SUMMARY

        This summary provides a brief overview of information contained elsewhere in this prospectus. You should read this entire prospectus and the documents to which we refer you before making an investment decision. You should carefully consider the information set forth under "Risk Factors," "Cautionary Statement Regarding Forward-Looking Statements" and "Management's Discussion and Analysis of Financial Condition and Results of Operations," as well as the historical financial statements and the related notes to those financial statements included elsewhere in this prospectus. The information presented in this prospectus assumes, unless otherwise indicated, that the underwriters' option to purchase additional common shares is not exercised.

        For a definition of certain terms used in this prospectus, please read "Certain Assumptions and Terms Used in this Prospectus" beginning on page vi. In addition, we include a glossary of certain commonly used terms in the oil and natural gas industry used in this prospectus as Appendix B.

Antero Midstream GP LP

        We are a Delaware limited partnership that will elect to be treated as a corporation for U.S. federal income tax purposes. We own the general partner of Antero Midstream Partners LP (NYSE: AM) ("Antero Midstream") and all of the incentive distribution rights ("IDRs") in Antero Midstream. Following the closing of this offering, we will continue to receive at least 94% of the cash distributions paid by Antero Midstream on the IDRs. Antero Midstream is a growth-oriented master limited partnership 59% owned by Antero Resources Corporation (NYSE: AR) ("Antero Resources") that was formed to own, operate and develop midstream energy infrastructure primarily to service Antero Resources' rapidly increasing production and completion activity in the Appalachian Basin's Marcellus Shale and Utica Shale located in West Virginia and Ohio. We believe that Antero Midstream's strategically located assets and integrated relationship with Antero Resources position it to be a leading Appalachian midstream provider across the midstream value chain. Through our ownership interest in Antero IDR Holdings LLC ("IDR LLC"), our subsidiary, we receive cash distributions from Antero Midstream on the IDRs. We expect these cash distributions to increase substantially over time as Antero Midstream executes its business strategy.

        Antero Resources is the second largest natural gas and the largest NGL producer in Appalachia and the eighth largest natural gas producer in North America based on fourth quarter 2016 production volumes. Antero Resources holds over 616,000 net acres as of December 31, 2016 in the highly prolific southwestern core of the Marcellus Shale in northwest West Virginia and southwestern Pennsylvania and the core of the Utica Shale in southern Ohio. Antero Resources believes that the Marcellus and Utica Shales are two of the premier North American shale plays. Since January 2010, the combined natural gas production in the Marcellus and Utica Shales has increased by over 18 Bcf/d from 4 Bcf/d in 2010 to 22 Bcf/d in 2016 and currently represents over 30% of total U.S. natural gas production. Additionally, according to Wood Mackenzie, Marcellus and Utica Shale production is expected to grow to 37 Bcf/d by 2021, which would account for 40% of total expected U.S. natural gas production.

        Since 2010, Antero Resources has drilled and completed 529 horizontal wells in the Marcellus Shale and 150 horizontal wells in the Utica Shale with a 100% drilling success rate. As of December 31, 2016, Antero Resources reported estimated net proved reserves of 15.4 Tcfe and its net proved, probable and possible ("3P") drilling inventory consisted of 3,630 identified potential horizontal well locations. Antero Resources' 2017 drilling and completion budget of $1.3 billion is expected to fund the completion of 170 wells, operating an average of seven drilling rigs, including four in the Marcellus Shale and three in the Utica Shale. For 2017, Antero Resources has publicly announced net daily production guidance of approximately 2.2 Bcfe/d, which represents an 85% compound annual growth rate since 2010. Antero Resources is Antero Midstream's largest customer and accounted for substantially all of Antero Midstream's revenues for the year ended December 31, 2016.

        Antero Midstream's assets consist of gathering pipelines, compressor stations, processing and fractionation plants and water handling and treatment infrastructure, through which Antero Midstream provides gathering, compression, processing, fractionation and integrated water services, including fresh water delivery services and other fluid handling services. These services are provided to Antero Resources under long-term, fixed-fee contracts, limiting Antero Midstream's direct exposure to commodity price volatility. As of December 31, 2016, all of Antero Resources' approximate 702,000 gross acres (616,000 net acres) are dedicated to Antero Midstream for gathering, compression and water services, except for approximately 173,000 gross acres subject to third-party gathering and compression commitments. Under its agreements with Antero Midstream, and subject to any pre-existing dedications or other third-party commitments, Antero Resources has dedicated to Antero Midstream all of its current and future acreage in West Virginia, Ohio and Pennsylvania for gathering and compression services and all of its acreage within defined services areas in West Virginia and Ohio for water services. Antero Midstream also has certain rights of first offer with respect to gathering, compression, processing and fractionation services and water services for acreage located outside of the existing dedicated areas. The gathering and compression and water services agreements each have a 20-year initial term and are subject to automatic annual renewal after the initial term. Additionally, in connection with Antero Midstream's entry into a joint venture with MarkWest Energy Partners, L.P., a wholly owned subsidiary of MPLX, LP, to develop processing and fractionation assets in Appalachia, Antero Midstream released to the Joint Venture its right to provide certain processing and fractionation services on 195,000 gross acres held by Antero Resources in Ritchie, Tyler and Wetzel Counties in West Virginia. The processing and fractionation arrangements are underpinned by long-term agreements subject to automatic annual renewal after the initial term.

        We own the IDRs in Antero Midstream through our interest in IDR LLC, which we control as the managing member. IDR LLC has issued all of its capital interests to us in the form of Series A Units and has issued Series B Units, representing profits interests that vest ratably over a three-year period, to certain senior members of Antero Midstream's management team. Through our interest in IDR LLC, we receive 100% of the first $7.5 million of quarterly cash distributions paid by Antero Midstream on the IDRs. The Series B Holders will receive up to 6% of all quarterly cash distributions in excess of $7.5 million paid by Antero Midstream on the IDRs and we will receive the remainder of such distributions. Based on Antero Midstream's existing incentive distribution structure, the IDRs are entitled to receive increasing percentages of Antero Midstream's quarterly cash distributions to the extent those distributions exceed $0.1955 per unit per quarter, including 50% of all incremental cash distributed by Antero Midstream per quarter after Antero Midstream has distributed $0.2550 per unit in respect of its common units for that quarter. We in turn will pay our shareholders, on a quarterly basis, distributions equal to the cash distributions we receive on the IDRs, less distributions paid to or reserved for the Series B Holders, taxes and other expenses.

        We believe that as Antero Midstream continues to execute on its business objective to consistently increase its distributions to its unitholders over time, Antero Midstream will in turn substantially increase its cash distributions on the IDRs. Since its initial public offering, Antero Midstream has grown its quarterly distribution 76% from its minimum quarterly distribution of $0.17 per unit ($0.68 per unit on an annualized basis) for the quarter ended December 31, 2014 (the initial quarter for which Antero Midstream paid a quarterly cash distribution) to $0.30 per unit ($1.20 per unit on an annualized basis) for the quarter ended March 31, 2017. For 2017, Antero Midstream has publicly announced distribution growth guidance of 28% to 30% as compared to 2016. Antero Midstream's ability to consistently grow its cash distributions is driven by a combination of Antero Resources' production growth and Antero Midstream's accretive build-out of additional midstream infrastructure to service that production growth.

