Exhibit 4.1

    

    

    

  

  
    IONIS PHARMACEUTICALS, INC.

      

      AND

      

      U.S. BANK NATIONAL ASSOCIATION,

      

      as Trustee

      

      INDENTURE

      

      Dated as of December 19, 2019

     

    0.125% Convertible Senior Notes due 2024

     

    
      
        


    

    
    	 	
            TABLE OF CONTENTS

          	 


    

    

    	 	 	
            Page

          
	 	 	 
	
            ARTICLE 1

          
	
            Definitions

          
	 	 	 
	
            Section 1.01 .

          	
            Definitions

          	
            1

          
	
            Section 1.02 .

          	
            References to Interest

          	
            13

          
	 
	
            ARTICLE 2

          
	
            Issue, Description, Execution, Registration and Exchange of Notes

          
	 
	
            Section 2.01 .

          	
            Designation and Amount

          	
            13

          
	
            Section 2.02 .

          	
            Form of Notes

          	
            13

          
	
            Section 2.03 .

          	
            Date and Denomination of Notes; Payments of Interest and Defaulted Amounts

          	
            14

          
	
            Section 2.04 .

          	
            Execution, Authentication and Delivery of Notes

          	
            16

          
	
            Section 2.05 .

          	
            Exchange and Registration of Transfer of Notes; Restrictions on Transfer; Depositary

          	
            16

          
	
            Section 2.06 .

          	
            Mutilated, Destroyed, Lost or Stolen Notes

          	
            22

          
	
            Section 2.07 .

          	
            Temporary Notes

          	
            23

          
	
            Section 2.08 .

          	
            Cancellation of Notes Paid, Converted, Etc

          	
            24

          
	
            Section 2.09 .

          	
            CUSIP Numbers

          	
            24

          
	
            Section 2.10 .

          	
            Additional Notes; Purchases

          	
            24

          
	 	 	 
	
            ARTICLE 3

          
	
            Satisfaction and Discharge

          
	 	 	 
	
            Section 3.01 .

          	
            Satisfaction and Discharge

          	
            25

          
	 	 	 
	
            ARTICLE 4

          
	
            Particular Covenants of the Company

          
	 
	
            Section 4.01 .

          	
            Payment of Principal and Interest

          	
            25

          
	
            Section 4.02 .

          	
            Maintenance of Office or Agency

          	
            25

          
	
            Section 4.03 .

          	
            Appointments to Fill Vacancies in Trustee’s Office

          	
            26

          
	
            Section 4.04 .

          	
            Provisions as to Paying Agent

          	
            26

          
	
            Section 4.05 .

          	
            Existence

          	
            27

          
	
            Section 4.06 .

          	
            Rule 144A Information Requirement and Annual Reports

          	
            27

          
	
            Section 4.07 .

          	
            Stay, Extension and Usury Laws

          	
            29

            

          
	
            Section 4.08 .

          	
            Compliance Certificate; Statements as to Defaults

          	
            30

          
	
            Section 4.09 .

          	
            Further Instruments and Acts

          	
            30

          


    

    

    
      i

      
        


    

    	
            ARTICLE 5

          
	
            Lists of Holders and Reports by the Company and the Trustee

          
	 	 	 
	
            Section 5.01 .

          	
            Lists of Holders

          	
            30

          
	
            Section 5.02 .

          	
            Preservation and Disclosure of Lists

          	
            30

          
	 
	
            ARTICLE 6

          
	
            Defaults and Remedies

          
	 	 	 
	
            Section 6.01 .

          	
            Events of Default

          	
            30

          
	
            Section 6.02 .

          	
            Acceleration; Rescission and Annulment

          	
            32

          
	
            Section 6.03 .

          	
            Additional Interest

          	
            33

          
	
            Section 6.04 .

          	
            Payments of Notes on Default; Suit Therefor

          	
            33

          
	
            Section 6.05 .

          	
            Application of Monies Collected by Trustee

          	
            35

          
	
            Section 6.06 .

          	
            Proceedings by Holders

          	
            36

          
	
            Section 6.07 .

          	
            Proceedings by Trustee

          	
            37

          
	
            Section 6.08 .

          	
            Remedies Cumulative and Continuing

          	
            37

          
	
            Section 6.09 .

          	
            Direction of Proceedings and Waiver of Defaults by Majority of Holders

          	
            37

          
	
            Section 6.10 .

          	
            Notice of Defaults

          	
            38

          
	
            Section 6.11 .

          	
            Undertaking to Pay Costs

          	
            38

          
	 	 	 
	
            ARTICLE 7

          
	
            Concerning the Trustee

          
	 	 	 
	
            Section 7.01 .

          	
            Duties and Responsibilities of Trustee

          	
            38

          
	
            Section 7.02 .

          	
            Reliance on Documents, Opinions, Etc

          	
            40

          
	
            Section 7.03 .

          	
            No Responsibility for Recitals, Etc

          	
            41

          
	
            Section 7.04 .

          	
            Trustee, Paying Agents, Conversion Agents, Bid Solicitation Agent or Note Registrar May Own Notes

          	
            42

          
	
            Section 7.05 .

          	
            Monies and Shares of Common Stock to Be Held in Trust

          	
            42

          
	
            Section 7.06 .

          	
            Compensation and Expenses of Trustee

          	
            42

          
	
            Section 7.07 .

          	
            Officer’s Certificate as Evidence

          	
            43

          
	
            Section 7.08 .

          	
            Eligibility of Trustee

          	
            43

          
	
            Section 7.09 .

          	
            Resignation or Removal of Trustee

          	
            43

          
	
            Section 7.10 .

          	
            Acceptance by Successor Trustee

          	
            44

          
	
            Section 7.11 .

          	
            Succession by Merger, Etc

          	
            45

          
	 	 	 
	
            ARTICLE 8

          
	
            Concerning the Holders

          
	 	 	 
	
            Section 8.01 .

          	
            Action by Holders

          	
            45

          
	
            Section 8.02 .

          	
            Proof of Execution by Holders

          	
            46

          
	
            Section 8.03 .

          	
            Who Are Deemed Absolute Owners

          	
            46

          
	
            Section 8.04 .

          	
            Company-Owned Notes Disregarded

          	
            46

          
	
            Section 8.05 .

          	
            Revocation of Consents; Future Holders Bound

          	
            47

          


    

    

    
      ii

      
        


    

    	
            ARTICLE 9

          
	
            Holders’ Meetings

          
	 	 	 
	
            Section 9.01 .

          	
            Purpose of Meetings

          	
            47

          
	
            Section 9.02 .

          	
            Call of Meetings by Trustee

          	
            48

          
	
            Section 9.03 .

          	
            Call of Meetings by Company or Holders

          	
            48

          
	
            Section 9.04 .

          	
            Qualifications for Voting

          	
            48

          
	
            Section 9.05 .

          	
            Regulations

          	
            48

          
	
            Section 9.06 .

          	
            Voting

          	
            49

            

          
	
            Section 9.07 .

          	
            No Delay of Rights by Meeting

          	
            49

            

          
	 	 	 
	
            ARTICLE 10

          
	
            Supplemental Indentures

          
	 	 	 
	
            Section 10.01 .

          	
            Supplemental Indentures Without Consent of Holders

          	
            49

            

          
	
            Section 10.02 .

          	
            Supplemental Indentures with Consent of Holders

          	
            51

          
	
            Section 10.03 .

          	
            Effect of Supplemental Indentures

          	
            52

          
	
            Section 10.04 .

          	
            Notation on Notes

          	
            52

          
	
            Section 10.05 .

          	
            Evidence of Compliance of Supplemental Indenture to Be Furnished Trustee

          	
            52

          
	 	 	 
	
            ARTICLE 11

          
	
            Consolidation, Merger, Sale, Conveyance and Lease

          
	 	 	 
	
            Section 11.01 .

          	
            Company May Consolidate, Etc. on Certain Terms

          	
            52

          
	
            Section 11.02 .

          	
            Successor Corporation to Be Substituted

          	
            53

          
	 	 	 
	
            ARTICLE 12

          
	
            Immunity of Incorporators, Stockholders, Officers and Directors

          
	 	 	 
	
            Section 12.01 .

          	
            Indenture and Notes Solely Corporate Obligations

          	
            53

          
	 	 	 
	
            ARTICLE 13

          
	
            Intentionally Omitted

          
	 	 	 
	
            ARTICLE 14

          
	
            Conversion of Notes

          
	 	 	 
	
            Section 14.01 .

          	
            Conversion Privilege

          	
            54

          
	
            Section 14.02 .

          	
            Conversion Procedure; Settlement Upon Conversion.

          	
            57

          
	
            Section 14.03 .

          	
            Increased Conversion Rate Applicable to Certain Notes Surrendered in Connection with Make-Whole
              Fundamental Changes

          	
            61

          
	
            Section 14.04 .

          	
            Adjustment of Conversion Rate

          	
            63

          
	
            Section 14.05 .

          	
            Adjustments of Prices

          	
            73

          
	
            Section 14.06 .

          	
            Shares to Be Fully Paid

          	
            73

          


    

    

    
      iii

      
        


    

    	
            Section 14.07 .

          	
            Effect of Recapitalizations, Reclassifications and Changes of the Common Stock.

          	
            73

          
	
            Section 14.08 .

          	
            Certain Covenants

          	
            75

          
	
            Section 14.09 .

          	
            Responsibility of Trustee

          	
            75

          
	
            Section 14.10 .

          	
            Notice to Holders Prior to Certain Actions

          	
            76

          
	
            Section 14.11 .

          	
            Stockholder Rights Plans

          	
            76

          
	
            Section 14.12 .

          	
            Limit on Issuance of Shares of Common Stock Upon Conversion

          	
            77

          
	
            Section 14.13 .

          	
            Exchange in Lieu of Conversion

          	
            77

          
	 	 	 
	
            ARTICLE 15

          
	
            Purchase of Notes at Option of Holders

          
	 	 	 
	
            Section 15.01 .

          	
            Intentionally Omitted.

          	
            78

            

          
	
            Section 15.02 .

          	
            Purchase at Option of Holders Upon a Fundamental Change

          	
            78

            

          
	
            Section 15.03 .

          	
            Withdrawal of Fundamental Change Purchase Notice

          	
            81

          
	
            Section 15.04 .

          	
            Deposit of Fundamental Change Purchase Price

          	
            81

          
	
            Section 15.05 .

          	
            Covenant to Comply with Applicable Laws Upon Purchase of Notes

          	
            82

          
	 	 	 
	
            ARTICLE 16

          
	
            No Optional Redemption

          
	 	 	 
	
            Section 16.01 .

          	
            No Optional Redemption

          	
            82

          
	 	 	 
	
            ARTICLE 17

          
	
            Miscellaneous Provisions

          
	 	 	 
	
            Section 17.01 .

          	
            Provisions Binding on Company’s Successors

          	
            82

          
	
            Section 17.02 .

          	
            Official Acts by Successor Corporation

          	
            82

          
	
            Section 17.03 .

          	
            Addresses for Notices, Etc

          	
            83

          
	
            Section 17.04 .

          	
            Governing Law

          	
            83

          
	
            Section 17.05 .

          	
            Evidence of Compliance with Conditions Precedent; Certificates and Opinions of Counsel to Trustee

          	
            83

          
	
            Section 17.06 .

          	
            Legal Holidays

          	
            84

          
	
            Section 17.07 .

          	
            No Security Interest Created

          	
            84

          
	
            Section 17.08 .

          	
            Benefits of Indenture

          	
            84

          
	
            Section 17.09 .

          	
            Table of Contents, Headings, Etc

          	
            84

          
	
            Section 17.10 .

          	
            Authenticating Agent

          	
            85

          
	
            Section 17.11 .

          	
            Execution in Counterparts

          	
            86

          
	
            Section 17.12 .

          	
            Severability

          	
            86

          
	
            Section 17.13 .

          	
            Waiver of Jury Trial

          	
            86

          
	
            Section 17.14 .

          	
            Force Majeure

          	
            86

          
	
            Section 17.15 .

          	
            Calculations

          	
            86

          
	
            Section 17.16 .

          	
            U.S.A. Patriot Act

          	
            86

          
	 	 	 
	
            EXHIBIT

          
	 	 	 
	
            Exhibit A

          	
            Form of Note

          	
            A-1

          


    

    

    
      iv

      
        


    

    INDENTURE dated as of December 19, 2019 between Ionis Pharmaceuticals, Inc., a Delaware corporation, as issuer (the “Company,” as more fully set forth in Section 1.01) and U.S. Bank National Association, a national banking association, as trustee (the “Trustee,” as more fully set forth in Section 1.01).

     

    W I T N E S S E T H:

     

    WHEREAS, for its lawful corporate purposes, the Company has duly authorized the issuance of its 0.125% Convertible Senior Notes due 2024 (the “Notes”), initially in an aggregate principal amount not to exceed $548,826,000, and in order to provide the terms and conditions upon which the Notes are to be
      authenticated, issued and delivered, the Company has duly authorized the execution and delivery of this Indenture; and

     

    WHEREAS, the Form of Note, the certificate of authentication to be borne by each Note, the Form of Notice of Conversion, the Form of Fundamental Change
      Purchase Notice and the Form of Assignment and Transfer to be borne by the Notes are to be substantially in the forms hereinafter provided; and

     

    WHEREAS, all acts and things necessary to make the Notes, when executed by the Company and authenticated and delivered by the Trustee or a duly
      authorized authenticating agent, as in this Indenture provided, the valid, binding and legal obligations of the Company, and this Indenture a valid agreement according to its terms, have been done and performed, and the execution of this Indenture
      and the issuance hereunder of the Notes have in all respects been duly authorized.

     

    NOW, THEREFORE, THIS INDENTURE WITNESSETH:

     

    That in order to declare the terms and conditions upon which the Notes are, and are to be, authenticated, issued and delivered, and in consideration of
      the premises and of the purchase and acceptance of the Notes by the Holders thereof, the Company covenants and agrees with the Trustee for the equal and proportionate benefit of the respective Holders from time to time of the Notes (except as
      otherwise provided below), as follows:

     

    ARTICLE 1

        Definitions

     

    Section 1.01.  Definitions.  The terms defined in this Section 1.01 (except as herein otherwise expressly provided or unless the context
        otherwise requires) for all purposes of this Indenture and of any indenture supplemental hereto shall have the respective meanings specified in this Section 1.01.  The words “herein,” “hereof,” “hereunder,” and words of similar import refer to this
        Indenture as a whole and not to any particular Article, Section or other subdivision.  The terms defined in this Article include the plural as well as the singular.

     

    
      
        


    

    
    “Additional Interest” means all amounts, if any, payable
      pursuant to Section 4.06(d), Section 4.06(e) and Section 6.03, as applicable.

     

    “Additional Shares” shall have the meaning specified in Section
      14.03(a).

     

    “Affiliate” of any specified Person means any other Person
      directly or indirectly controlling or controlled by or under direct or indirect common control with such specified Person.  For the purposes of this definition, “control,” when used with respect to any specified Person means the power to direct or
      cause the direction of the management and policies of such Person, directly or indirectly, whether through the ownership of voting securities, by contract or otherwise; and the terms “controlling” and “controlled” have meanings correlative to the
      foregoing.

     

    “Agent Members” shall have the meaning specified in Section
      8.03.

     

    “Bid Solicitation Agent” means the Company or the Person
      appointed by the Company to solicit bids for the Trading Price of the Notes in accordance with Section 14.01(b)(i).  The Company shall initially act as the Bid Solicitation Agent.

     

    “Board of Directors” means the board of directors of the Company
      or a duly authorized committee of such board.

     

    “Board Resolution” means a copy of a resolution certified by the
      Secretary or an Assistant Secretary of the Company to have been duly adopted by the Board of Directors, and to be in full force and effect on the date of such certification, and delivered to the Trustee.

     

    “Business Day” means, with respect to any Note, any day other
      than a Saturday, a Sunday or a day on which banking institutions are not required to be open in The City of New York.

     

    “Capital Stock” means, for any entity, any and all shares,
      interests, rights to purchase, warrants, options, participations or other equivalents of or interests in (however designated) stock issued by that entity, but, for the avoidance of doubt, excluding any debt securities convertible into such stock.

     

    “Cash Settlement” shall have the meaning specified in Section
      14.02(a).

     

    “Clause A Distribution” shall have the meaning specified in
      Section 14.04(c).

     

    “Clause B Distribution” shall have the meaning specified in
      Section 14.04(c).

     

    “Clause C Distribution” shall have the meaning specified in
      Section 14.04(c).

     

    “close of business” means 5:00 p.m. (New York City time).

     

    “Combination Settlement” shall have the meaning specified in
      Section 14.02(a).

     

    
      2

      
        


    

    “Commission” means the U.S. Securities and Exchange Commission.

     

    “Common Equity” of any Person means Capital Stock of such Person
      that is generally entitled (a) to vote in the election of directors of such Person or (b) if such Person is not a corporation, to vote or otherwise participate in the selection of the governing body, partners, managers or others that will control the
      management or policies of such Person.

     

    “Common Stock” means the common stock of the Company, par value
      $0.001 per share, as it exists on the date of this Indenture, subject to Section 14.07.

     

    “Company” shall have the meaning specified in the first
      paragraph of this Indenture, and subject to the provisions of Article 11, shall include its successors and assigns.

     

    “Company Order” means a written order of the Company, signed by
      an Officer of the Company and delivered to the Trustee.

     

    “Conversion Agent” shall have the meaning specified in Section
      4.02.

     

    “Conversion Date” shall have the meaning specified in Section
      14.02(c).

     

    “Conversion Obligation” shall have the meaning specified in
      Section 14.01(a).

     

    “Conversion Price” means as of any date, $1,000, divided by the Conversion Rate as of such date.

     

    “Conversion Rate” shall have the meaning specified in Section
      14.01(a).

     

    “Corporate Trust Office” means the principal office of the
      Trustee at which at any time its corporate trust business shall be administered, which office at the date hereof is located at U.S. Bank National Association, One Federal Street, Boston, MA 02110, Attention: Karen Leyden-Beard, Vice President, or
      such other address as the Trustee may designate from time to time by notice to the Holders and the Company, or the principal corporate trust office of any successor Trustee (or such other address as such successor Trustee may designate from time to
      time by notice to the Holders and the Company).

     

    “Custodian” means the Trustee, as custodian for The Depository
      Trust Company, with respect to the Global Notes, or any successor entity thereto.

