Alcoa Corporation

Investor Presentation

May 2018 Important information

Cautionary statement regarding forward-looking statements

This presentation contains statements that relate to future events and expectations and as such constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include those containing such words as “anticipates,” “believes,” “could,” “estimates,” “expects,” “forecasts,” “goal,” “intends,” “may,” “outlook,” “plans,” “projects,” “seeks,” “sees,” “should,” “targets,” “will,” “would,” or other words of similar meaning. All statements by Alcoa Corporation that reflect expectations, assumptions or projections about the future, other than statements of historical fact, are forward-looking statements, including, without limitation, forecasts concerning global demand growth for bauxite, alumina, and aluminum, and supply/demand balances; statements, projections or forecasts of future or targeted financial results or operating performance; and statements about strategies, outlook, and business and financial prospects. These statements reflect beliefs and assumptions that are based on Alcoa Corporation’s perception of historical trends, current conditions, and expected future developments, as well as other factors that management believes are appropriate in the circumstances. Forward-looking statements are not guarantees of future performance and are subject to known and unknown risks, uncertainties, and changes in circumstances that are difficult to predict. Although Alcoa Corporation believes that the expectations reflected in any forward-looking statements are based on reasonable assumptions, it can give no assurance that these expectations will be attained and it is possible that actual results may differ materially from those indicated by these forward-looking statements due to a variety of risks and uncertainties. Such risks and uncertainties include, but are not limited to: (a) material adverse changes in aluminum industry conditions, including global supply and demand conditions and fluctuations in London Metal Exchange-based prices and premiums, as applicable, for primary aluminum, alumina, and other products, and fluctuations in indexed-based and spot prices for alumina; (b) deterioration in global economic and financial market conditions generally; (c) unfavorable changes in the markets served by Alcoa Corporation; (d) the impact of changes in foreign currency exchange rates on costs and results; (e) increases in energy costs; (f) declines in the discount rates used to measure pension liabilities or lower-than-expected investment returns on pension assets, or unfavorable changes in laws or regulations that govern pension plan funding; (g) the inability to achieve the level of revenue growth, cash generation, cost savings, improvement in profitability and margins, fiscal discipline, or strengthening of competitiveness and operations anticipated from restructuring programs and productivity improvement, cash sustainability, technology advancements, and other initiatives; (h) the inability to realize expected benefits, in each case as planned and by targeted completion dates, from acquisitions, divestitures, facility closures, curtailments, restarts, expansions, or joint ventures; (i) political, economic, trade, and regulatory risks in the countries in which Alcoa Corporation operates or sells products; (j) the outcome of contingencies, including legal proceedings, government or regulatory investigations, and environmental remediation; (k) the impact of cyberattacks and potential information technology or data security breaches; and (l) the other risk factors discussed in Item 1A of Alcoa Corporation’s Form 10-K for the fiscal year ended December 31, 2017 and other reports filed by Alcoa Corporation with the U.S. Securities and Exchange Commission (SEC). Alcoa Corporation disclaims any obligation to update publicly any forward-looking statements, whether in response to new information, future events or otherwise, except as required by applicable law. Market projections are subject to the risks discussed above and other risks in the market.

Any information contained in the following slides that has been previously publicly presented by Alcoa speaks as of the date that it was originally presented, as indicated. Alcoa is not updating or affirming any of such information as of today’s date. The provision of this information shall not imply that the information has not changed since it was originally presented.

2 Important information (continued)

Non-GAAP financial measures

Some of the information included in this presentation is derived from Alcoa’s consolidated financial information but is not presented in Alcoa’s financial statements prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). Certain of these data are considered “non-GAAP financial measures” under SEC rules. Alcoa Corporation believes that the presentation of non-GAAP financial measures is useful to investors because such measures provide both additional information about the operating performance of Alcoa Corporation and insight on the ability of Alcoa Corporation to meet its financial obligations by adjusting the most directly comparable GAAP financial measure for the impact of, among others, “special items” as defined by the Company, non-cash items in nature, and/or nonoperating expense or income items. The presentation of non-GAAP financial measures is not intended to be a substitute for, and should not be considered in isolation from, the financial measures reported in accordance with GAAP. Reconciliations to the most directly comparable GAAP financial measures and management’s rationale for the use of the non-GAAP financial measures can be found in the appendix to this presentation.

This presentation includes a range of forecasted 2018 Adjusted EBITDA for the Company. Alcoa Corporation has not provided a reconciliation of this forward-looking non- GAAP financial measure to the most directly comparable GAAP financial measure for the following reasons. The Company’s financial results are heavily dependent on market-driven factors, such as LME-based prices for aluminum, index- and spot-based prices for alumina, and foreign currency exchange rates. As such, the Company may experience significant volatility on a daily basis related to its forecasted Adjusted EBITDA. Management applies estimated sensitivities, such as relating to aluminum and alumina prices and foreign currency exchange rates, to the components that comprise Adjusted EBITDA. However, a similar analysis cannot be performed relating to the components necessary to reconcile Adjusted EBITDA to the most directly comparable GAAP financial measure without unreasonable effort due to the additional variability and complexity associated with forecasting such items. Consequently, management believes such reconciliation would imply a degree of precision that would be confusing and/or potentially misleading to investors. Financial presentation information

On January 1, 2018, Alcoa Corporation adopted guidance issued by the Financial Accounting Standards Board to the presentation of net periodic benefit cost related to pension and other postretirement benefit plans. This guidance requires the non-service cost components of net periodic benefit cost to be reported separately from the service cost component in an entity’s income statement. Additionally, this guidance is required to be applied retrospectively. Accordingly, previously reported amounts for Cost of goods sold, Selling, general administrative, and other expenses, and Other expenses (income), net on Alcoa Corporation’s consolidated income statement have been recast to reflect these changes. As a result, previously reported amounts for Adjusted EBITDA on both a consolidated basis and for each of the Company’s three segments have been updated to reflect these changes. See the appendix for additional information. Glossary of terms

A glossary of abbreviations and defined terms used throughout this presentation can be found in the appendix. 3 Strong start as new independent company