        Based on Antero Midstream's quarterly distribution of $0.28 per unit for the fourth quarter of 2016 and the number of outstanding Antero Midstream units as of February 1, 2017, the record date for such distribution, Antero Midstream's aggregate quarterly cash distributions in respect of the IDRs were

approximately $7.5 million for that quarter. The graph below illustrates the growth in Antero Midstream's historical quarterly distributions per unit and the aggregate distributions paid by Antero Midstream on all of its partnership interests, including the IDRs, during each of the periods presented.

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(1)

Antero Midstream's historical distributions are not necessarily indicative of its ability to distribute similar amounts or continue to increase such distributions in the future. Please read "Risk Factors—Risks Related to Antero Midstream's Business" for a description of the risks that could cause Antero Midstream's future distributions to differ materially from its historical distributions.

(2)

Represents quarterly distributions per unit declared and paid since the completion of Antero Midstream's initial public offering on November 10, 2014 (the "Antero Midstream IPO"). On April 10, 2017, the board of directors of Antero Midstream's general partner declared a cash distribution of $0.30 per unit ($1.20 per unit annualized) for the first quarter of 2017. Please read "—Recent Developments—First Quarter 2017 Distribution Announcement for Antero Midstream."

(3)

Represents the aggregate quarterly cash value of distributions declared and paid on Antero Midstream's common and subordinated units and IDRs since the Antero Midstream IPO.

(4)

Antero Midstream paid a cash distribution of $0.0943 per unit for the partial quarter ended December 31, 2014, the quarter in which it completed the Antero Midstream IPO. This amount represented the prorated minimum quarterly distribution of $0.17 per unit, or $0.68 per unit on an annualized basis.

(5)

On February 9, 2017, in connection with the payment of the fourth quarter 2016 quarterly distribution to Antero Midstream's unitholders of record on February 1, 2017, all of the subordinated units in Antero Midstream converted into common units on a one-for-one basis.

        The following graph presents the impact on aggregate cash available for distribution resulting from potential changes in Antero Midstream's 2016 annualized distribution of $1.03 per unit. The potential distribution increases presented are consistent with Antero Midstream's 2017 annual distribution growth guidance of 28% to 30%. This information is presented for illustrative purposes only and is not intended to be a prediction of our actual future performance.

        As demonstrated in the graph above, we expect our cash available for distribution to grow at a multiple of the underlying rate of growth of Antero Midstream's distributions on its units. Accordingly, our primary business objective is to increase our cash available for distribution to our shareholders through Antero Midstream's execution of its business strategy. The impact of changes in Antero Midstream's per unit cash distribution levels on our cash available for distribution will vary depending on several factors, including the number of outstanding Antero Midstream common units on the record date for cash distributions. In addition, the level of our cash available for distribution is subject to risks associated with the underlying business of, and an investment in, Antero Midstream. Please read "Risk Factors—Risks

Related to Antero Midstream's Business." If one or more of these risks were to occur, Antero Midstream's cash available for distribution would decrease, which would decrease the distributions paid to IDR LLC and, in turn, the distributions IDR LLC pays to us. Please read "Risk Factors—Risks Inherent in an Investment in Us—A reduction in Antero Midstream's distributions will disproportionately affect the amount of cash distributions on the IDRs." Such a decrease would reduce our cash available for distribution and the distributions we pay our shareholders.

        We expect our quarterly cash distributions for the twelve-month period ending June 30, 2018 to total $0.32 per common share. In general, distributions on the common shares will be treated as distributions on corporate stock for federal income tax purposes. No Schedule K-1s will be issued with respect to the common shares, but instead holders of common shares will receive a Form 1099 with respect to distributions received on the common shares. Please read "—The Offering—Material U.S. Federal Income Tax Consequences."

The Appalachian Basin

        The Appalachian Basin, the area in which Antero Midstream and Antero Resources are exclusively based, covers a broad area with current industry activity extending primarily through West Virginia, Ohio and Pennsylvania in the Marcellus and Utica Shales. This area is considered a highly attractive natural resource producing region with a long history of natural gas, NGL and oil production. Importantly, the Appalachian Basin is strategically located near the high energy demand markets in the northeast and midwest regions of the United States. According to Baker Hughes, over 50% of the horizontal drilling rigs targeting shale gas reservoirs in the United States were operating in Appalachia as of December 31, 2016. Since January 2010, the combined natural gas production in the Marcellus and Utica Shales has increased by over 18 Bcf/d to 22 Bcf/d in 2016, representing over 30% of total U.S. natural gas production. According to Wood Mackenzie, Marcellus and Utica Shale production is expected to grow to 37 Bcf/d by 2021, which would account for 40% of overall expected natural gas production in the U.S.

Marcellus Shale

        The Devonian-aged Marcellus Shale is an unconventional reservoir that produces natural gas, NGL and oil and is the largest and most prolific unconventional natural gas reservoir in the U.S., producing nearly 25% of total U.S. natural gas supply in 2016. Antero Resources believes that the Marcellus Shale is a premier North American shale play due to its consistent and predictable geology, high well recoveries relative to drilling and completion costs and significant hydrocarbon resources in place, which collectively provide for attractive well economics. Antero Resources and other Marcellus Shale operators have continued to improve drilling and completion efficiencies by employing techniques such as multiple wells per pad, longer laterals, rotary steerable drilling, increasing concentrations of proppant and water and more efficient completion stage sequencing ("zipper fracs"), significantly increasing the level of economic inventory at current prices.

        According to Wood Mackenzie, natural gas production in the Marcellus Shale grew by more than 1.3 Bcf/d in 2016 (approximately 8%) and is expected to grow further from 18.6 Bcf/d in 2017 to more than 29.3 Bcfe/d in 2021, representing a 58% increase. We believe that Antero Resources' and Antero Midstream's assets located in the southwestern core of the Marcellus Shale are among the most productive and economic areas of the play, distinguished by processed EURs above 2.0 Bcfe per 1,000-feet of lateral length (assuming ethane rejection) and low finding and development costs.

Utica Shale

        The Ordovician-aged Utica Shale is an unconventional reservoir with productive limits covering a broad area primarily in West Virginia, Ohio and Pennsylvania. The richest and thickest concentration of organic-carbon content is present within the Point Pleasant Shale layer of the Lower Utica formation, which is Antero Resources' primary target in the Ohio Utica Shale. As is the case in the Marcellus Shale,

Antero Resources and other Utica Shale producers have enjoyed improved drilling and completion efficiencies, resulting in an increased inventory of economic well locations and attractive well economics.

        According to Wood Mackenzie, production in the Utica Shale grew by more than 1.2 Bcf/d in 2016 (approximately 45%) and is expected to grow further from 4.6 Bcf/d in 2017 to more than 7.7 Bcf/d in 2021, representing a 67% increase. We believe Antero Resources' and Antero Midstream's assets in the core of this play are located in the most productive and economic areas in the liquids-rich window, distinguished by industry-leading processed EURs ranging between 2.2 and 2.5 Bcfe per 1,000-feet of lateral length (assuming ethane rejection) and low finding and development costs. Additionally, the industry has drilled exploration wells in the deep dry gas window of the Utica Shale play in northeastern West Virginia and Pennsylvania. Results in this play have been encouraging with EURs ranging between 1.5 and 3.0 Bcf per 1,000-feet of lateral but with higher well costs than the Ohio Utica.