     

    “Daily Conversion Value” means, for each of the 30 consecutive
      Trading Days during the applicable Observation Period, one-thirtieth (1/30th) of the product of (a) the Conversion Rate on such Trading Day and (b) the Daily VWAP on such Trading Day.

     

    “Daily Measurement Value” means the Specified Dollar Amount (if
      any), divided by 30.

     

    “Daily Settlement Amount,” for each of the 30 consecutive
      Trading Days during the Observation Period, shall consist of:

     

    
      3

      
        


    

    (a)          cash in an amount equal to the lesser
        of (i) the Daily Measurement Value and (ii) the Daily Conversion Value on such Trading Day; and

     

    (b)          if the Daily Conversion Value on such
        Trading Day exceeds the Daily Measurement Value, a number of shares of Common Stock equal to (i) the difference between the Daily Conversion Value and the Daily Measurement Value, divided by (ii) the Daily VWAP for such Trading Day.

     

    “Daily VWAP” means, for each of the 30 consecutive Trading Days
      during the applicable Observation Period, the per share volume-weighted average price as displayed under the heading “Bloomberg VWAP” on Bloomberg page “IONS <equity> AQR” (or its equivalent successor if such page is not available) in respect
      of the period from the scheduled open of trading until the scheduled close of trading of the primary trading session on such Trading Day (or if such volume-weighted average price is unavailable, the market value of one share of the Common Stock on
      such Trading Day determined, using a volume-weighted average method, by a nationally recognized independent investment banking firm retained for this purpose by the Company).  The “Daily VWAP” shall be determined without regard to after-hours trading or any other trading outside of the regular trading session trading hours.

     

    “Default” means any event that is, or after notice or passage of
      time, or both, would be, an Event of Default.

     

    “Defaulted Amounts” means any amounts on any Note (including,
      without limitation, the Fundamental Change Purchase Price, principal and interest) that are payable but are not punctually paid or duly provided for.

     

    “Depositary” means, with respect to each Global Note, the Person
      specified in Section 2.05(c) as the Depositary with respect to such Notes, until a successor shall have been appointed and become such pursuant to the applicable provisions of this Indenture, and thereafter, “Depositary” shall mean or include such successor.

     

    “Designated Institution” shall have the meaning specified in
      Section 14.13(a).

     

    “Distributed Property” shall have the meaning specified in
      Section 14.04(c).

     

    “effective date” means, for purposes of Section 14.04 and
      Section 14.05, the first date on which the shares of the Common Stock trade on the applicable exchange or in the applicable market, regular way, reflecting the relevant transaction.

     

    “Effective Date” shall have the meaning specified in Section
      14.03(c).

     

    “Event of Default” shall have the meaning specified in Section
      6.01.

     

    “Ex-Dividend Date” means the first date on which shares of the
      Common Stock trade on the applicable exchange or in the applicable market, regular way, without the right to receive the issuance, dividend or distribution in question, from the Company or, if applicable, from the seller of Common Stock on such
      exchange or market (in the form of due bills or otherwise) as determined by such exchange or market.

     

    
      4

      
        


    

    “Exchange Act” means the Securities Exchange Act of 1934, as
      amended, and the rules and regulations promulgated thereunder.

     

    “Exchange Election” shall have the meaning specified in Section
      14.13(a).

     

    “Expiration Date” shall have the meaning specified in Section
      14.04(e).

     

    “Expiration Time” shall have the meaning specified in Section
      14.04(e).

     

    “Form of Assignment and Transfer” shall mean the “Form of
      Assignment and Transfer” attached as Attachment 3 to the Form of Note.

     

    “Form of Fundamental Change Purchase Notice” shall mean the
      “Form of Fundamental Change Purchase Notice” attached as Attachment 2 to the Form of Note.

     

    “Form of Note” means the “Form of Note” attached hereto as
      Exhibit A.

     

    “Form of Notice of Conversion” shall mean the “Form of Notice of
      Conversion” attached as Attachment 1 to the Form of Note.

     

    “Fundamental Change” shall be deemed to have occurred at the
      time after the Notes are originally issued if any of the following occurs:

     

    (a)          any “person” or “group” (within the
        meaning of Section 13(d) of the Exchange Act) other than the Company, its Subsidiaries or the employee benefit plans of the Company or any such Subsidiary, files a Schedule TO, any schedule, form or report under the Exchange Act disclosing that
        such person or group has become the direct or indirect ultimate “beneficial owner,” as defined in Rule 13d-3 under the Exchange Act, of the Company’s Common Equity representing more than 50% of the voting power of the Company’s Common Equity;

     

    (b)          the consummation of (A) any
        recapitalization, reclassification or change of the Common Stock (other than changes resulting from a subdivision or combination) as a result of which the Common Stock would be converted into, or exchanged for, stock, other securities or other
        property or assets; (B) any share exchange, consolidation or merger of the Company pursuant to which the Common Stock will be converted into cash, stock, other securities or other property or assets (in each of cases (A) and (B), other than any
        such transaction which is effected solely to change the Company’s jurisdiction of incorporation to another State within the United States of America or the District of Columbia and that results in a reclassification, conversion or exchange of the
        outstanding shares of the Common Stock solely into shares of common stock of the surviving entity); or (C) any sale, lease or other transfer in one transaction or a series of transactions of all or substantially all of the consolidated assets of
        the Company and its Subsidiaries, taken as a whole, to any Person other than one of the Company’s Subsidiaries; provided, however, that a transaction
        described in clauses (A) or (B) in which the holders of all classes of the Company’s Common Equity immediately prior to such transaction own, directly or indirectly, more than 50% of all classes of Common Equity of the continuing or surviving
        corporation or transferee or the parent thereof immediately after such transaction in substantially the same proportions (relative to each other and with respect to the securities received in such transaction) as such ownership immediately prior to
        such transaction shall not be a Fundamental Change pursuant to this clause (b);

     

    
      5

      
        


    

    (c)          the stockholders of the Company
        approve any plan or proposal for the liquidation or dissolution of the Company; or

     

    (d)          the Common Stock (or other common
        stock into which the Notes are then convertible) ceases to be quoted or listed for trading on any of The New York Stock Exchange, The Nasdaq Global Select Market or The Nasdaq Global Market (or any of their respective successors),

     

    provided, however, that a transaction or event described in clause (a) or (b) above shall not constitute a Fundamental Change if at least 90% of the consideration received or to be received by the holders of Common Stock,
      excluding cash payments for fractional shares or pursuant to statutory dissenters’ appraisal rights, in connection with the transaction or transactions constituting the Fundamental Change consists of shares of common stock that are quoted or listed for trading on any of The New York Stock Exchange, The Nasdaq Global Select Market or The Nasdaq Global Market (or any of their respective successors) or that will be so quoted
      or listed when issued or exchanged in connection with such transaction or transactions and, as a result of such transaction or transactions, the Notes become convertible into or exchangeable for such consideration, excluding cash payments for
      fractional shares or pursuant to statutory dissenters’ appraisal rights (subject to the provisions of Section 14.02(a)).  Any transaction or event that constitutes a Fundamental Change pursuant to both clause (a) and clause (b) above shall be deemed
      a Fundamental Change solely under clause (b) above.  If any transaction or event occurs in which the Reference Property into which the Notes become convertible pursuant to Section 14.07 consists of shares of common stock or other Common Equity of
      another entity, following completion of such transaction or event or, if applicable, any related Make-Whole Fundamental Change Period, references to the Company in this definition shall instead be references to such other entity.

     

    “Fundamental Change Company Notice” shall have the meaning
      specified in Section 15.02(c).

     

    “Fundamental Change Purchase Date” shall have the meaning
      specified in Section 15.02(a).

     

    “Fundamental Change Purchase Notice” shall have the meaning
      specified in Section 15.02(b)(i).

     

    
      6

      
        


    

    “Fundamental Change Purchase Price” shall have the meaning
      specified in Section 15.02(a).

     

    “given,” with respect to any notice to be given to a Holder
      pursuant to this Indenture, shall mean notice (x) given to the Depositary (or its designee) pursuant to the standing instructions from the Depositary or its designee, including by electronic mail in accordance with accepted practices or procedures at
      the Depositary (in the case of a Global Note) or (y) mailed to such Holder by first class mail, postage prepaid, at its address as it appears on the Note Register, in each case in accordance with Section 17.03. Notice so “given” shall be deemed to
      include any notice to be “mailed” or “delivered,” as applicable, under this Indenture.

     

    “Global Note” shall have the meaning specified in Section
      2.05(b).

     

    “Holder,” as applied to any Note, or other similar terms (but
      excluding the term “beneficial holder”), shall mean any person in whose name at the time a particular Note is registered on the Note Register.

     

    “Indenture” means this instrument as originally executed or, if
      amended or supplemented as herein provided, as so amended or supplemented.

     

    “Interest Payment Date” means each June 15 and December 15 of
      each year, beginning on June 15, 2020.

     

    “Irrevocable Election” shall have the meaning specified in
      Section 14.02.

     

    “Last Reported Sale Price” of the Common Stock on any date means
      the closing sale price per share (or if no closing sale price is reported, the average of the bid and ask prices per share of Common Stock or, if more than one in either case, the average of the average bid and the average ask prices per share of
      Common Stock) on that date as reported in composite transactions for the principal U.S. national or regional securities exchange on which the Common Stock is traded.  If the Common Stock is not listed for trading on a U.S. national or regional
      securities exchange on the relevant date, the “Last Reported Sale Price” shall be the last quoted bid price for the Common Stock in the over-the-counter market
      on the relevant date as reported by OTC Markets Group Inc. or a similar organization.  If the Common Stock is not so quoted, the “Last Reported Sale Price” shall
      be the average of the mid-point of the last bid and ask prices for the Common Stock on the relevant date from each of at least three nationally recognized independent investment banking firms selected by the Company for this purpose.  The “Last Reported Sale Price” shall be determined without reference to after-hours trading or any other trading outside of the regular trading session hours.

     

    “Make-Whole Fundamental Change” means any transaction or event
      that constitutes a Fundamental Change under clauses (a), (b) and (d) of the definition thereof and determined after giving effect to any exceptions to or exclusions from such definition, including, without limitation, the paragraph following clause
      (d) but without regard to the proviso in clause (b) of the definition thereof.

     

    
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    “Make-Whole Fundamental Change Period” shall have the meaning
      specified in Section 14.03(a).

     

    “Market Disruption Event” means (a) a failure by the primary
      U.S. national or regional securities exchange or market on which the Common Stock is listed or admitted for trading to open for trading during its regular trading session or (b) the occurrence or existence during the one half-hour period ending on
      the scheduled close of trading on any Trading Day of any material suspension or limitation imposed on trading (by reason of movements in price exceeding limits permitted by the relevant stock exchange or otherwise) in the Common Stock or in any
      options, contracts or futures contracts relating to the Common Stock; provided that for purposes of determining amounts due upon conversion only, “Market Disruption Event” means (x) a failure by the primary U.S. national or regional securities exchange or market on which the Common Stock is listed or admitted
      for trading to open for trading during its regular trading session or (y) the occurrence or existence prior to 1:00 p.m., New York City time, on any Scheduled Trading Day for the Common Stock for more than one half-hour period in the aggregate during
      regular trading hours of any suspension or limitation imposed on trading (by reason of movements in price exceeding limits permitted by the relevant stock exchange or otherwise) in the Common Stock or in any options contracts or futures contracts
      relating to the Common Stock.

     

    “Maturity Date” means December 15, 2024.

     

    “Measurement Period” shall have the meaning specified in Section
      14.01(b)(i).

     

    “Merger Event” shall have the meaning specified in Section
      14.07(a).

     

    “Note” or “Notes” shall have the meaning specified in the first paragraph of the recitals of this Indenture.

     

    “Note Register” shall have the meaning specified in Section
      2.05(a).

     

    “Note Registrar” shall have the meaning specified in Section
      2.05(a).

     

    “Notice of Conversion” shall have the meaning specified in
      Section 14.02(b).

     

    “Observation Period” with respect to any Note surrendered for
      conversion means: (i) if the relevant Conversion Date occurs prior to August 1, 2024, the 30 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 August 1, 2024, the 30 consecutive Trading Days beginning on, and including, the 31st Scheduled Trading Day immediately preceding the Maturity Date.

     

    “Officer” means, with respect to the Company, the Chairman of
      the Board of Directors, President, the Chief Executive Officer, the Treasurer, Assistant Treasurer, the Secretary, Assistant Secretary, any Executive or Senior Vice President, Managing Director, Controller, Assistant Controller or any Vice President
      (whether or not designated by a number or numbers or word or words added before or after the title “Vice President”).

     

    
      8

      
        


    

    “Officer’s Certificate,” when used with respect to the Company,
      means a certificate that is delivered to the Trustee and that is signed by an Officer of the Company.  Each such certificate shall include the statements provided for in Section 17.05 if and to the extent required by the provisions of such Section. 
      The Officer giving an Officer’s Certificate pursuant to Section 4.08 shall be the principal executive, financial or accounting officer of the Company.

     

    “open of business” means 9:00 a.m. (New York City time).

     

    “Opinion of Counsel” means an opinion in writing signed by legal
      counsel, who may be an employee of or counsel to the Company or other counsel acceptable to the Trustee, that is delivered to the Trustee.  Each such opinion shall include, without limitation, the statements provided for in Section 17.05 if and to
      the extent required by the provisions of such Section 17.05.

     

    “outstanding,” when used with reference to Notes, shall, subject
      to the provisions of Section 8.04, mean, as of any particular time, all Notes authenticated and delivered by the Trustee under this Indenture, except:

     

    (a)          Notes theretofore canceled by the
        Trustee or accepted by the Trustee for cancellation;

     

    (b)          Notes, or portions thereof, that have
        become due and payable and in respect of which monies in the necessary amount shall have been deposited in trust with the Trustee or with any Paying Agent (other than the Company) or shall have been set aside and segregated in trust by the Company
        (if the Company shall act as its own Paying Agent);

     

    (c)          Notes that have been paid pursuant to
        Section 2.06 or Notes in lieu of which, or in substitution for which, other Notes shall have been authenticated and delivered pursuant to the terms of Section 2.06 (including Predecessor Notes) unless proof satisfactory to the Trustee is presented
        that any such Notes are held by protected purchasers in due course (in which case such other Notes shall not be deemed to be outstanding);

     

    (d)          Notes converted pursuant to Article 14 and required to be cancelled pursuant to Section 2.08; and

     

    (e)          Notes purchased by the Company
        pursuant to the penultimate sentence of Section 2.10 after the Company surrenders them to the Trustee for cancellation in accordance with Section 2.08.

     

    “Paying Agent” shall have the meaning specified in Section 4.02.

     

    “Person” means an individual, a corporation, a limited liability
      company, an association, a partnership, a joint venture, a joint stock company, a trust, an unincorporated organization, any other entity or organization or a government or an agency or a political subdivision thereof.

     

    
      9

      
        


    

    “Physical Notes” means permanent certificated Notes in
      registered form issued in denominations of $1,000 principal amount and multiples thereof.

     

    “Physical Settlement” shall have the meaning specified in
      Section 14.02(a).

     

    “Predecessor Note” of any particular Note means every previous
      Note evidencing all or a portion of the same debt as that evidenced by such particular Note; and, for the purposes of this definition, any Note authenticated and delivered under Section 2.06 in lieu of or in exchange for a mutilated, lost, destroyed
      or stolen Note shall be deemed to evidence the same debt as the mutilated, lost, destroyed or stolen Note that it replaces.

     

    “Record Date” means, with respect
      to any dividend, distribution or other transaction or event in which the holders of Common Stock (or other applicable security) have the right to receive any cash, securities or other property or in which the Common Stock (or other applicable
      security) is exchanged for or converted into any combination of cash, securities or other property, the date fixed for determination of holders of Common Stock (or other applicable security) entitled to receive such cash, securities or other property
      (whether such date is fixed by the Board of Directors, by statute, by contract or otherwise).

     

    “Reference Property” shall have the meaning specified in Section
      14.07(a).

     

    “Regular Record Date,” with respect to any Interest Payment
      Date, shall mean the June 1 or December 1 (whether or not such day is a Business Day) immediately preceding the applicable June 15 or December 15 Interest Payment Date, respectively.

     

    “Resale Restriction Termination Date” shall have the meaning
      specified in Section 2.05(c).

     

    “Responsible Officer” means, when used with respect to the
      Trustee, any officer within the corporate trust department of the Trustee, including any vice president, assistant vice president, assistant secretary, assistant treasurer, trust officer or any other officer of the Trustee who customarily performs
      functions similar to those performed by the Persons who at the time shall be such officers, respectively, or to whom any corporate trust matter is referred because of such person’s knowledge of and familiarity with the particular subject and who
      shall have direct responsibility for the administration of this Indenture.

     

    “Restricted Securities” shall have the meaning specified in
      Section 2.05(c).

     

    “Rule 144” means Rule 144 as promulgated under the Securities
      Act, including any successor rule thereto.

     

    “Rule 144A” means Rule 144A as promulgated under the Securities
      Act.

     

    “Scheduled Trading Day” means a day that is scheduled to be a
      Trading Day on the principal U.S. national or regional securities exchange or market on which the Common Stock is listed or admitted for trading.  If the Common Stock is not so listed or admitted for trading, “Scheduled Trading Day” means a Business Day.

     

    
      10

      
        


    

    “Securities Act” means the Securities Act of 1933, as amended,
      and the rules and regulations promulgated thereunder.

     

    “Settlement Amount” has the meaning specified in Section 14.02(a)(iv).

     

    “Settlement Method” means, with respect to any conversion of
      Notes, Physical Settlement, Cash Settlement or Combination Settlement, as elected (or deemed to have been elected) by the Company.

     

    “Settlement Notice” has the meaning specified in Section
      14.02(a)(iii).

     

    “Shelf Registration Statement” means a registration statement of
      the Company filed with the Commission on either (i) Form S-3 (or any successor form or other appropriate form under the Securities Act) or (ii) if the Company is not permitted to file a registration statement on Form S-3, an evergreen registration
      statement on Form S-1 (or any successor form or other appropriate form under the Securities Act), in each case for an offering to be made on a continuous or delayed basis pursuant to Rule 415 under the Securities Act covering Notes and any Common
      Stock issuable upon conversion thereof.

