NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS - UNAUDITED

1. Summary of Significant Accounting Policies

This Quarterly Report on Form 10-Q (this "Report") should be read in conjunction with the Company's Annual Report on Form 10-K for the year ended December 31, 2016 . Unless the context otherwise requires, references in these notes to interim consolidated financial statements - unaudited to "Kaiser Aluminum Corporation," "we," "us," "our," "the Company" and "our Company" refer collectively to Kaiser Aluminum Corporation and its subsidiaries.

Organization and Nature of Operations. Kaiser Aluminum Corporation specializes in the production of semi-fabricated specialty aluminum mill products, such as aluminum plate and sheet and extruded and drawn products, for the following end market applications: aerospace and high strength ("Aero/HS products"), automotive applications ("Automotive Extrusions"), general engineering ("GE products") and other industrial ("Other products"). Our business is organized into one operating segment, Fabricated Products. See Note 10 for additional information regarding our reportable segment and business unit.

Principles of Consolidation and Basis of Presentation. The accompanying unaudited consolidated financial statements include the accounts of our wholly owned subsidiaries and are prepared in accordance with United States generally accepted accounting principles ("GAAP") and the rules and regulations of the Securities and Exchange Commission ("SEC") applicable for interim periods and, therefore, do not include all information and footnotes required by GAAP for complete financial statements. In management's opinion, all adjustments (which include normal recurring adjustments) considered necessary for a fair presentation have been included. The results of operations for our interim periods are not necessarily indicative of the results of operations that may be achieved for the entire 2017 fiscal year. The financial information as of December 31, 2016 is derived from our audited consolidated financial statements and footnotes included in our Annual Report on Form 10-K for the year ended December 31, 2016 .

Use of Estimates in the Preparation of Financial Statements. The preparation of financial statements in accordance with GAAP requires the use of estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities known to exist as of the date the financial statements are published and the reported amounts of revenues and expenses during the reporting period. Uncertainties with respect to such estimates and assumptions are inherent in the preparation of our consolidated financial statements; accordingly, it is possible that the actual results could differ from these estimates and assumptions, which could have a material effect on the reported amounts of our consolidated financial position and results of operations.

Inventories. Inventories are stated at the lower of cost or market value. On March 31, 2016, we recorded a lower of cost or market inventory write-down of $4.9 million as a result of a decrease in our net realizable value of inventory. The net realizable value reflected commitments as of that date from customers to purchase our inventory at prices that exceeded the Midwest Transaction Price ("Midwest Price"), which reflects the primary aluminum supply/demand dynamics in North America, reduced by an approximate normal profit margin. There were no additional lower of cost or market inventory adjustments during the remainder of 2016 or the first quarter of 2017.

Finished products, work-in-process and raw material inventories are stated on the last-in, first-out ("LIFO") basis. At March 31, 2017 , the current cost of inventory exceeded its stated LIFO value by $1.9 million . At December 31, 2016 (after inventory write-down adjustments) the stated LIFO value of our inventory represented its net realizable value (less a normal profit margin) and exceeded the current cost of our inventory by $8.5 million . Other inventories are stated on the first-in, first-out basis and consist of operating supplies, which are materials and supplies to be consumed during the production process. Inventory costs consist of material, labor and manufacturing overhead, including depreciation. Abnormal costs, such as idle facility expenses, freight, handling costs and spoilage, are accounted for as current period charges. All of our inventories at March 31, 2017 and December 31, 2016 were included in the Fabricated Products segment (see Note 2 for the components of inventories).

Replacement Parts. Replacement parts consist of preventative maintenance and capital spare parts, which are stated on the first-in, first-out basis. Replacement parts are recorded within Prepaid expenses and other current assets or Other assets depending on whether or not the expected utilization of the replacement parts is to occur within the current operating cycle.

Property, Plant and Equipment – Net. Property, plant and equipment – net is recorded at cost and includes construction in progress (see Note 2 ). Interest related to the construction of qualifying assets is capitalized as part of the construction costs. The

amount of interest expense capitalized as construction in progress was $0.5 million and $0.9 million during the quarters ended March 31, 2017 and March 31, 2016 , respectively.

Depreciation is computed using the straight-line method at rates based on the estimated useful lives of the various classes of assets. Capital lease assets and leasehold improvements are depreciated on a straight-line basis over the shorter of the estimated useful lives of the assets or the lease term. Depreciation expense is not included in Cost of products sold, excluding depreciation and amortization and other items, but is included in Depreciation and amortization.