Antero Resources Corporation

        Antero Resources is Antero Midstream's largest customer and is the second largest natural gas and the largest NGL producer in Appalachia and the eighth largest natural gas producer in North America. Antero Resources' projected net daily production of 2.2 Bcfe/d (assuming the midpoint of Antero Resources' guidance for 2017) represents an 85% CAGR since 2010.

        The chart below illustrates the significant Appalachian Basin production growth achieved by Antero Resources since 2010. Antero Resources relies primarily on Antero Midstream to deliver the gathering, compression, processing and water handling and treatment infrastructure necessary to support its continued growth, which should result in significant increases in gathering, compression, processing, fresh water delivery and other fluid handling services volumes. Antero Resources has publicly announced annual production growth guidance of 20% to 25% for 2017 as compared to 2016 guidance of 1.8 Bcfe/d.

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(1)

Based on Antero Resources' publicly disclosed forecast of estimated net daily production for 2017. We cannot assure you that actual net daily production will meet or exceed estimated amounts. For a description of certain factors that could negatively impact Antero Resources' business and cause its actual net daily production to be less than estimated amounts, please read "Risk Factors—Risks Related to Antero Midstream's Business—Because substantially all of Antero Midstream's revenue is derived from Antero Resources and Antero Resources' capital decisions drive our operations, any development that materially and adversely affects Antero Resources' operations, financial condition or market reputation could have a material and adverse impact on us."

        The following table highlights the scale of Antero Resources' gross acreage position and gross drilling locations dedicated to Antero Midstream and to third parties for gathering and compression services and water services, respectively, as of December 31, 2016. With 3,630 identified potential horizontal well locations in Antero Resources' net 3P reserves as of December 31, 2016, Antero Resources maintains an approximate 21-year drilling inventory (based on its expected 2017 completion activity), which we believe will provide significant demand for further gathering and compression services and water services. In connection with its entry into the Joint Venture, Antero Midstream released to the Joint Venture its right to provide certain processing and fractionation services on 195,000 gross acres held by Antero Resources in Ritchie, Tyler and Wetzel Counties in West Virginia.

Antero Midstream Partners LP

        Antero Midstream is a growth-oriented master limited partnership 59% owned by Antero Resources and formed to own, operate and develop midstream energy infrastructure primarily to service Antero Resources' rapidly increasing production and completion activity under long-term, fixed-fee contracts. Antero Midstream's assets are located both in the southwestern core of the Marcellus Shale in northwest West Virginia and in the core of the Utica Shale in southern Ohio, which Antero Resources believes are two of the premier North American shale plays and are its primary operating areas.

Gathering and Processing Assets

        Antero Midstream's gathering assets consist of 8-, 12-, 16-, 20- and 24-inch low and high pressure gathering pipelines and compressor stations that collect natural gas and condensate from Antero Resources' wells in the Marcellus Shale in West Virginia and the Utica Shale in Ohio. Additionally, Antero Midstream owns a 15% non-controlling equity interest in Stonewall Gas Gathering, LLC, for which Antero Resources is an anchor shipper. As of December 31, 2016, Antero Midstream owned and operated 173 miles of low-pressure pipeline, 134 miles of high-pressure pipeline and 19 miles of condensate pipeline, as well as 11 compression stations with 1,135 MMcf/d of throughput capacity. Average daily low pressure gathering volumes increased from 1,016 MMcf/d for the year ended December 31, 2015 to 1,403 MMcf/d for the year ended December 31, 2016 as Antero Resources continued to increase its production. Under its gathering and compression agreement with Antero Resources, Antero Midstream receives a low pressure gathering fee of $0.31 per Mcf, a high pressure gathering fee of $0.19 per Mcf, a compression fee of $0.19 per Mcf and a condensate gathering fee of $4.17 per Bbl as of December 31, 2016. In each case, these fees are fixed and subject to annual CPI-based adjustments.

        Antero Midstream's processing assets include a 50% non-operated equity interest in the Sherwood 7 natural gas processing plant in West Virginia through the Joint Venture. The Joint Venture also owns a 33¹/3% interest in the recently commissioned Hopedale 3 fractionator at the Hopedale complex. Please read "—Recent Developments—Antero Midstream Strategic Processing and Fractionation Joint Venture and Increased 2017 Guidance." In connection with its entry into the Joint Venture, Antero Midstream released to the Joint Venture its right to provide certain processing and fractionation services on 195,000 gross acres held by Antero Resources in Ritchie, Tyler and Wetzel Counties in West Virginia. The Joint Venture's processing activity commenced with Plant 7 at the Sherwood processing facility in the first quarter of 2017 and will continue with Plants 8, 9 and 10, which are under construction or planned and scheduled to be placed into service during the third quarter of 2017, first quarter of 2018 and third quarter of 2018, respectively.

        The Joint Venture's processing assets are underpinned by long-term, fee-based arrangements pursuant to which the Joint Venture will process Antero Resources' liquids-rich production from the Marcellus Shale. In addition to the processing assets, the Joint Venture will own C3+ fractionation capacity at the Hopedale complex in Harrison County, Ohio supported by Antero Resources and other third-party producers. The Joint Venture will have the option to participate in additional fractionation capacity in the future, contingent on further C3+ NGL production growth from the Joint Venture processing plants.

Water Handling and Treatment Assets

        Antero Midstream's water handling and treatment assets include fresh water delivery systems and other fluid handling assets. Antero Midstream's fresh water delivery assets consist of two independent systems that deliver fresh water from sources including the Ohio River, local reservoirs as well as several regional waterways. The other fluid handling assets also consist of flowback and produced water assets used to provide services for well completion and production operations in Antero Resources' operating areas. The fresh water delivery assets consist of permanent buried pipelines, surface pipelines and fresh water storage facilities, as well as pumping stations and impoundments to transport fresh water throughout the systems. The other fluid handling services assets consist of wastewater transportation, disposal and treatment, including services to be provided through the Antero Clearwater Facility, a 60,000 Bbl/d advanced wastewater treatment complex that is currently under construction in Doddridge County, West Virginia and is expected to be placed in service in the fourth quarter of 2017. Once in service, we expect the Antero Clearwater Facility will be the largest advanced wastewater treatment facility in the world specifically built for oil and gas operations. In West Virginia, Antero Midstream owned and operated 203 miles of buried and surface fresh water pipelines that service Antero Resources' drilling activities, as well as 22 centralized water storage facilities, as of December 31, 2016. In Ohio, Antero Midstream owned and operated 83 miles of buried and surface fresh water pipelines that service Antero Resources' drilling activities in the Utica Shale, as well as 14 centralized water storage facilities, as of December 31, 2016. Under its water services agreement with Antero Resources, Antero Midstream receives a fixed fee of $3.69 per barrel in West Virginia and a fixed fee of $3.64 per barrel in Ohio and all other locations for fresh water deliveries by pipeline directly to the well site as of December 31, 2016. In each case, these fees are fixed and subject to annual CPI-based adjustments.