     

    “Significant Subsidiary” means a Subsidiary of the Company that
      meets the definition of “significant subsidiary” in Article 1, Rule 1-02(w) of Regulation S-X under the Exchange Act (or any successor rule), in each case subject to the three immediately succeeding sentences of this definition. For purposes of
      Article 6 (other than Section 6.01(g)), the term “Significant Subsidiary” shall be deemed to include any group of Subsidiaries of the Company that, in the aggregate, would constitute a “Significant Subsidiary” as defined in the preceding sentence.
      For purposes of Section 6.01(g) only, the term “Significant Subsidiary” shall not include any Subsidiary that meets the criteria of clause (3) of the definition thereof in Article 1, Rule 1-02(w) of Regulation S-X but not clause (1) or (2) thereof,
      in each case as such rule is in effect on the date of this Indenture, unless the Subsidiary’s income (or loss) from continuing operations before income taxes, extraordinary items and cumulative effect of a change in accounting principle exclusive of
      amounts attributable to any non-controlling interests for the last completed fiscal year prior to the date of such determination exceeds $35,000,000. For the avoidance of doubt, for purposes of Section 6.01(g), to the extent any such Subsidiary would
      not be deemed to be a “significant subsidiary” under the relevant definition set forth in Article 1, Rule 1-02(w) of Regulation S-X (or any successor rule) as in effect on the relevant date of determination, such Subsidiary shall not be deemed to be
      a “Significant Subsidiary” under this Indenture irrespective of whether such Subsidiary would otherwise be deemed to be a “Significant Subsidiary” pursuant to the immediately preceding sentence.

     

    “Specified Dollar Amount” means the maximum cash amount per
      $1,000 principal amount of Notes to be received upon conversion as specified in the Settlement Notice related to any converted Notes.

     

    “Spin-Off” shall have the meaning specified in Section 14.04(c).

     

    “Stock Price” shall have the meaning specified in Section
      14.03(c).

     

    
      11

      
        


    

    “Subsidiary” means, with respect to any Person, any corporation,
      association, partnership or other business entity of which more than 50% of the total voting power of shares of Capital Stock or other interests (including partnership interests) entitled (without regard to the occurrence of any contingency) to vote
      in the election of directors, managers, general partners or trustees thereof is at the time owned or controlled, directly or indirectly, by (i) such Person; (ii) such Person and one or more Subsidiaries of such Person; or (iii) one or more
      Subsidiaries of such Person.

     

    “Successor Company” shall have the meaning specified in Section
      11.01(a).

     

    “Term Sheet” means the final pricing term sheet dated December
      11, 2019, relating to the offering and sale of the Notes.

     

    “Trading Day” means a day on which (i) there is no Market
      Disruption Event, (ii) trading in the Common Stock (or other security for which a closing sale price must be determined) generally occurs on The Nasdaq Global Select Market or, if the Common Stock (or such other security) is not then listed on The
      Nasdaq Global Select Market, on the principal other U.S. national or regional securities exchange on which the Common Stock (or such other security) is then listed or, if the Common Stock (or such other security) is not then listed on a U.S. national
      or regional securities exchange, on the principal other market on which the Common Stock (or such other security) is then listed or admitted for trading and (iii) a Last Reported Sale Price for the Common Stock (or closing sale price for such other
      security) is available on such securities exchange or market, except that if the Common Stock (or such other security) is not so listed or admitted for trading, “Trading
        Day” means a Business Day; provided that for purposes of determining amounts due upon conversion only, “Trading Day” means a day on which (x) there is no Market Disruption Event and (y) trading in the Common Stock generally occurs on The Nasdaq Global Select Market or, if the Common Stock is not then
      listed on The Nasdaq Global Select Market, on the principal other U.S. national or regional securities exchange on which the Common Stock is then listed or, if the Common Stock is not then listed on a U.S. national or regional securities exchange, on
      the principal other market on which the Common Stock is then listed or admitted for trading, except that if the Common Stock is not so listed or admitted for trading, “Trading
        Day” means a Business Day.

     

    “Trading Price” per $1,000 principal amount of Notes on any date
      of determination means the average of the secondary market bid quotations obtained by the Bid Solicitation Agent for $5,000,000 principal amount of Notes at approximately 3:30 p.m., New York City time, on such determination date from three
      independent U.S. nationally recognized securities dealers selected by the Company for this purpose; provided that if three such bids cannot reasonably be
      obtained by the Bid Solicitation Agent, but two such bids are obtained, then the average of the two bids shall be used, and if only one such bid can reasonably be obtained by the Bid Solicitation Agent, that one bid shall be used. If the Bid
      Solicitation Agent cannot reasonably obtain at least one bid for $5,000,000 principal amount of Notes from any such nationally recognized securities dealer selected by the Company on any date of determination, then the Trading Price per $1,000
      principal amount of Notes on such date shall be deemed to be less than 98% of the product of the Last Reported Sale Price of the Common Stock and the applicable Conversion Rate.

     

    
      12

      
        


    

    “transfer” shall have the meaning specified in Section 2.05(c).

     

    “Trigger Event” shall have the meaning specified in Section
      14.04(c).

     

    “Trust Indenture Act” means the Trust Indenture Act of 1939, as
      amended, as it was in force at the date of execution of this Indenture; provided, however, that in the event the Trust Indenture Act of 1939 is amended after the date hereof, the term “Trust Indenture Act” shall mean, to the extent required by such amendment, the Trust Indenture Act of 1939, as so amended.

     

    “Trustee” means the Person named as the “Trustee” in the first paragraph of this Indenture until a successor Trustee shall have become such pursuant to the applicable provisions of this Indenture, and thereafter “Trustee” shall mean or include each Person who is then a Trustee hereunder.

     

    “unit of Reference Property” shall have the meaning specified in
      Section 14.07(a).

     

    Section 1.02.  References to Interest.  Unless the context otherwise requires, any reference to interest on, or in respect of, any Note in this Indenture shall be deemed to include Additional Interest if, in such context, Additional Interest
        is, was or would be payable pursuant to any of Section 4.06(d), Section 4.06(e) and Section 6.03. Unless the context otherwise requires, any express mention of Additional Interest in any provision hereof shall not be construed as excluding
        Additional Interest in those provisions hereof where such express mention is not made.

     

    ARTICLE 2

        Issue, Description, Execution, Registration and Exchange of Notes

     

    Section 2.01.  Designation and Amount.  The Notes shall be designated as the “0.125% Convertible Senior Notes due 2024.” The aggregate principal amount of Notes that may be authenticated and delivered under this Indenture is initially limited
        to $548,826,000 subject to Section 2.10 and except for Notes authenticated and delivered upon registration or transfer of, or in exchange for, or in lieu of other Notes to the extent expressly permitted hereunder.

     

    Section 2.02.  Form of Notes.  The Notes and the Trustee’s certificate of authentication to be borne by such Notes shall be substantially in the respective forms set forth in Exhibit A, the terms and provisions of which shall constitute, and
        are hereby expressly incorporated in and made a part of this Indenture.  To the extent applicable, the Company and the Trustee, by their execution and delivery of this Indenture, expressly agree to such terms and provisions and to be bound thereby.

     

    Any Global Note may be endorsed with or have incorporated in the text thereof such legends or recitals or changes not inconsistent with the provisions of
      this Indenture as may be required by the Custodian or the Depositary, or as may be required to comply with any applicable law or any regulation thereunder or with the rules and regulations of any securities exchange or automated quotation system upon
      which the Notes may be listed or traded or designated for issuance or to conform with any usage with respect thereto, or to indicate any special limitations or restrictions to which any particular Notes are subject.

     

    
      13

      
        


    

    Any of the Notes may have such letters, numbers or other marks of identification and such notations, legends or endorsements as any Officer executing the
      same may approve (execution thereof to be conclusive evidence of such approval) and as are not inconsistent with the provisions of this Indenture, or as may be required to comply with any law or with any rule or regulation made pursuant thereto or
      with any rule or regulation of any securities exchange or automated quotation system on which the Notes may be listed or designated for issuance, or to conform to usage or to indicate any special limitations or restrictions to which any particular
      Notes are subject.

     

    Each Global Note shall represent such principal amount of the outstanding Notes as shall be specified therein and shall provide that it shall represent
      the aggregate principal amount of outstanding Notes from time to time endorsed thereon and that the aggregate principal amount of outstanding Notes represented thereby may from time to time be increased or reduced to reflect purchases, cancellations,
      conversions, transfers, exchanges or issuances of additional Notes permitted hereby (to the extent that such issuances are fungible with the Notes represented by such Global Note for U.S. federal income tax and securities law purposes).  Any
      endorsement of the Global Note to reflect the amount of any increase or decrease in the amount of outstanding Notes represented thereby shall be made by the Trustee or the Custodian, at the direction of the Trustee, in such manner and upon
      instructions given by the Holder of such Notes in accordance with this Indenture.  Payment of principal (including the Fundamental Change Purchase Price, if applicable) of, and accrued and unpaid interest on, the Global Note shall be made to the
      Holder of such Note on the date of payment, unless a record date or other means of determining Holders eligible to receive payment is provided for herein.

     

    Section 2.03.  Date and Denomination of Notes; Payments of Interest and Defaulted Amounts.  (a) The Notes shall be issuable in registered form without coupons in denominations of $1,000 principal amount and multiples thereof.  Each Note shall
        be dated the date of its authentication and shall bear interest from the date specified on the face of the Form of Note.  Accrued interest on the Notes shall be computed on the basis of a 360-day year composed of twelve 30-day months and, for
        partial months, on the basis of the number of days actually elapsed in a 30-day month.

     

    (b)      The Person in whose name any Note (or its Predecessor Note) is registered on
        the Note Register at the close of business on any Regular Record Date with respect to any Interest Payment Date shall be entitled to receive the interest payable on such Interest Payment Date.  Interest (x) in the case of any Physical Note, shall
        be payable at the office or agency of the Company maintained by the Company for such purposes, which shall initially be the Corporate Trust Office and (y) in the case of any Global Note, shall be payable by wire transfer of immediately available
        funds to the account of the Depositary or its nominee. The Company shall pay or cause the Paying Agent to pay interest (i) on any Physical Notes (A) to Holders holding Physical Notes having an aggregate principal amount of $5,000,000 or less, by
        check mailed to the Holders of these Notes at their address as it appears in the Note Register and (B) to Holders holding Physical Notes having an aggregate principal amount of more than $5,000,000, either by check mailed to such Holders or, upon
        application by such Holder to the Note Registrar not later than the relevant Regular Record Date, by wire transfer in immediately available funds to that Holder’s account within the United States of America, which application shall remain in effect
        until the Holder notifies, in writing, the Note Registrar to the contrary or (ii) on any Global Note by wire transfer of immediately available funds to the account of the Depositary or its nominee.

     

    
      14

      
        


    

    (c)      Any Defaulted Amounts shall forthwith cease to
        be payable to the Holder on the relevant payment date but shall accrue interest per annum at the rate borne by the Notes from, and including, such relevant payment date, and such Defaulted Amounts together with such interest thereon shall be paid
        by the Company, at its election in each case, as follows:

     

    
      
        (i)      The Company may elect to make
          payment of any Defaulted Amounts to the Persons in whose names the Notes (or their respective Predecessor Notes) are registered at the close of business on a special record date for the payment of such Defaulted Amounts, which shall be fixed in
          the following manner.  The Company shall notify the Trustee in writing of the amount of the Defaulted Amounts proposed to be paid on each Note and the date of the proposed payment (which shall be not less than 20 days after the receipt by the
          Trustee of such notice, unless the Trustee shall consent to an earlier date), and at the same time the Company shall deposit with the Trustee an amount of money equal to the aggregate amount to be paid in respect of such Defaulted Amounts or
          shall make arrangements satisfactory to the Trustee for such deposit on or prior to the date of the proposed payment, such money when deposited to be held in trust for the benefit of the Persons entitled to such Defaulted Amounts as in this
          clause provided.  Thereupon the Company shall fix a special record date for the payment of such Defaulted Amounts which shall be not more than 15 days and not less than 10 days prior to the date of the proposed payment, and not less than 10 days
          after the receipt by the Trustee of the notice of the proposed payment (unless the Trustee shall consent to an earlier date).  The Company shall promptly notify the Trustee in writing of such special record date and the Trustee, in the name and
          at the expense of the Company, shall cause notice of the proposed payment of such Defaulted Amounts and the special record date therefor to be mailed, first-class postage prepaid, to each Holder at its address as it appears in the Note Register,
          in the case of Physical Notes, or delivered in accordance with the Depositary’s applicable procedures, in the case of Notes represented by a Global Note, in each case not less than 10 calendar days prior to such special record date.  Notice of
          the proposed payment of such Defaulted Amounts and the special record date therefor having been so mailed, such Defaulted Amounts shall be paid to the Persons in whose names the Notes (or their respective Predecessor Notes) are registered at the
          close of business on such special record date and shall no longer be payable pursuant to the following clause (ii) of this Section 2.03(c).

      

    

    
      
         

          

        (ii)      The Company may make payment of
          any Defaulted Amounts in any other lawful manner not inconsistent with the requirements of any securities exchange or automated quotation system on which the Notes may be listed or designated for issuance, and upon such notice as may be required
          by such exchange or automated quotation system, if, after notice given by the Company to the Trustee of the proposed payment pursuant to this clause, such manner of payment shall be deemed practicable by the Trustee.

      

    

    
      
         

          

        
          15

          
            


        

        (iii)     The Trustee shall not at any
          time be under any duty or responsibility to any Holder to determine the Defaulted Amount, or with respect to the nature, extent or calculation of the Defaulted Amount owed or with respect to the method employed in such calculation of the
          Defaulted Amount.

      

    

     

      

    Section 2.04.  Execution, Authentication and Delivery of Notes. 
        The Notes shall be signed in the name and on behalf of the Company by the manual or facsimile signature of any Officer.

     

    At any time and from time to time after the execution and delivery of this Indenture, the Company may deliver Notes executed by the Company to the
      Trustee for authentication, together with a Company Order for the authentication and delivery of such Notes, and the Trustee in accordance with such Company Order shall authenticate and deliver such Notes, without any further action by the Company
      hereunder.

     

    Only such Notes as shall bear thereon a certificate of authentication substantially in the form set forth on the Form of Note, executed manually by an
      authorized signatory of the Trustee (or an authenticating agent appointed by the Trustee as provided by Section 17.10), shall be entitled to the benefits of this Indenture or be valid or obligatory for any purpose.  Such certificate by the Trustee
      (or such an authenticating agent) upon any Note executed by the Company shall be conclusive evidence that the Note so authenticated has been duly authenticated and delivered hereunder and that the Holder is entitled to the benefits of this Indenture.

     

    In case any Officer of the Company who shall have signed any of the Notes shall cease to be such Officer before the Notes so signed shall have been
      authenticated and delivered by the Trustee, or disposed of by the Company, such Notes nevertheless may be authenticated and delivered or disposed of as though the Person who signed such Notes had not ceased to be such Officer of the Company; and any
      Note may be signed on behalf of the Company by such persons as, at the actual date of the execution of such Note, shall be an Officer of the Company, although at the date of the execution of this Indenture any such person was not such an Officer.

     

    Section 2.05.  Exchange and Registration of Transfer of Notes; Restrictions on Transfer; Depositary.  (a) The Company shall cause to be kept
        at the office of the Note Registrar and the Note Registrar agrees to keep a register (the register maintained in such office or in any other office or agency of the Company designated pursuant to Section 4.02, the “Note Register”) in which, subject to such reasonable regulations as it may prescribe, the Company shall
        provide for the registration of Notes and transfers of Notes.  Such register shall be in written form or in any form capable of being converted into written form within a reasonable period of time.  The Trustee is hereby initially appointed the “Note Registrar” for the purpose of registering Notes and transfers of Notes as herein provided.  The Company may appoint a new Note Registrar without prior notice
        to Holders.  The Company may appoint one or more co-Note Registrars in accordance with Section 4.02.

     

    
      16

      
        


    

    Upon surrender for registration of transfer of any Note to the Note Registrar or any co-Note Registrar, and satisfaction of the requirements for such
      transfer set forth in this Section 2.05, the Company shall execute, and the Trustee shall, upon receipt of a Company Order, authenticate and deliver, in the name of the designated transferee or transferees, one or more new Notes of any authorized
      denominations and of a like aggregate principal amount and bearing such restrictive legends as may be required by this Indenture.

     

    Notes may be exchanged for other Notes of any authorized denominations and of a like aggregate principal amount, upon surrender of the Notes to be
      exchanged at any such office or agency maintained by the Company pursuant to Section 4.02.  Whenever any Notes are so surrendered for exchange, the Company shall execute, and the Trustee shall, upon receipt of a Company Order, authenticate and
      deliver, the Notes that the Holder making the exchange is entitled to receive, bearing registration numbers not contemporaneously outstanding.

     

    All Notes presented or surrendered for registration of transfer or for exchange, purchase or conversion shall (if so required by the Company, the
      Trustee, the Note Registrar or any co-Note Registrar) be duly endorsed, or be accompanied by a written instrument or instruments of transfer in form satisfactory to the Company and duly executed, by the Holder thereof or its attorney-in-fact duly
      authorized in writing.

     

    No service charge shall be imposed by the Company, the Trustee, the Note Registrar or any co-Note Registrar for any exchange or registration of transfer
      of Notes, but the Company or the Trustee may require a Holder to pay a sum sufficient to cover any documentary, stamp or similar issue or transfer tax required by law or permitted pursuant to Section 14.02(d) or Section 14.02(e).

     

    None of the Company, the Trustee, the Note Registrar or any co-Note Registrar shall be required to exchange or register a transfer of (i) any Notes
      surrendered for conversion or, if a portion of any Note is surrendered for conversion, such portion thereof surrendered for conversion or (ii) any Notes, or a portion of any Note, surrendered for purchase (and not withdrawn) in accordance with
      Article 15.

     

    All Notes issued upon any registration of transfer or exchange of Notes in accordance with this Indenture shall be the valid obligations of the Company,
      evidencing the same debt, and entitled to the same benefits under this Indenture as the Notes surrendered upon such registration of transfer or exchange.

     

    (b)          So long as the Notes are eligible for
        book-entry settlement with the Depositary, unless otherwise required by law, subject to the fourth paragraph from the end of Section 2.05(c) all Notes shall be represented by one or more Notes in global form (each, a “Global Note”) registered in the name of the Depositary or the nominee of the Depositary.  The transfer and exchange of beneficial interests in a Global Note that does not involve the
        issuance of a Physical Note, shall be effected through the Depositary (but not the Trustee or the Custodian) in accordance with this Indenture (including the restrictions on transfer set forth herein) and the procedures of the Depositary therefor.