We classify assets as held for sale only when an asset is being actively marketed and expected to sell within 12 months. Assets held for sale are initially measured at the lesser of the assets' carrying amount and the fair value less costs to sell.

Self Insurance of Workers' Compensation and Employee Healthcare Liabilities . We self-insure the majority of the costs of workers' compensation benefits and employee healthcare benefits and rely on insurance coverage to protect us from large losses on individual claims. Workers' compensation liabilities are based on a combination of estimates for: (i) incurred-but-not-reported claims and (ii) the ultimate expense of incurred claims. Such estimates are based on judgment, using our historical claims data and information and analysis provided by actuarial and claims advisors, our insurance carriers and other professionals. Our undiscounted workers' compensation liabilities were estimated at $26.8 million at both March 31, 2017 and December 31, 2016 . However, we account for our workers' compensation accrued liability on a discounted basis, using a discount rate of 2.00% at both March 31, 2017 and December 31, 2016 . Accrued liabilities for employee healthcare benefits, which are estimates of unpaid incurred medical and prescription drug costs as provided by our healthcare administrators, were $3.8 million and $3.6 million for the periods ended March 31, 2017 and December 31, 2016 , respectively.

Derivative Financial Instruments. Hedging transactions using derivative financial instruments are primarily designed to mitigate our exposure to changes in the market price of aluminum, alloying metals and energy and, to a lesser extent, to mitigate our exposure to changes in foreign currency exchange rates. From time to time, we also enter into hedging arrangements in connection with financing transactions to mitigate financial risks.

We do not utilize derivative financial instruments for trading or other speculative purposes. Our derivative activities are initiated within guidelines established by management and approved by our Board of Directors. Hedging transactions are executed centrally on behalf of all of our operations to minimize transaction costs, monitor consolidated net exposures and allow for increased responsiveness to changes in market factors.

We recognize derivative instruments as assets or liabilities in our Consolidated Balance Sheets and measure these instruments at fair value by "marking-to-market" all of our hedging positions at each period's end (see Note 8 ). Because we do not meet the documentation requirements for hedge (deferral) accounting related to aluminum and energy derivatives, unrealized and realized gains and losses associated with these hedges are reflected as a reduction or increase, respectively, in: (i) Unrealized gain on derivative instruments and (ii) Cost of products sold, excluding depreciation and amortization and other items.

From time to time, we enter into foreign currency forward contracts to protect the value of anticipated foreign currency expenses associated with cash commitments for equipment purchases. These derivative instruments are designated and qualify for cash flow hedge accounting and are adjusted to current market values each reporting period. Both realized and unrealized periodic gains and losses of derivative instruments designated as cash flow hedges are deferred in Accumulated other comprehensive loss until depreciation on the underlying equipment commences. Upon commencement, realized gains and losses are recorded in Net income as an adjustment to depreciation expense in the period in which depreciation is recognized on the underlying equipment. Additionally, to limit our economic (i.e. cash exposure) to future price increases of alloying metals, such as zinc and/or copper, used as raw materials in our fabrication operations, we enter into forward swap contracts ("Alloy Hedges"). These Alloy Hedges are designated and qualify for cash flow hedge accounting and are adjusted to current market values each reporting period. The effective portion of the fair value on these Alloy Hedges is recorded within Other comprehensive income, net of tax and is reclassified into the Statements of Consolidated Income during the month of settlement to Cost of products sold, excluding depreciation and amortization and other items. Depending on the time to maturity and asset or liability position, the carrying values of cash flow hedges are included in Prepaid expenses and other current assets, Other assets, Other accrued liabilities or Long-term liabilities. We report the effective portion of our cash flow hedges in the same financial statement line item as changes in the fair value of the hedged item.

Fair Value Measurements. We apply the fair value hierarchy established by GAAP for the recognition and measurement of certain financial assets and liabilities. An asset or liability's fair value classification within the hierarchy is determined based on

the lowest level input that is significant to the fair value measurement. In determining fair value, we utilize valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible and consider counterparty risk in our assessment of fair value.

The fair values of financial assets and liabilities are evaluated and measured on a recurring basis. As part of that evaluation process, we review the underlying inputs that are significant to the fair value measurement of financial instruments to determine if a transfer among hierarchy levels is appropriate. We historically have not had significant transfers into or out of each hierarchy level.