        The following table sets forth selected Antero Midstream operating and financial data for the years ended December 31, 2015 and 2016:

Recent Developments

Antero Midstream Preliminary First Quarter 2017 Results

        On April 24, 2017, Antero Midstream disclosed the following preliminary unaudited financial results for the three months ended March 31, 2017. The information presented below is based upon information available to Antero Midstream as of April 24, 2017 and is not a comprehensive statement of Antero Midstream's financial results. These are preliminary non-reviewed unaudited financial results. Antero Midstream's completed results to be reported for the three months ended March 31, 2017 may differ materially from this preliminary data. During the course of the preparation of Antero Midstream's combined consolidated financial statements and related notes to be included in Antero Midstream's Quarterly Report on Form 10-Q for the three months ended March 31, 2017, additional adjustments to the preliminary financial information presented below may be identified. Any such adjustments may be material.

        Based on preliminary analysis of the financial results for the three months ended March 31, 2017, Antero Midstream expects net income to be between $73 million and $77 million and Adjusted EBITDA to be between $114 million and $124 million, respectively.

        The following reconciles net income to Adjusted EBITDA based on these preliminary financial results for the three months ended March 31, 2017:

        Antero Midstream views Adjusted EBITDA as an important indicator of Antero Midstream's performance. Antero Midstream defines Adjusted EBITDA as net income before equity-based compensation expense, interest expense, depreciation expense, accretion of contingent acquisition consideration, excluding equity in earnings of unconsolidated affiliates, and including distributions from unconsolidated affiliate.

        Antero Midstream uses Adjusted EBITDA to assess:

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the financial performance of Antero Midstream's assets, without regard to financing methods in the case of Adjusted EBITDA, capital structure or historical cost basis;



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Antero Midstream's operating performance and return on capital as compared to other publicly traded partnerships in the midstream energy sector, without regard to financing or capital structure; and



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the viability of acquisitions and other capital expenditure projects.

First Quarter 2017 Distribution Announcement for Antero Midstream

        On April 10, 2017, the board of directors of Antero Midstream's general partner declared a cash distribution of $0.30 per unit ($1.20 per unit annualized) for the first quarter of 2017. This distribution represents a 28% increase compared to the first quarter of 2016 and a 7% increase over the distribution paid with respect to the fourth quarter of 2016. This distribution is Antero Midstream's ninth consecutive quarterly distribution increase since the Antero Midstream IPO in November 2014. The distribution will be payable on May 10, 2017 to Antero Midstream unitholders of record as of May 3, 2017. In connection with this distribution, approximately $11 million will be distributed to us on the IDRs with respect to the first quarter of 2017. Any additional distributions received by IDR LLC from Antero Midstream relating to periods prior to the closing of this offering will be distributed to the ARI Members.

Antero Midstream Strategic Processing and Fractionation Joint Venture and Increased 2017 Guidance

        On February 6, 2017, Antero Midstream announced the formation of a joint venture to develop processing and fractionation assets in Appalachia with MarkWest, a wholly owned subsidiary of MPLX. In connection with its entry into the Joint Venture, Antero Midstream released to the Joint Venture its right to provide certain processing and fractionation services on 195,000 gross acres held by Antero Resources in Ritchie, Tyler and Wetzel Counties in West Virginia. The Joint Venture will not participate in the six existing Sherwood plants, which will continue to be owned and operated solely by MarkWest. The existing plants have the capacity to process over 1.2 Bcf per day of liquids-rich gas and are currently running at full capacity. The Joint Venture processing facilities, starting with Plant 7, will be operated by MarkWest and will have the potential to support an incremental eleven plants, or 2.2 Bcf per day of capacity, to facilitate liquids-rich production growth from Antero Resources. In addition to the processing assets, the Joint Venture will own C3+ fractionation capacity at the Hopedale complex in Harrison County, Ohio supported by Antero Resources and other third-party producers.

        In connection with its entry into the Joint Venture, Antero Midstream increased its 2017 forecast for net income to $305 million to $345 million, Adjusted EBITDA to $520 million to $560 million and distributable cash flow ("DCF") to $405 million to $445 million, as a result of additional cash flows expected from the Joint Venture. Additionally, Antero Midstream reaffirmed its projected distribution growth of 28% to 30%, resulting in an average DCF coverage ratio of 1.30x to 1.45x over the

corresponding period. Additionally, Antero Midstream increased its 2017 capital budget to $800 million in connection with its entry into the Joint Venture.

2017 Guidance for Antero Resources and Antero Midstream

        On January 4, 2017, Antero Resources announced a 2017 drilling and completion capital budget of $1.3 billion and net production growth guidance of 20% to 25% for 2017 as compared to 2016 guidance of 1.8 Bcfe/d. In conjunction with Antero Resources' drilling and completion budget and production growth guidance, Antero Midstream announced a midstream capital budget of $525 million and distribution growth guidance of 28% to 30% for 2017 as compared to the prior year. The Antero Midstream capital budget was subsequently increased to $800 million upon announcement of the Joint Venture on February 6, 2017. Additionally, Antero Midstream expects a distribution coverage ratio of 1.30x to 1.45x over the corresponding period.

Antero Midstream's Business Strategies

        Antero Midstream's principal business objective is to increase the quarterly cash distributions that it pays to its unitholders over time while ensuring the ongoing stability of its business. Antero Midstream expects to achieve this objective through the following business strategies:

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Leveraging extensive asset base to meet Antero Resources' current and future infrastructure needs.  Antero Midstream owns and operates a newly-constructed, high-capacity asset base that will allow it to gather, compress and process significant incremental natural gas volumes, as well as fractionate incremental C3+ NGL volumes. Additionally, the high-capacity asset base will allow it to deliver incremental fresh water volumes and provide fluid-handling services for significant incremental produced and flowback water volumes. Antero Midstream intends to continue to develop its midstream infrastructure to move Antero Resources' growing production to market. Antero Resources' publicly announced production growth guidance of 20% to 25% in 2017 is expected to result in Antero Midstream throughput volume growth in excess of 20% to 25%, and is driven by Antero Resources' plan to complete approximately 170 horizontal wells with an average lateral length of approximately 9,300 feet, the vast majority of which are focused on Antero Midstream dedicated acreage. Antero Resources expects to execute advanced completions on these locations, resulting in increased water volumes and higher sand concentrations. In 2016, Antero Resources' advanced completions resulted in increased fresh water volumes delivered by Antero Midstream and improved throughput on the gathering and compression assets driven by higher overall wellhead recoveries. In addition, as of December 31, 2016, Antero Resources' drilling inventory consisted of 3,630 identified proved, probable and possible horizontal well locations on its contiguous acreage position, giving Antero Resources an approximate 21-year drilling inventory (based on expected 2017 completion activity) and, consequently, visible long-term demand for Antero Midstream's services.



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Focusing on stable, fixed-fee business to avoid direct commodity price exposure.  Antero Midstream's gathering, compression, processing, fractionation and water services arrangements with Antero Resources provide for a fixed-fee structure, and Antero Midstream intends to continue to pursue additional fixed-fee opportunities with Antero Resources and third parties in order to avoid direct commodity price exposure. Antero Midstream will focus on obtaining additional long-term commitments from customers, which may include reservation-based charges, volume commitments and acreage dedications.



