EXHIBIT 99.1

RISK FACTORS

An investment in the notes involves significant risks. Prior to making a decision about investing in the notes, and in consultation with your own financial and legal advisors, you should carefully consider, among other matters, the following risk factors, as well as those incorporated by reference in this prospectus supplement and the accompanying prospectus from our Annual Report on Form 10-K for the fiscal year ended December 31, 2014, filed with the SEC on February 12, 2015, as updated by our Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2015, filed with the SEC on April 30, 2015, and any future filings we make with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act. The risk factors we have described are not the only ones we face. Our operations could also be impaired by additional risks and uncertainties. If any of these risks and uncertainties develop into actual events, our business, financial condition and results of operations could be materially adversely affected and you could lose all or a part of your investment.

Risks Related to the Notes and this Offering

We expect that the trading price of the notes will be significantly affected by changes in the market price of our common stock, the interest rate environment and our credit quality, each of which could change substantially at any time.

We expect that the trading price of the notes will depend on a variety of factors, including, without limitation, the market price of our common stock, the interest rate environment and our credit quality. Each of these factors may be volatile, and may or may not be within our control.

For example, the trading price of the notes will increase with the market price and volatility of our common stock. We cannot, however, predict whether the market price of our common stock will rise or fall or whether the volatility of our common stock will continue at its historical level. The market price of our common stock could fluctuate significantly for many reasons, including in response to the risks described in this section, elsewhere in this prospectus supplement or the documents we have incorporated by reference in this prospectus supplement or for reasons unrelated to our operations, such as reports by industry analysts, investor perceptions or negative announcements by our customers, competitors or suppliers regarding their own performance, as well as industry conditions and general financial, economic and political instability. Additionally, the stock market in recent years has experienced significant price and volume fluctuations that have often been unrelated to the operating performance of companies. A decrease in the market price of our common stock would likely adversely impact the trading price of the notes. The market price of our common stock could also be affected by possible sales of our common stock by investors who view the notes as a more attractive means of equity participation in us and by hedging or arbitrage trading activity that we expect to develop involving our common stock. This trading activity could, in turn, affect the trading price of the notes.

Likewise, if interest rates, or expected future interest rates, rise during the term of the notes, the yield of the notes will likely decrease, but the value of the conversion option embedded in the notes will likely increase. Because interest rates and interest rate expectations are influenced by a wide variety of factors, many of which are beyond our control, we cannot assure you that changes in interest rates or interest rate expectations will not adversely affect the trading price of the notes.

Furthermore, the trading price of the notes will likely be significantly affected by any change in our credit quality. Because our credit quality is influenced by a variety of factors, some of which are beyond our control, we cannot guarantee that we will maintain or improve our credit quality during the term of the notes. In addition, because we may choose to take actions that adversely affect our credit quality, such as incurring additional debt, there can be no guarantee that our credit quality will not decline during the term of the notes, which would likely negatively impact the trading price of the notes.

The notes are effectively subordinated to our secured debt and any liabilities of our subsidiaries.

The notes will rank senior in right of payment to any of our indebtedness that is expressly subordinated in right of payment to the notes; equal in right of payment to any of our liabilities that are not so subordinated; effectively junior in right of payment to any of our secured indebtedness and other secured obligations to the extent of the value of the assets securing such indebtedness or other obligations; and structurally junior to all indebtedness and other liabilities (including trade payables) of our subsidiaries. In the event of our bankruptcy, liquidation, reorganization or other winding up, our

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assets that secure debt ranking senior in right of payment to the notes will be available to pay obligations on the notes only after the secured debt has been repaid in full from these assets. There may not be sufficient assets remaining to pay amounts due on any or all of the notes then outstanding. The indenture governing the notes does not prohibit us from incurring additional senior debt or secured debt, nor does it prohibit any of our subsidiaries from incurring additional liabilities.

As of March 31, 2015, our total consolidated indebtedness was $2,599 million, of which an aggregate of $1,871 million was senior secured indebtedness. As of March 31, 2015, our subsidiaries had $2,599 million of indebtedness and other liabilities (which amount includes trade payables, but excludes intercompany obligations and liabilities of a type not required to be reflected on a balance sheet of such subsidiaries in accordance with GAAP) to which the notes would have been structurally subordinated. After giving effect to the issuance of the notes (assuming no exercise of the underwriters’ over-allotment option) and the use of proceeds therefrom, our total consolidated indebtedness would have been $2,589 million.