Company overview

Strategic priorities Keys to Alcoa

Global network of world-class assets; well-positioned across market events

Disciplined capital allocation framework; actions and investments aligned to support future growth

World-class governance with management incentives aligned to stockholder’s interests

4 World class, low cost assets

2017 Cost curve and business position

Bauxite Alumina Aluminum

1st Quartile 1st Quartile 2nd Quartile

▪ World’s second largest bauxite ▪ Largest alumina refiner and largest ▪ Top 10 global aluminum smelter miner, with a first quartile cost long position, outside of China with mid-second quartile cost position position ▪ Low cost, global network of ▪ Long-lived assets with low-cost refineries with a collective mid-first ▪ Segment includes Warrick rolling growth opportunities quartile cost position mill and Brazilian energy assets

Source for 2017 cost curve and business position: CRU and Alcoa analysis. 5 Large, globally diverse bauxite portfolio

Bauxite segment information

2017 Production by country, Mdmt Key considerations

▪ Globally diverse, large, low-cost bauxite portfolio, advantaged in a high caustic price environment ▪ Strategically located in proximity to major Saudi Arabia: 0.9 Atlantic and Pacific markets Guinea: 3.2 ▪ Operational control of four mines (two in Australia and two in Brazil) ▪ Ownership interest in three additional mines Brazil: 8.5 (Brazil, Guinea and Saudi Arabia) ▪ Outside of the AWAC JV, Alcoa owned Australia: 33.2 approximately 1.5 Mdmt of production in Brazil in 2017

6 Premier alumina refining portfolio

Alumina segment information

Alcoa consolidated operating capacity, kmt Key considerations

Current Operating Ownership ▪ World’s largest, low-cost third-party alumina Facility Country Capacity Consideration business Kwinana Australia 2,190 AWAC ▪ Highly efficient consumer of caustic soda Pinjarra Australia 4,234 AWAC ▪ Mid-first quartile cost curve position allows Wagerup Australia 2,555 AWAC for cash flow generation through all points in the commodity cycle Poços de Caldas Brazil 176 Alcoa 72% AWAC rd São Luís Brazil 1,890 ▪ ~95% of 3 party smelter-grade alumina 28% Alcoa shipments priced on API/spot San Ciprián Spain 1,500 AWAC ▪ Annualized EBITDA sensitivity: $80M for Point Comfort U.S. - AWAC +$10/mt API (consolidated basis) Total 12,545 ▪ 2,519 kmt of curtailed refining capacity Ras Al Khair1 Saudi Arabia 452 AWAC globally

1. The Company’s proportionate share of earnings from its equity investment in the Saudi Arabian joint venture does not impact adjusted EBITDA. 7 Transformed and integrated aluminum business

Aluminum segment information

Integrated aluminum value chain Key considerations

▪ Transformed the smelting portfolio by divesting, closing or curtailing uneconomic assets to move into the mid-2nd quartile on the global cost curve ▪ ~70% of electricity consumed by our smelters is generated by hydroelectric power ▪ Operating 2,148 kmt of smelting capacity with optionality to restart ~900 kmt of curtailed capacity ▪ Segment includes aluminum smelting, ▪ Restarting 161 kmt of smelting capacity at casting, and rolling operations, along with our Warrick facility to reduce complexity and ownership interests in several hydroelectric improve overall profitability of the complex energy assets in Brazil ▪ Brazilian hydroelectric assets generated over $90 million in adjusted EBITDA in 2017 8 Alcoa uniquely positioned across products, geographies

2017 Bauxite production, and refining and smelting capacity, kmt

North America South America Europe, Middle East1 & Africa Australia

33,200 Operating Curtailed 8,979 8,500

33,200 4,100 8,500 8,979 2,305 2,280 1,712 214 1,952 4,100 1,220 2,305 709 30 2,066 268 1,952 56 197 1,003 1,164 167 Bauxite Alumina Aluminum Bauxite Alumina Aluminum Bauxite Alumina Aluminum Bauxite Alumina Aluminum

▪ Well-balanced global portfolio with long positions across all three segments ▪ Globally diverse bauxite portfolio; advantaged in a high caustic price environment ▪ Alumina refineries with large strategic positions in both the Atlantic and Pacific markets ▪ Cost competitive, global network of smelters with optionality to restart capacity in each region

1. Includes Alcoa’s equity share of alumina refining and aluminum smelting capacity for our Saudi Arabian joint venture. 9 Balanced capital allocation approach for 2018

Capital allocation strategy

2018 Framework Disciplined approach for 2018

Maintain liquidity ▪ Target holding $1 billion in cash on hand Greater than $1B cash balance ▪ Maintain the assets by spending close to $300 million in sustaining capital expenditures Return cash to Sustain the ▪ Invest approximately $150 million in stockholders operations return-seeking capital projects 50% excess ~$300M in sustaining cash above $1B capital expenditures ▪ Provide additional funding of approximately $300 million into pension plans in 2018 Optimize Drive value ▪ Split excess cash above $1 billion liabilities creation balance, 50% to reduce leverage and ~$300M plus 50% ~$150M in return-seeking excess cash above $1B capital expenditures 50% returns to stockholders

10 World-class governance profile

Important governance factors

Independent non-executive chairman ✓ Annually elected directors ✓ Independent Board committees ✓ Majority vote standard in uncontested elections ✓ Director retirement and resignation policies ✓ Proxy access ✓ High “say-on-pay” approval ✓ Stock ownership guidelines for executives and directors ✓ Stockholder ability to call special meetings1 ✓

1. Stockholders owning 25% for at least one year. 11 Management incentives aligned to stockholder’s interests

Executive compensation overview

Example policies and practices Components of compensation program

▪ What we do: ▪ Three primary components – base salary, ▪ Pay for performance annual incentive compensation and long- term incentive awards ▪ Maintain robust stock ownership guidelines ▪ Mix of long-term incentive awards for named ▪ Schedule equity award grants to promote executive officers transparency and consistency Performance-based restricted share units ▪ Clawback policies incorporated into plans Time-vested stock options 20% Time-based restricted share units ▪ What we don’t do: 20% 60% ▪ No employment contracts ▪ No dividend equivalents on stock options and unvested restricted share units ▪ Long-term performance-based equity awards ▪ No discounting of stock options or repricing are tied to return on capital improvement and of underwater stock options (including relative total stockholder return compared to cash-outs) the S&P 500 12 Strong start as new independent company