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Investing in a significant backlog of attractive organic growth opportunities.  Antero Midstream's strategy is to organically develop midstream infrastructure to support Antero Resources' robust development program. Antero Midstream believes that organic projects will be a key driver of its growth in the future and expects to construct additional gathering systems, compressor stations,

processing and fractionation plants and water handling and treatment assets to meet Antero Resources' significant long-term production growth expectations. We believe Antero Midstream's organic growth strategy generally provides more attractive returns and project economics than an approach based on third-party acquisitions or sponsor drop-downs, as it avoids the risks and costs associated with the competitive acquisition market and the reliance on capital markets for acquisition financing. Additionally, Antero Midstream's significant acreage dedication and relationship with Antero Resources provides Antero Midstream with increased visibility into the timing and magnitude of Antero Resources' development program, supporting a just-in-time approach to infrastructure investment and further enhancing project economics.

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Growing Antero Midstream's business through Antero Resources' continuing expansion of its acreage footprint in the Marcellus and Utica Shales.  Antero Resources' management team has significant experience in mergers and acquisitions and will selectively review opportunities to acquire assets from third parties. From its initial public offering in 2013 through 2016, Antero Resources has increased its overall acreage position by 45%, driving incremental greenfield expansion projects.



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Expanding beyond existing services to operate across the midstream value chain.  While traditionally Antero Midstream has provided gathering, compression and water services to Antero Resources, Antero Midstream has recently expanded its midstream services to include natural gas processing and C3+ NGL fractionation through its interest in the Joint Venture. In addition, Antero Midstream may expand its existing services to include other midstream services such as long-haul interstate pipelines, NGL product pipelines, terminaling and storage to be provided to Antero Resources and other third parties. Antero Midstream expects significant growth in demand for all of its midstream services as a result of the anticipated production growth from Antero Resources and third parties based on the increasing productivity of completed wells and low cost nature of the Marcellus and Utica Shales.



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Expanding Antero Midstream's business by developing a third-party customer base in the most productive natural gas basins in North America in the future.  Antero Resources represented 99.86% of Antero Midstream's revenues for the year ended December 31, 2016, while third-party customers represented the remaining amount. While Antero Midstream will continue to devote substantially all of its resources to meeting Antero Resources' needs for the foreseeable future, Antero Midstream may market its services to, and pursue customer relationships with, third-party producers in the future in the highly productive, low cost Marcellus and Utica Shales. We believe that Antero Midstream's significant footprint of gathering, compression, water handling and water treatment infrastructure in the Marcellus and Utica Shales provides it with a competitive advantage that we believe will allow Antero Midstream to attract third-party throughput volumes in the future. However, Antero Midstream's forecast contains no third-party volumes for the twelve-month period ending June 30, 2018.

        Antero Midstream cannot assure you, however, that it will be able to execute its business strategies described above. For further discussion of the risks that Antero Midstream faces, please read "Risk Factors—Risks Related to Antero Midstream's Business."

Antero Midstream's Competitive Strengths

        Antero Midstream is well-positioned to significantly grow distributions on its partnership interests, including its IDRs, by capitalizing on the following competitive strengths:

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Sustainable outsized growth.  Antero Midstream commenced cash distributions on its IDRs in the third quarter of 2015. In addition, Antero Midstream's fourth quarter 2016 distribution of $0.28 per unit represented a 65% increase as compared to its minimum quarterly distribution of $0.17 per unit and represented the second quarter that Antero Midstream's distribution was above the 50% tier distribution target amount, entitling the IDRs to receive up to 50% of all incremental cash

distributed in a given quarter after each common and subordinated unit of Antero Midstream received $0.255 per unit for that quarter. Since its initial public offering in November 2014, Antero Midstream has increased its quarterly distribution each quarter while maintaining average distributable cash flow coverage of 1.58x. Antero Midstream expects to declare distributions in 2017 that are 28% to 30% above the distributions declared for 2016.

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Appalachia core focused with exposure to diverse hydrocarbon mix.  Antero Midstream believes it has the largest dedicated acreage position in the core of the combined Marcellus and Utica Shales due to its gathering, compression, processing, fractionation and water services arrangements with Antero Resources, providing a diverse investment opportunity set for gas, NGL and condensate gathering, compression, processing and fractionation, as well as water handling and treatment projects. The diverse hydrocarbon mix provides Antero Midstream with multiple points at which to service a hydrocarbon unit generating multiple investment and growth opportunities over time. The anticipated natural gas, NGL, condensate and fresh and produced and flowback water volume growth is driven by Antero Resources' peer-leading development program in two of the lowest-cost shale plays in North America.



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Economic strength of Antero Resources' development program.  We believe the attractiveness of Antero Resources' portfolio of both liquids-rich and dry acreage and its low development cost per unit will support long-term demand for Antero Midstream's services in a variety of commodity price environments. The economic strength of Antero Resources' development program is substantially supported by:



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Antero Resources' multi-decade drilling inventory.    Antero Resources' drilling inventory as of December 31, 2016 consisted of 3,630 identified potential horizontal well locations, which include more than 2,500 locations that deliver breakeven economics (defined as a pre-tax rate of return of 20% at below $3.00 per MMBtu NYMEX prices assuming December 31, 2016 strip pricing for oil and NGLs). Antero Resources believes its core inventory is the largest in Appalachia, with 3,400 of such identified locations being in the core of the Marcellus and Utica Shales as of December 31, 2016. Based on its expected 2017 completion activity, these core locations give Antero Resources a 20-year drilling inventory as of December 31, 2016.



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Antero Resources' exposure to a large resource of liquids-rich gas and condensate.    Liquids-rich gas production generally enhances well economics due to the processing margin generated by typically higher-value NGL products, such as propane and butane. In addition, the wellhead condensate often associated with liquids-rich production can further increase well economics. Approximately 70% of Antero Resources' 3,630 identified potential horizontal well locations as of December 31, 2016 target the liquids-rich gas regions of the Marcellus and Utica Shales.



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Antero Resources' status as a low-cost leader.    Antero Resources has implemented operational efficiencies to give it some of the lowest development costs per Mcfe in the Marcellus and Utica Shales, such as (i) pad drilling that is expected to average nine wells per pad in the Marcellus Shale and six wells per pad in the Utica Shale in 2017, (ii) drilling longer laterals expected to average 9,300 feet in 2017, (iii) the use of rotary steerable drilling equipment and increased mud pump circulation rates, (iv) the use of shorter stage lengths and advanced completions incorporating increased proppant and fluid loading, (v) the use of Antero Midstream's fresh water delivery systems, (vi) more efficient completion stage sequencing, or zipper fracs and (vii) the use of less expensive, intermediate drilling rigs to drill to the kick-off point just above the target formation, prior to the arrival of large drilling rigs to drill the horizontal wellbore.



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Antero Resources' access to committed processing and firm takeaway capacity in the Marcellus and Utica Shales.    Antero Resources' existing contractual commitments for processing and firm long-haul transportation help minimize disruptions to its drilling program that might otherwise

exist as a result of insufficient outlets for growing production as well as optimize pricing for its products. Antero Resources has committed to a total of 2.0 Bcf/d of processing capacity in the Marcellus Shale, 1.2 Bcf/d of which is currently in service. Similarly, Antero Resources has 600 MMcf/d of contracted processing capacity in the Utica Shale, all of which is currently in service. In addition, Antero Resources has secured an average of 4.85 Bcf/d of long-haul natural gas firm transportation capacity or firm sales that is expected to be in service by year end of 2018. Antero Resources has also committed to 20,000 Bbl/d of ethane takeaway capacity to Mont Belvieu and has entered into an agreement to provide an additional 30,000 Bbl/d of ethane to the planned Shell Chemical LP ("Shell") ethane cracker. Additionally, Antero Resources has entered into firm transportation agreements on Mariner East 2 for 61,500 Bbl/d of capacity, consisting of 11,500 Bbl/d of ethane, 35,000 Bbl/d of propane and 15,000 Bbl/d of butane and has doubling rights on its propane and butane commitments that would result in capacity of 70,000 Bbl/d and 30,000 Bbl/d, respectively. Antero Midstream believes its midstream infrastructure, together with Antero Resources' significant processing and takeaway capacity, will allow Antero Resources to commercialize its production more quickly at favorable prices and keep pace with its robust drilling plan.