The notes are our obligations only and our operations are conducted through, and substantially all of our consolidated assets are held by, our subsidiaries.

The notes are our obligations exclusively and, as a holding company, we have no material assets other than certain investments and our ownership of the common stock of our subsidiaries. We will rely entirely upon distributions from our subsidiaries to meet the payment obligations under the notes. Our subsidiaries are separate and distinct legal entities and have no obligation, contingent or otherwise, to pay amounts due under the notes or otherwise to make any funds available to us including the payment of dividends or other distributions or the extension of loans or advances. Furthermore, the ability of our subsidiaries to make any payments to us would be dependent upon the terms of any credit facilities or other agreements of the subsidiaries and upon the subsidiaries’ earnings, which are subject to various business risks. In a bankruptcy or insolvency proceeding, claims of holders of the notes would be satisfied solely from our equity interests in our subsidiaries remaining after the satisfaction of claims of creditors of the subsidiaries. Accordingly, the notes are effectively subordinated to existing and future liabilities of our subsidiaries to their respective creditors. The notes also are effectively subordinated to any secured debt that we incur to the extent of the value of the assets securing that indebtedness.

Servicing our debt requires a significant amount of cash, and we may not have sufficient cash flow from our business to pay our substantial debt.

Our ability to make scheduled payment of the principal of, to pay interest on or to refinance our consolidated indebtedness, including the notes, depends on our future performance, which is subject to economic, financial, competitive and other factors beyond our control. Our business may not continue to generate cash flow from operations in the future sufficient to service our debt and make necessary capital expenditures. If we are unable to generate such cash flow, we may be required to adopt one or more alternatives, such as selling assets, restructuring debt or obtaining additional equity capital on terms that may be onerous or highly dilutive. Our ability to refinance our indebtedness will depend on the capital markets and our financial condition at such time. We may not be able to engage in any of these activities or engage in these activities on desirable terms, which could result in a default on our debt obligations.

Recent and future regulatory actions and other events may adversely affect the trading price and liquidity of the notes.

We expect that many investors in, and potential purchasers of, the notes will employ, or seek to employ, a convertible arbitrage strategy with respect to the notes. Investors would typically implement such a strategy by selling short the common stock underlying the notes and dynamically adjusting their short position while continuing to hold the notes. Investors may also implement this type of strategy by entering into swaps on our common stock in lieu of or in addition to short selling the common stock.

The SEC and other regulatory and self-regulatory authorities have implemented various rules and taken certain actions, and may in the future adopt additional rules and take other actions, that may impact those engaging in short selling activity involving equity securities (including our common stock). Such rules and actions include Rule 201 of SEC Regulation SHO, the adoption by the Financial Industry Regulatory Authority, Inc. (“FINRA”) and the national securities exchanges of a “Limit Up-Limit Down” program, the imposition of market-wide circuit breakers that halt trading of securities for certain periods following specific market declines, and the implementation of certain regulatory reforms required by the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010. Any governmental or regulatory action that restricts the ability of investors in, or potential purchasers of, the notes to effect short sales of our common stock, borrow our common stock or enter into swaps on our common stock could adversely affect the trading price and the liquidity of the notes.

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Despite our current debt levels, we may still incur substantially more debt or take other actions which would intensify the risks discussed above.

Despite our current consolidated debt levels, we and our subsidiaries may be able to incur substantial additional debt in the future, subject to the restrictions contained in our debt instruments, some of which may be secured debt. We will not be restricted under the terms of the indenture governing the notes from incurring additional debt, securing existing or future debt, recapitalizing our debt or taking a number of other actions that are not limited by the terms of the indenture governing the notes that could have the effect of diminishing our ability to make payments on the notes when due.

We may not have the ability to raise the funds necessary to settle conversions of the notes or to repurchase the notes upon a fundamental change, and our future debt may contain limitations on our ability to pay cash upon conversion or repurchase of the notes.

