#1PROJECT BRONCO CONFIDENTIAL DISCUSSION MATERIALS October 1, 2018 Confidential - Preliminary Draft BAIRD#2reliminary Draft COMPONENTS OF TOTAL CONSIDERATION UNDER LATEST AMGP PROPOSAL ($ in millions) AR AM 1.6023x Equity Exchange Ratio 1.6350x Equity Exchange Ratio AR Special Committee position on the appropriate exchange ratio for purposes of "Distribution Maintenance" calculation Source: Bloomberg market data as of September 21, 2018. 0.174x Our understanding of the exchange ratio GS/AMGP is using for purposes of "Distribution Maintenance" calculation $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 Cash Consideration 1.776x All-In Exchange Ratio 1.809x 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 1.776x BAIRD Total Transaction Economics 1.833x Total Transaction Economics Project Bronco | Page 2#3DISTRIBUTION MAINTENANCE ANALYSIS 2019 Implied Dividends per Share Under Discussed Scenarios Status Quo AM Distribution / Unit Exchange Ratio Target Used for Distribution Maintenance Calc. Implied 2019 AMGP Dividend Per Share Public AM Unitholder 2019 Dividend Analysis (¹) Dividend per Share Equity Exchange Ratio Total PF Dividend (per current AM unit held) PF Accretion/ (Dilution) to 2019 Status Quo Distribution/Unit (vs. $2.21) AR 2019 Dividend Analysis ( Dividend per Share Equity Exchange Ratio Total PF Dividend (per current AM unit held) PF Accretion/ (Dilution) to 2019 Status Quo Distribution/Unit (vs. $2.21) AR Special Cte Position (1) Based on equity exchange ratio component only, under the base deal structure (as presented in the bridge on the prior page). $2.21 1.6023x $1.379 $1.379 1.6350x $2.255 2.0% $1.379 1.6023x $2.210 0.0% Treliminary Praft GS/AMGP Construct $2.21 1.8087x $1.222 $1.222 1.6350x $1.998 (9.6%) $1.222 1.6023x $1.958 (11.4%) BAIRD Project Bronco | Page 3#4#5#6#7CASH ELECTION ANALYSIS ($ in millions) Public AM Cash Election / Unit $3.00 $2.50 $2.00 $1.50 $1.00 $0.50 $0.00 Additional AR Implied Cash Equity to AR Exchange $0 45 89 134 178 223 268 1.6023x 1.5762x 1.5501x 1.5239x 1.4978x 1.4717x 1.4456x 2019 Total Dividends $219 215 211 208 204 201 197 2019 Dividend Dilution VS. Status Quo 0.0% (1.6%) (3.3%) (4.9%) (6.5%) (8.2%) (9.8%) Source: Bloomberg market data as of September 21, 2018. (1) Assumes 1.776x "all-in" equity exchange ratio and 20-day VWAP for purposes of calculating implied equity exchange. Total Cash to AR (At Merger + 2019-22 Dividends) $1,539 1,563 1,588 1,612 1,636 1,661 1,685 Cash Increase / (Decrease) VS Base Deal 0.0% 1.6% 3.2% 4.8% 6.3% 7.9% 9.5% Preliminary Praft Total Cash to AR + Retained Value of Midstream Holdings $4,287 4,267 4,247 4,226 4,206 4,185 4,165 BAIRD Total Value Increase / (Decrease) VS Base Deal 0.0% (0.5%) (1.0%) (1.4%) (1.9%) (2.4%) (2.9%) Project Bronco | Page 7