#1PROJECT BRONCO CONFIDENTIAL DISCUSSION MATERIALS September 23, 2018. Confidential - Preliminary Draft BAIRD#2SUMMARY OF REVISED PROPOSAL 7 Reflects AMGP letter received Sept. 22 and most up-to-date units counts provided by Antero management ($ and shares in millions) Equity Component Cash Components (assuming 20-day VWAP) Total Exchange Ratio Equity Exchange Ratio per AM Common Unit AM Units Receiving Consideration (¹) New AMGP Shares Issued Merger Cash Consideration Cash per AM Unit AM Units Receiving Merger Consideration Total Merger Cash Consideration Cash Consideration Equivalent Exchange Ratio Special Cash Dividend Special Dividend per AM Unit AM Units Receiving Special Consideration Total Special Dividend Consideration Cash Consideration Equivalent Exchange Ratio "ALL-IN EXCHANGE RATIO" at 20-day VWAP at Last Close Source: Bloomberg market data as of September 21, 2018. Includes 1.1 million LTIP units. I I I I AR 1.6023x 98.870 158.420 AR $3.000 98.870 $296.6 0.174x 98.870 0.000x I AR 1.776x 1.775x ! AM 1.6350x 89.231 145.893 AM $3.000 89.231 $267.7 0.174x $0.415 89.231 $37.0 0.024x AM 1.833x 1.832x Series B 17.354 Treliminary Praft Series B Total Shares 321.667 Total Cash $564.3 $37.0 Existing AMGP Shares AMGP AM 186.209 Stock Prices as of 9/21/18 1 $17.35 30.05 BAIRD Total "AMC" Shares Project Bronco Last Close 20-day VWAP 507.876 $17.27 29.93 Page 1#3HISTORICAL EXCHANGE RATIO ANALYSIS Based on September 21, 2018 closing prices 1.90x 1.80x 1.70x 1.60x 1.50x 1.40x 1.30x 1.20x AMGP IPO 07/26/17 10/18/17 01/11/18 04/05/18 Note: Avg. "Unaffected" represents the average exchange rate from AMGP IPO to 2/23/18, last close to announcement of the special committees. Trellminar. Draft N 06/28/18 All-in to AM: 1.832x BAIRD All-in to AR: 1.775x Current: 1.732x Average "Unaffected": 1.55x 09/21/18 Project Bronco Page 2#4Per AMGP September 12 Letter Equity Exchange Ratio per AM Common Unit AM Units Receiving Consideration New AMGP Shares Issued Per AMGP September 22 Letter Equity Exchange Ratio per AM Common Unit AM Units Receiving Consideration New AMGP Shares Issued SUMMARY CHANGES IN CONSIDERATION Reflects AMGP letters received Sept. 12 and 22 and most up-to-date units counts provided by Antero management Total Share Impact Current AMGP Share Price (9/21/18) Share Value Impact vs. Prior AMGP Proposal Less: Elimination of Series B Dividend Holiday Total Value Impact vs. Prior AMGP Proposal Source: Bloomberg market data as of September 21, 2018. AR 1.6084x 98.870 159.023 AR 1.6023x 98.870 158.420 (0.603) $17.35 ($10.5) ($10.5) AM 1.6084x 89.231 143.519 AM 1.6350x 89.231 145.893 2.374 $17.35 $41.2 $41.2 Series B 18.500 Series B 17.354 (1.146) $17.35 ($19.9) $7.9 ($11.9) Total Shares 321.042 Total Shares Trellminar. Draft 321.667 Existing AMGP Shares 186.209 Existing AMGP Shares 186.209 LEA 17.354 x 1/3 unvested 5.785 x $1.37 $7.948 BAIRD Total "AMC" Shares 507.252 Total 'AMC" Shares Project Bronco 507.876 Units Issued to Series B "AMC" PF 2019 Dividend Page 3#5... REVISED COMPONENTS OF TOTAL CONSIDERATION ($ in millions) AR AM 1.6084x Starting Equity Component 1.6084x Starting Equity Component Source: Bloomberg market data as of September 21, 2018. 