Holders of the notes will have the right to require us to repurchase their notes upon the occurrence of a fundamental change at a fundamental change repurchase price equal to 100% of the principal amount of the notes to be repurchased, plus accrued and unpaid interest, if any, as described under “Description of Notes—Fundamental Change Permits Holders to Require Us to Repurchase Notes.” In addition, upon conversion of the notes, unless we elect to deliver solely shares of our common stock to settle such conversion (other than paying cash in lieu of delivering any fractional share), we will be required to make cash payments in respect of the notes being converted as described under “Description of Notes—Conversion Rights—Settlement upon Conversion.” However, we may not have enough available cash or be able to obtain financing at the time we are required to make repurchases of notes surrendered therefor or notes being converted. In addition, our ability to repurchase the notes or to pay cash upon conversions of the notes may be limited by law, by regulatory authority or by agreements governing our future indebtedness. Our failure to repurchase notes at a time when the repurchase is required by the indenture or to pay any cash payable on future conversions of the notes as required by the indenture would constitute a default under the indenture. A default under the indenture or the fundamental change itself could also lead to a default under agreements governing our future indebtedness. If the repayment of the related indebtedness were to be accelerated after any applicable notice or grace periods, we may not have sufficient funds to repay the indebtedness and repurchase the notes or make cash payments upon conversions thereof.

The conditional conversion feature of the notes, if triggered, may adversely affect our financial condition and operating results.

In the event the conditional conversion feature of the notes is triggered, holders of notes will be entitled to convert the notes at any time during specified periods at their option. See “Description of Notes—Conversion Rights.” If one or more holders elect to convert their notes, unless we elect to satisfy our conversion obligation by delivering solely shares of our common stock (other than paying cash in lieu of delivering any fractional share), we would be required to settle a portion or all of our conversion obligation through the payment of cash, which could adversely affect our liquidity. In addition, even if holders do not elect to convert their notes, we could be required under applicable accounting rules to reclassify all or a portion of the outstanding principal of the notes as a current rather than long-term liability, which would result in a material reduction of our net working capital.

Future sales of our common stock in the public market could lower the market price for our common stock and adversely impact the trading price of the notes.

In the future, we may sell additional shares of our common stock to raise capital. In addition, a substantial number of shares of our common stock is reserved for issuance upon the exercise of stock options and upon conversion of the notes. We cannot predict the size of future issuances or the effect, if any, that they may have on the market price for our common stock. The issuance and sale of substantial amounts of common stock, or the perception that such issuances and sales may occur, could adversely affect the trading price of the notes and the market price of our common stock and impair our ability to raise capital through the sale of additional equity securities.

Holders of notes will not be entitled to any rights with respect to our common stock, but they will be subject to all changes made with respect to them to the extent our conversion obligation includes shares of our common stock.

Holders of notes will not be entitled to any rights with respect to our common stock (including, without limitation, voting rights and rights to receive any dividends or other distributions on our common stock) prior to the conversion date

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relating to such notes (if we have elected to settle the relevant conversion by delivering solely shares of our common stock (other than paying cash in lieu of delivering any fractional share)) or the last trading day of the relevant observation period (if we elect to pay and deliver, as the case may be, a combination of cash and shares of our common stock in respect of the relevant conversion), but holders of notes will be subject to all changes affecting our common stock. For example, if an amendment is proposed to our certificate of incorporation or by-laws requiring stockholder approval and the record date for determining the stockholders of record entitled to vote on the amendment occurs prior to the conversion date related to a holder’s conversion of its notes (if we have elected to settle the relevant conversion by delivering solely shares of our common stock (other than paying cash in lieu of delivering any fractional share)) or the last trading day of the relevant observation period (if we elect to pay and deliver, as the case may be, a combination of cash and shares of our common stock in respect of the relevant conversion), such holder will not be entitled to vote on the amendment, although such holder will nevertheless be subject to any changes affecting our common stock.

The conditional conversion feature of the notes could result in your receiving less than the value of our common stock into which the notes would otherwise be convertible.

Prior to the close of business on the business day immediately preceding September 1, 2021, you may convert your notes only if specified conditions are met. If the specific conditions for conversion are not met, you will not be able to convert your notes, and you may not be able to receive the value of the cash, common stock or a combination of cash and common stock, as applicable, into which the notes would otherwise be convertible. Therefore, you may not be able to realize the appreciation, if any, in the value of our common stock after the issuance of the notes in this offering and prior to such date. In addition, the inability to freely convert your notes prior to such date may also adversely affect the trading price of the notes and your ability to resell the notes.