Financial assets and liabilities that we measure at fair value each period as required by GAAP include our derivative instruments and available for sale securities, consisting of debt investment securities and investments related to our deferred compensation plan (see Note 5 ). Additionally, we measure at fair value once each year at December 31 the plan assets of the Salaried VEBA (defined in Note 5 ) and our Canadian defined benefit pension plan. We record our remaining financial assets and liabilities at carrying value.

The majority of our non-financial assets and liabilities, which include goodwill, intangible assets, inventories and property, plant and equipment, are not required to be measured at fair value on a recurring basis. However, if certain triggering events occur (or at least annually for goodwill), an evaluation of the affected non-financial asset or liability is required, potentially resulting in an adjustment to the carrying amount of such asset or liability.

As of March 31, 2017 , following a qualitative review of operations at the Chandler, Arizona (Extrusion) facility, we determined that no adjustment to the carrying value of its goodwill or intangible asset was required. However, if the facility is unable to reduce its costs and/or increase sales volumes in the near term, it is reasonably possible that the carrying values of its related assets, including goodwill, could be reduced within the next 12 months .

We concluded that none of our other non-financial assets and liabilities subject to fair value assessments on a non-recurring basis required a material adjustment to the carrying amount of such assets and liabilities for the quarter ended March 31, 2017 .

New Accounting Pronouncements. Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09") , was issued in May 2014 and requires an entity to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In August 2015 , ASU 2014-09 was amended by ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which defers the effective date of ASU 2014-09 by one year for all entities and permits early adoption on a limited basis. ASU 2014-09 was subsequently amended by four additional pronouncements: (i) ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing ; (ii) ASU No. 2016-11, Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815): Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting ; (iii) ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients ; and (iv) ASU No. 2016-20, Revenue from Contracts with Customers (Topic 606): Technical Corrections and Improvements to Topic 606 . We expect to adopt ASU 2014-09, including its subsequent amendments discussed above, using the modified retrospective transition approach for the fiscal year ending December 31, 2018. Based on our initial assessment, we have concluded that revenue from certain contracts will continue to be recognized at a point-in-time, while revenue from other contracts, primarily from our Aero/HS products and Automotive Extrusions, will be required to be recognized over time. We are currently assessing the impact that over-time recognition will have on our consolidated financial statements.

ASU No. 2016-02, Leases (Topic 842): Amendments to the Financial Accounting Standards Board Accounting Standards Codification ("ASU 2016-02"), was issued in February 2016. Under ASU 2016-02, lessees will need to recognize a right-of-use asset and a lease liability for virtually all of their leases (other than leases that meet the definition of a short-term lease). For income statement purposes, a dual model was retained, requiring leases to be classified as either operating or finance. Operating leases will result in straight-line expense (similar to current operating leases) while finance leases will result in a front-loaded expense pattern (similar to current capital leases). ASU 2016-02 becomes effective for us in the first quarter of 2019. We are currently assessing the impact and expect the adoption of this ASU in 2019 to have a material impact on our consolidated financial statements.

We do not anticipate any material impact on our consolidated financial statements upon the adoption of the following accounting pronouncements: (i) ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and

Measurement of Financial Assets and Financial Liabilities ; (ii) ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ; and (iii) ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.

There were no material impacts on our consolidated financial statements resulting from our early adoption in the first quarter of 2017 of the following accounting pronouncements: (i) ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments ; (ii) ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash ; and (iii) ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.

2. Supplemental Balance Sheet Information

5.875% Senior Notes. In May 2016, we issued $375.0 million principal amount of 5.875% unsecured senior notes due May 15, 2024 ("5.875% Senior Notes") at 100% of the principal amount. The unamortized amount of debt issuance costs as of March 31, 2017 was $6.1 million . Interest expense, including amortization of debt issuance costs, relating to the 5.875% Senior Notes was $5.7 million for the quarter ended March 31, 2017 . A portion of the interest relating to the 5.875% Senior Notes was capitalized as construction in progress. The effective interest rate of the 5.875% Senior Notes is approximately 6.1% per annum, taking into account the amortization of debt issuance costs. The fair value of the outstanding 5.875% Senior Notes, which are Level 1 liabilities, was calculated based on broker quotes and was approximately $390.0 million and $390.8 million at March 31, 2017 and December 31, 2016 , respectively.