     

    
      17

      
        


    

    (c)          Every Note that bears or is required under
        this Section 2.05(c) to bear the legend set forth in this Section 2.05(c) (together with any Common Stock issued upon conversion of the Notes and required to bear the legend set forth in Section 2.05(d), collectively, the “Restricted Securities”) shall be subject to the restrictions on transfer set forth in this Section 2.05(c) (including the legend set forth below), unless such restrictions on
        transfer shall be eliminated or otherwise waived by written consent of the Company, and the Holder of each such Restricted Security, by such Holder’s acceptance thereof, agrees to be bound by all such restrictions on transfer.  As used in this
        Section 2.05(c) and Section 2.05(d), the term “transfer” encompasses any sale, pledge, transfer or other disposition whatsoever of any Restricted Security.

     

    Until the date (the “Resale Restriction Termination Date”) that
      is the later of (1) the date that is one year after the last date of original issuance of the Notes, or such shorter period of time as permitted by Rule 144 or any successor provision thereto, and (2) such later date, if any, as may be required by
      applicable law, any certificate evidencing such Note (and all securities issued in exchange therefor or substitution thereof, other than Common Stock, if any, issued upon conversion thereof, which shall bear the legend set forth in Section 2.05(d),
      if applicable) shall bear a legend in substantially the following form (unless such Notes have been transferred pursuant to a registration statement that has become or been declared effective under the Securities Act and that continues to be
      effective at the time of such transfer, or sold pursuant to the exemption from registration provided by Rule 144 or any similar provision then in force under the Securities Act, or unless otherwise agreed by the Company in writing, with notice
      thereof to the Trustee):

     

    THIS SECURITY AND THE COMMON STOCK, IF ANY, ISSUABLE UPON CONVERSION OF THIS SECURITY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
      AMENDED (THE “SECURITIES ACT”), AND MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE WITH THE FOLLOWING SENTENCE. BY ITS ACQUISITION HEREOF OR OF A BENEFICIAL INTEREST HEREIN, THE ACQUIRER:

     

    (1)          REPRESENTS THAT IT AND ANY ACCOUNT
        FOR WHICH IT IS ACTING IS A “QUALIFIED INSTITUTIONAL BUYER” (WITHIN THE MEANING OF RULE 144A UNDER THE SECURITIES ACT) AND THAT IT EXERCISES SOLE INVESTMENT DISCRETION WITH RESPECT TO EACH SUCH ACCOUNT, AND

     

    (2)          AGREES FOR THE BENEFIT OF THE COMPANY
        THAT IT WILL NOT OFFER, SELL, PLEDGE OR OTHERWISE TRANSFER THIS SECURITY OR ANY BENEFICIAL INTEREST HEREIN PRIOR TO THE DATE THAT IS THE LATER OF (X) ONE YEAR AFTER THE LAST ORIGINAL ISSUE DATE HEREOF OR SUCH SHORTER PERIOD OF TIME AS PERMITTED BY
        RULE 144 UNDER THE SECURITIES ACT OR ANY SUCCESSOR PROVISION THERETO, AND (Y) SUCH LATER DATE, IF ANY, AS MAY BE REQUIRED BY APPLICABLE LAW, EXCEPT:

     

    (A)          TO IONIS PHARMACEUTICALS, INC. (THE
        “COMPANY”) OR ANY SUBSIDIARY THEREOF, OR

     

    
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    (B)          PURSUANT TO A REGISTRATION STATEMENT
        WHICH HAS BECOME EFFECTIVE UNDER THE SECURITIES ACT, OR

     

    (C)          TO A QUALIFIED INSTITUTIONAL BUYER IN
        COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, OR

     

    (D)          PURSUANT TO AN EXEMPTION FROM
        REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT OR ANY OTHER AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT.

     

    PRIOR TO THE REGISTRATION OF ANY TRANSFER IN ACCORDANCE WITH CLAUSE (2)(D) ABOVE, THE COMPANY AND THE TRUSTEE RESERVE THE RIGHT TO REQUIRE THE DELIVERY
      OF SUCH LEGAL OPINIONS, CERTIFICATIONS OR OTHER EVIDENCE AS MAY REASONABLY BE REQUIRED IN ORDER TO DETERMINE THAT THE PROPOSED TRANSFER IS BEING MADE IN COMPLIANCE WITH THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS. NO REPRESENTATION IS
      MADE AS TO THE AVAILABILITY OF ANY EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT.

     

    No transfer of any Note prior to the Resale Restriction Termination Date will be registered by the Note Registrar unless the applicable box on the Form
      of Assignment and Transfer has been checked.

     

    Any Note (or security issued in exchange or substitution therefor) (i) as to which such restrictions on transfer shall have expired in accordance with
      their terms, (ii) that has been transferred pursuant to a registration statement that has become effective or been declared effective under the Securities Act and that continues to be effective at the time of such transfer or (iii) that has been sold
      pursuant to the exemption from registration provided by Rule 144 or any similar provision then in force under the Securities Act, may, upon surrender of such Note for exchange to the Note Registrar in accordance with the provisions of this Section
      2.05, be exchanged for a new Note or Notes, of like tenor and aggregate principal amount, which shall not bear the restrictive legend required by this Section 2.05(c) and shall not be
        assigned a restricted CUSIP number. The Company shall be entitled to instruct the Custodian in writing to so surrender any Global Note as to which any of the conditions set forth in clause (i) through (iii) of the immediately preceding
      sentence have been satisfied, and, upon such instruction, the Custodian shall so surrender such Global Note for exchange; and any new Global Note so exchanged therefor shall not bear the
        restrictive legend specified in this Section 2.05(c) and shall not be assigned a restricted CUSIP number.  The Company shall promptly notify the Trustee upon the
      occurrence of the Resale Restriction Termination Date and promptly after a registration statement, if any, with respect to the Notes or any Common Stock issued upon conversion of the Notes has been declared effective under the Securities Act.

     

    
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    Notwithstanding any other provisions of this Indenture (other than the provisions set forth in this Section 2.05(c)), a
      Global Note may not be transferred as a whole or in part except (i) by the Depositary to a nominee of the Depositary or by a nominee of the Depositary to the Depositary or another nominee of the Depositary or by the Depositary or any such nominee to
      a successor Depositary or a nominee of such successor Depositary and (ii) for transfers of portions of a Global Note in certificated form made upon request of a member of, or a participant in, the Depositary (for itself or on behalf of a beneficial
      owner) by written notice given to the Trustee by or on behalf of the Depositary in accordance with customary procedures of the Depositary and in compliance with this Section 2.05(c).

     

    The Depositary shall be a clearing agency registered under the Exchange Act.  The Company initially appoints The Depository Trust Company to act as
      Depositary with respect to each Global Note.  Initially, each Global Note shall be issued to the Depositary, registered in the name of Cede & Co., as the nominee of the Depositary, and deposited with the Trustee as custodian for Cede & Co.

     

    If (i) the Depositary notifies the Company at any time that the Depositary is unwilling or unable to continue as depositary for the Global Notes and a
      successor depositary is not appointed within 90 days, (ii) the Depositary ceases to be registered as a clearing agency under the Exchange Act and a successor depositary is not appointed within 90 days or (iii) an Event of Default with respect to the
      Notes has occurred and is continuing and a beneficial owner of any Note requests that its beneficial interest therein be issued as a Physical Note, the Company shall execute, and the Trustee, upon receipt of an Officer’s Certificate and a Company
      Order for the authentication and delivery of Notes, shall authenticate and deliver (x) in the case of clause (iii), a Physical Note to such beneficial owner in a principal amount equal to the principal amount of such Note corresponding to such
      beneficial owner’s beneficial interest and (y) in the case of clause (i) or (ii), Physical Notes to each beneficial owner of the related Global Notes (or a portion thereof) in an aggregate principal amount equal to the aggregate principal amount of
      such Global Notes in exchange for such Global Notes, and upon delivery of the Global Notes to the Trustee such Global Notes shall be canceled.

     

    Physical Notes issued in exchange for all or a part of the Global Note pursuant to this Section 2.05(c) shall be registered in such names and in such
      authorized denominations as the Depositary, pursuant to instructions from its direct or indirect participants or otherwise, or, in the case of clause (iii) of the immediately preceding paragraph, the relevant beneficial owner, shall instruct the
      Trustee in writing.  Upon execution and authentication, the Trustee shall deliver such Physical Notes to the Persons in whose names such Physical Notes are so registered.

     

    At such time as all interests in a Global Note have been converted, canceled, purchased or transferred, such Global Note shall be, upon receipt thereof,
      canceled by the Trustee in accordance with standing procedures and existing instructions between the Depositary and the Custodian.  At any time prior to such cancellation, if any interest in a Global Note is exchanged for Physical Notes, converted,
      canceled, purchased or transferred to a transferee who receives Physical Notes therefor or any Physical Note is exchanged or transferred for part of such Global Note, the principal amount of such Global Note shall, in accordance with the standing
      procedures and instructions existing between the Depositary and the Custodian, be appropriately reduced or increased, as the case may be, and an endorsement shall be made on such Global Note, by the Trustee or the Custodian, at the direction of the
      Trustee, to reflect such reduction or increase.

     

    
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    Neither the Company, the Trustee nor any agent of the Company or the Trustee shall have any responsibility or liability for any aspect of the records
      relating to or payments made on account of beneficial ownership interests of a Global Note or maintaining, supervising or reviewing any records relating to such beneficial ownership interests.

     

    Neither the Trustee nor any agent shall have any responsibility or liability for any actions taken or not taken by the Depositary.

     

    (d)          Until the Resale Restriction Termination
        Date, any stock certificate representing Common Stock issued upon conversion of such Note shall bear a legend in substantially the following form (unless the Note or such Common Stock has been transferred pursuant to a registration statement that
        has become or been declared effective under the Securities Act and that continues to be effective at the time of such transfer, or pursuant to the exemption from registration provided by Rule 144 or any similar provision then in force under the
        Securities Act, or such Common Stock has been issued upon conversion of Notes that have been transferred pursuant to a registration statement that has become or been declared effective under the Securities Act and that continues to be effective at
        the time of such transfer, or pursuant to the exemption from registration provided by Rule 144 or any similar provision then in force under the Securities Act, or unless otherwise agreed by the Company with written notice thereof to the Trustee and
        any transfer agent for the Common Stock):

     

    THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND MAY NOT BE OFFERED, SOLD, PLEDGED OR
      OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE WITH THE FOLLOWING SENTENCE. BY ITS ACQUISITION HEREOF OR OF A BENEFICIAL INTEREST HEREIN, THE ACQUIRER:

     

    (1)          REPRESENTS THAT IT AND ANY ACCOUNT
        FOR WHICH IT IS ACTING IS A “QUALIFIED INSTITUTIONAL BUYER” (WITHIN THE MEANING OF RULE 144A UNDER THE SECURITIES ACT) AND THAT IT EXERCISES SOLE INVESTMENT DISCRETION WITH RESPECT TO EACH SUCH ACCOUNT, AND

     

    (2)          AGREES FOR THE BENEFIT OF IONIS
        PHARMACEUTICALS, INC. (THE “COMPANY”) THAT IT WILL NOT OFFER, SELL, PLEDGE OR OTHERWISE TRANSFER THIS SECURITY OR ANY BENEFICIAL INTEREST HEREIN PRIOR TO THE DATE THAT IS THE LATER OF (X) ONE YEAR AFTER THE LAST ORIGINAL ISSUE DATE OF THE SERIES OF
        NOTES UPON THE CONVERSION OF WHICH THIS SECURITY WAS ISSUED OR SUCH SHORTER PERIOD OF TIME AS PERMITTED BY RULE 144 UNDER THE SECURITIES ACT OR ANY SUCCESSOR PROVISION THERETO AND (Y) SUCH LATER DATE, IF ANY, AS MAY BE REQUIRED BY APPLICABLE LAW,
        EXCEPT:

     

    (A)          TO THE COMPANY OR ANY SUBSIDIARY
        THEREOF, OR

     

    (B)          PURSUANT TO A REGISTRATION STATEMENT
        WHICH HAS BECOME EFFECTIVE UNDER THE SECURITIES ACT, OR

     

    
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    (C)          TO A QUALIFIED INSTITUTIONAL BUYER IN
        COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, OR

     

    (D)          PURSUANT TO AN EXEMPTION FROM
        REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT OR ANY OTHER AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT.

     

    PRIOR TO THE REGISTRATION OF ANY TRANSFER IN ACCORDANCE WITH CLAUSE (2)(D) ABOVE, THE COMPANY AND THE TRUSTEE RESERVE THE RIGHT TO REQUIRE THE DELIVERY
      OF SUCH LEGAL OPINIONS, CERTIFICATIONS OR OTHER EVIDENCE AS MAY REASONABLY BE REQUIRED IN ORDER TO DETERMINE THAT THE PROPOSED TRANSFER IS BEING MADE IN COMPLIANCE WITH THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS. NO REPRESENTATION IS
      MADE AS TO THE AVAILABILITY OF ANY EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT.

     

    Any such Common Stock (i) as to which such restrictions on transfer shall have expired in accordance with their terms may or (ii) that has been
      transferred pursuant to, and in accordance with, a registration statement that has become effective or been declared effective under the Securities Act and that continues to be effective at the time of such transfer, upon surrender of the
      certificates representing such shares of Common Stock for exchange in accordance with the procedures of the transfer agent for the Common Stock, be exchanged for a new certificate or certificates for a like aggregate number of shares of Common Stock,
      which shall not bear the restrictive legend required by this Section 2.05(d).

     

    (e)          Any Note or Common Stock issued upon the conversion or exchange of a Note
        that is purchased or owned by the Company or any Affiliate thereof may not be resold by the Company or such Affiliate unless registered under the Securities Act or resold pursuant to an exemption from the registration requirements of the Securities
        Act in a transaction that results in such Notes or Common Stock, as the case may be, no longer being “restricted securities” (as defined under Rule 144).

     

    Section 2.06.  Mutilated, Destroyed, Lost or Stolen Notes.  In case any Note shall
        become mutilated or be destroyed, lost or stolen, the Company in its discretion may execute, and upon receipt of a Company Order request the Trustee or an authenticating agent appointed by the Trustee shall authenticate and deliver, a new Note,
        bearing a registration number not contemporaneously outstanding, in exchange and substitution for the mutilated Note, or in lieu of and in substitution for the Note so destroyed, lost or stolen.  In every case the applicant for a substituted Note
        shall furnish to the Company, to the Trustee and, if applicable, to such authenticating agent such security or indemnity as may be required by them to save each of them harmless from any loss, liability, cost or expense caused by or connected with
        such substitution, and, in every case of destruction, loss or theft, the applicant shall also furnish to the Company, to the Trustee and, if applicable, to such authenticating agent evidence to their satisfaction of the destruction, loss or theft
        of such Note and of the ownership thereof.

     

    
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    The Trustee or such authenticating agent may authenticate any such substituted Note and deliver the same upon the receipt of such security or indemnity
      as the Trustee, the Company and, if applicable, such authenticating agent may require.  Upon the issuance of any substitute Note, the Company or the Trustee may require the payment by the Holder of a sum sufficient to cover any tax, assessment or
      other governmental charge that may be imposed in relation thereto and any other expenses connected therewith.  In case any Note that has matured or is about to mature or has been surrendered for required purchase or is about to be converted in
      accordance with Article 14 shall become mutilated or be destroyed, lost or stolen, the Company may, in its sole discretion, instead of issuing a substitute Note, pay or authorize the payment of or convert or authorize the conversion of the same
      (without surrender thereof except in the case of a mutilated Note), as the case may be, if the applicant for such payment or conversion shall furnish to the Company, to the Trustee and, if applicable, to such authenticating agent such security or
      indemnity as may be required by them to save each of them harmless for any loss, liability, cost or expense caused by or connected with such substitution, and, in every case of destruction, loss or theft, evidence satisfactory to the Company, the
      Trustee and, if applicable, any Paying Agent or Conversion Agent evidence of their satisfaction of the destruction, loss or theft of such Note and of the ownership thereof.

     

    Every substitute Note issued pursuant to the provisions of this Section 2.06 by virtue of the fact that any Note is destroyed, lost or stolen shall
      constitute an additional contractual obligation of the Company, whether or not the destroyed, lost or stolen Note shall be found at any time, and shall be entitled to all the benefits of (but shall be subject to all the limitations set forth in) this
      Indenture equally and proportionately with any and all other Notes duly issued hereunder.  To the extent permitted by law, all Notes shall be held and owned upon the express condition that the foregoing provisions are exclusive with respect to the
      replacement, payment, conversion or purchase of mutilated, destroyed, lost or stolen Notes and shall preclude any and all other rights or remedies notwithstanding any law or statute existing or hereafter enacted to the contrary with respect to the
      replacement, payment, conversion or purchase of negotiable instruments or other securities without their surrender.

     

    Section 2.07.  Temporary Notes.  Pending the preparation of Physical Notes, the Company may execute and the Trustee or an authenticating agent appointed by the Trustee shall,
        upon receipt of a Company Order, authenticate and deliver temporary Notes (printed or lithographed).  Temporary Notes shall be issuable in any authorized denomination, and substantially in the form of the Physical Notes but with such omissions,
        insertions and variations as may be appropriate for temporary Notes, all as may be determined by the Company.  Every such temporary Note shall be executed by the Company and authenticated by the Trustee or such authenticating agent upon the same
        conditions and in substantially the same manner, and with the same effect, as the Physical Notes.  Without unreasonable delay, the Company shall execute and deliver to the Trustee or such authenticating agent Physical Notes (other than any Global
        Note) and thereupon any or all temporary Notes (other than any Global Note) may be surrendered in exchange therefor, at each office or agency maintained by the Company pursuant to Section 4.02 and the Trustee or such authenticating agent, upon
        receipt of a Company Order, shall authenticate and deliver in exchange for such temporary Notes an equal aggregate principal amount of Physical Notes.  Such exchange shall be made by the Company at its own expense and without any charge therefor. 
        Until so exchanged, the temporary Notes shall in all respects be entitled to the same benefits and subject to the same limitations under this Indenture as Physical Notes authenticated and delivered hereunder.