Upon conversion of the notes, you may receive less valuable consideration than expected because the value of our common stock may decline after you exercise your conversion right but before we settle our conversion obligation.

Under the notes, a converting holder will be exposed to fluctuations in the value of our common stock during the period from the date such holder surrenders notes for conversion until the date we settle our conversion obligation.

Upon conversion of the notes, we have the option to pay or deliver, as the case may be, cash, shares of our common stock, or a combination of cash and shares of our common stock. If we elect to satisfy our conversion obligation in cash or a combination of cash and shares of our common stock, the amount of consideration that you will receive upon conversion of your notes will be determined by reference to the volume-weighted average price of our common stock for each trading day in a 70 trading day observation period. As described under “Description of Notes—Settlement upon Conversion,” this period would be (i) if the relevant conversion date occurs prior to September 1, 2021, the 70 consecutive trading day period beginning on, and including, the second trading day immediately succeeding such conversion date; and (ii) if the relevant conversion date occurs on or after September 1, 2021, and on or prior to the second scheduled trading day immediately preceding the maturity date, the 70 consecutive trading days beginning on, and including, the72nd scheduled trading day immediately preceding the maturity date. Accordingly, if the price of our common stock decreases during this period, the amount and/or value of consideration you receive will be adversely affected. In addition, if the market price of our common stock at the end of such period is below the average volume-weighted average price of our common stock during such period, the value of any shares of our common stock that you will receive in satisfaction of our conversion obligation will be less than the value used to determine the number of shares that you will receive.

If we elect to satisfy our conversion obligation solely in shares of our common stock upon conversion of the notes, we will be required to deliver the shares of our common stock, together with cash for any fractional share, no later than the third scheduled trading day following the relevant conversion date. Accordingly, if the price of our common stock decreases during this period, the value of the shares that you receive will be adversely affected and would be less than the conversion value of the notes on the conversion date.

The notes are not protected by restrictive covenants.

The indenture governing the notes does not contain any financial or operating covenants or restrictions on the payments of dividends, the incurrence of liens or indebtedness or the issuance or repurchase of securities by us or any of our subsidiaries. The indenture contains no covenants or other provisions to afford protection to holders of the notes in the event of a fundamental change or other corporate transaction involving us except to the extent described under “Description of Notes—Fundamental Change Permits Holders to Require Us to Repurchase Notes,” “Description of Notes—Conversion Rights—Increase in Conversion Rate upon Conversion upon a Make-Whole Fundamental Change” and “Description of Notes—Consolidation, Merger and Sale of Assets.”

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The increase in the conversion rate for notes converted in connection with a make-whole fundamental change may not adequately compensate you for any lost value of your notes as a result of such transaction.

If a make-whole fundamental change occurs prior to the maturity date, under certain circumstances, we will increase the conversion rate by a number of additional shares of our common stock for notes converted in connection with such make-whole fundamental change. The increase in the conversion rate will be determined based on the date on which the specified corporate transaction becomes effective and the price paid (or deemed to be paid) per share of our common stock in such transaction, as described below under “Description of Notes—Conversion Rights—Increase in Conversion Rate upon Conversion upon a Make-Whole Fundamental Change.” The increase in the conversion rate for notes converted in connection with a make-whole fundamental change may not adequately compensate you for any lost value of your notes as a result of such transaction. In addition, if the price of our common stock in the transaction is greater than $300.00 per share or less than $55.89 per share (in each case, subject to adjustment), no additional shares will be added to the conversion rate. Moreover, in no event will the conversion rate per $1,000 principal amount of notes as a result of this adjustment exceed 17.8922 shares of common stock, subject to adjustment in the same manner as the conversion rate as set forth under “Description of Notes—Conversion Rights—Conversion Rate Adjustments.”

Our obligation to increase the conversion rate for notes converted in connection with a make-whole fundamental change could be considered a penalty, in which case the enforceability thereof would be subject to general principles of reasonableness and equitable remedies.