Company overview

Strategic priorities Keys to Alcoa

Global network of world-class assets; well-positioned across market events

Disciplined capital allocation framework; actions and investments aligned to support future growth

World-class governance with management incentives aligned to stockholder’s interests

13 1Q18 Financial Results and Other Information as presented on April 18, 2018 1Q18 Income statement

Quarterly income statement Prior Year Sequential M, Except realized prices and per share amounts 1Q17 4Q17 1Q18 Change Change

Realized primary aluminum price ($/mt) $2,080 $2,365 $2,483 $403 $118 Realized alumina price ($/mt) $325 $406 $385 $60 $(21) Revenue $2,655 $3,174 $3,090 $435 $(84) Cost of goods sold $2,023 $2,339 $2,381 $358 $42 SG&A and R&D expenses $78 $78 $75 $(3) $(3) Adjusted EBITDA $554 $757 $634 $80 $(123) Depreciation, depletion and amortization $179 $187 $194 $15 $7 Other expenses / (income), net $(79) $30 $21 $100 $(9) Interest expense $26 $27 $26 $- $(1) Restructuring and other charges $10 $297 $(19) $(29) $(316) Tax provision $110 $272 $138 $28 $(134) Net income (loss) $308 $(56) $274 $(34) $330 Less: Net income attributable to noncontrolling interest $83 $140 $124 $41 $(16) Net income (loss) attributable to Alcoa Corporation $225 $(196) $150 $(75) $346 Diluted earnings (loss) per share $1.21 $(1.06) $0.80 $(0.41) $1.86 Diluted shares outstanding 186.3 185.1 188.5 2.2 3.4

15 Special items total $(5) million

Breakdown of special items by income statement classification – gross basis

M, Except per share amounts 1Q17 4Q17 1Q18 Description of significant 1Q18 special items

Net income (loss) attributable to Alcoa Corporation $225 $(196) $150

Diluted earnings (loss) per share $1.21 $(1.06) $0.80

Special items $(108) $391 $(5)

Cost of goods sold - $39 $19 Warrick smelter restart costs

Selling, general administrative and other - - -

Restructuring and other charges $10 $297 $(19) Pension and OPEB actions in U.S. and Canada

Interest expense - - -

Other expenses / (income), net $(124) $(1) $(17) Mark-to-market energy contracts

Tax provision $3 $68 $12 Taxes on special items

Noncontrolling interest $3 $(12) -

Adjusted net income attributable to Alcoa Corporation $117 $195 $145

Adjusted diluted earnings per share $0.63 $1.04 $0.77

16 Adjusted EBITDA excluding special items of $653 million

Quarterly income statement excluding special items

Prior Year Sequential M, Except realized prices and per share amounts 1Q17 4Q17 1Q18 Change Change Realized primary aluminum price ($/mt) $2,080 $2,365 $2,483 $403 $118 Realized alumina price ($/mt) $325 $406 $385 $60 $(21) Revenue $2,655 $3,174 $3,090 $435 $(84) Cost of goods sold $2,023 $2,300 $2,362 $339 $62 COGS % revenue 76.2% 72.5% 76.4% 0.2% pts. 3.9% pts. SG&A and R&D expenses $78 $78 $75 $(3) $(3) SG&A and R&D % revenue 2.9% 2.5% 2.4% (0.5)% pts. (0.1)% pts. Adjusted EBITDA $554 $796 $653 $99 $(143) Depreciation, depletion and amortization $179 $187 $194 $15 $7 Other expenses / (income), net $45 $31 $38 $(7) $7 Interest expense $26 $27 $26 $- $(1) Tax provision $107 $204 $126 $19 $(78) Operational tax rate 35.3% 37.1% 31.9% (3.4)% pts. (5.2)% pts. Adjusted net income $197 $347 $269 $72 $(78) Less: Net income attributable to noncontrolling interest $80 $152 $124 $44 $(28) Adjusted net income attributable to Alcoa Corporation $117 $195 $145 $28 $(50) Adjusted diluted earnings per share $0.63 $1.04 $0.77 $0.14 $(0.27) Diluted shares outstanding 186.3 188.0 188.5 2.2 0.5

17 1Q18 Financial summary

Three months ending March 31, 2018, excluding special items

Corporate $M inventory Other Bauxite Alumina Aluminum4,5 Transformation accounting corporate Total

Total revenue1 $296 $1,368 $2,115 $19 $(708) - $3,090 Third-party revenue $47 $914 $2,111 $18 - - $3,090 Adjusted EBITDA2 $110 $392 $153 $(2) $31 $(31) $653 Adjusted EBITDA margin % 37.2% 28.7% 7.2% - - - 21.1%

Depreciation, depletion and amortization $29 $53 $106 $1 - $5 $194 Other expenses / (income), net3 - $1 - - - $37 $38 Interest expense $26 Provision for income taxes $126

Adjusted net income $269

Net income attributable to noncontrolling interest $124 Adjusted net income attributable to Alcoa Corp. $145

1. Intersegment eliminations included in Corporate inventory accounting. 2. Includes the Company’s proportionate share of earnings from equity investments in certain bauxite mines, hydroelectric generation facilities, and an aluminum smelter located in Brazil, Canada, and/or Guinea. 3. Amounts for Alumina and Aluminum represent the Company’s proportionate share of earnings from its equity investment in the Saudi Arabian joint venture. 4. Flat-rolled aluminum shipments, revenue, and adjusted EBITDA were 0.13 Mmt, $429M and $11M, respectively. 5. Third-party energy sales volume, revenue and adjusted EBITDA in Brazil were 885 GWh, $45M and $25M, respectively. 18 1Q18 Adjusted EBITDA drivers

Adjusted EBITDA excluding special items sequential changes, $M

78 $796 61 36 (146) $653 (24) (40) (46) (45) (17)

4Q17 Metal API Currency Volume Price / Operational Energy Raw Other 1Q18 Prices Mix Impacts Materials