     

    
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    Section 2.08.  Cancellation of Notes Paid, Converted, Etc.  The Company shall cause all Notes surrendered for the purpose of payment at maturity, registration of transfer or exchange or conversion, if surrendered to any Person that the
        Company controls (other than the Trustee), to be surrendered to the Trustee for cancellation and they will no longer be considered outstanding under this Indenture upon their payment at maturity, registration of transfer or exchange or conversion. 
        All Notes delivered to the Trustee shall be canceled promptly by it. Except for any Notes surrendered for registration of transfer or exchange, or as otherwise expressly permitted by any of the provisions of this Indenture, no Notes shall be
        authenticated in exchange for any Notes surrendered to the Trustee for cancellation.  The Trustee shall dispose of canceled Notes in accordance with its customary procedures. After such cancellation, the Trustee shall deliver a certificate of such
        cancellation to the Company, at the Company’s written request in a Company Order.

     

    Section 2.09.  CUSIP Numbers.  The Company in issuing the Notes may use “CUSIP” numbers (if then generally in use), and, if so, the Trustee shall use “CUSIP” numbers in all
        notices issued to Holders as a convenience to such Holders; provided that any such notice may state that no representation is made as to the correctness of
        such numbers either as printed on the Notes or on such notice and that reliance may be placed only on the other identification numbers printed on the Notes.  The Company shall promptly notify the Trustee in writing of any change in the “CUSIP”
        numbers.

     

    Section 2.10.  Additional Notes; Purchases.  The Company may, without the consent of, or notice to, the Holders and notwithstanding Section 2.01, reopen this Indenture and
        issue additional Notes hereunder with the same terms and with the same CUSIP number as the Notes initially issued hereunder (other than differences in the issue dates, issue price and interest accrued prior to the issue date of such additional
        Notes) in an unlimited aggregate principal amount; provided that if any such additional Notes are not fungible with the Notes initially issued hereunder for
        U.S. federal income tax or securities law purposes, such additional Notes will have one or more separate CUSIP numbers.  Prior to the issuance of any such additional Notes, the Company shall deliver to the Trustee a Company Order, an Officer’s
        Certificate and an Opinion of Counsel, such Officer’s Certificate and Opinion of Counsel to cover such matters, in addition to the due authorization, execution, delivery, validity and enforceability of such Additional Notes and those required by
        Section 17.05, as the Trustee shall reasonably request.  In addition, the Company may, to the extent permitted by law and without the consent of Holders, and directly or indirectly (regardless of whether such Notes are surrendered to the Company),
        purchase or repurchase Notes in the open market or otherwise, whether by the Company or its Subsidiaries or through a private or public tender or exchange offer or through counterparties to private agreements, including by cash-settled swaps or
        other derivatives (in each case without prior notice to Holders).  The Company may, to the extent permitted by applicable law, reissue, resell or surrender to the Trustee for cancellation in accordance with Section 2.08 any Notes that the Company
        may purchase or repurchase, in the case of a reissuance or resale, so long as such Notes do not constitute “restricted securities” (as defined under Rule 144) upon such resissuance or resale.  Any Notes that the Company may purchase or repurchase
        shall be considered outstanding for all purposes under this Indenture unless and until such time the Company surrenders them to the Trustee for cancellation in accordance with Section 2.08 and, upon receipt of a written order from the Company, the
        Trustee shall cancel all Notes so surrendered.

     

    
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    ARTICLE 3

        Satisfaction and Discharge

     

    Section 3.01.  Satisfaction and Discharge.  This Indenture shall cease to be of further effect when (a) all Notes theretofore authenticated and delivered (other than (x) Notes which have been destroyed, lost or stolen and which have been
        replaced, paid or converted as provided in Section 2.06 and (y) Notes for whose payment money has theretofore been deposited in trust or segregated and held in trust by the Company and thereafter repaid to the Company or discharged from such trust,
        as provided in Section 4.04(d)) have been delivered to the Trustee for cancellation; or (b) the Company has irrevocably deposited with the Trustee or delivered to Holders, as applicable, after the Notes have become due and payable, whether at the
        Maturity Date, any Fundamental Change Purchase Date, upon conversion or otherwise, cash or cash, shares of Common Stock or a combination thereof, as applicable, solely to satisfy the Company’s Conversion Obligation, sufficient to pay all of the
        outstanding Notes (other than (x) Notes which have been destroyed, lost or stolen and which have been replaced, paid or converted as provided in Section 2.06) and, in either
        case, the Company pays all other sums due and payable under this Indenture by the Company with respect to the outstanding Notes. At the cost and expense of the Company, the Trustee shall acknowledge satisfaction and discharge of this Indenture with
        respect to the Notes on demand of the Company accompanied by an Officer’s Certificate and an Opinion of Counsel, each stating that all conditions precedent herein provided for relating to the satisfaction and discharge of this Indenture have been
        complied with.  Notwithstanding the satisfaction and discharge of this Indenture, the obligations of the Company to the Trustee under Section 7.06 shall survive.

     

    ARTICLE 4

        Particular Covenants of the Company

     

    Section 4.01.  Payment of Principal and Interest.  The Company covenants and agrees that it will pay or cause to be paid the principal (including the Fundamental Change
        Purchase Price, if applicable) of, and accrued and unpaid interest on, each of the Notes at the places, at the respective times and in the manner provided herein and in the Notes.

     

    Section 4.02.  Maintenance of Office or Agency.  The
        Company will maintain in a State of the United States of America or the District of Columbia, an office or agency where the Notes may be surrendered for registration of transfer or exchange or for presentation for payment or purchase (“Paying Agent”) or for conversion (“Conversion Agent”) and where notices
        and demands to or upon the Company in respect of the Notes and this Indenture may be served.  The Company will give prompt written notice to the Trustee of the location, and any change in the location, of such office or agency.  If at any time the
        Company shall fail to maintain any such required office or agency or shall fail to furnish the Trustee with the address thereof, such presentations, surrenders, notices and demands may be made or served at the Corporate Trust Office or the office
        or agency of the Trustee.

     

    
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    The Company may also from time to time designate as co-Note Registrars one or more other offices or agencies where the Notes may be presented or
      surrendered for any or all such purposes and may from time to time rescind such designations; provided that no such designation or rescission shall in any
      manner relieve the Company of its obligation to maintain an office or agency in any State of the United States of America of the District of Columbia for such purposes.  The Company will give prompt written notice to the Trustee of any such
      designation or rescission and of any change in the location of any such other office or agency.  The terms “Paying Agent” and “Conversion Agent” include any such additional or other offices or agencies, as applicable.

     

    The Company hereby initially designates the Trustee as the Paying Agent, Note Registrar, Custodian and Conversion Agent and the Corporate Trust Office
      shall be considered as one such office or agency of the Company for each of the aforesaid purposes.

     

    Section 4.03.  Appointments to Fill Vacancies in Trustee’s Office.  The Company, whenever necessary to avoid or fill a vacancy in the office of Trustee, will appoint, in the manner provided in Section 7.09, a
        Trustee, so that there shall at all times be a Trustee hereunder.

     

    Section 4.04.  Provisions as to Paying Agent.  (a) If the Company shall appoint a Paying Agent other than the Trustee, the Company will cause
        such Paying Agent to execute and deliver to the Trustee an instrument in which such agent shall agree with the Trustee, subject to the provisions of this Section 4.04:

     

    
      
        (i)       that it will hold all sums held
          by it as such agent for the payment of the principal (including the Fundamental Change Purchase Price, if applicable) of, and accrued and unpaid interest on, the Notes in trust for the benefit of the Holders of the Notes;

      

    

    
      
         

          

        (ii)      that it will give the Trustee
          prompt written notice of any failure by the Company to make any payment of the principal (including the Fundamental Change Purchase Price, if applicable) of, and accrued and unpaid interest on, the Notes when the same shall be due and payable;
          and

      

    

    
      
         

          

        (iii)    that at any time during the
          continuance of an Event of Default, upon request of the Trustee, it will forthwith pay to the Trustee all sums so held in trust.

      

    

     

    

    The Company shall, on or before each due date of the principal (including the Fundamental Change Purchase Price, if applicable) of, or accrued and unpaid
      interest on, the Notes, deposit with the Paying Agent a sum sufficient to pay such principal (including the Fundamental Change Purchase Price, if applicable) or accrued and unpaid interest, and (unless such Paying Agent is the Trustee) the Company
      will promptly notify the Trustee in writing of any failure to take such action; provided that if such deposit is made on the due date, such deposit must be
      received by the Paying Agent by 11:00 a.m., New York City time, on such date.

     

    
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    (b)          If the Company shall act as its own Paying Agent, it will, on or before
        each due date of the principal (including the Fundamental Change Purchase Price, if applicable) of, and accrued and unpaid interest on, the Notes, set aside, segregate and hold in trust for the benefit of the Holders of the Notes a sum sufficient
        to pay such principal (including the Fundamental Change Purchase Price, if applicable) and accrued and unpaid interest so becoming due and will promptly notify the Trustee in writing of any failure to take such action and of any failure by the
        Company to make any payment of the principal (including the Fundamental Change Purchase Price, if applicable) of, or accrued and unpaid interest on, the Notes when the same shall become due and payable.

     

    (c)          Anything in this Section 4.04 to the contrary notwithstanding, the Company
        may, at any time, for the purpose of obtaining a satisfaction and discharge of this Indenture, or for any other reason, pay, cause to be paid or deliver to the Trustee all sums or amounts held in trust by the Company or any Paying Agent hereunder
        as required by this Section 4.04, such sums or amounts to be held by the Trustee upon the trusts herein contained and upon such payment or delivery by the Company or any Paying Agent to the Trustee, the Company or such Paying Agent shall be
        released from all further liability but only with respect to such sums or amounts.

     

    (d)          Any money and shares of Common Stock
        deposited with the Trustee or any Paying Agent, or then held by the Company, in trust for the payment of the principal (including the Fundamental Change Purchase Price, if applicable) of, and accrued and unpaid interest on, any Note and remaining
        unclaimed for two years after such principal (including the Fundamental Change Purchase Price, if applicable) or interest has become due and payable shall be paid to the Company on request of the Company contained in an Officer’s Certificate, or
        (if then held by the Company) shall be discharged from such trust; and the Holder of such Note shall thereafter, as an unsecured general creditor, look only to the Company for payment thereof, and all liability of the Trustee or such Paying Agent
        with respect to such trust money and shares of Common Stock, and all liability of the Company as trustee thereof, shall thereupon cease.

     

    Section 4.05.  Existence.  Subject to Article 11, the Company shall do or cause to be done all things necessary to preserve and keep in full force and effect its corporate existence.

     

    Section 4.06.  Rule 144A Information Requirement and Annual Reports.  (a)  At any time the Company is not subject to Sections 13 or 15(d) of the
        Exchange Act, the Company shall, so long as any of the Notes or any shares of Common Stock issuable upon conversion thereof shall, at such time, constitute “restricted securities” within the meaning of Rule 144(a)(3) under the Securities Act,
        promptly provide to the Trustee and shall, upon written request, provide to any Holder, beneficial owner or prospective purchaser of such Notes or any shares of Common Stock issued upon conversion of such Notes, the information required to be
        delivered pursuant to Rule 144A(d)(4) under the Securities Act to facilitate the resale of such Notes or shares of Common Stock pursuant to Rule 144A.  The Company shall take such further action as any Holder or beneficial owner of such Notes or
        such Common Stock may reasonably request to the extent required from time to time to enable such Holder or beneficial owner to sell such Notes or shares of Common Stock in accordance with Rule 144A, as such rule may be amended from time to time.

     

    
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    (b)          The Company shall file with the Trustee
        within 15 days after the same are required to be filed with the Commission, copies of any annual or quarterly reports on Form 10-K or 10-Q (or any successor form) the Company is required to file with the Commission pursuant to Section 13 or 15(d)
        of the Exchange Act (giving effect to any grace period provided by Rule 12b-25 under the Exchange Act).  Any such document or report that the Company files with the Commission via the Commission’s EDGAR system (or any successor thereto) shall be
        deemed to be filed with the Trustee for purposes of this Section 4.06(b) at the time such documents are filed via the EDGAR system (or any successor thereto); provided that the Trustee shall have no obligation whatsoever to determine whether or not
        any such report has been filed via the EDGAR system (or such successor).

     

    (c)          Delivery of the reports and documents described in subsection (b) above to
        the Trustee is for informational purposes only, and the Trustee’s receipt of such shall not constitute constructive notice of any information contained therein or determinable from information contained therein, including the Company’s compliance
        with any of its covenants hereunder (as to which the Trustee is entitled to conclusively rely on an Officer’s Certificate).

     

    (d)          If, at any time during the six-month period
        beginning on, and including, the date that is six months after the last date of original issuance of the Notes, the Company fails to timely file any document or report that it is required to file with the Commission pursuant to Section 13 or 15(d)
        of the Exchange Act, as applicable (after giving effect to all applicable grace periods thereunder and other than reports on Form 8-K), or the Notes are not otherwise freely tradable by Holders other than the Company’s Affiliates or Holders that
        were the Company’s Affiliates at any time during the three months preceding (as a result of restrictions pursuant to Rule 144), the Company shall pay Additional Interest on the Notes.  Such Additional Interest shall accrue on the Notes at the rate
        of (i) 0.25% per annum of the principal amount of the Notes outstanding for each day during the first 90 days and (ii) 0.50% per annum of the principal amount of Notes outstanding for each day from, and including the 91st day for which the
        Company’s failure to file has occurred and is continuing, or the Notes are not otherwise freely tradable by Holders other than the Company’s Affiliates (or Holders that were the Company’s Affiliates at any time during the three months preceding)
        without restrictions pursuant to Rule 144.  As used in this Section 4.06(d), documents or reports that the Company is required to “file” with the Commission pursuant to Section 13 or 15(d) of the Exchange Act does not include documents or reports
        that the Company furnishes to the Commission pursuant to Section 13 or 15(d) of the Exchange Act.

     

    (e)          Subject to Section 4.06(i), if, and for so
        long as, the restrictive legend on the Notes specified in Section 2.05(c) has not been removed, the Notes are assigned a restricted CUSIP number or the Notes are not otherwise freely tradable by Holders other than the Company’s Affiliates or
        Holders that were the Company’s Affiliates at any time during the three months preceding (without restrictions pursuant to Rule 144 or the terms of this Indenture or the Notes) as of the 380th day after the last date of original issuance of the
        Notes, the Company shall pay Additional Interest on the Notes at a rate equal to 0.50% per annum of the principal amount of Notes outstanding until the restrictive legend on the Notes has been removed in accordance with Section 2.05(c), the Notes
        are assigned an unrestricted CUSIP number and the Notes are freely tradable by Holders other than the Company’s Affiliates (or Holders that were the Company’s Affiliates at any time during the three months preceding) without restrictions pursuant
        to Rule 144 or the terms of this Indenture or the Notes.

     

    
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    (f)          Additional Interest will be payable in arrears on each Interest Payment
        Date following accrual in the same manner as regular interest on the Notes.

     

    (g)          The Additional Interest that is payable in accordance with Section 4.06(d)
        or Section 4.06(e) shall be in addition to, and not in lieu of, any Additional Interest that may be payable as a result of the Company’s election pursuant to Section 6.03.

     

    (h)          If Additional Interest is payable by the Company pursuant to Section
        4.06(d), Section 4.06(e) or Section 6.03, the Company shall deliver to the Trustee an Officer’s Certificate to that effect stating (i) the amount of such Additional Interest that is payable and (ii) the date on which such Additional Interest is
        payable.  Unless and until a Responsible Officer of the Trustee receives at the Corporate Trust Office such a certificate, the Trustee may assume without inquiry that no such Additional Interest is payable.  If the Company has paid Additional
        Interest directly to the Persons entitled to it, the Company shall deliver to the Trustee an Officer’s Certificate setting forth the particulars of such payment.

     

    (i)          Notwithstanding the foregoing, the Company shall not be required to pay
        Additional Interest pursuant to Section 4.06(d) or Section 4.06(e) (x) on any date on which (A) the Company shall have filed a Shelf Registration Statement for the resale of the Notes and any Common Stock issuable upon conversion of the Notes, (B)
        such Shelf Registration Statement is effective and usable by holders identified therein as selling security holders for the resale of the Notes and any Common Stock issued upon conversion of the Notes, (C) the holders may register the resale of
        their Notes under such Shelf Registration Statement on terms customary for the resale of convertible securities offered in reliance on Rule 144A and (D) the Notes and/or Common Stock sold pursuant to such Shelf Registration Statement become freely
        tradable as a result of such sale; or (y) once the Company shall have complied with the requirements set forth in subclause (x) above for a period of two years.

     

    Section 4.07.  Stay, Extension and Usury Laws.  The Company covenants (to the extent that it may lawfully do so) that it shall not at any time insist upon, plead, or in any manner whatsoever claim or take the benefit or advantage of, any
        stay, extension or usury law or other law that would prohibit or forgive the Company from paying all or any portion of the principal of or interest on the Notes as contemplated herein, wherever enacted, now or at any time hereafter in force, or
        that may affect the covenants or the performance of this Indenture; and the Company (to the extent it may lawfully do so) hereby expressly waives all benefit or advantage of any such law, and covenants that it will not, by resort to any such law,
        hinder, delay or impede the execution of any power herein granted to the Trustee, but will suffer and permit the execution of every such power as though no such law had been enacted.

     

    
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    Section 4.08.  Compliance Certificate; Statements as to Defaults.  The Company shall deliver to the Trustee within 120 days after the end of each fiscal year of the Company (beginning with the fiscal year ending on December 31, 2019) an
        Officer’s Certificate stating whether or not the signers thereof have knowledge of any failure by the Company to comply with all conditions and covenants then required to be performed under this Indenture and, if so, specifying each such failure
        and the nature thereof.

     

    In addition, the Company shall deliver to the Trustee, as soon as possible, and in any event within 30 days after the Company becomes aware of the
      occurrence of any Event of Default or Default that is continuing, an Officer’s Certificate setting forth the details of such Event of Default or Default, its status and the action that the Company is taking or proposes to take with respect thereto.

     

    Section 4.09.  Further Instruments and Acts.  Upon request of the Trustee, the Company will execute and deliver such further instruments and do such further acts as may be reasonably necessary or proper to carry
        out more effectively the purposes of this Indenture.

     

    ARTICLE 5

        Lists of Holders and Reports by the Company and the Trustee

     

    Section 5.01.  Lists of Holders.  The Company covenants and agrees that it will furnish or cause to be furnished to the Trustee,
        semi-annually, not more than 15 days after each June 15 and December 15 in each year beginning with June 15, 2020, and at such other times as the Trustee may request in writing, within 30 days after receipt by the Company of any such request (or
        such lesser time as the Trustee may reasonably request in order to enable it to timely provide any notice to be provided by it hereunder), a list in such form as the Trustee may reasonably require of the names and addresses of the Holders as of a
        date not more than 15 days (or such other date as the Trustee may reasonably request in order to so provide any such notices) prior to the time such information is furnished, except that no such list need be furnished so long as the Trustee is
        acting as Note Registrar.