0.006x Share Reduction 0.027x Share Increase 1.6023x Equity Exchange Ratio 1.6350x Equity Exchange Ratio 0.174x $3.00/unit cash converted to exchange ratio equivalent based on AMGP 20-day VWAP Cash Consideration 0.174x $3.00/unit cash converted to exchange ratio equivalent based on AMGP 20-day VWAP 1.776x Cash Consideration All-In Exchange Ratio From an all-in exchange ratio perspective, AM is $0.98/unit better off than AR, which is more than offset by its expected tax burden 1.809x Treliminant Draft All-In Exchange Ratio X Special Dividend 0.024x $0.415/unit cash converted to exchange ratio equivalent based on AMGP 20-day VWAP Special Dividend BAIRD 1.776x Total Transaction Economics 1.833x Total Transaction Economics Project BroNICO I Page 4#6PRO FORMA IMPACT ($ in millions, unless otherwise noted) Dividend per AR-Owned AM Unit $5.00 $4.00 $3.00 $2.00 $1.00 $0.00 $3.00 $2.00 $1.00 $0.00 0.0% $0.00 Excludes cash received at close $2.21 $2.21 1.31x 1.19x 2019E 2020E Dividend per AMGP Share $0.49 55.3% $0.89 Accretion/ (Dilution) ($0.09) (3.3%) $1.38 $2.85 $2.76 1.16x 1.16x $0.38 28.4% $1.34 ($0.01) (0.2%) $3.42 $3.41 Accretion/(Dilution) 1.11x 1.11x 2020E 2021E $0.39 22.2% $1.72 $1.74 $2.13 Status Quo 2021E $0.08 2.0% $4.10 $4.18 1.05x 1.05x 2022E $0.39 17.4% $2.22 $2.61 2022E $5.00 $4.00 $3.00 $2.00 $1.00 Dividend per Public AM Unit $0.00 $50 $40 $30 $20 $10 Cantide Clerreliminary. Praft Pro Forma $0 $0.05 2.0% Excludes cash received at close $2.21 $2.26 2019E Cash Flow to Series B $12 $12 96% $24 2019E Accretion/(Dilution) $2.85 $2.81 ($0.04) (1.3%) 2020E $19 $11 55% $30 2019E Source: Antero management projections. Assumes AMGP purchases 100% of AM public units (188.1 million on a fully diluted basis) with a combination of equity and cash; AMGP issues 304.3 million shares to current AM unitholders. Also assumes that AMGP issues 17.354 million shares in exchange for 100% of the Series B units. Further, the 2019 pro forma dividend is adjusted such that dividends to AR-owned AM units are held flat. Accretion/(Dilution) $3.42 $3.48 2020E $0.06 1.8% 2021E $26 $11 44% $37 2021E $4.10 $33 BAIRD $0.17 4.1% 2022E Project Bronco $4.27 $12 37% $45 2022E Page 5#7ECONOMIC IMPACT TO AR ($ in millions, unless otherwise noted) Total Cash to AR from Midstream Holdings $0 $297 At Close I $219 $219 2019 $282 $273 AR 31.2% 2020 Pro Forma Ownership of "AMC" AM 28.7% AMGP 36.7% $338 $337 2021 Status Quo ries 3.4% $405 $414 2022 Pro Forma Undiscounted $1,244 SQ Total Cash Through 2022 $1,539 PF Preliminary Praft $2,971 SQ $1,009 Market Value of Midstream Holdings Assuming Current AMGP Stock Price SQ -$222 $2,749 Source: Antero management projections. Assumes AMGP purchases 100% of AM public units (188.1 million on a fully diluted basis) with a combination of equity and cash; AMGP issues 304.3 million shares to current AM unitholders. Also assumes that AMGP issues 17.354 million shares in exchange for 100% of the Series B units. Further, the 2019 pro forma dividend is adjusted such that dividends to AR-owned AM units are held flat. PV-10 PF +$280 $1,289 PF BAIRD Project Bronco Page 6#8PRO FORMA AMC LEVERAGE ANALYSIS NET DEBT/LTM EBITDA AT YEAR-END 2.3x 3.0x 2018 E Status Quo 3.1x Source: Antero management projections. 2.2x 2.9x 2019E Pro Forma excl. Special Dividend 2.9x 2.2x 2.8x 2.8x 2020E Pro Forma incl. Special Dividend 2.1x 2.6x 2.6x Treliminar. Draft 2021E 2.0x 2.4x 2022E ***** 2.4x Project Bronco BAIRD Page 7