8.25% Senior Notes. In May 2012, we issued $225.0 million principal amount of 8.25% unsecured senior notes due June 1, 2020 ("8.25% Senior Notes"), of which $197.8 million principal amount remained outstanding at December 31, 2015 . On June 1, 2016 we redeemed in full all remaining 8.25% Senior Notes at a redemption price of 104.125% of the principal amount. Interest expense, including amortization of debt issuance costs, relating to the 8.25% Senior Notes was $4.3 million for the quarter ended March 31, 2016 . A portion of the interest relating to the 8.25% Senior Notes was capitalized as construction in progress.

Revolving Credit Facility

Our credit agreement with JPMorgan Chase Bank, N.A., as administrative agent, and the other financial institutions party thereto ("Revolving Credit Facility") provides us with a $300.0 million funding commitment through December 2020. We had $293.9 million of borrowing availability under the Revolving Credit Facility at March 31, 2017 , based on the borrowing base determination then in effect. At March 31, 2017 , there were no borrowings under the Revolving Credit Facility and $7.7 million was being used to support outstanding letters of credit, leaving $286.2 million of net borrowing availability. The interest rate applicable to any overnight borrowings under the Revolving Credit Facility would have been 4.25% at March 31, 2017 .

The income tax provision for the quarters ended March 31, 2017 and March 31, 2016 was $18.5 million and $15.1 million , reflecting an effective tax rate of 34.0% and 36.5% , respectively. The difference between the effective tax rate and the projected blended statutory tax rate for the quarter ended March 31, 2017 was due to: (i) a decrease of $1.6 million for the recognition of excess tax benefits from stock-based compensation, resulting in a 2.9% decrease to the blended statutory tax rate and (ii) a decrease of $0.4 million to the valuation allowance for certain state net operating losses, resulting in a 0.8% decrease to the blended statutory tax rate. The difference between the effective tax rate and the projected blended statutory tax rate for the quarter ended March 31, 2016 was due to: (i) a decrease of $0.7 million for the recognition of excess tax benefits from stock-based compensation, resulting in a 1.7% decrease to the blended statutory tax rate, which was partially offset by (ii) an increase of $0.3 million to the valuation allowance for certain state net operating losses, resulting in a 0.7% increase to the blended statutory tax rate.

Our gross unrecognized benefits relating to uncertain tax positions were $1.8 million at both March 31, 2017 and December 31, 2016 , of which, $0.7 million would be recorded through our income tax provision and thus impact the effective tax rate at both March 31, 2017 and December 31, 2016 if the gross unrecognized tax benefits were to be recognized.

We do not expect our gross unrecognized tax benefits to significantly change within the next 12 months .

5. Employee Benefits

Pension and Similar Benefit Plans. We provide contributions to: (i) multi-employer pension plans sponsored by the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union AFL-CIO, CLC ("USW"), the International Association of Machinists and certain other unions at certain of our production facilities; (ii) defined contribution 401(k) savings plans for salaried employees and certain hourly employees; (iii) a defined benefit plan for salaried employees at our London, Ontario (Canada) facility; and (iv) a non-qualified, unfunded, unsecured plan of deferred compensation for key employees who would otherwise suffer a loss of benefits under our defined contribution plan.

VEBA Postretirement Obligations. Certain eligible retirees participate in a voluntary employees' beneficiary association ("VEBA") that provides healthcare and medical cost reimbursement benefits for eligible retirees represented by certain unions and their surviving spouses and eligible dependents ("Union VEBA"). We have an obligation to make variable cash contributions to the Union VEBA with respect to periods through September 2017. During the first quarter of 2017, we paid $17.1 million to the Union VEBA with respect to the twelve months ended December 31, 2016 , and in the first quarter of 2018, we will make a final cash contribution to the Union VEBA with respect to the nine months ending September 30, 2017. The final contribution amount is variable but cannot exceed $12.8 million . As of March 31, 2017 , $11.5 million was recorded within Other accrued liabilities for this final contribution.

Additionally, certain other retirees who retired prior to 2004 and certain employees who were hired prior to February 2002 and have subsequently retired or will retire with the requisite age and service, along with their surviving spouses and eligible dependents, are eligible to participate in a separate VEBA that provides healthcare and medical cost reimbursement benefits ("Salaried VEBA"). We have an ongoing obligation with no express termination date to make annual variable cash contributions to the Salaried VEBA based on the contribution formula discussed in Note 6 of Notes to Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2016 . The contribution amount cannot exceed $2.9 million per year. Our contribution with respect to 2016 was $2.9 million , which we paid in the first quarter of 2017. We account for the Salaried VEBA as a defined benefit plan in our financial statements.