19 1Q18 Adjusted EBITDA drivers by segment

Sequential adjusted EBITDA excl. special items change impacts by segment vs. 4Q17, $M

Adj. Adj. EBITDA Metal Op. Raw EBITDA Segment 4Q17 Prices API Currency Volume Price/Mix Impacts Energy Materials Other 1Q18

Bauxite $105 - - (3) (16) 3 (1) (1) - 23 $110

Alumina $562 - (144) (9) (22) 55 (22) (1) (14) (13) $392

Aluminum $246 64 (113) (12) (8) 3 (17) 38 (31) (17) $153

Segment $913 64 (257) (24) (46) 61 (40) 36 (45) (7) $655 Total

20 Segment and total adjusted EBITDA information

Adjusted EBITDA excluding special items breakdown

Segment information, $M Total adjusted EBITDA information, $M

4Q17 1Q18 4Q17 1Q18 Change -30% Segment total $913 $655 $(258) $562 Transformation 10 (2) (12) $392 -38% Corporate inventory accounting1 (95) 31 126 +5% $246 $153 Other corporate (32) (31) 1 $105 $110 Total adjusted EBITDA $796 $653 $(143)

Bauxite Alumina Aluminum

1Q18 Segment Adj. EBITDA Margin % 37.2% 28.7% 7.2% Change vs. 4Q17, 2.9% pts. -8.3% pts. -4.3% pts. Margin %

1. Includes intercompany eliminations, and impact from both LIFO and metal price lag. 21 Cash summary

Quarterly cash comparison and cash flows, $M

Quarter ending cash balance Free cash flow and change in cash

1Q17 2Q17 3Q17 4Q17 1Q18 +239 (162) Cash provided from operations $74 $311 $384 $455 $55 1,358 +165 Capital expenditures (71) (88) (96) (150) (74) 1,196 +150 1,119 Free cash flow $3 $223 $288 $305 $(19) (49) 954 853 804 1Q17 2Q17 3Q17 4Q17 1Q18

Cash provided from operations $74 $311 $384 $455 $55

Cash used for financing (260) (78) (115) (53) (147)

Cash provided from (used for) investing1 131 (87) (100) (170) (74)

Effect of exchange rate changes on cash1 6 4 (4) 7 4

Net change in cash1 $(49) $150 $165 $239 $(162)

4Q16 1Q17 2Q17 3Q17 4Q17 1Q18

1. On January 1, 2018, Alcoa adopted changes issued by the Financial Accounting Standards Board to the presentation of restricted cash in the statement of cash flows. For these three line items, there was no impact to the 1Q18 and 4Q17 amounts. The impact to these three line items for 1Q17, 2Q17, and 3Q17 was not material. As a result, the amounts reflected in the table for 1Q17, 2Q17, and 3Q17 are as previously reported. 22 Balance sheet summary

Key financial metrics as of March 31, 2018

1Q18 Days Cash working capital $1,196M 18 Days

1Q18 Capital 1Q18 Annualized expenditures1 return on capital $74M 8.4%

Net debt-to-LTM Pension & OPEB adjusted EBITDA net liability2 0.11x $3.3B

1. $18M in return-seeking capital expenditures and $56M in sustaining capital expenditures 2. U.S. and Canadian salaried pension plans and U.S. salaried OPEB plan remeasured as of January 31, 2018 due to retirement benefit changes. 23 2018 Outlook

FY18 Key metrics

Total shipments Adjusted EBITDA excl. special items impacts 1Q18 Actual FY18 Outlook 1Q18 Actual FY18 Outlook

Bauxite (Mdmt) 11.5 47.5 – 48.5 Adjusted EBITDA excl. special items $0.7B $3.5 – $3.7B1

Alumina (Mmt) 3.5 13.8 – 14.0 Transformation EBITDA impacts $(2)M ~ $(30)M

Aluminum (Mmt) 0.8 3.1 – 3.3 Corporate inventory EBITDA impacts $31M ~ $(60)M

Other corporate EBITDA impacts $(31)M ~ $(140)M Cash flow impacts 1Q18 Actual FY18 Outlook Other income statement excl. special items impacts Minimum required pension/OPEB funding $67M ~ $450M 1Q18 Actual FY18 Outlook

Additional pension funding – ~ $300M Non-operating pension/OPEB expense $38M ~ $160M

Return-seeking capital expenditures2 $18M ~ $150M Depreciation, depletion and amortization $194M ~ $775M

Sustaining capital expenditures2 $56M ~ $300M Interest expense $26M ~ $110M

DOJ / SEC (final payment January 2018) $74M $74M Operational tax rate 31.9% ~ 35%

Environmental and ARO payments3 $25M $110M – $130M Net income of noncontrolling interest $124M 40% of AWAC NI

1. Information is as presented on April 18, 2018 and is not being updated as of the date of this presentation; includes1Q18 actual results; outlook for unpriced sales at $2,300 LME, $500 API, $0.21 Midwest premium and updated regional premiums and currencies. 2. AWAC portion of FY18 Outlook: ~55% of return-seeking capital expenditures, and ~60% of sustaining capital expenditures. 3. Environmental remediation reserve balance of $284M at March 31, 2018. Carrying value of ARO liability as of March 31, 2018 was $732M. 24 Aluminum value chain

1Q18 Alcoa product shipments by segment, Mmt

Bauxite Alumina Aluminum

0.8

32% 100% Aluminum 3rd Party

3.5

91% 68% Alumina 3rd Party

11.5

9% Bauxite 3rd Party

25 Composition of alumina and aluminum production costs

Alcoa 1Q18 production cash costs

Alumina refining Input Inventory Pricing Estimated Annual Cost Flow Convention Cost Sensitivity

Bauxite Caustic Soda 5 - 6 Months Quarterly $9M per $10/dmt Conversion 31% 36%

Natural Gas1 N/A N/A N/A

5% 15% Fuel Oil 1 - 2 Months Prior Month $3M per $1/bbl Fuel Oil 13% Caustic Natural Gas