The conversion rate of the notes may not be adjusted for all dilutive events.

The conversion rate of the notes is subject to adjustment for certain events, including, but not limited to, the issuance of certain stock dividends on our common stock, the issuance of certain rights or warrants, subdivisions, combinations, distributions of capital stock, indebtedness, or assets, cash dividends and certain issuer tender or exchange offers as described under “Description of Notes—Conversion Rights—Conversion Rate Adjustments.” However, the conversion rate will not be adjusted for other events, such as a third-party tender or exchange offer or an issuance of common stock for cash, that may adversely affect the trading price of the notes or our common stock. An event that adversely affects the value of the notes may occur, and that event may not result in an adjustment to the conversion rate.

Some significant restructuring transactions may not constitute a fundamental change, in which case we would not be obligated to offer to repurchase the notes.

Upon the occurrence of a fundamental change, you have the right to require us to repurchase your notes. However, the fundamental change provisions will not afford protection to holders of notes in the event of other transactions that could adversely affect the notes. For example, transactions such as leveraged recapitalizations, refinancings, restructurings, or acquisitions initiated by us, or a significant change in the composition of our board may not constitute a fundamental change requiring us to repurchase the notes. In the event of any such transaction, the holders would not have the right to require us to repurchase the notes, even though each of these transactions could increase the amount of our indebtedness, or otherwise adversely affect our capital structure or any credit ratings, thereby adversely affecting the holders of notes.

We cannot assure you that an active trading market will develop for the notes.

Prior to this offering, there has been no trading market for the notes, and we do not intend to apply to list the notes on any securities exchange or to arrange for quotation on any automated dealer quotation system. We have been informed by the underwriters that they intend to make a market in the notes after the offering is completed. However, the underwriters may cease their market-making at any time without notice. In addition, the liquidity of the trading market in the notes, and the market price quoted for the notes, may be adversely affected by changes in the overall market for this type of security and by changes in our financial performance or prospects or in the prospects for companies in our industry generally. As a result, we cannot assure you that an active trading market will develop for the notes. If an active trading market does not develop or is not maintained, the market price and liquidity of the notes may be adversely affected. In that case you may not be able to sell your notes at a particular time or you may not be able to sell your notes at a favorable price.

Any adverse rating of the notes may cause their trading price to fall.

We do not intend to seek a rating on the notes. However, if a rating service were to rate the notes and if such rating service were to lower its rating on the notes below the rating initially assigned to the notes or otherwise announces its intention to put the notes on credit watch, the trading price of the notes could decline.

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You may be subject to tax if we make or fail to make certain adjustments to the conversion rate of the notes even though you do not receive a corresponding cash distribution.

The conversion rate of the notes is subject to adjustment in certain circumstances, including the payment of cash dividends. If the conversion rate is adjusted as a result of a distribution that is taxable to our common stockholders, such as a cash dividend, you may be deemed to have received a dividend subject to U.S. federal income tax without the receipt of any cash. In addition, a failure to adjust (or to adjust adequately) the conversion rate after an event that increases your proportionate interest in us could be treated as a deemed taxable dividend to you. If a make-whole fundamental change occurs prior to the maturity date, under some circumstances, we will increase the conversion rate for notes converted in connection with the make-whole fundamental change. Such increase may also be treated as a distribution subject to U.S. federal income tax as a dividend. See “Material U.S. Federal Income Tax Considerations.” If you are a non-U.S. holder (as defined in “Material U.S. Federal Income Tax Considerations”), any deemed dividend would be subject to U.S. federal withholding tax at a 30% rate, or such lower rate as may be specified by an applicable treaty, which may be withheld from subsequent payments on the notes. See “Material U.S. Federal Income Tax Considerations.”

The convertible note hedge and warrant transactions may affect the value of the notes and our common stock.