Fair Value of Plan Assets. The plan assets of the Salaried VEBA and our Canadian pension plan are measured annually on December 31 and reflected in our Consolidated Balance Sheets at fair value. In determining the fair value of the plan assets at an annual period end, we utilize primarily the results of valuations supplied by the investment advisors responsible for managing the assets of each plan, which we independently review for reasonableness.

Deferred Compensation Program . In addition to the Canadian pension plan and Salaried VEBA, we have a non-qualified, unfunded, unsecured plan of deferred compensation for key employees who would otherwise suffer a loss of benefits under our defined contribution plan as a result of the limitations imposed by the Internal Revenue Code of 1986. Despite the plan being an unfunded plan, we make an annual contribution to a rabbi trust to fulfill future funding obligations as contemplated by the terms of the plan. These assets are held in various investment funds at certain registered investment companies and are accounted for as available for sale securities within Level 2 of the fair value hierarchy and are measured and recorded at fair value based on their quoted market prices. The fair value of these assets at March 31, 2017 and December 31, 2016 was $8.6 million and $8.2 million , respectively, and are included in Other assets. Offsetting liabilities relating to the deferred compensation plan are included in Long-term liabilities.

Components of Net Periodic Benefit Cost. Our results of operations included the following impacts associated with the Canadian defined benefit plan and the Salaried VEBA: (i) charges for service rendered by employees; (ii) a charge for accretion of interest; (iii) a benefit for the return on plan assets; and (iv) amortization of net gains or losses on assets, prior service costs associated with plan amendments and actuarial differences. Net periodic benefit cost related to the Canadian defined benefit plan was not material for the quarters ended March 31, 2017 and March 31, 2016 . The following table presents the components of Net periodic postretirement benefit cost relating to Salaried VEBA for the periods presented (in millions of dollars):

For all periods presented, substantially all of the Fabricated Products segment's employee benefits related charges are in Cost of products sold, excluding depreciation and amortization and other items with the remaining balance in Selling, general, administrative, research and development ("SG&A and R&D").

6. Employee Incentive Plans

Short-Term Incentive Plans ("STI Plans")

We have annual short-term incentive compensation plans for senior management and certain other employees payable at our election in cash, shares of common stock, or a combination of cash and shares of common stock. Amounts earned under STI Plans are based on our adjusted earnings before interest, taxes, depreciation and amortization ("Adjusted EBITDA"), modified for certain safety, quality, delivery, cost and individual performance factors. The Adjusted EBITDA targets are determined based on the return on adjusted net assets of our Fabricated Products business. Most of our production facilities have similar programs for both hourly and salaried employees. As of March 31, 2017 , we had a liability of $5.5 million recorded within Accrued salaries, wages and related expenses for estimated probable future payments relating to the three month performance period of our 2017 STI Plan.

Long-Term Incentive Programs ("LTI Programs")

General . Prior to May 26, 2016, executive officers and other key employees of the Company, as well as non-employee directors of the Company, were eligible to participate in the Kaiser Aluminum Corporation Amended and Restated 2006 Equity and Performance Incentive Plan ("2006 Plan"). On May 26, 2016, our stockholders approved the Kaiser Aluminum Corporation 2016 Equity and Incentive Compensation Plan ("2016 Plan"), which replaced and succeeded in its entirety the 2006 Plan. No grants will be made under the 2006 Plan on or after May 26, 2016, but outstanding awards granted under the 2006 Plan will continue unaffected. Subject to certain adjustments that may be required from time to time to prevent dilution or enlargement of the rights of participants under the 2016 Plan, the number of shares of common stock available for awards is limited to 1,045,000 shares, minus, (i) one share for every one share subject to an award granted under the 2006 Plan between December 31, 2015 and the effective date of the 2016 Plan, plus (ii) any shares of our common stock that become available under the 2016 Plan as a result of forfeiture, cancellation, expiration, or cash settlement of awards. At March 31, 2017 , 768,191 shares were available for awards under the 2016 Plan.

Non-vested Common Shares and Restricted Stock Units. We grant non-vested common shares to our non-employee directors and non-vested common shares and restricted stock units to our executive officers and other key employees. The restricted stock units have rights similar to the rights of non-vested common shares and each restricted stock unit that becomes vested entitles the recipient to receive one common share or a cash amount equaling the value of one common share. For both non-vested common shares and restricted stock units, the service period is generally one year for non-employee directors and three years for executive officers and other key employees.