Aluminum smelting Input Inventory Pricing Estimated Annual Conversion Cost Flow Convention Cost Sensitivity 15% Materials Alumina ~2 Months 30-day lag to API $43M per $10/mt 6% Alumina 42% Spot, Quarterly & Petroleum Coke 1 - 2 Months $7M per $10/mt 23% Semi-annual Power Spot, Quarterly & Coal Tar Pitch 1 - 2 Months $1.5M per $10/mt 14% Semi-annual Carbon

1. Australia is priced on a rolling 16 quarter average. 26 2018 Business information

Estimated annual EBITDA sensitivities

$M AUD BRL CAD EUR ISK NOK LME API Midwest Europe Japan + 0.01 + 0.10 + 0.01 + 0.01 + 10 + 0.10 Segment + $100/mt + $10/mt + $100/mt + $100/mt + $100/mt USD/AUD BRL/USD CAD/USD USD/EUR ISK/USD NOK/USD

Bauxite (3) 4

Alumina 119 (16) 6 (1)

Aluminum 203 (39) 106 102 24 (1) (3) 3 (4) 6 3

Total 203 80 106 102 24 (20) 7 3 (5) 6 3

Pricing conventions Regional premium breakdown

Primary aluminum % of Segment 3rd-Party Revenue Regional premiums 2018 shipments

Bauxite • Negotiated prices Midwest ~45%

• ~95% of third-party smelter-grade alumina priced on API/Spot Alumina Rotterdam Duty Paid ~45% • API based on prior month average of spot prices

• LME + Regional Premium + Product Premium Aluminum • Primary aluminum 15-day lag; flat rolled aluminum 30-day lag CIF Japan ~10% • Brazilian hydroelectric sales at market prices

27 Pension and OPEB summary

Pension and OPEB net liability and financial impacts

Net liability as of March 31, 20181 Estimated financial impacts, $M

Expense impact 2018 OPEB Segment pension ~85% Total Segment OPEB ~5% $1.2B U.S. Corporate ~10% $1.2 Pension Total adj. EBITDA impact ~$65M U.S. Non-operating ~$160M $1.8 Total 2 $2.1B Special items (curtailment/settlement) ~$152M Total expense impact ~$377M ROW $0.3 Cash flow impact 2018 Pension funding status as of December 31, 2017 Minimum required pension funding ~40%  U.S. ERISA ~83% Additional pension funding ~40%  GAAP Worldwide ~70% OPEB payments ~20% Total cash impact ~$750M U.S. pension contributions currently not tax deductible 1. U.S. and Canadian salaried pension plans and U.S. OPEB plan remeasured as of January 31, 2018 due to plan changes. All other pension and OPEB valuations as of December 31, 2017. 2. Includes impacts from previously announced U.S. and Canadian pension and OPEB plan changes, and impact from annuitization of certain Canadian pension plan benefits. 28 Market outlook

Projected 2018 market balances

Bauxite Alumina Aluminum (3rd-party seaborne) (smelter grade) (primary)

2018 Outlook Balanced Deficit Deficit

2018 Supply/Demand Balance, Mmt

Global 1 to 6; stockpile growth -1.1 to -0.3; deficit -1.0 to -0.6; deficit

China -70 to -67; deficit -2.5 to -2.1; deficit 1.0 to 1.2; surplus

World ex-China 68 to 73; surplus 1.4 to 1.8; surplus -2.0 to -1.8; deficit

Demand growth, 2018 vs. 2017 Stockpile growth; Indonesia and Balances before Chinese • Global = 4.25 to 5.25% 2018 Notes Guinea supply growth alumina imports of 1.5 Mmt • China = 5.75 to 6.25% • World ex-China = 3.25 to 3.75%

Source: Alcoa analysis, CRU, Wood Mackenzie, CM Group, IAI, CNIA, NBS, Aladdiny, Bloomberg. Pre-trade balances. Information is as presented on April 18, 2018 and is not being updated as of the date of this presentation. 29 Production and capacity information

Alcoa Corporation annual consolidated amounts

Bauxite production, Mdmt Alumina refining, kmt Aluminum smelting, kmt

2017 Mine Country Production Facility Country Capacity Curtailed Facility Country Capacity Curtailed

Darling Range Australia 33.2 Kwinana Australia 2,190 - Portland Australia 197 30

Juruti Brazil 5.6 Pinjarra Australia 4,234 - São Luís Brazil 268 268

Poços de Caldas Brazil 0.2 Wagerup Australia 2,555 - Baie Comeau Canada 280 -

Trombetas Brazil 2.7 Poços de Caldas Brazil 390 214 Bécancour Canada 310 207

Boké Guinea 3.2 São Luís Brazil 1,890 - Deschambault Canada 260 -

Al Ba’itha1 Saudi Arabia 0.9 San Ciprián Spain 1,500 - Fjarðaál Iceland 344 -

Total 45.8 Point Comfort U.S. 2,305 2,305 Lista Norway 94 -

Total 15,064 2,519 Mosjøen Norway 188 -

Ras Al Khair1 Saudi Arabia 452 - Avilés Spain 93 32

La Coruña Spain 87 24

San Ciprián Spain 228 -

Intalco U.S. 279 49

Massena West U.S. 130 -

Warrick2 U.S. 269 269

Wenatchee U.S. 184 184

Total 3,211 1,063

Ras Al Khair1 Saudi Arabia 186 -

1. The Company’s proportionate share of earnings from its equity investment in the Saudi Arabian joint venture does not impact adjusted EBITDA. 2. Restarting 161 kmt of curtailed capacity to be completed in the second quarter of 2018. 30 Appendix & Reconciliations Investments summary

P&L Location Ownership Carrying Value as of of Equity 4 Investee Country Nature of Investment Interest March 31, 2018 Earnings Ma’aden Aluminum Company1 Saudi Arabia Aluminum smelter 25.1%

Ma’aden Bauxite and Alumina Company1 Saudi Arabia Bauxite mine and Alumina refinery 25.1%5

Ma’aden Rolling Company1 Saudi Arabia Aluminum rolling mill 25.1%

Subtotal Ma’aden $885M Other Expenses / (Income)

Halco Mining, Inc.2 Guinea Bauxite mine 45%5

Energetica Barra Grande S.A. Brazil Hydroelectric generation facility 42.18%

Mineração Rio do Norte S.A. Brazil Bauxite mine 18.2%5

Pechiney Reynolds Quebec, Inc.3 Canada Aluminum smelter 50%

Consorcio Serra do Facão Brazil Hydroelectric generation facility 34.97%

Manicouagan Power Limited Partnership Canada Hydroelectric generation facility 40%