     

    Section 5.02.  Preservation and Disclosure of Lists.  The Trustee shall preserve, in as current a form as is reasonably practicable, all information as to the names and addresses of the Holders contained in the
        most recent list furnished to it as provided in Section 5.01 or maintained by the Trustee in its capacity as Note Registrar, if so acting.  The Trustee may destroy any list furnished to it as provided in Section 5.01 upon receipt of a new list so
        furnished.

     

    ARTICLE 6

        Defaults and Remedies

     

    Section 6.01.  Events of Default. 
        The following events shall be “Events of Default” with respect to the Notes:

     

    
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    (a)          default in any payment of interest on any
        Note when due and payable, and the default continues for a period of 30 days;

     

    (b)          default in the payment of principal of any
        Note when due and payable on the Maturity Date, upon any required purchase, upon declaration of acceleration or otherwise;

     

    (c)          failure by the Company to comply with its obligation to convert the Notes
        in accordance with this Indenture upon exercise of a Holder’s conversion right and such failure continues for a period of three (3) Business Days;

     

    (d)          failure by the Company to comply with its obligations under Article 11;

     

    (e)          failure by
          the Company to issue a Fundamental Change Company Notice in accordance with Section 15.02(c) or notice of a specified corporate event in accordance with Section
        14.01(b)(ii) or Section 14.01(b)(iii), in each case when due;

     

    (f)          failure by the Company for 60 days after written notice from the Trustee
        or the Holders of at least 25% in principal amount of the Notes then outstanding (a copy of which notice, if given by holders, also to be given to the Trustee) has been received by the Company to comply with any of its other agreements contained in
        the Notes or this Indenture;

     

    (g)          default by the
        Company or any Significant Subsidiary of the Company in the payment of the principal or interest under any loan or other instrument under which there may be outstanding, or by which there may be secured or evidenced, any indebtedness for money
        borrowed in excess of $100,000,000 in the aggregate of the Company and/or any such Significant Subsidiary (other than indebtedness for borrowed money secured only by the real property to which the indebtedness relates and which is non-recourse to
        the Company or such Significant Subsidiary), whether such indebtedness now exists or shall hereafter be created, (x) resulting in such indebtedness becoming or being declared due and payable or (y) constituting a failure to pay the principal and
        interest of any such indebtedness when due and payable at its stated maturity or required purchase or, subject to subclause (x) above, upon declaration or acceleration or otherwise, and such acceleration shall not have been rescinded or annulled,
        or such failure to pay cured, within 60 days after written notice to the Company by the Trustee or to the Company and the Trustee by the Holders of at least 25% in aggregate principal amount of the Notes then outstanding; or

     

    (h)          the Company or any Significant Subsidiary
        shall commence a voluntary case or other proceeding seeking liquidation, reorganization or other relief with respect to the Company or any such Significant Subsidiary or its debts under any bankruptcy, insolvency or other similar law now or
        hereafter in effect or seeking the appointment of a trustee, receiver, liquidator, custodian or other similar official of the Company or any such Significant Subsidiary or any substantial part of its property, or shall consent to any such relief or
        to the appointment of or taking possession by any such official in an involuntary case or other proceeding commenced against it, or shall make a general assignment for the benefit of creditors;

     

    
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    (i)          an involuntary case or other proceeding shall
        be commenced against the Company or any Significant Subsidiary seeking liquidation, reorganization or other relief with respect to the Company or such Significant Subsidiary or its debts under any bankruptcy, insolvency or other similar law now or
        hereafter in effect or seeking the appointment of a trustee, receiver, liquidator, custodian or other similar official of the Company or such Significant Subsidiary or any substantial part of its property, and such involuntary case or other
        proceeding shall remain undismissed and unstayed for a period of 90 consecutive days.

     

    Section 6.02.  Acceleration; Rescission and Annulment.  In case one or more Events of Default shall have occurred and be continuing, then, and in each and every such case (other
        than an Event of Default specified in Section 6.01(h) or Section 6.01(i) with respect to the Company (and not solely with respect to any of its Significant Subsidiaries), unless the principal of all of the Notes shall have already become due and
        payable, either the Trustee or the Holders of at least 25% in aggregate principal amount of the Notes then outstanding determined in accordance with Section 8.04, by notice in writing to the Company (and to the Trustee if given by Holders), may
        declare 100% of the principal of, and accrued and unpaid interest on, all the Notes to be due and payable immediately, and upon any such declaration the same shall become and shall automatically be immediately due and payable, anything in this
        Indenture or in the Notes contained to the contrary notwithstanding.  If an Event of Default specified in Section 6.01(h) or Section 6.01(i) with respect to the Company (and not solely with respect to any of its Significant Subsidiaries) occurs and
        is continuing, 100% of the principal of, and accrued and unpaid interest, if any, on, all Notes shall become and shall automatically be immediately due and payable.

     

    The immediately preceding paragraph, however, is subject to the conditions that if, at any time after the principal of the Notes shall have been so
      declared due and payable, and before any judgment or decree for the payment of the monies due shall have been obtained or entered as hereinafter provided, and if (1) rescission would not conflict with any judgment or decree of a court of competent
      jurisdiction and (2) any and all existing Events of Default under this Indenture, other than the nonpayment of the principal of and accrued and unpaid interest, if any, on Notes that shall have become due solely by such acceleration, shall have been
      cured or waived pursuant to Section 6.09, then and in every such case (except as provided in the immediately succeeding sentence) the Holders of a majority in aggregate principal amount of the Notes then outstanding, by written notice to the Company
      and to the Trustee, may waive all Defaults or Events of Default with respect to the Notes and rescind and annul such declaration and its consequences and such Default shall cease to exist, and any Event of Default arising therefrom shall be deemed to
      have been cured for every purpose of this Indenture; but no such waiver or rescission and annulment shall extend to or shall affect any subsequent Default or Event of Default, or shall impair any right consequent thereon.  Notwithstanding anything to
      the contrary herein, no such waiver or rescission and annulment shall extend to or shall affect any Default or Event of Default resulting from (i) the nonpayment of the principal of, or accrued and unpaid interest on, any Notes, (ii) a failure to
      purchase any Notes when required or (iii) a failure to pay or deliver, as the case may be, the consideration due upon conversion of the Notes.

     

    
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    Section 6.03.  Additional Interest.  Notwithstanding anything in this Indenture or in the Notes to the contrary,
        to the extent the Company elects, the sole remedy for an Event of Default relating to the Company’s failure to comply with its obligations as set forth in Section 4.06(b) shall, for the
          first 360 days after the occurrence of such an Event of Default, consist exclusively of the right to receive Additional Interest on the Notes at a rate equal to (i) 0.25% per annum of the principal amount of the Notes outstanding for each
        day during the 180-day period on which such Event of Default is continuing beginning on, and including, the date on which such an Event of Default first occurs and (ii) 0.50% per annum of the principal amount of the Notes outstanding for each day
        during the 180-day period on which such Event of Default is continuing beginning on, and including, the 181st day after which such Event of Default first occurs.  Additional Interest payable pursuant to this Section 6.03 shall be in addition to,
        not in lieu of, any Additional Interest payable pursuant to Section 4.06(d) or Section 4.06(e).  If the Company so elects, such Additional Interest shall be payable in the same manner and on the same dates as regular interest payable on the Notes. 
        On the 361st day after such Event of Default (if the Event of Default relating to the Company’s reporting obligations is not cured or waived prior to such 361st day), the Notes will be subject to acceleration as provided in Section 6.02.  The
        provisions described in this Section 6.03 will not affect the rights of the Holders of the Notes in the event of the occurrence of any other Event of Default.  In the event the Company does not elect to pay Additional Interest following an Event of
        Default in accordance with this Section 6.03, or the Company elects to make such payment but does not pay the Additional Interest when due, the Notes shall be immediately subject to acceleration as provided in Section 6.02. In no event shall
        Additional Interest payable at the Company’s election pursuant to this Section 6.03 accrue at a rate per annum in excess of the applicable rate specified above, irrespective of the number of events or circumstances constituting an Event of Default
        relating to the Company’s failure to comply with its obligations as set forth in Section 4.06 once an election has been made pursuant to this Section 6.03 to pay Additional Interest.

     

    In order to elect to pay Additional Interest as the sole remedy during the first 360 days after the occurrence of any Event of Default described in the
      immediately preceding paragraph, the Company must notify all Holders of the Notes, the Trustee and the Paying Agent in writing of such election prior to the beginning of such 360-day period.  Upon the failure to timely give such notice, the Notes
      shall be immediately subject to acceleration as provided in Section 6.02.

     

    Section 6.04.  Payments of Notes on Default; Suit Therefor.  If an Event of Default described in clause (a) or (b) of Section 6.01 shall have occurred, the Company shall, upon demand of the Trustee, pay to the Trustee, for the benefit of the
        Holders of the Notes, the whole amount then due and payable on the Notes for principal and interest, if any, with interest on any overdue principal and interest, if any, at the rate borne by the Notes at such time and, in addition thereto, such
        further amount as shall be sufficient to cover any amounts due to the Trustee under Section 7.06.  If the Company shall fail to pay such amounts forthwith upon such demand, the Trustee, in its own name and as trustee of an express trust, may
        institute a judicial proceeding for the collection of the sums so due and unpaid, may prosecute such proceeding to judgment or final decree and may enforce the same against the Company or any other obligor upon the Notes and collect the monies
        adjudged or decreed to be payable in the manner provided by law out of the property of the Company or any other obligor upon the Notes, wherever situated.

     

    
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    In the event there shall be pending proceedings for the bankruptcy or for the reorganization of the Company or any other obligor on the Notes under Title
      11 of the United States Code, or any other applicable law, or in case a receiver, assignee or trustee in bankruptcy or reorganization, liquidator, sequestrator or similar official shall have been appointed for or taken possession of the Company or
      such other obligor, the property of the Company or such other obligor, or in the event of any other judicial proceedings relative to the Company or such other obligor upon the Notes, or to the creditors or property of the Company or such other
      obligor, the Trustee, irrespective of whether the principal of the Notes shall then be due and payable as therein expressed or by declaration or otherwise and irrespective of whether the Trustee shall have made any demand pursuant to the provisions
      of this Section 6.04, shall be entitled and empowered, by intervention in such proceedings or otherwise, to file and prove a claim or claims for the whole amount of principal and accrued and unpaid interest, if any, in respect of the Notes, and, in
      case of any judicial proceedings, to file such proofs of claim and other papers or documents and to take such other actions as it may deem necessary or advisable in order to have the claims of the Trustee (including any claim for the reasonable
      compensation, expenses, disbursements and advances of the Trustee, its agents and counsel) and of the Holders allowed in such judicial proceedings relative to the Company or any other obligor on the Notes, its or their creditors, or its or their
      property, and to collect and receive any monies or other property payable or deliverable on any such claims, and to distribute the same after the deduction of any amounts due to the Trustee under Section 7.06; and any receiver, assignee or trustee in
      bankruptcy or reorganization, liquidator, custodian or similar official is hereby authorized by each of the Holders to make such payments to the Trustee, as administrative expenses, and, in the event that the Trustee shall consent to the making of
      such payments directly to the Holders, to pay to the Trustee any amount due it for reasonable compensation, expenses, advances and disbursements, including agents and counsel fees, and including any other amounts due to the Trustee under Section
      7.06, incurred by it up to the date of such distribution.  To the extent that such payment of reasonable compensation, expenses, advances and disbursements out of the estate in any such proceedings shall be denied for any reason, payment of the same
      shall be secured by a lien on, and shall be paid out of, any and all distributions, dividends, monies, securities and other property that the Holders of the Notes may be entitled to receive in such proceedings, whether in liquidation or under any
      plan of reorganization or arrangement or otherwise.

     

    Nothing herein contained shall be deemed to authorize the Trustee to authorize or consent to or accept or adopt on behalf of any Holder any plan of
      reorganization, arrangement, adjustment or composition affecting such Holder or the rights of any Holder thereof, or to authorize the Trustee to vote in respect of the claim of any Holder in any such proceeding.

     

    All rights of action and of asserting claims under this Indenture, or under any of the Notes, may be enforced by the Trustee without the possession of
      any of the Notes, or the production thereof at any trial or other proceeding relative thereto, and any such suit or proceeding instituted by the Trustee shall be brought in its own name as trustee of an express trust, and any recovery of judgment
      shall, after provision for the payment of the reasonable compensation, expenses, disbursements and advances of the Trustee, its agents and counsel, be for the ratable benefit of the Holders of the Notes.

     

    In any proceedings brought by the Trustee (and in any proceedings involving the interpretation of any provision of this Indenture to which the Trustee
      shall be a party) the Trustee shall be held to represent all the Holders of the Notes, and it shall not be necessary to make any Holders of the Notes parties to any such proceedings.

     

    
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    In case the Trustee shall have proceeded to enforce any right under this Indenture and such proceedings shall have been discontinued or abandoned because
      of any waiver pursuant to Section 6.09 or any rescission and annulment pursuant to Section 6.02 or for any other reason or shall have been determined adversely to the Trustee, then and in every such case the Company, the Holders, and the Trustee
      shall, subject to any determination in such proceeding, be restored respectively to their several positions and rights hereunder, and all rights, remedies and powers of the Company, the Holders, and the Trustee shall continue as though no such
      proceeding had been instituted.

     

    Section 6.05.  Application of Monies Collected by Trustee.  Any monies collected by the Trustee pursuant to this Article 6 with respect to the Notes shall be applied in the
        order following, at the date or dates fixed by the Trustee for the distribution of such monies, upon presentation of the several Notes, and stamping thereon the payment, if only partially paid, and upon surrender thereof, if fully paid:

     

    First, to the payment of all amounts due the Trustee its agents and its counsel under this Indenture;

     

    Second, in case the principal of the outstanding Notes shall not have become due and be unpaid, to the payment of interest on, and any cash due upon
      conversion of, the Notes in default in the order of the date due of the payments of such interest and cash due upon conversion, as the case may be, with interest (to the extent that such interest has been collected by the Trustee) upon such overdue
      payments at the rate borne by the Notes at such time, such payments to be made ratably to the Persons entitled thereto;

     

    Third, in case the principal of the outstanding Notes shall have become due, by declaration or otherwise, and be unpaid to the payment of the whole
      amount (including, if applicable, the payment of the Fundamental Change Purchase Price and any cash due upon conversion) then owing and unpaid upon the Notes for principal and interest, if any, with interest on the overdue principal and, to the
      extent that such interest has been collected by the Trustee, upon overdue installments of interest at the rate borne by the Notes at such time, and in case such monies shall be insufficient to pay in full the whole amounts so due and unpaid upon the
      Notes, then to the payment of such principal (including, if applicable, the Fundamental Change Purchase Price and the cash due upon conversion) and interest without preference or priority of principal over interest, or of interest over principal or
      of any installment of interest over any other installment of interest, or of any Note over any other Note, ratably to the aggregate of such principal (including, if applicable, the Fundamental Change Purchase Price and any cash due upon conversion)
      and accrued and unpaid interest; and

     

    Fourth, to the payment of the remainder, if any, to the Company.

     

    
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    Section 6.06.  Proceedings by Holders.  Except to enforce the right to receive payment of principal (including,
        if applicable, the Fundamental Change Purchase Price) or interest when due, or the right to receive payment or delivery of the consideration due upon conversion, no Holder of any Note shall have any right by virtue of or by availing of any
        provision of this Indenture to institute any suit, action or proceeding in equity or at law upon or under or with respect to this Indenture, or for the appointment of a receiver, trustee, liquidator, custodian or other similar official, or for any
        other remedy hereunder, unless:

     

    (a)          such Holder previously shall have given to the Trustee written notice of
        an Event of Default and of the continuance thereof, as herein provided;

     

    (b)          Holders of at least 25% in aggregate principal amount of the Notes then
        outstanding shall have made written request upon the Trustee to institute such action, suit or proceeding in its own name as Trustee hereunder;

     

    (c)          such Holders shall have offered to the Trustee such security or indemnity
        reasonably satisfactory to it against any loss, liability or expense to be incurred therein or thereby;

     

    (d)          the Trustee for 60 days after its receipt of such notice, request and
        offer of such security or indemnity, shall have neglected or refused to institute any such action, suit or proceeding; and

     

    (e)          no direction that, in the opinion of the Trustee, is inconsistent with
        such written request shall have been given to the Trustee by the Holders of a majority of the aggregate principal amount of the Notes then outstanding within such 60-day period pursuant to Section 6.09,

     

    it being understood and intended, and being expressly covenanted by the taker and Holder of every Note with every other taker and Holder and the Trustee that no one or more
      Holders shall have any right in any manner whatever by virtue of or by availing of any provision of this Indenture to affect, disturb or prejudice the rights of any other Holder (it being understood that the Trustee does not have an affirmative duty
      to ascertain whether such actions or forbearances are unduly prejudicial to such Holders), or to obtain or seek to obtain priority over or preference to any other such Holder, or to enforce any right under this Indenture, except in the manner herein
      provided and for the equal, ratable and common benefit of all Holders, except as otherwise provided herein.  For the protection and enforcement of this Section 6.06, each and every Holder and the Trustee shall be entitled to such relief as can be
      given either at law or in equity.

     

    Notwithstanding any other provision of this Indenture and any provision of any Note, the right of any Holder to receive payment or delivery, as the case
      may be, of (x) the principal (including the Fundamental Change Purchase Price, if applicable) of, (y) accrued and unpaid interest, if any, on, and (z) the consideration due upon conversion of, such Note, on or after the respective due dates expressed
      or provided for in such Note or in this Indenture, or to institute suit for the enforcement of any such payment or delivery, as the case may be, on or after such respective dates against the Company shall not be impaired or affected without the
      consent of such Holder.

     

    
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    Section 6.07.  Proceedings by Trustee.  In case of an Event of Default the Trustee may in its discretion proceed to protect and enforce the rights vested in it by this Indenture by such appropriate judicial proceedings as are necessary to
        protect and enforce any of such rights, either by suit in equity or by action at law or by proceeding in bankruptcy or otherwise, whether for the specific enforcement of any covenant or agreement contained in this Indenture or in aid of the
        exercise of any power granted in this Indenture, or to enforce any other legal or equitable right vested in the Trustee by this Indenture or by law.