Performance Shares . In addition to non-vested common shares and restricted stock units, we grant performance shares to executive officers and other key employees. Each performance share that becomes vested and earned entitles the recipient to receive one common share or a cash amount equaling the value of one common share. During the first quarter of 2017 , performance shares granted in 2014 under the 2014-2016 LTI Program vested (see " Summary of Activity " below). The number of performance shares that vested and resulted in the issuance of common shares was determined based on our total shareholder return ("TSR") compared to the TSR of a specified group of peer companies over a three -year performance period.

Performance shares granted in 2015 are subject to performance conditions pertaining to our TSR relative to the TSR of a specified group of peer companies over a three -year performance period ("TSR-Based Performance Shares").

Performance shares granted in 2016 consist of TSR-Based Performance Shares and performance shares subject to performance requirements pertaining to our total controllable cost performance over a three -year performance period ("CP-Based Performance Shares").

Performance shares granted in 2017 consist of TSR-Based Performance Shares, CP-Based Performance Shares and performance shares subject to performance conditions pertaining to our economic value added ("EVA") performance, determined based on our adjusted pre-tax operating income in excess of a capital charge, over a three -year performance period ("EVA-Based Performance Shares").

The number of performance shares under the 2015-2017, 2016-2018 and 2017-2019 LTI Programs that may be earned and result in the issuance of common shares ranges between 0% to 200% of the target number of underlying common shares, which is approximately one-half of the maximum payout. The performance shares granted under the 2015-2017, 2016-2018 and 2017-2019 LTI Programs will vest in 2018, 2019 and 2020, respectively.

Non-Cash Compensation Expense. Non-cash compensation expense relating to all awards is included in SG&A and R&D. Non-cash compensation expense by type of award under LTI Programs was as follows for each period presented (in millions of dollars):

The following table presents the allocation of the charges detailed above, by segment (in millions of dollars):

Summary of Activity. A summary of the activity with respect to non-vested common shares, restricted stock units, TSR-Based Performance Shares, CP-Based Performance Shares and EVA-Based Performance Shares for the quarter ended March 31, 2017 is as follows:

The weighted-average grant-date fair value per share for shares granted by type of award was as follows for each period presented:

Stock Options. As of December 31, 2016 and March 31, 2017 , we had 1,543 fully-vested outstanding stock options exercisable to purchase common shares at $80.01 per share, all of which subsequently expired on April 2, 2017. During the quarter ended March 31, 2017 , no options were granted, exercised, expired or forfeited.

Under each of the 2006 Plan and 2016 Plan, participants may elect to have us withhold common shares to satisfy minimum statutory tax withholding obligations arising in connection with the exercise of stock options and vesting of non-vested shares, restricted stock units and performance shares. We cancel any such shares withheld on the applicable vesting dates or earlier dates when service requirements are satisfied, which correspond to the times at which income to the employee is recognized. When we withhold these common shares, we are required to remit to the appropriate taxing authorities the fair value of the shares withheld as of the vesting date. During the quarters ended March 31, 2017 and March 31, 2016 , 55,888 and 35,162 common shares, respectively, were withheld and canceled for this purpose. The withholding of common shares by us could be deemed a purchase of the common shares.

7. Commitments and Contingencies

Commitments. We have a variety of financial commitments, including purchase agreements, forward foreign exchange and forward sales contracts, indebtedness and letters of credit (see Note 3 and Note 8 ).

Environmental Contingencies. We are subject to a number of environmental laws and regulations, to potential fines or penalties assessed for alleged breaches of such laws and regulations and to potential claims based upon such laws and regulations. We are also subject to legacy environmental contingencies related to activities that occurred at operating facilities within Fabricated Products prior to July 6, 2006 while such operating facilities were being operated by a predecessor, which represent the majority of our environmental accruals. The status of these environmental contingencies are discussed below. We have established procedures for regularly evaluating environmental loss contingencies. Our environmental accruals represent our undiscounted estimate of costs reasonably expected to be incurred based on presently enacted laws and regulations, existing requirements, currently available facts, existing technology and our assessment of the likely remediation actions to be taken.