Subtotal other $528M COGS

Total investments $1,413M

1. Alcoa Corporation has an investment in a joint venture related to the ownership and operation of an integrated aluminum complex (bauxite mine, alumina refinery, aluminum smelter, and rolling mill) in Saudi Arabia. The joint venture is owned 74.9% by the Saudi Arabian Mining Company (known as “Ma’aden”) and 25.1% by Alcoa Corporation. 2. Halco Mining, Inc. owns 100% of Boké Investment Company, which owns 51% of Compagnie des Bauxites de Guinée. 3. Pechiney Reynolds Quebec, Inc. owns a 50.1% interest in the Bécancour smelter in Quebec, Canada thereby entitling Alcoa Corporation to a 25.05% interest in the smelter. Through two wholly-owned Canadian subsidiaries, Alcoa Corporation also owns 49.9% of the Bécancour smelter. 4. Each of the investees either owns the facility listed or has an ownership interest in an entity that owns the facility listed. 5. A portion or all of each of these ownership interests are held by wholly-owned subsidiaries that are part of AWAC. 32 Bauxite mines

Expiration Probable Proven Available Reactive Silica 2017 Annual Owners’ Mining Rights Date of Reserves2 Reserves2 Alumina Content Content (%) Production 1 Country Project (% Entitlement) Mining Rights (Mdmt) (Mdmt) (%) AvAl2O3 RxSiO2 (Mdmt) 3 Australia Darling Range Alcoa of Australia Limited (“AofA”) 2024 109.2 70.0 32.8 1.0 33.2 Mines ML1SA (100%) 4 5 Brazil Poços de Caldas Alcoa Alumínio S.A. (“Alumínio”) 2020 0.2 1.5 39.3 4.6 0.2 (100%)

5 5 Juruti RN101, RN102, Alcoa World Alumina Brasil Ltda. 2100 22 3.8 46.6 4.4 5.6 3 RN103, RN104, #34 (“AWA Brasil”) (100%) Equity interests: 6 5 Brazil Trombetas Mineração Rio do Norte S.A. (“MRN”) 2046 2.7 6.1 49.0 5.1 2.7 (18.2%)

8 9 9 Guinea Boké Compagnie des Bauxites de Guinée 2038 36.0 37.8 TAl2O3 TSiO2 3.2 7 (“CBG”) (22.95%) 48.8 1.7

11 11 Kingdom of Al Ba’itha Ma’aden Bauxite & Alumina Company 2037 33.8 18.1 TAA TSiO2 0.9 10 Saudi Arabia (100%) 49.4 8.7

1. This table shows only the AWAC and/or Alcoa Corporation share (proportion) of reserve and annual production tonnage. 2. Reserves are in place for all mines other than Juruti and Trombetas, where the ore is beneficiated and a wash recovery factor is applied. 3. This entity is part of the AWAC group of companies and is ultimately owned 60% by Alcoa Corporation and 40% by Alumina Limited. 4. Alumínio is ultimately owned 100% by Alcoa Corporation. 5. Brazilian mineral legislation does not establish the duration of mining concessions. The concession remains in force until the exhaustion of the deposit. The company estimates that (i) the concessions at Poços de Caldas will last at least until 2020, (ii) the concessions at Trombetas will last until 2046 and (iii) the concessions at Juruti will last until 2100. Depending, however, on actual and future needs, the rate at which the deposits are exploited and government approval is obtained, the concessions may be extended to (or expire at) a later (or an earlier) date. 6. Alumínio holds an 8.58% total interest, AWA Brasil holds a 4.62% total interest and AWA LLC holds a 5% total interest in MRN. MRN is jointly owned with affiliates of Rio Tinto Alcan Inc., Companhia Brasileira de Alumínio, Vale, South32, and Norsk Hydro. Alumínio, AWA Brasil, and AWA LLC purchase bauxite from MRN under long-term supply contracts. 7. AWA LLC owns a 45% interest in Halco (Mining), Inc. (“Halco”). Halco owns 100% of Boké Investment Company, a Delaware company, which owns 51% of CBG. The Guinean Government owns 49% of CBG, which has the exclusive right through 2038 to develop and mine bauxite in certain areas within an approximately 2,939 square-kilometer concession in northwestern Guinea. 8. AWA LLC and Alũmina Española, S.A. have bauxite purchase contracts with CBG that expire in 2033. Before that expiration date, AWA LLC and Alũmina Española, S.A expect to negotiate extensions of their contracts as CBG will have concession rights until 2038. The CBG concession can be renewed beyond 2038 by agreement of the Government of Guinea and CBG should more time be required to commercialize the remaining economic bauxite within the concession. 9. Guinea—Boké: CBG prices bauxite and plans the mine based on the bauxite content of total alumina (TAl2O3) and total silica (TSiO2). 10. Ma’aden Bauxite & Alumina Company is a joint venture owned by Saudi Arabian Mining Company (“Ma’aden”) (74.9%) and AWA Saudi Limited (25.1%). AWA Saudi Limited is part of the AWAC group of companies and is ultimately owned 60% by Alcoa Corporation and 40% by Alumina Limited. 11. Kingdom of Saudi Arabia—Al Ba’itha: Bauxite reserves and mine plans are based on the bauxite qualities of total available alumina (TA.Al2O3) and total silica (TSiO2). 33 Alumina refineries

Alcoa Corporation Nameplate Capacity1 Consolidated Capacity2 Country Facility Owners (% of Ownership) (kmt / year) (kmt / year) 3 Australia Kwinana AofA (100%) 2,190 2,190 Pinjarra AofA (100%) 4,234 4,234 Wagerup AofA (100%) 2,555 2,555

4 Brazil Poços de Caldas Alumínio (100%) 390 390

3 São Luís (“Alumar”) AWA Brasil (39%), 3,500 1,890 5 Rio Tinto Alcan Inc. (10%) Alumínio (15%) 5 South32 (36%)

3 Spain San Ciprián Alúmina Española, S.A. (100%) 1,500 1,500

3 6 United States Point Comfort, TX AWA LLC (100%) 2,305 2,305

Total 16,674 15,064

Equity interests:

Kingdom of Saudi Arabia Ras Al Khair Ma'aden Bauxite & Alumina Company (100%)7 1,800 452

1. Nameplate Capacity is an estimate based on design capacity and normal operating efficiencies and does not necessarily represent maximum possible production. 2. The figures in this column reflect Alcoa’s share of production from these facilities. For facilities wholly-owned by AWAC entities, Alcoa takes 100% of the production. 3. This entity is part of the AWAC group of companies and is ultimately owned 60% by Alcoa and 40% by Alumina Limited. 4. The operating capacity at this refinery is producing at an approximately 45% output level. 5. With respect to Rio Tinto Alcan Inc. and South32, the named company or an affiliate thereof holds the interest. 6. The Point Comfort alumina refinery is fully curtailed. 7. The Ras Al Khair facility is 100% owned by Ma’aden Bauxite & Alumina Company, a joint venture owned by Ma’aden (74.9%) and AWA Saudi Limited (25.1%). AWA Saudi Limited is part of the AWAC group of companies and is ultimately owned 60% by Alcoa and 40% by Alumina Limited. 34 Aluminum smelters

Nameplate Alcoa Corporation Country Facility Owners (% Of Ownership) Capacity1 Consolidated Capacity2 (kmt / year) (kmt / year) 3 3 4,5 Australia Portland AofA (55%), CITIC (22.5%), Marubeni (22.5%) 358 197 3 6 Brazil São Luís (“Alumar”) Alumínio (60%), South32 (40%) 447 268 Baie Comeau, Québec Alcoa Corporation (100%) 280 280 7 8 Canada Bécancour, Québec Alcoa Corporation (74.95%), Rio Tinto Alcan Inc. (25.05%) 413 310 Deschambault, Québec Alcoa Corporation (100%) 260 260 Iceland Fjarðaál Alcoa Corporation (100%) 344 344 Lista Alcoa Corporation (100%) 94 94 Norway Mosjøen Alcoa Corporation (100%) 188 188 Avilés Alcoa Corporation (100%) 93 939 Spain La Coruña Alcoa Corporation (100%) 87 879 San Ciprián Alcoa Corporation (100%) 228 228 Massena West, NY Alcoa Corporation (100%) 130 130 Ferndale, WA (“Intalco”) Alcoa Corporation (100%) 279 27910 United States Wenatchee, WA Alcoa Corporation (100%) 184 18411 Evansville, IN (“Warrick”) Alcoa Corporation (100%) 269 26912 Total 3,654 3,211 Equity Interests: Kingdom of Saudi Arabia Ras Al Khair Ma'aden Aluminum Company13 (100%) 740 186

1. Nameplate Capacity is an estimate based on design capacity and normal operating efficiencies and does not necessarily represent maximum possible production. 2. The figures in this column reflect Alcoa’s share of production based on Nameplate Capacity from the smelter facilities. 3. The named company or an affiliate thereof holds this interest. 4. This figure includes the minority interest of Alumina Limited in the Portland facility, which is owned by AofA, an AWAC company. From this facility, AWAC takes 100% of the production allocated to AofA. 5. The Portland smelter has approximately 30,000 mtpy of idle capacity. 6. The Alumar smelter and casthouse have been fully curtailed since April 2015. 7. The Bécancour facility is owned by Alcoa (74.95%) and Rio Tinto Alcan Inc. (25.05%) through Rio Tinto Alcan Inc.’s interest in Pechiney Reynolds Québec, Inc., which is owned by Rio Tinto Alcan Inc. and Alcoa. 8. On January 11, 2018, a lockout of the bargained hourly employees commenced at the Bécancour smelter. As a result, only one of the three potlines is operating. 9. The Avilés and La Coruña smelters have approximately 56,000 mtpy of idle capacity combined. 10. The Intalco smelter has approximately 49,000 mtpy of idle capacity. 11. The Wenatchee smelter has been fully curtailed since the end of 2015. 12. In July 2017, the Company announced that it would restart three of five potlines at the Warrick smelter by the end of the second quarter of 2018. 13. The Ras Al Khair facility is 100% owned by Ma’aden Aluminum Company, a joint venture owned by Ma’aden (74.9%) and Alcoa Corporation (25.1%). 35 Adjusted EBITDA structure and information

4Q17 Adjusted EBITDA excluding special items comparison

Adjusted EBITDA Prior Adjusted EBITDA New excl. special items, $M structure excl. special items, $M structure Notes

Bauxite $106 Bauxite $105 ▪ Adjusted for pension/OPEB accounting change

Alumina $562 Alumina $562 ▪ Adjusted for pension/OPEB accounting change

Aluminum $234 Aluminum $246 ▪ Adjusted for pension/OPEB accounting change

Segment total $902 Segment total $913

Transformation & legacy pension/OPEB $(4) Transformation $10 ▪ Adjusted for pension/OPEB accounting change

▪ Combined intercompany eliminations with impact Impact of LIFO and metal price lag $(51) Corporate inventory accounting $(95) of LIFO and metal price lag ▪ Adjusted for pension/OPEB accounting change; Other corporate expense $(72) Other corporate $(32) Reclassed intercompany eliminations

Alcoa Corporation Total $775 Alcoa Corporation Total $796

36 Adjusted EBITDA reconciliation

LTM ending $M 1Q17 4Q17 1Q18 3/31/18 Net income (loss) attributable to Alcoa Corporation $225 $(196) $150 $142

Add:

Net income attributable to noncontrolling interest 83 140 124 383

Provision for income taxes 110 272 138 628 Other expenses / (income), net (79) 30 21 127 Interest expense 26 27 26 104 Restructuring and other charges 10 297 (19) 280 Depreciation, depletion and amortization 179 187 194 765 Adjusted EBITDA 554 757 634 2,429