     

    Section 6.08.  Remedies Cumulative and Continuing.  Except as provided in the last paragraph of Section 2.06, all powers and remedies given by this Article 6 to the Trustee or to the Holders shall, to the extent
        permitted by law, be deemed cumulative and not exclusive of any thereof or of any other powers and remedies available to the Trustee or the Holders of the Notes, by judicial proceedings or otherwise, to enforce the performance or observance of the
        covenants and agreements contained in this Indenture, and no delay or omission of the Trustee or of any Holder of any of the Notes to exercise any right or power accruing upon any Default or Event of Default shall impair any such right or power, or
        shall be construed to be a waiver of any such Default or Event of Default or any acquiescence therein; and, subject to the provisions of Section 6.06, every power and remedy given by this Article 6 or by law to the Trustee or to the Holders may be
        exercised from time to time, and as often as shall be deemed expedient, by the Trustee or by the Holders.

     

    Section 6.09.  Direction of Proceedings and Waiver of Defaults
          by Majority of Holders.  The Holders of a majority of the aggregate principal amount of the Notes at the time outstanding determined in accordance with Section 8.04 shall have the right to direct the time, method and place of conducting
        any proceeding for any remedy available to the Trustee pursuant to this Indenture or exercising any trust or power conferred on the Trustee with respect to Notes; provided,
        however, that (a) such direction shall not be in conflict with any rule of law or with this Indenture, and (b) the Trustee may take any other action deemed
        proper by the Trustee that is not inconsistent with such direction.  The Trustee may refuse to follow any direction that it determines is unduly prejudicial to the rights of any other Holder or that would involve the Trustee in personal liability. 
        The Holders of a majority in aggregate principal amount of the Notes at the time outstanding determined in accordance with Section 8.04 may on behalf of the Holders of all of the Notes waive any past Default or Event of Default hereunder and its
        consequences except (i) a default in the payment of accrued and unpaid interest, if any, on, or the principal (including any Fundamental Change Purchase Price) of, the Notes when due that has not been cured pursuant to the provisions of Section
        6.01, (ii) a failure by the Company to pay or deliver, as the case may be, the consideration due upon conversion of the Notes or (iii) a default in respect of a covenant or
        provision hereof which under Article 10 cannot be modified or amended without the consent of each Holder of an outstanding Note affected.  Upon any such waiver the Company, the Trustee and the Holders of the Notes shall be restored to their former
        positions and rights hereunder; but no such waiver shall extend to any subsequent or other Default or Event of Default or impair any right consequent thereon.  Whenever any Default or Event of Default hereunder shall have been waived as permitted
        by this Section 6.09, said Default or Event of Default shall for all purposes of the Notes and this Indenture be deemed to have been cured and to be not continuing; but no such waiver shall extend to any subsequent or other Default or Event of
        Default or impair any right consequent thereon.

     

    
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    Section 6.10.  Notice of Defaults.  The Trustee shall, within 90 days after the occurrence and continuance of a Default of which is actually known to a Responsible Officer, send to all Holders as the names and addresses of such Holders appear
        upon the Note Register, notice of all Defaults known to a Responsible Officer, unless such Defaults shall have been cured or waived before the giving of such notice; provided that, except in the case of a Default in the payment of the principal of (including the Fundamental Change Purchase Price, if applicable), or accrued and unpaid interest on, any of the Notes or a Default in the payment or
        delivery of the consideration due upon conversion, the Trustee shall be protected in withholding such notice if and so long as the Trustee in good faith determines that the withholding of such notice is in the interests of the Holders.

     

    Section 6.11.  Undertaking to Pay Costs.  All parties to this Indenture agree, and each Holder of any Note by its acceptance thereof shall be deemed to have agreed, that any court may, in its discretion,
        require, in any suit for the enforcement of any right or remedy under this Indenture, or in any suit against the Trustee for any action taken or omitted by it as Trustee, the filing by any party litigant in such suit of an undertaking to pay the
        costs of such suit and that such court may in its discretion assess reasonable costs, including reasonable attorneys’ fees and expenses, against any party litigant in such suit, having due regard to the merits and good faith of the claims or
        defenses made by such party litigant; provided that the provisions of this Section 6.11 (to the extent permitted by law) shall not apply to any suit
        instituted by the Trustee, to any suit instituted by any Holder, or group of Holders, holding in the aggregate more than 10% in principal amount of the Notes at the time outstanding determined in accordance with Section 8.04, or to any suit
        instituted by any Holder for the enforcement of the payment of the principal of or accrued and unpaid interest, if any, on any Note (including, but not limited to, the Fundamental Change Purchase Price with respect to the Notes being purchased as
        provided in this Indenture) on or after the due date expressed or provided for in such Note or to any suit for the enforcement of the right to convert any Note in accordance with the provisions of Article 14.

     

    ARTICLE 7

        Concerning the Trustee

     

    Section 7.01.  Duties and
          Responsibilities of Trustee.  The Trustee, prior to the occurrence of an Event of Default and after the curing or waiver of all Events of Default that may have occurred, undertakes to perform such duties and only such duties as are
        specifically set forth in this Indenture.  In case an Event of Default has occurred that has not been cured or waived the Trustee shall exercise such of the rights and powers vested in it by this Indenture, and use the same degree of care and skill
        in their exercise, as a prudent person would exercise or use under the circumstances in the conduct of such person’s own affairs; provided that if an Event
        of Default occurs and is continuing, the Trustee will be under no obligation to exercise any of the rights or powers under this Indenture at the request or direction of any of the Holders unless such Holders have offered to the Trustee indemnity or
        security satisfactory to it against the costs, loss, expenses and liabilities that might be incurred by it in compliance with such request or direction.

     

    
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    No provision of this Indenture shall be construed to relieve the Trustee from liability for its own grossly negligent action, its own grossly negligent
      failure to act or its own willful misconduct, except that:

     

    (a)          prior to the occurrence of an Event of Default and after the curing or
        waiving of all Events of Default that may have occurred:

     

    
      
        (i)     the duties and obligations of the
          Trustee shall be determined solely by the express provisions of this Indenture, and the Trustee shall not be liable except for the performance of such duties and obligations as are specifically set forth in this Indenture and no implied covenants
          or obligations shall be read into this Indenture against the Trustee; and

      

    

    
      
         

          

        (ii)    in the absence of bad faith on
          the part of the Trustee, the Trustee may conclusively rely, as to the truth of the statements and the correctness of the opinions expressed therein, upon any certificates or opinions furnished to the Trustee and conforming to the requirements of
          this Indenture; but, in the case of any such certificates or opinions that by any provisions hereof are specifically required to be furnished to the Trustee, the Trustee shall be under a duty to examine the same to determine whether or not they
          conform to the requirements of this Indenture (but need not confirm or investigate the accuracy of any mathematical calculations or other facts stated therein);

      

    

     

      

    (b)          the Trustee shall not be liable for any error of judgment made in good
        faith by a Responsible Officer or Officers of the Trustee, unless it shall be proved that the Trustee was grossly negligent in ascertaining the pertinent facts;

     

    (c)          the Trustee shall not be liable with respect to any action taken or
        omitted to be taken by it in good faith in accordance with the direction of the Holders of not less than a majority of the aggregate principal amount of the Notes at the time outstanding determined as provided in Section 8.04 relating to the time,
        method and place of conducting any proceeding for any remedy available to the Trustee, or exercising any trust or power conferred upon the Trustee, under this Indenture;

     

    (d)          whether or not therein provided, every provision of this Indenture
        relating to the conduct or affecting the liability of, or affording protection to, the Trustee shall be subject to the provisions of this Section 7.01;

     

    (e)          the Trustee shall not be liable in respect of any payment (as to the
        correctness of amount, entitlement to receive or any other matters relating to payment) or notice effected by the Company or any Paying Agent or any records maintained by any co-Note Registrar with respect to the Notes;

     

    (f)          if any party fails to deliver a notice relating to an event the fact of
        which, pursuant to this Indenture, requires notice to be sent to the Trustee, the Trustee may conclusively rely on its failure to receive such notice as reason to act as if no such event occurred, unless such Responsible Officer of the Trustee had
        actual knowledge of such event;

     

    
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    (g)          in the absence of written investment direction from the Company, all cash
        received by the Trustee shall be placed in a non-interest bearing trust account, and in no event shall the Trustee be liable for the selection of investments or for investment losses incurred thereon or for losses incurred as a result of the
        liquidation of any such investment prior to its maturity date or the failure of the party directing such investments prior to its maturity date or the failure of the party directing such investment to provide timely written investment direction,
        and the Trustee shall have no obligation to invest or reinvest any amounts held hereunder in the absence of such timely and written investment direction from the Company;

     

    (h)          in the event that the Trustee is also acting as Custodian, Note Registrar,
        Paying Agent, Conversion Agent, transfer agent or other agent hereunder, the rights and protections afforded to the Trustee pursuant to this Article 7 shall also be afforded to such Custodian, Note Registrar, Paying Agent, Conversion Agent,
        transfer agent or other agent hereunder;

     

    (i)           the Trustee shall not be required to give any bond or surety in respect
        of the execution of the trusts and powers or otherwise in respect of this Indenture; and

     

    (j)           under no circumstances, shall the Trustee be liable in its individual
        capacity for the obligations evidenced by the Notes.

     

    None of the provisions contained in this Indenture shall require the Trustee to expend or risk its own funds or otherwise incur any financial liability
      in the performance of any of its duties or in the exercise of any of its rights or powers.

     

    Section 7.02.  Reliance on Documents, Opinions, Etc.  Except as otherwise provided in Section 7.01:

     

    (a)          the Trustee may conclusively rely and shall be fully protected in acting
        upon any resolution, certificate, statement, instrument, opinion, report, notice, request, consent, order, bond, Note, coupon, other evidence of indebtedness or other paper or document believed by it in good faith to be genuine and to have been
        signed or presented by the proper party or parties;

     

    (b)          any request, direction, order or demand of the Company mentioned herein
        shall be sufficiently evidenced by an Officer’s Certificate (unless other evidence in respect thereof be herein specifically prescribed); and any Board Resolution may be evidenced to the Trustee by a copy thereof certified by the Secretary or an
        Assistant Secretary of the Company;

     

    (c)          the Trustee may consult with counsel of its selection and require an
        Opinion of Counsel and any advice of such counsel or Opinion of Counsel shall be full and complete authorization and protection in respect of any action taken or omitted by it hereunder in good faith and in accordance with such advice or Opinion of
        Counsel;

     

    (d)          the Trustee shall not be bound to make any investigation into the facts or
        matters stated in any resolution, certificate, statement, instrument, opinion, report, notice, request, direction, consent, order, bond, debenture or other paper or document, but the Trustee, in its discretion, may make such further inquiry or
        investigation into such facts or matters as it may see fit, and, if the Trustee shall determine to make such further inquiry or investigation, it shall be entitled to examine the books, records and premises of the Company, personally or by agent or
        attorney at the expense of the Company and shall incur no liability of any kind by reason of such inquiry or investigation;

     

    
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    (e)          the Trustee may execute any of the trusts or powers hereunder or perform
        any duties hereunder either directly or by or through agents, custodians, nominees or attorneys and the Trustee shall not be responsible for any misconduct or negligence on the part of any agent, custodian, nominee or attorney appointed by it with
        due care hereunder;

     

    (f)          the permissive rights of the Trustee enumerated herein shall not be
        construed as duties;

     

    (g)          in no event shall the Trustee be liable for any consequential, indirect,
        punitive or special loss or damage of any kind whatsoever (including but not limited to lost profits), even if the Trustee has been advised of the likelihood of such loss or damage and regardless of the form of action;

     

    (h)          the Trustee shall not be charged with knowledge of any Default or Event of
        Default with respect to the Notes, unless either (1) a Responsible Officer shall have actual knowledge of such Default or Event of Default or (2) written notice of such Default or Event of Default shall have been given to the Trustee at its
        Corporate Trust Office by the Company or by any Holder of the Notes;

     

    (i)           the Trustee shall not be liable for any action taken, suffered, or
        omitted to be taken by it in good faith and reasonably believed by it to be authorized or within the discretion or rights or powers conferred upon it by this Indenture; provided, however, that the Trustee’s conduct does not constitute willful misconduct, gross negligence or bad faith;

     

    (j)           the rights, privileges, protections, immunities and benefits given to
        the Trustee, including, without limitation, its right to be indemnified, are extended to, and shall be enforceable by, the Trustee in each of its capacities hereunder, and each agent, custodian and other Person employed to act hereunder; and

     

    (k)          the Trustee may request that the Company deliver a certificate setting
        forth the names of individuals and/or titles of officers authorized at such time to take specified actions pursuant to this Indenture.

     

    Section 7.03.  No Responsibility for Recitals, Etc.  The recitals contained herein and in the Notes (except in the Trustee’s certificate of authentication) shall be taken as
        the statements of the Company, and the Trustee assumes no responsibility for the correctness of the same.  The Trustee makes no representations as to the validity or sufficiency of this Indenture or of the Notes.  The Trustee shall not be
        accountable for the use or application by the Company of any Notes or the proceeds of any Notes authenticated and delivered by the Trustee in conformity with the provisions of this Indenture.

     

    
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    Section 7.04.  Trustee, Paying Agents, Conversion Agents, Bid Solicitation Agent or Note Registrar May Own Notes.  The Trustee, any Paying Agent, any Conversion Agent, Bid
        Solicitation Agent (if other than the Company) or Note Registrar, in its individual or any other capacity, may become the owner or pledgee of Notes with the same rights it would have if it were not the Trustee, Paying Agent, Conversion Agent, Bid
        Solicitation Agent or Note Registrar.

     

    Section 7.05.  Monies and Shares of Common Stock to Be Held in Trust.  All monies and shares of Common Stock received by the Trustee shall, until used or applied as herein
        provided, be held in trust for the purposes for which they were received.  Money and shares of Common Stock held by the Trustee in trust hereunder need not be segregated from other funds except to the extent required by law.  The Trustee shall be
        under no liability for interest on any money or shares of Common Stock received by it hereunder except as may be agreed in writing from time to time by the Company and the Trustee.

     

    Section 7.06.  Compensation and Expenses of Trustee.  The Company covenants and agrees to pay to the Trustee from time to time, and the Trustee shall receive, such compensation for all services rendered by it
        hereunder in any capacity (which shall not be limited by any provision of law in regard to the compensation of a trustee of an express trust) as mutually agreed to in writing between the Trustee and the Company, and the Company will pay or
        reimburse the Trustee upon its request for all reasonable expenses, disbursements and advances reasonably incurred or made by the Trustee in accordance with any of the provisions of this Indenture in any capacity thereunder (including the
        reasonable compensation and the expenses and disbursements of its agents and counsel and of all Persons not regularly in its employ) except any such expense, disbursement or advance as shall have been caused by its gross negligence, willful
        misconduct or bad faith.  The Company also covenants to indemnify the Trustee in any capacity under this Indenture and any other document or transaction entered into in connection herewith and its agents and any authenticating agent or any
        successor Trustee for, and to hold them harmless against, any loss, claim, damage, liability or expense incurred without gross negligence, willful misconduct or bad faith on the part of the Trustee, its officers, directors, agents or employees, or
        such agent or authenticating agent, as the case may be, and arising out of or in connection with the acceptance or administration of this Indenture or in any other capacity hereunder, including the costs and expenses of defending themselves against
        any claim of liability (whether asserted by the Company, a Holder or any other Person) in the premises.  The obligations of the Company under this Section 7.06 to compensate or indemnify the Trustee and to pay or reimburse the Trustee for expenses,
        disbursements and advances shall be secured by a senior claim to which the Notes are hereby made subordinate on all money or property held or collected by the Trustee, except, subject to the effect of Section 6.05, funds held in trust herewith for
        the benefit of the Holders of particular Notes.  The Trustee’s right to receive payment of any amounts due under this Section 7.06 shall not be subordinate to any other liability or indebtedness of the Company (even though the Notes may be so
        subordinated).  The obligation of the Company under this Section 7.06 shall survive the satisfaction and discharge of this Indenture and the earlier resignation or removal or the Trustee.  The Company need not pay for any settlement made without
        its consent, which consent shall not be unreasonably withheld.  The indemnification provided in this Section 7.06 shall extend to the officers, directors, agents and employees of the Trustee.

     

    
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    Without prejudice to any other rights available to the Trustee under applicable law, when the Trustee and its agents and any authenticating agent incur
      expenses or render services after an Event of Default specified in Section 6.01(h) or Section 6.01(i) occurs, the expenses and the compensation for the services are intended to
      constitute expenses of administration under any bankruptcy, insolvency or similar laws.

     

    Section 7.07.  Officer’s Certificate as Evidence.  Except as otherwise provided in Section 7.01, whenever in the administration of the provisions of this Indenture the Trustee shall deem it necessary or desirable that a matter be proved or
        established prior to taking or omitting any action hereunder, such matter (unless other evidence in respect thereof be herein specifically prescribed) may, in the absence of gross negligence, willful misconduct and bad faith on the part of the
        Trustee, be deemed to be conclusively proved and established by an Officer’s Certificate delivered to the Trustee, and such Officer’s Certificate, in the absence of gross negligence, willful misconduct and bad faith on the part of the Trustee,
        shall be full warrant to the Trustee for any action taken or omitted by it under the provisions of this Indenture upon the faith thereof.

     

    Section 7.08.  Eligibility of Trustee.  There shall at all times be a Trustee hereunder which shall be a Person that is eligible pursuant to the Trust Indenture Act (as if the Trust Indenture Act were applicable
        hereto) to act as such and has a combined capital and surplus of at least $50,000,000.  If such Person publishes reports of condition at least annually, pursuant to law or to the requirements of any supervising or examining authority, then for the
        purposes of this Section 7.08, the combined capital and surplus of such Person shall be deemed to be its combined capital and surplus as set forth in its most recent report of condition so published.  If at any time the Trustee shall cease to be
        eligible in accordance with the provisions of this Section, it shall resign immediately in the manner and with the effect hereinafter specified in this Article 7.