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Antero Resources' peer-leading hedging program.    Antero Resources maintains a hedging program designed to mitigate volatility in commodity prices and regional basis differentials and to protect its expected future cash flows. As of December 31, 2016, Antero Resources had entered into hedging contracts through December 31, 2022 covering a total of approximately 3.4 Tcfe of its projected natural gas, NGLs and oil production at a weighted average index equivalent price of $3.63 per MMBtu. Pursuant to this hedging program, Antero Resources has hedged volumes of 2,163 BBtu/d, 2,015 BBtu/d and 2,330 BBtu/d at weighted average prices of $3.51 MMBtu, $3.91 MMBtu and $3.70 MMBtu for 2017, 2018 and 2019, respectively. We believe that Antero Resources' active hedging program will allow its drilling schedule to remain robust through a variety of commodity price environments.



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Extensive dedication, system scale and long-term, fixed fee contracts to support stable cash flows.  As of December 31, 2016, Antero Resources has dedicated all of its 702,000 gross acres (616,000 net acres) to Antero Midstream for gathering and compression services, except for approximately 173,000 gross acres subject to third-party commitments, and substantially all of Antero Resources' approximate 702,000 gross acres to Antero Midstream for water services. In addition, the gathering and compression agreement provides that any acreage that Antero Resources acquires in West Virginia, Ohio and Pennsylvania subsequent to the Antero Midstream IPO completed in November 2014 that is not subject to a pre-existing dedication or other third-party commitment, will be dedicated to Antero Midstream for gathering and compression services and, with respect to certain acreage in Ohio and West Virginia, Antero Midstream's integrated water services pursuant to the water services agreement. We believe that Antero Resources' drilling activity will result in the significant growth of Antero Midstream's operations. Antero Midstream's fixed-fee, long-term contract structure helps to eliminate direct exposure to commodity price risk and provide Antero Midstream with more stable long-term cash flow.



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Financial flexibility and strong capital structure.  As of December 31, 2016 and after giving effect to Antero Midstream's offering of 6.9 million common units on February 6, 2017 and the Joint Venture, Antero Midstream had approximately $1.2 billion of available borrowing capacity under its $1.5 billion revolving credit facility, as well as approximately $185 million of available capacity under its at-the-market equity offering program. We believe that Antero Midstream's borrowing capacity, the available offering capacity under its at-the-market equity offering program and the organic nature of its business plan, which significantly limits the need for access to the debt and equity capital markets, provides Antero Midstream with the financial flexibility necessary to execute its business strategy.

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Experienced and incentivized management team led by co-founders.  Antero Resources' Chairman and Chief Executive Officer and its President and Chief Financial Officer are co-founders of Antero Resources and its officers, who also manage Antero Midstream's business and will manage our business, have an average of over 30 years of industry experience and have successfully built, grown and sold two unconventional resource-focused upstream companies and one midstream company in the past 15 years. We believe Antero Resources' experience and expertise from both an upstream and midstream perspective provides a distinct competitive advantage. Through Antero Resources' ownership of 59% of the common units of Antero Midstream, the management team of Antero Resources and Antero Midstream is highly incentivized to grow Antero Midstream's distributions and the value of its business.

        We cannot assure you, however, that Antero Midstream will be able to utilize its competitive strengths to successfully execute its business strategies described above. For further discussion of the risks and challenges that Antero Midstream faces, please read "Risk Factors—Risks Related to Antero Midstream's Business."

Organizational Structure

        The diagram below depicts our organizational structure immediately following the closing of this offering (assuming the underwriters' option to purchase additional common shares is not exercised) and the Reorganization (but does not give effect to the liquidation of Antero Investment, which we expect will occur following the completion of this offering at a time to be determined by the ARI Members):

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(1)

Series B Units represent the right to receive up to 6% of the aggregate distributions paid by IDR LLC in excess of $7.5 million. Each Series B Holder will also have the right to redeem all or a portion of its vested Series B Units in exchange for newly-issued common shares in us with a value equal to its pro rata share of up to 6% of any increase in our equity value (calculated by reference to the 20-day volume weighted average price of our common shares preceding the date of the redemption request) in excess of $2.0 billion.

(2)

We own all of the capital interests in IDR LLC, which owns all of the IDRs in Antero Midstream. Following the completion of this offering, we will continue to receive at least 94% of the cash distributions paid by Antero Midstream on its IDRs.

Reorganization

        Our Predecessor was formed as a limited liability company in September 2013 and has elected to be taxed as a corporation for U.S. federal income tax purposes. In connection with the completion of this offering, certain reorganization transactions will be effected, which will result in the revised organizational structure depicted above. For additional information regarding the Reorganization, please read "Organizational Structure—Reorganization."

        In connection with the Reorganization, we will convert into a Delaware limited partnership and will elect to be taxed as a corporation for U.S. federal income tax purposes. Our sole assets consist of our interest in the general partner of Antero Midstream and all of the capital interests in IDR LLC, which directly owns the IDRs. In connection with the Reorganization, ARMM will distribute to the ARI Members all of its cash, including any cash distributions received or to be received by ARMM in respect of

Antero Midstream's cash distributions on its IDRs for periods prior to the closing of this offering, net of payments for liabilities for income taxes and accrued expenses. Such net cash distribution by ARMM will result in a reduction in members' equity to $0 on a pro forma basis after giving effect to this offering and the Reorganization. As part of the Reorganization, Antero Investment will liquidate following the completion of this offering.

Series B Units and Redemption Right

        IDR LLC has two classes of membership interests: (i) capital interests referred to as Series A Units and (ii) profits interests referred to as Series B Units. Following the completion of this offering, we will continue to own all of the Series A Units and the Series B Holders will continue to own all of the Series B Units.

        The Series B Holders will receive an aggregate distribution of up to 6% of all quarterly cash distributions in excess of $7.5 million distributed by Antero Midstream on the IDRs and we will receive all remaining distributions. The Series B Units are subject to restrictions on transfer and vest over three years in one-third increments upon each anniversary of the vesting commencement date.

        Each Series B Holder will also have the right to redeem all or a portion of its vested Series B Units in exchange for newly-issued common shares in us with a value equal to its pro rata share of up to 6% of any increase in our equity value (calculated by reference to the 20-day volume weighted average price of our common shares preceding the date of the redemption request) in excess of $2.0 billion. We refer to this right as the Redemption Right. In no event will the aggregate number of newly-issued common shares issued pursuant to the Redemption Right exceed 6% of the total number of our issued and outstanding common shares. Upon the exercise of the Redemption Right, the redeeming member will surrender its Series B Units to IDR LLC for cancellation.