In 2012, we submitted a final feasibility study to the Washington State Department of Ecology ("Washington State Ecology") that included recommendations for remediation alternatives primarily to address the historical use of oils containing polychlorinated biphenyls ("PCBs") at our Spokane, Washington ("Trentwood") facility. We also signed an amended work order in 2012 with Washington State Ecology allowing certain remediation activities to begin, including the initiation of a treatability study in regards to proposed PCB remediation methods. We began implementation of certain approved sections of the work plan in 2013 and throughout 2014, completing a number of these sections in 2014 and receiving approval from Washington State Ecology on completed sections. In cooperation with Washington State Ecology, in 2015 we constructed a pilot test facility to determine the treatability and evaluate the feasibility of removing PCBs from ground water under the Trentwood facility. We initiated and began operating the treatment test facility in the first half of 2016. As the success of the new methodology cannot be reasonably determined at this time, it is possible we may need to make upward adjustments to our related accruals as facts and cost estimates regarding the groundwater treatment method and the operation of the treatment facility become available. 

 During 2013, at the request of the Ohio Environmental Protection Agency ("OEPA"), we initiated an investigational study of the Newark, Ohio ("Newark") facility related to historical on-site waste disposal. Since 2014, we completed a number of preliminary steps in the preparation of completing the final risk assessment and feasibility study, both of which are subject to review and approval by the OEPA. As work continues and progresses to a final risk assessment and feasibility study, we will establish and update estimates for probable and estimable remediation, if any. The actual and final cost for remediation will not be fully determinable until a final feasibility study is submitted and accepted by the OEPA and work plans are prepared, which is expected to occur in the next 12 to 15 months .

At March 31, 2017 , our environmental accrual of $17.1 million represented our estimate of the incremental remediation cost based on: (i) proposed alternatives in the final feasibility study related to the Trentwood facility; (ii) currently available facts with respect to our Newark facility; and (iii) facts related to certain other locations owned or formerly owned by us. In accordance with approved and proposed remediation action plans, we expect that the implementation and ongoing monitoring could occur over a period of 30 or more years.

As additional facts are developed, feasibility studies are completed, draft remediation plans are modified, necessary regulatory approvals for the implementation of remediation are obtained, alternative technologies are developed, and/or other factors change, there may be revisions to management's estimates and actual costs may exceed the current environmental accruals. We believe at this time that it is reasonably possible that undiscounted costs associated with these environmental matters may exceed current accruals by amounts that could be, in the aggregate, up to an estimated $12.3 million over the remediation period. It is reasonably possible that our recorded estimate will change in the next 12 months .

Other Contingencies. We are party to various lawsuits, claims, investigations and administrative proceedings that arise in connection with past and current operations. We evaluate such matters on a case-by-case basis and our policy is to vigorously contest any such claims we believe are without merit. We accrue for a legal liability when it is both probable that a liability has been incurred and the amount of the loss is reasonably estimable. Quarterly, in addition to when changes in facts and circumstances require it, we review and adjust these accruals to reflect the impacts of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular case. While uncertainties are inherent in the final outcome of such matters and it is presently impossible to determine the actual cost that may ultimately be incurred, we believe that we have sufficiently accrued for such matters and that the ultimate resolution of pending matters will not have a material impact on our consolidated financial position, operating results or liquidity.

8. Derivatives, Hedging Programs and Other Financial Instruments

Overview . In conducting our business, we enter into derivative transactions, including forward contracts and options, to limit our economic (i.e. cash) exposure resulting from: (i) metal price risk related to our sale of fabricated aluminum products and the purchase of metal used as raw material for our fabrication operations; (ii) energy price risk relating to fluctuating prices of natural gas and electricity used in our production processes; and (iii) foreign currency requirements with respect to our foreign subsidiaries and cash commitments for equipment purchases denominated in foreign currency.

Our derivative activities are overseen by a hedging committee ("Hedging Committee"), which is composed of our chief executive officer, chief operating officer, chief financial officer, chief accounting officer, treasurer and other officers and employees selected by the chief executive officer. The Hedging Committee meets regularly to review derivative positions and strategy and reports to our Board of Directors on the scope of its activities.

We are exposed to counterparty credit risk on all of our derivative instruments, which we manage by monitoring the credit quality of our counterparties and allocating our hedging positions among multiple counterparties to limit exposure to any single entity. Our counterparties are major, investment grade financial institutions or trading companies. Hedging transactions are governed by negotiated reciprocal credit lines, which require collateral to be posted above specified credit thresholds. We believe the risk of loss is remote and contained due to counterparty credit quality, our diversification practice and collateral requirements.