Special items before tax and noncontrolling interest - 39 19 107

Adjusted EBITDA excl. special items $554 $796 $653 $2,536

Alcoa Corporation’s definition of Adjusted EBITDA is net margin plus an add-back for depreciation, depletion, and amortization. Net margin is equivalent to Sales minus the following items: Cost of goods sold; Selling, general administrative, and other expenses; Research and development expenses; and Provision for depreciation, depletion, and amortization. Adjusted EBITDA is a non-GAAP financial measure. Management believes that this measure is meaningful to investors because Adjusted EBITDA provides additional information with respect to Alcoa Corporation’s operating performance and the Company’s ability to meet its financial obligations. The Adjusted EBITDA presented may not be comparable to similarly titled measures of other companies. 37 Special items detail, net of tax and noncontrolling interest

$M 1Q17 4Q17 1Q18 P&L classification Special items $(108) $391 $(5) Warrick restart costs - 29 16 Cost of goods sold Rockdale inventory writedown - 6 - Cost of goods sold Becancour labor negotiation costs - 3 2 Cost of goods sold Mark-to-market energy contracts 4 2 (17) Other expenses / (income), net Gain on asset sales (120) (2) - Other expenses / (income), net Restructuring-related items 9 290 (20) Restructuring and other charges Income tax items (1) 63 14 Tax provision

38 Free Cash Flow reconciliation

$M 1Q17 2Q17 3Q17 4Q17 1Q18 Cash from operations $74 $311 $384 $455 $55 Capital expenditures (71) (88) (96) (150) (74) Free cash flow $3 $223 $288 $305 $(19)

Free Cash Flow is a non-GAAP financial measure. Management believes that this measure is meaningful to investors because management reviews cash flows generated from operations after taking into consideration capital expenditures, which are both considered necessary to maintain and expand Alcoa Corporation’s asset base, and expected to generate future cash flows from operations. It is important to note that Free Cash Flow does not represent the residual cash flow available for discretionary expenditures since other non-discretionary expenditures, such as mandatory debt service requirements, are not deducted from the measure. 39 Net Debt reconciliation

$M 4Q17 1Q18 Short-term borrowings $8 $- Long-term debt due within one year 16 15 Long-term debt, less amount due within one year 1,388 1,445 Total debt 1,412 1,460 Less: Cash and cash equivalents 1,358 1,196 Net debt $54 $264

Net debt is a non-GAAP financial measure. Management believes that this measure is meaningful to investors because management assesses Alcoa Corporation’s leverage position after considering available cash that could be used to repay outstanding debt. 40 Days Working Capital

$M 4Q16 1Q17 2Q17 3Q17 4Q17 1Q18 Receivables from customers $668 $708 $789 $840 $811 $814 Add: Inventories 1,160 1,294 1,287 1,323 1,453 1,630 Less: Accounts payable, trade 1,455 1,434 1,508 1,618 1,898 1,813 DWC working capital $373 $568 $568 $545 $366 $631 Sales $2,537 $2,655 $2,859 $2,964 $3,174 $3,090 Number of days in the quarter 92 90 91 92 92 90 Days Working Capital1 14 19 18 17 11 18

1. Days Working Capital = DWC working capital divided by (sales / number of days in the quarter). 41 Annualized Return on Capital (ROC)

Reconciliation and calculation information

(PBT + net interest3 + special items) x 4 x (1 – fixed tax rate4) $M 1Q17 1Q18 ROC % = X 100 Numerator: (Assets – cash – current liabilities + short term debt) Net income attributable to Alcoa Corporation 225 150 Add: Net income attributable to noncontrolling interest 83 124 Add: Provision for income taxes 110 138 1Q17 ($418 + $24 - $114) x 4) x (1 – 0.35) Profit before taxes (PBT) 418 412 ROC % = X 100 = 6.2% Add: Interest expense 26 26 ($17,076 – $824 – $2,623 + $23) Less: Interest income 2 4 Add: Special items1 (114) (17) ROC earnings before taxes 328 417 ($412 + $22 - $17) x 4) x (1 – 0.35) ROC earnings before taxes multiplied by four2 1,312 1,668 1Q18 X 100 = 8.4% ROC earnings after fixed tax rate of 35% 853 1,084 ROC % = ($17,096 – $1,204 – $2,976 + $15) Denominator2: Total assets 17,076 17,096 Less: Cash, cash equivalents, restricted cash and short-term investments 824 1,204 Less: Current liabilities 2,623 2,976 Add: Long-term debt due within one year and short-term borrowings 23 15 Average capital base2 13,652 12,931

ROC 6.2% 8.4%

1. Special items are before taxes and noncontrolling interest. 2. Denominator calculated using quarter ending balances. 3. Interest expense less interest income. 4. Fixed tax rate of 35%. 42 Glossary of terms

Abbreviations listed in alphabetical order Abbreviation Description Abbreviation Description % pts. Percentage points ISK Icelandic krona 1Q## Three months ending March 31 JV Joint venture 2Q## Three months ending June 30 kmt Thousand metric tons 3Q## Three months ending September 30 LIFO Last in first out method of inventory accounting 4Q## Three months ending December 31 LME London Metal Exchange Adj. Adjusted LTM Last twelve months API Alumina Price Index M Million Approx. Approximately Mdmt Million dry metric tons ARO Asset retirement obligations Mmt Million metric tons AUD Australian dollar mt Metric ton AWAC Alcoa World Alumina and Chemicals Mmtpa Million metric tons per annum B Billion MWP Midwest premium bbl Barrel N/A Not applicable BRL Brazilian real NI Net income CAD Canadian dollar NOK Norwegian krone CIF Cost, insurance and freight Op. Operational COGS Cost of goods sold OPEB Other postretirement employee benefits dmt Dry metric ton P&L Profit and loss DOJ U.S. Department of Justice PBT Profit before taxes DWC Days working capital R&D Research and development EBITDA Earnings before interest, taxes, depreciation and amortization ROC Return on capital ERISA Employee Retirement Income Security Act of 1974 ROW Rest of world EUR Euro SEC U.S. Securities and Exchange Commission ex. or excl. Excluding SG&A Selling, general administrative and other FOB Free on board U.S. United States of America FY## Twelve months ending December 31 USD United States dollar GAAP Accounting principles generally accepted in the United States of America WA Western Australia GWh Gigawatt hour YTD Year to date 43