        For additional information, please read "Certain Relationships and Related Party Transactions—Limited Liability Company Agreement of IDR LLC."

Management

        AMGP GP LLC, our general partner ("AMGP GP"), will manage our operations and activities, including, among other things, establishing the quarterly cash distribution for our common shares and cash reserves it believes are prudent to provide for the proper conduct of our business. Antero Midstream Partners GP LLC ("AMP GP"), the general partner of Antero Midstream, will be responsible for the management of Antero Midstream's operations and activities, which are designed to service Antero Resources as the primary beneficiary of Antero Midstream. However, as the managing member of AMP GP, we will appoint all of the members of the board of directors of AMP GP. In addition, we are the sole managing member of IDR LLC. As a result, we will be responsible for the business and affairs of Antero Midstream and IDR LLC, and our general partner will be responsible for exercising on our behalf any rights we have with respect to AMP GP and IDR LLC.

        Our general partner's limited liability company agreement will provide for a board of directors consisting of up to eight members. Following the Reorganization, the Sponsors will collectively own 100% of the membership interest in our general partner and will have the ability to appoint all the members of our general partner's board of directors, including at least three directors that are independent and qualify for service on the audit committee in accordance with applicable NYSE and SEC rules. The limited liability company agreement of our general partner will further provide that the Chief Executive Officer of our general partner will serve as a director and chairman of the board of directors of our general partner.

        For additional information regarding our governance and related matters, please read "Management—Designation of Directors."

Services Agreement

        In connection with the closing of this offering, we, our general partner, IDR LLC and Antero Resources will enter into a services agreement that will govern, among other things, certain administrative services that Antero Resources will provide to us.

        We and our general partner have no employees. All of our officers and other personnel necessary for our business to function (to the extent not outsourced) will be employed by Antero Resources, and our general partner will pay Antero Resources an annual fee for corporate, general and administrative services. This fee will initially be $0.5 million per year and will be subject to an annual CPI-based adjustment, beginning on January 1, 2018. The fee will also be subject to adjustment to reflect any increase in the cost of providing services due to changes in applicable law, rules or regulations and any increase in the scope and extent of the services provided. The fee will not be decreased below the initial fee unless the type or extent of services provided materially decreases. In addition to the general and administrative services provided to us by Antero Resources, we also expect to incur direct annual expenses of approximately $1.5 million per year for recurring costs associated with being a separate publicly traded entity, including expenses associated with (i) compensation for new directors, (ii) incremental director and officer liability insurance, (iii) listing on the NYSE, (iv) investor relations, (v) legal services, (vi) tax services and (vii) accounting services. We will be responsible for all of these direct expenses and income taxes payable by us.

        In addition to the fee and expenses described above, we will reimburse Antero Resources for costs and expenses to the extent that such costs and expenses are directly allocable to the provision of services to us, our general partner, or our subsidiaries (other than Antero Midstream and its subsidiaries), including expenses associated with insurance coverage, recurring costs associated with being a separate publicly traded entity, and taxes, other than payroll taxes, or other direct operating expenses, paid by Antero Resources for our benefit. We will also reimburse our general partner for any additional expenses incurred on our behalf or to maintain our legal existence and good standing. There is no limit on the amount of fees and expenses our general partner may be required to pay to its affiliates on our behalf pursuant to the services agreement. Please read "Certain Relationships and Related Party Transactions" for additional information.

Principal Executive Offices

        Our principal executive offices are located at 1615 Wynkoop Street, Denver, Colorado 80202, and our telephone number is (303) 357-7310. Our website is located at www.anteromidstreamgp.com. We expect to make available our periodic reports and other information filed with or furnished to the SEC free of charge through our website, as soon as reasonably practicable after those reports and other information are electronically filed with or furnished to the SEC. Information on our website or any other website is not incorporated by reference herein and does not constitute a part of this prospectus.

Risk Factors

        An investment in our common shares involves risks associated with our business and our organizational structure. Because of our relationship with Antero Midstream, adverse developments or announcements concerning Antero Midstream could materially adversely affect our business. We have presented below a summary of certain key risk factors that you should consider in evaluating an investment in our common shares. However, this list is not exhaustive and you should read the full discussion of these risks and the other risks described in "Risk Factors." You should consider carefully these risk factors together with all of the other information included in this prospectus before you invest in our common shares.

Risks Inherent in an Investment in us

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Our cash flow will be entirely dependent upon the ability of Antero Midstream to make cash distributions on the IDRs.



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In the future, we may not have sufficient cash to pay our estimated initial quarterly distribution or to increase distributions.



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The assumptions underlying the estimated cash available for distribution that we included in "Our Cash Distribution Policy and Restrictions on Distributions" are inherently uncertain and are subject to significant business, financial, regulatory and competitive risks and uncertainties that could cause actual results to differ materially from those forecasted.



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Our right to receive distributions paid by Antero Midstream on the IDRs may be limited or modified by our general partner without the consent of our shareholders, which may reduce cash distributions to you.



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A reduction in Antero Midstream's distributions will disproportionately affect the amount of cash distributions on the IDRs.

Risks Related to Conflicts of Interest

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Conflicts of interest may arise as a result of our organizational structure and the relationships among us, Antero Midstream, our respective general partners, Antero Resources and other affiliated entities.



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Our partnership agreement defines our general partner's duties to us and contains provisions that reduce the remedies available to our shareholders for actions that might otherwise be challenged as breaches of fiduciary or other duties under state law.



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The Sponsors may have interests that conflict with holders of our common shares.



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Antero Resources does not own our general partner and is under no obligation to adopt a business strategy that favors us.



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Our general partner's affiliates and the Sponsors may compete with us.

Risks Related to Antero Midstream's Business

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Because substantially all of Antero Midstream's revenue is derived from Antero Resources and Antero Resources' capital decisions drive our operations, any development that materially and adversely affects Antero Resources' operations, financial condition or market reputation could have a material and adverse impact on us.



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The amount of cash Antero Midstream can distribute on its units principally depends upon the amount of cash Antero Midstream generates from its operations, which will fluctuate from quarter to quarter.



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Because of the natural decline in production from existing wells, Antero Midstream's success depends, in part, on Antero Resources' ability to replace declining production and Antero Midstream's ability to secure new sources of natural gas from Antero Resources or third parties. Additionally, Antero Midstream's water services are directly associated with Antero Resources' well completion activities, the volumes of produced water from such activities and water needs, which are partially driven by horizontal lateral lengths and the number of completion stages per well. Any decrease in volumes of natural gas that Antero Resources produces or any decrease in the number of wells that Antero Resources completes could adversely affect Antero Midstream's business and operating results.

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The gathering and compression agreement only includes minimum volume commitments under certain circumstances.



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Antero Midstream may not be able to attract third-party gathering and compression volumes or opportunities to provide water services, which could limit its ability to grow and maintain its dependence on Antero Resources.



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Antero Midstream owns a 50% interest in the Joint Venture, which will be operated by MarkWest. While Antero Midstream has the ability to influence certain business decisions affecting the Joint Venture, the success of its investment in the Joint Venture will depend on MarkWest's operation of the Joint Venture.



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If the Joint Venture is not successful or if the Joint Venture does not perform as expected, Antero Midstream's future financial performance may be negatively impacted.