In a majority of our hedging counterparty agreements, our counterparty offers us a credit line that adjusts up or down, depending on our liquidity. Below specified liquidity thresholds, we may have to post collateral if the fair value of our net liability with such counterparty exceeds our reduced credit line. We manage this risk by allocating hedging transactions among multiple counterparties, using options as part of our hedging activities, or both. The aggregate fair value of our derivative instruments that were in a net liability position was zero and $0.1 million at March 31, 2017 and December 31, 2016 , respectively, and we had no collateral posted as of those dates.

Additionally, our firm-price customer sales commitments create incremental customer credit risk related to metal price movements. Under certain circumstances, we mitigate this risk by periodically requiring cash collateral from them, which we classify as deferred revenue and include as a component of Other accrued liabilities. At March 31, 2017 , we had no cash collateral posted with any of our customers. For more information about concentration risks concerning customers and suppliers, see Note 10 .

Notional Amount of Derivative Contracts . The following table summarizes our derivative positions at March 31, 2017 :

We have physical delivery commitments at firm prices covering approximately 54% of our expected electricity purchases for each of the remainder of 2017 , 2018 and 2019 , respectively.

Non-Designated Hedges of Operational Risks . Our pricing of fabricated aluminum products is generally intended to lock in a conversion margin (representing the value added from the fabrication process(es)) and to pass through metal price fluctuations to our customers. For some of our higher value added products sold on a spot basis, the pass through of metal price movements can sometimes lag by as much as several months, with a favorable impact to us when metal prices decline and an adverse impact to us when metal prices increase. Additionally, in certain instances, we enter into firm-price arrangements with our customers for stipulated volumes to be delivered in the future. Because we generally purchase primary and secondary aluminum on a floating price basis, the lag in passing through metal price movements to customers on some of our higher value added products sold on a spot basis and the volume that we have committed to sell to our customers under a firm-price arrangement create metal price risk for us. We use third-party hedging instruments to limit exposure to metal price risk related to the metal pass through lag on some of our products and firm-price customer sales contracts.

We are also exposed to risk of fluctuating prices for natural gas and electricity. We, from time to time, in the ordinary course of business, enter into hedging transactions and/or physical delivery commitments with third parties to mitigate our risk from fluctuations in natural gas and electricity prices.

Designated Foreign Currency Cash Flow Hedges . We are exposed to foreign currency exchange risk related to firm-price agreements for equipment purchases from foreign manufacturers. Such agreements require that we make payments in foreign currency to the vendor over time based on milestone achievements. We use foreign currency forward contracts in order to mitigate the exposure to currency exchange rate fluctuations related to these purchases. The timing and amounts of the forward contract settlements are designed to line up with the timing and amounts of scheduled payments to the foreign equipment manufacturers and are therefore expected to be highly effective hedges. As of March 31, 2017 , we had one remaining open foreign currency forward contract with a weighted average exchange rate of 1.12 euro to US dollar. The effective portion of the fair value on our designated foreign currency cash flow hedges is recorded within Other comprehensive income, net of tax and is reclassified into the Statements of Consolidated Income on the same line item and the same period in which the underlying equipment is depreciated.

Designated Alloying Metal Hedges . We enter into agreements with suppliers to purchase alloying metals (zinc and copper) used as raw materials in our fabrication operations. Because we are unable to pass along fluctuations in the cost of these alloying metals to our customers, we are exposed to metal price risk. Beginning in the fourth quarter of 2016, to limit our economic (i.e., cash) exposure to future price increases of zinc and/or copper, we entered into Alloy Hedges with third-party financial institutions. Under these Alloy Hedges, we are able to purchase the required alloying metals at predetermined/fixed prices at stated delivery dates. Our Alloy Hedges settle monthly and correspond to forecasted purchases of alloying metals by our manufacturing facilities and are therefore expected to be highly effective hedges. The effective portion of the fair value on these Alloy Hedges is recorded within Other comprehensive income, net of tax and is reclassified into the Statements of Consolidated Income during the month of settlement to Cost of products sold (See Note 13 ). As of March 31, 2017 , we estimate the net gain of $0.1 million will be reclassified from Accumulated other comprehensive loss into Net income within the next 12 months. We incurred no ineffectiveness on these hedges during the quarter ended March 31, 2017 .