the SEC, the Partnership completed its evaluation of potential subsequent events for disclosure and no items requiring disclosure were identified other than as disclosed in Note 9 – Subsequent Events.

(b) Principles of Consolidation

The unaudited condensed consolidated financial statements include the accounts of AMGP, AMP GP (its wholly-owned subsidiary), and IDR LLC.

AMGP has determined that Antero Midstream is a variable interest entity (“VIE”) for which we are not the primary beneficiary and therefore, do not consolidate. We have concluded that Antero Resources is the primary beneficiary of Antero Midstream and Antero Resources should consolidate Antero Midstream’s financial results. Antero Resources is the primary beneficiary based on its power to direct the activities that most significantly impact Antero Midstream’s economic performance and its obligations to absorb losses or receive benefits of Antero Midstream that could be significant to Antero Midstream. Antero Resources owns approximately 52.9% of the outstanding limited partner interests in Antero Midstream and its officers and management group also act as management of Antero Midstream. Antero Midstream was formed to own, operate, and develop midstream energy assets to service Antero Resources’ production under long term contracts as described herein. We do not own any limited partnership interests in Antero Midstream and have no capital interests in Antero Midstream. We have not provided and do not anticipate providing financial support to Antero Midstream.

Antero Resources and Antero Midstream have contracts with 20-year initial terms and automatic renewal provisions, whereby Antero Resources has dedicated the rights for gathering and compression, and water handling and treatment services to Antero Midstream on a fixed-fee basis. Such dedications cover a substantial portion of Antero Resources’ current acreage and future acquired acreage, in each case, except for acreage that was already dedicated to other parties prior to entering into the service contracts or that was acquired subject to a pre-existing dedication. The contracts call for Antero Resources to present, in advance, drilling and completion plans in order for Antero Midstream to put in place gathering and compression, water handling, and gas processing assets to service Antero Resources’ assets. The drilling and completion capital investment decisions made by Antero Resources control the development and operation of all of Antero Midstream’s assets. Antero Resources therefore controls the activities that most significantly impact Antero Midstream’s economic performance. Because of these contractual obligations and the capital requirements related to these obligations, Antero Midstream has devoted and, for the foreseeable future, will devote substantially all of its resources to servicing Antero Resources’ operations. Additionally, revenues from Antero Resources will provide substantially all of Antero Midstream’s financial support and therefore, its ability to finance its operations. Because of the long term contractual commitment to support Antero Resources’ substantial growth plans, Antero Midstream will be practically and physically constrained from providing any substantive amount of services to other parties.

AMGP’s ownership of the non-economic general partner interest in Antero Midstream provides it with significant influence over Antero Midstream, but not control over the decisions that most significantly impact the economic performance of Antero Midstream. AMGP’s indirect ownership of the IDRs of Antero Midstream entitles it to receive cash distributions from Antero Midstream when distributions exceed certain target amounts. Our ownership of these interests does not require us to provide financial support to Antero Midstream. We obtained these interests upon its formation for no consideration. Therefore, they have no cost basis and are classified as long term investments. Our share of Antero Midstream’s earnings as a result of our ownership of the IDRs is accounted for using the equity method of accounting. AMGP recognizes distributions earned from Antero Midstream as “Equity in earnings of Antero Midstream Partners LP” on its statement of operations in the period in which they are earned and are allocated to its capital account. Our long term interest in the IDRs on the balance sheet is recorded in “Investment in Antero Midstream Partners LP.” The ownership of the general partner interests and IDRs do not provide AMGP with any claim to the assets of Antero Midstream other than the balance in its Antero Midstream capital account. Income related to the IDRs is recognized as earned and increases AMGP’s capital account and equity investment. When these distributions are paid to us, they reduce our capital account and our equity investment in Antero Midstream. See Note 5—Distributions from Antero Midstream.

(d) Use of Estimates

The preparation of the unaudited condensed consolidated financial statements and notes in conformity with GAAP requires that management formulate estimates and assumptions that affect income, expenses, assets, and liabilities. Changes in facts and circumstances or discovery of new information may result in revised estimates, and actual results could differ from those estimates.