Tax Risks

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The tax treatment of Antero Midstream depends on its status as a partnership for U.S. federal income tax purposes, as well as it not being subject to a material amount of entity-level taxation by individual states. If the Internal Revenue Service were to treat Antero Midstream as a corporation or Antero Midstream becomes subject to additional amounts of entity-level taxation for state or foreign tax purposes, it would reduce the amount of cash available for distribution to us.



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The tax treatment of publicly traded partnerships such as Antero Midstream could be subject to potential legislative, judicial or administrative changes and differing interpretations, possibly on a retroactive basis.

Summary of Conflicts of Interest and Duties

        Our general partner has a duty to manage us in a manner it believes is in the best interests of our partnership and our shareholders. However, the officers and directors of our general partner also have a duty to manage the business of our general partner in a manner they believe is in the best interests of its owners, the Sponsors. As a result of this relationship, conflicts of interest may arise in the future between us and our shareholders, on the one hand, and our general partner and its affiliates, including the Sponsors, on the other hand. For example, our general partner will be entitled to make determinations that affect the amount of cash distributions we make to our shareholders. For a more detailed description of the conflicts of interest and duties of our general partner, please read "Risk Factors—Risks Related to Conflicts of Interest" and "Conflicts of Interest and Fiduciary Duties."

        We anticipate that all of the officers and a majority of the directors of our general partner will also be officers or directors of Antero Resources and Antero Midstream and, as a result, have separate duties that govern their management of the respective businesses of those entities. Consequently, these officers and directors may encounter situations in which their obligations to us, on the one hand, and Antero Resources or Antero Midstream, on the other hand, are in conflict. The resolution of these conflicts may not always be in our best interest or that of our shareholders.

        In addition, our general partner's officers, who also serve as officers of Antero Resources or AMP GP, may face conflicts in allocating their time spent on our behalf, on behalf of Antero Resources and on behalf of Antero Midstream. These time allocations may adversely affect our, Antero Resources' or Antero Midstream's results of operations, cash flows and financial condition. It is unlikely that these allocations will be the result of arms-length negotiations between our general partner, Antero Resources and AMP GP.

        Delaware law provides that Delaware limited partnerships may, in their partnership agreements, expand, restrict or eliminate the fiduciary duties owed by the general partner to limited partners and the partnership. Pursuant to these provisions, our partnership agreement will contain various provisions that

eliminate and replace the fiduciary duties that would otherwise be owed by our general partner with contractual standards governing the duties of our general partner and the methods of resolving conflicts of interest. The effect of these provisions is to restrict the remedies available to our shareholders for actions taken by our general partner that might otherwise constitute breaches of its fiduciary duties. Our partnership agreement will also provide that affiliates of our general partner, including the Sponsors and their respective affiliates, are not restricted from competing with us, and neither our general partner nor its affiliates have any obligation to present business opportunities to us. By purchasing a common share, the purchaser agrees to be bound by the terms of our partnership agreement, and each common shareholder is treated as having consented to various actions and potential conflicts of interest contemplated in our partnership agreement that might otherwise be considered a breach of fiduciary or other duties under Delaware law. Please read "Conflicts of Interest and Fiduciary Duties—Fiduciary Duties of Our General Partner" for a description of the fiduciary duties imposed on our general partner by Delaware law, the replacement of those duties with contractual standards under our partnership agreement and certain legal rights and remedies available to holders of our common shares. For a description of our other relationships with our affiliates, please read "Certain Relationships and Related Party Transactions."

Implications of Being an Emerging Growth Company

        We qualify as an "emerging growth company" as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. An emerging growth company may take advantage of specified reduced reporting and other regulatory requirements for up to five years that are otherwise applicable generally to public companies. These provisions include:

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a requirement to present only two years of audited financial statements and only two years of related Management's Discussion and Analysis;



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exemption from the auditor attestation requirement on the effectiveness of our system of internal control over financial reporting pursuant to Section 404 of the Sarbanes-Oxley Act;



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exemption from compliance with any new requirements adopted by the Public Company Accounting Oversight Board requiring mandatory audit firm rotation or a supplement to the auditor's report in which the auditor would be required to provide additional information about the audit and the financial statements of the issuer; and



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reduced disclosure about executive compensation arrangements in our periodic reports.

        In addition, the JOBS Act provides that an emerging growth company can delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. However, we intend to irrevocably opt out of the extended transition period.

        Except as set forth in the immediately preceding paragraph, we have elected to take advantage of all other applicable JOBS Act provisions. Accordingly, the information that we provide you may be different than what you may receive from other public companies in which you hold equity interests.

        We will cease to be an emerging growth company prior to the last day of the fiscal year following the fifth anniversary of this offering if we (i) have more than $1.07 billion in annual revenues, (ii) issue more than $1.0 billion of non-convertible debt over a three-year period or (iii) qualify as a "large accelerated filer" under the SEC rules, which require, among other things, that we have more than $700 million in market value of our limited partner interests held by non-affiliates on the last business day of the most recently completed second fiscal quarter and have been subject to the reporting requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 for at least 12 calendar months.

The Offering

Summary Historical Financial Data

        Prior to the formation of IDR LLC, our Predecessor, Antero Resources Midstream Management LLC, owned the general partner interest in Antero Midstream and the IDRs, and in connection with IDR LLC's formation, our Predecessor conveyed the IDRs to IDR LLC in exchange for all of the Series A Units. In connection with the Reorganization, our Predecessor will (i) convey its 100% interest in the non-economic general partner interest in Antero Midstream to AMP GP, a wholly owned subsidiary of our Predecessor and (ii) convert into a Delaware limited partnership named Antero Midstream GP LP, which will elect to be taxed as a corporation for U.S. federal income tax purposes. In addition, in connection with the Reorganization, our Predecessor will distribute to the ARI Members all of its cash, including cash distributions received or to be received by ARMM in respect of Antero Midstream's cash distributions on its IDRs for periods prior to the closing of this offering, net of payments for liabilities for income taxes and accrued expenses. Such net cash distribution by ARMM will result in a reduction in members' equity to $0 on a pro forma basis after giving effect to this offering and the Reorganization. Please read "Organizational Structure—Reorganization."

        The historical financial data of our Predecessor reflect our ownership of the general partner interest in Antero Midstream through our interest in AMP GP and our ownership of the IDRs through our ownership of the capital interests of IDR LLC, which we will control as managing member. We have used the equity method to account for our investment in Antero Midstream because we are not the primary beneficiary of Antero Midstream for financial reporting purposes. Additionally, we currently have no separate operating activities apart from those conducted by Antero Midstream, and our cash flows will consist solely of distributions from IDR LLC related to its ownership of the IDRs.

        In the sections below, we present historical financial information for both our Predecessor and Antero Midstream.

Predecessor Summary Historical Financial Data

        The summary historical statements of operations and cash flow data of our Predecessor for the years ended December 31, 2015 and 2016 and the balance sheet data as of December 31, 2015 and 2016 are derived from the audited financial statements of our Predecessor included elsewhere in this prospectus.

Summary Historical Financial Table

Antero Midstream Summary Historical Financial Data

        The summary historical statements of operations and cash flow data of Antero Midstream for the years ended December 31, 2015 and 2016 and the balance sheet data as of December 31, 2015 and 2016 are derived from the audited financial statements of Antero Midstream included elsewhere in this prospectus.