In connection with the pricing of the notes, we entered into convertible note hedge transactions with the option counterparties. The convertible note hedge transactions are expected generally to reduce the potential dilution to our common stock upon any conversion of notes and/or offset any cash payments we are required to make in excess of the principal amount of converted notes, as the case may be. We also entered into warrant transactions with the option counterparties. However, the warrant transactions could separately have a dilutive effect on our earnings per share to the extent that the market price per share of our common stock exceeds the applicable strike price of the warrants. Accordingly, when the convertible note hedge transactions and the warrant transactions are taken together, the extent to which the convertible note hedge transactions reduce the potential dilution to our common stock (or the cash payments in excess of the principal amount of the notes) upon conversion of the notes is effectively capped by the warrant transaction at the strike price of the warrant. If the underwriters exercise their over-allotment option, we may enter into additional convertible note hedge transactions and additional warrant transactions.

In connection with establishing their initial hedge of the convertible note hedge and warrant transactions, the option counterparties or their respective affiliates expect to enter into various hedging transactions, including (without limitation) derivative transactions, with respect to our common stock concurrently with or shortly after the pricing of the notes. This activity could impact the market price of our common stock or the notes at that time.

In addition, the option counterparties or their respective affiliates may modify their hedge positions by entering into or unwinding various hedging transactions, including (without limitation) derivatives, with respect to our common stock and/or purchasing or selling our common stock or other securities of ours in secondary market transactions following the pricing of the notes and prior to the maturity of the notes (and are likely to do so during any observation period related to a conversion of notes). This activity could also cause or avoid an increase or a decrease in the market price of our common stock or the notes, which could affect your ability to convert the notes and, to the extent the activity occurs during any observation period related to a conversion of notes, it could affect the number of shares and value of the consideration that you will receive upon conversion of the notes.

In addition, if any such convertible note hedge and warrant transactions fail to become effective, whether or not this offering of notes is completed, the option counterparties or their respective affiliates may unwind their hedge positions with respect to our common stock, which could adversely affect the value of our common stock and, if the notes have been issued, the value of the notes.

Risks Related to Our Common Stock

Our common stock share price has been subject to fluctuations in value.

The trading price of our common stock is subject to material fluctuations in response to a variety of factors, including quarterly variations in our operating results, conditions of the airfreight market and global economic conditions or other events and factors that are beyond our control.

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In the past, following periods of significant volatility in the overall market and in the market price of a company’s securities, securities class action litigation has been instituted against these companies in some circumstances. If this type of litigation were instituted against us following a period of volatility in the market price for our common stock, it could result in substantial costs and a diversion of our management’s attention and resources, which could have a material adverse effect on our business, results of operations and financial condition and on the value of your notes.

In addition, the sale of substantial amounts of our common stock could adversely impact its price. As of April 27, 2015, we had outstanding approximately 25,003,943 shares of our common stock. The sale or the availability for sale of a large number of shares of our common stock in the public market could cause the price of our common stock, and the value of your notes, to decline.

Provisions in our restated certificate of incorporation and by-laws and Delaware law might discourage, delay or prevent a change in control of the Company and, therefore, depress the trading price of our common stock and the value of your notes.

Provisions of our restated certificate of incorporation, by-laws and Delaware law may render more difficult or discourage any attempt to acquire our company, even if such acquisition may be believed to be favorable to the interests of our stockholders. These provisions may also discourage bids for our common stock at a premium over market price or adversely affect the market price of our common stock and the value of your notes. See “Description of Capital Stock” in the accompanying prospectus.

U.S. citizenship requirements may limit common stock voting rights.

Under U.S. federal law and DOT requirements, we must be owned and actually controlled by “citizens of the United States,” a statutorily defined term requiring, among other things, that not more than 25% of our issued and outstanding voting stock be owned and controlled, directly or indirectly, by non-U.S. citizens. The DOT periodically conducts airline citizenship reviews and, if it finds that this requirement is not met, may require adjustment of the voting rights of the airline’s issued shares.

As one means to effect compliance, our certificate of incorporation and by-laws provide that the failure of non-U.S. citizens to register their shares on a separate stock record, which we refer to as the “Foreign Stock Record,” results in a suspension of their voting rights. Our by-laws further limit the number of shares of our capital stock that may be registered on the Foreign Stock Record to 25% of our issued and outstanding shares. Registration on the Foreign Stock Record is made in chronological order based on the date we receive a written request for registration. As a result, if a non-U.S. citizen acquires shares of our common stock and does not or is not able to register those shares on our Foreign Stock Record, they may lose their ability to vote those shares. See “Description of Capital Stock” in the accompanying prospectus.

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