(e) Income Taxes

AMGP regularly reviews its tax positions in each significant taxing jurisdiction during the process of evaluating our tax provision. AMGP makes adjustments to its tax provision when: (i) facts and circumstances regarding a tax position change, causing a change in management’s judgment regarding that tax position; and/or (ii) a tax position is effectively settled with a tax authority at a differing amount.

Equity-based compensation expense related to the Series B Units and certain IPO costs that are not deductible for federal income tax purposes. These non-deductible expenses and costs, along with the effect of state taxes, account for the difference between the federal tax rate of 35% and 21% for the three and nine months ended September 30, 2017 and 2018, respectively, and the effective rate of income tax expense for financial reporting purposes.

(f) General and Administrative Expenses

General and administrative costs incurred pre-IPO in 2017 primarily relate to legal and other costs incurred in connection with our IPO. Post-IPO general and administrative expense consists primarily of management fees paid to Antero Resources, and other legal and administrative expenses. Additionally, in connection with the formation of a conflicts committee of the board of directors of the Partnership’s general partner to consider potential transactions involving us in connection with Antero Resources’ and Antero Midstream’s efforts to explore, review, and evaluate potential measures related to its valuation, the conflicts committee retained an investment advisor and attorneys. The agreement with the investment advisor calls for a $2 million retainer fee, which has been expensed. Attorneys’ fees related to this matter are charged to expense as incurred.

(g) Fair Value Measures

The Financial Accounting Standards Board (the “FASB”) Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosures, clarifies the definition of fair value, establishes a framework for measuring fair value, and expands disclosures about fair value measurements. This guidance also relates to all nonfinancial assets and liabilities that are not recognized or disclosed on a recurring basis (e.g., the initial recognition of asset retirement obligations and impairments of long‑lived assets). The fair value is the price that we estimate would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A fair value hierarchy is used to prioritize inputs to valuation techniques used to estimate fair value. An asset or liability subject to the fair value requirements is categorized within the hierarchy based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. The highest priority (Level 1) is given to unadjusted quoted market prices in active markets for identical assets or liabilities, and the lowest priority (Level 3) is given to unobservable inputs. Level 2 inputs are data, other than quoted prices included within Level 1, which are observable for the asset or liability, either directly or indirectly.

(h) Net Income per Common Share

Net income per common share – basic for each period is computed by dividing net income attributable to common shareholders by the basic weighted average number of common shares outstanding during the period. Net income per common share – diluted for each period is computed after giving consideration to the potential dilution from outstanding Series B Units, calculated using the if-converted method. During the periods in which AMGP incurs a net loss, diluted weighted average shares outstanding are equal to basic weighted average common shares outstanding because the effect of all equity awards is anti-dilutive.

Based on AMGP’s market capitalization as of September 30, 2018, 4,091,741 AMGP shares would be issuable upon conversion of all outstanding Series B Units. The effect of these awards is anti-dilutive for the three and nine months ended September 30, 2018, and thus, our diluted net income per common share for the three and nine months ended September 30, 2018 is equal to its basic net income per common share.

(i) Recently Adopted Accounting Standard

On June 20, 2018, the FASB issued Accounting Standards Update (“ASU”) No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting, which aligns the accounting for employee and nonemployee share-based payments. The new standard becomes effective for AMGP on January 1, 2019. Early adoption of the standard is permitted. The standard requires a cumulative-effect adjustment to partners’ capital at the beginning of the fiscal year of adoption. AMGP has elected to adopt the standard as of October 1, 2018. No cumulative-effect adjustment to partners’ capital will be required as the awards were remeasured to fair value as of September 30, 2018. As a result of adopting this standard, AMGP will reclassify its $3 million liability for equity-based compensation to partners’ capital as of September 30, 2018 in the fourth quarter of 2018. See Note 4 – Long-Term Incentive Plans.