     

    Section 7.09.  Resignation or Removal of Trustee.  (a) The Trustee may at any time resign by giving written notice of such resignation to the Company and by mailing notice
        thereof to the Holders at their addresses as they shall appear on the Note Register.  Upon receiving such notice of resignation, the Company shall promptly appoint a successor trustee by written instrument, in duplicate, executed by order of the
        Board of Directors, one copy of which instrument shall be delivered to the resigning Trustee and one copy to the successor trustee.  If no successor trustee shall have been so appointed and have accepted appointment within 30 days after the mailing
        of such notice of resignation to the Holders, the resigning Trustee may, at the expense of the Company, upon 10 Business Days’ notice to the Company and the Holders, petition any court of competent jurisdiction for the appointment of a successor
        trustee, or any Holder who has been a bona fide holder of a Note or Notes for at least six months may, subject to the provisions of Section 6.11, on behalf of himself or herself and all others similarly situated, petition any such court for the
        appointment of a successor trustee.  Such court may thereupon, after such notice, if any, as it may deem proper and prescribe, appoint a successor trustee.

     

    (b)          In case at any time any of the following shall occur:

     

    
      
        (i)      the Trustee shall cease to be
          eligible in accordance with the provisions of Section 7.08 and shall fail to resign after written request therefor by the Company or by any such Holder, or

      

    

    
      
         

          

        
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        (ii)    the Trustee shall become
          incapable of acting, or shall be adjudged a bankrupt or insolvent, or a receiver of the Trustee or of its property shall be appointed, or any public officer shall take charge or control of the Trustee or of its property or affairs for the purpose
          of rehabilitation, conservation or liquidation,

         

        

      

    

    then, in either case, the Company may by a Board Resolution remove the Trustee and appoint a successor trustee by written instrument, in duplicate, executed by order of the
      Board of Directors, one copy of which instrument shall be delivered to the Trustee so removed and one copy to the successor trustee, or, subject to the provisions of Section 6.11, any Holder who has been a bona fide holder of a Note or Notes for at
      least six months may, on behalf of himself or herself and all others similarly situated, petition any court of competent jurisdiction for the removal of the Trustee and the appointment of a successor trustee.  Such court may thereupon, after such
      notice, if any, as it may deem proper and prescribe, remove the Trustee and appoint a successor trustee.

     

    (c)          The Holders of a majority in aggregate principal amount of the Notes at
        the time outstanding, as determined in accordance with Section 8.04, may at any time remove the Trustee and nominate a successor trustee that shall be deemed appointed as successor trustee unless within 10 days after notice to the Company of such
        nomination the Company objects thereto, in which case the Trustee so removed or any Holder, upon the terms and conditions and otherwise as in Section 7.09(a) provided, may, at the expense of the Company, petition any court of competent jurisdiction
        for an appointment of a successor trustee.

     

    (d)          Any resignation or removal of the Trustee and appointment of a successor
        trustee pursuant to any of the provisions of this Section 7.09 shall become effective upon acceptance of appointment by the successor trustee as provided in Section 7.10.

     

    Section 7.10.  Acceptance by Successor Trustee.  Any successor trustee appointed as provided in Section 7.09 shall execute, acknowledge and deliver to the Company and to its
        predecessor trustee an instrument accepting such appointment hereunder, and thereupon the resignation or removal of the predecessor trustee shall become effective and such successor trustee, without any further act, deed or conveyance, shall become
        vested with all the rights, powers, duties and obligations of its predecessor hereunder, with like effect as if originally named as Trustee herein; but, nevertheless, on the written request of the Company or of the successor trustee, the trustee
        ceasing to act shall, upon payment of any amounts then due it pursuant to the provisions of Section 7.06, execute and deliver an instrument transferring to such successor trustee all the rights and powers of the trustee so ceasing to act.  Upon
        request of any such successor trustee, the Company shall execute any and all instruments in writing for more fully and certainly vesting in and confirming to such successor trustee all such rights and powers.  Any trustee ceasing to act shall,
        nevertheless, retain a senior claim to which the Notes are hereby made subordinate on all money or property held or collected by such trustee as such, except for funds held in trust for the benefit of Holders of particular Notes, to secure any
        amounts then due it pursuant to the provisions of Section 7.06.

     

    No successor trustee shall accept appointment as provided in this Section 7.10 unless at the time of such acceptance such successor trustee shall be
      eligible under the provisions of Section 7.08.

     

    
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    Upon acceptance of appointment by a successor trustee as provided in this Section 7.10, each of the Company and the successor trustee, at the written
      direction and at the expense of the Company shall mail or cause to be mailed notice of the succession of such trustee hereunder to the Holders at their addresses as they shall appear on the Note Register.  If the Company fails to mail such notice
      within 10 days after acceptance of appointment by the successor trustee, the successor trustee shall cause such notice to be mailed at the expense of the Company.

     

    Section 7.11.  Succession by Merger, Etc.  Any corporation or other entity into which the Trustee may be merged or converted or with which it may be consolidated, or any corporation or other entity resulting
        from any merger, conversion or consolidation to which the Trustee shall be a party, or any corporation or other entity succeeding to all or substantially all of the corporate trust business of the Trustee (including the administration of this
        Indenture), shall be the successor to the Trustee hereunder without the execution or filing of any paper or any further act on the part of any of the parties hereto; provided that in the case of any corporation or other entity succeeding to all or substantially all of the corporate trust business of the Trustee such corporation or other entity shall be eligible under the provisions of Section
        7.08.

     

    In case at the time such successor to the Trustee shall succeed to the trusts created by this Indenture, any of the Notes shall have been authenticated
      but not delivered, any such successor to the Trustee may adopt the certificate of authentication of any predecessor trustee or authenticating agent appointed by such predecessor trustee, and deliver such Notes so authenticated; and in case at that
      time any of the Notes shall not have been authenticated, any successor to the Trustee or an authenticating agent appointed by such successor trustee may authenticate such Notes either in the name of any predecessor trustee hereunder or in the name of
      the successor trustee; and in all such cases such certificates shall have the full force which it is anywhere in the Notes or in this Indenture provided that the certificate of the Trustee shall have; provided, however, that the right to adopt the certificate of authentication of any predecessor trustee or to
      authenticate Notes in the name of any predecessor trustee shall apply only to its successor or successors by merger, conversion or consolidation.

     

    ARTICLE 8

        Concerning the Holders

     

    Section 8.01.  Action by Holders.  Whenever in this Indenture it is provided that the Holders of a specified percentage of the aggregate principal amount of the Notes may
        take any action (including the making of any demand or request, the giving of any notice, consent or waiver or the taking of any other action), the fact that at the time of taking any such action, the Holders of such specified percentage have
        joined therein may be evidenced (a) by any instrument or any number of instruments of similar tenor executed by Holders in person or by agent or proxy appointed in writing, or (b) by the record of the Holders voting in favor thereof at any meeting
        of Holders duly called and held in accordance with such rules as may be established in accordance with the provisions of Article 9, or (c) by a combination of such instrument or
        instruments and any such record of such a meeting of Holders.  Whenever the Company or the Trustee solicits the taking of any action by the Holders of the Notes, the Company or the Trustee may fix, but shall not be required to, in advance of such
        solicitation, a date as the record date for determining Holders entitled to take such action.  The record date if one is selected shall be not more than fifteen days prior to the date of commencement of solicitation of such action.

     

    
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    Section 8.02.  Proof of Execution by Holders.  Subject to the provisions of Section 7.01, Section 7.02 and Section 9.05, proof of the
        execution of any instrument by a Holder or its agent or proxy shall be sufficient if made in accordance with such reasonable rules and regulations as may be prescribed by the Trustee or in such manner as shall be satisfactory to the Trustee.  The
        holding of Notes shall be proved by the Note Register or by a certificate of the Note Registrar.  The record of any Holders’ meeting shall be proved in the manner provided in Section 9.06.

     

    Section 8.03.  Who Are Deemed Absolute Owners.  The Company, the Trustee, any authenticating agent, any Paying Agent, any Conversion Agent and any Note Registrar may deem the
        Person in whose name a Note shall be registered upon the Note Register to be, and may treat it as, the absolute owner of such Note (whether or not such Note shall be overdue and notwithstanding any notation of ownership or other writing thereon
        made by any Person other than the Company or any Note Registrar) for the purpose of receiving payment of or on account of the principal of and (subject to Section 2.03) accrued and unpaid interest on such Note, for conversion of such Note and for
        all other purposes; and neither the Company nor the Trustee nor any Paying Agent nor any Conversion Agent nor any Note Registrar shall be affected by any notice to the contrary.  All such payments or deliveries so made to any Holder for the time
        being, or upon its order, shall be valid, and, to the extent of the sums or shares of Common Stock so paid or delivered, effectual to satisfy and discharge the liability for monies payable or shares deliverable upon any such Note.  Notwithstanding
        anything to the contrary in this Indenture or the Notes following an Event of Default, any holder of a beneficial interest in a Global Note may directly enforce against the Company, without the consent, solicitation, proxy, authorization or any
        other action of the Depositary or any other Person, such holder’s right to exchange such beneficial interest for a Note in certificated form in accordance with the provisions of this Indenture. Subject to the foregoing, members of, or participants
        in, the Depositary (“Agent Members”) shall have no rights under this Indenture with respect to any Global Note held on their behalf by the Depositary, or the
        Trustee as its custodian, or under the Global Note. The Depositary may be treated by the Company, the Trustee and any agent of the Company or the Trustee as the absolute owner of the Global Note for all purposes whatsoever. Notwithstanding the
        foregoing, nothing herein shall prevent the Company, the Trustee or any agent of the Company or the Trustee from giving effect to any written certification, proxy or other authorization furnished by the Depositary or impair, as between the
        Depositary and its Agent Members, the operation of customary practices governing the exercise of the rights of any Holder.

     

    Section 8.04.  Company-Owned Notes Disregarded.  In determining whether the Holders of the requisite aggregate principal amount of Notes have concurred in any direction,
        consent, waiver or other action under this Indenture, Notes that are owned by the Company or by any Person directly or indirectly controlling or controlled by or under direct or indirect common control with the Company shall be disregarded and
        deemed not to be outstanding for the purpose of any such determination; provided that for the purposes of determining whether the Trustee shall be protected
        in relying on any such direction, consent, waiver or other action only Notes that a Responsible Officer knows are so owned shall be so disregarded.  Notes so owned that have been pledged in good faith may be regarded as outstanding for the purposes
        of this Section 8.04 if the pledgee shall establish to the satisfaction of the Trustee the pledgee’s right to so act with respect to such Notes and that the pledgee is not the Company or a Person directly or indirectly controlling or controlled by
        or under direct or indirect common control with the Company.  In the case of a dispute as to such right, any decision by the Trustee taken upon the advice of counsel shall be full protection to the Trustee.  Upon request of the Trustee, the Company
        shall furnish to the Trustee promptly an Officer’s Certificate listing and identifying all Notes, if any, known by the Company to be owned or held by or for the account of any of the above described Persons; and, subject to Section 7.01, the
        Trustee shall be entitled to accept such Officer’s Certificate as conclusive evidence of the facts therein set forth and of the fact that all Notes not listed therein are outstanding for the purpose of any such determination.

     

    
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    Section 8.05.  Revocation of Consents; Future Holders Bound.  At any time prior to (but not after) the evidencing to the Trustee, as provided in Section 8.01, of the taking of any action by the Holders of the
        percentage of the aggregate principal amount of the Notes specified in this Indenture in connection with such action, any Holder of a Note that is shown by the evidence to be included in the Notes the Holders of which have consented to such action
        may, by filing written notice with the Trustee at its Corporate Trust Office and upon proof of holding as provided in Section 8.02, revoke such action so far as concerns such Note.  Except as aforesaid, any such action taken by the Holder of any
        Note shall be conclusive and binding upon such Holder and upon all future Holders and owners of such Note and of any Notes issued in exchange or substitution therefor or upon registration of transfer thereof, irrespective of whether any notation in
        regard thereto is made upon such Note or any Note issued in exchange or substitution therefor or upon registration of transfer thereof.

     

    ARTICLE 9

        Holders’ Meetings

     

    Section 9.01.  Purpose of Meetings.  A meeting of Holders may be called at any time and from time to time pursuant to the provisions of this Article 9 for any of the following purposes:

     

    (a)          to give any notice to the Company or to the Trustee, or to give any
        directions to the Trustee permitted under this Indenture, or to consent to the waiving of any Default or Event of Default hereunder and its consequences, or to take any other action authorized to be taken by Holders pursuant to any of the
        provisions of Article 6;

     

    (b)          to remove the Trustee and nominate a successor trustee pursuant to the
        provisions of Article 7;

     

    (c)          to consent to the execution of an indenture or indentures supplemental
        hereto pursuant to the provisions of Section 10.02; or

     

    (d)          to take any other action authorized to be taken by or on behalf of the
        Holders of any specified aggregate principal amount of the Notes under any other provision of this Indenture or under applicable law.

     

    
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    Section 9.02.  Call of Meetings by Trustee.  The Trustee may at any time call a meeting of Holders to take any action specified in Section 9.01, to be held at such time and
        at such place as the Trustee shall determine.  Notice of every meeting of the Holders, setting forth the time and the place of such meeting and in general terms the action proposed to be taken at such meeting and the establishment of any record
        date pursuant to Section 8.01, shall be mailed to Holders of such Notes at their addresses as they shall appear on the Note Register.  Such notice shall also be mailed to the Company.  Such notices shall be mailed not less than 20 nor more than 90
        calendar days prior to the date fixed for the meeting.

     

    Any meeting of Holders shall be valid without notice if the Holders of all Notes then outstanding are present in person or by proxy or if notice is
      waived before or after the meeting by the Holders of all Notes then outstanding, and if the Company and the Trustee are either present by duly authorized representatives or have, before or after the meeting, waived notice.

     

    Section 9.03.  Call of Meetings by Company or Holders.  In case at any time the Company, pursuant to a Board Resolution, or the Holders of at
        least 10% of the aggregate principal amount of the Notes then outstanding, shall have requested the Trustee to call a meeting of Holders, by written request setting forth in reasonable detail the action proposed to be taken at the meeting, and the
        Trustee shall not have mailed the notice of such meeting within 20 days after receipt of such request, then the Company or such Holders may determine the time and the place for such meeting and may call such meeting to take any action authorized in
        Section 9.01, by mailing notice thereof as provided in Section 9.02.

     

    Section 9.04.  Qualifications for Voting.  To be entitled to vote at any meeting of Holders a Person shall (a) be a Holder of one or more Notes on the record date pertaining
        to such meeting or (b) be a Person appointed by an instrument in writing as proxy by a Holder of one or more Notes on the record date pertaining to such meeting.  The only Persons who shall be entitled to be present or to speak at any meeting of
        Holders shall be the Persons entitled to vote at such meeting and their counsel and any representatives of the Trustee and its counsel and any representatives of the Company and its counsel.

     

    Section 9.05.  Regulations.  Notwithstanding any other provisions of this Indenture, the Trustee may make such reasonable regulations as it may deem advisable for any meeting of Holders, in regard to proof of the holding of Notes and of the
        appointment of proxies, and in regard to the appointment and duties of inspectors of votes, the submission and examination of proxies, certificates and other evidence of the right to vote, and such other matters concerning the conduct of the
        meeting as it shall think fit.

     

    The Trustee shall, by an instrument in writing, appoint a temporary chairman of the meeting, unless the meeting shall have been called by the Company or
      by Holders as provided in Section 9.03, in which case the Company or the Holders calling the meeting, as the case may be, shall in like manner appoint a temporary chairman.  A permanent chairman and a permanent secretary of the meeting shall be
      elected by vote of the Holders of a majority in aggregate principal amount of the Notes represented at the meeting and entitled to vote at the meeting.

     

    
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    Subject to the provisions of Section 8.04, at any meeting of Holders each Holder or proxyholder shall be entitled to one vote for each $1,000 principal
      amount of Notes held or represented by him or her; provided, however,
      that no vote shall be cast or counted at any meeting in respect of any Note challenged as not outstanding and ruled by the chairman of the meeting to be not outstanding.  The chairman of the meeting shall have no right to vote other than by virtue of
      Notes held by it or instruments in writing as aforesaid duly designating it as the proxy to vote on behalf of other Holders.  Any meeting of Holders duly called pursuant to the provisions of Section 9.02 or Section 9.03 may be adjourned from time to
      time by the Holders of a majority of the aggregate principal amount of Notes represented at the meeting, whether or not constituting a quorum, and the meeting may be held as so adjourned without further notice.

     

    Section 9.06.  Voting.  The vote upon any resolution submitted to any meeting of Holders shall be by written ballot on which shall be subscribed the signatures of the Holders or of their representatives by proxy
        and the outstanding aggregate principal amount of the Notes held or represented by them.  The permanent chairman of the meeting shall appoint two inspectors of votes who shall count all votes cast at the meeting for or against any resolution and
        who shall make and file with the secretary of the meeting their verified written reports in duplicate of all votes cast at the meeting.  A record in duplicate of the proceedings of each meeting of Holders shall be prepared by the secretary of the
        meeting and there shall be attached to said record the original reports of the inspectors of votes on any vote by ballot taken thereat and affidavits by one or more Persons having knowledge of the facts setting forth a copy of the notice of the
        meeting and showing that said notice was mailed as provided in Section 9.02.  The record shall show the aggregate principal amount of the Notes voting in favor of or against any resolution.  The record shall be signed and verified by the affidavits
        of the permanent chairman and secretary of the meeting and one of the duplicates shall be delivered to the Company and the other to the Trustee to be preserved by the Trustee, the latter to have attached thereto the ballots voted at the meeting.

     

    Any record so signed and verified shall be conclusive evidence of the matters therein stated.

     

    Section 9.07.  No Delay of Rights by Meeting.  Nothing contained in this Article 9 shall be deemed or
        construed to authorize or permit, by reason of any call of a meeting of Holders or any rights expressly or impliedly conferred hereunder to make such call, any hindrance or delay in the exercise of any right or rights conferred upon or reserved to
        the Trustee or to the Holders under any of the provisions of this Indenture or of the Notes.

     

    ARTICLE 10

        Supplemental Indentures

     

    Section 10.01.  Supplemental Indentures Without Consent of Holders.  The Company, when authorized by the resolutions of the Board of Directors and the Trustee, at the
        Company’s expense, may from time to time and at any time enter into an indenture or indentures supplemental hereto for one or more of the following purposes:

     

    
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    (a)          to cure any ambiguity, omission, defect or inconsistency in this Indenture
        as set forth in an Officer’s Certificate;

     

    (b)          to provide for the assumption by a Successor Company of the obligations of
        the Company under this Indenture pursuant to Article 11;

     

    (c)          to provide for the conversion of Notes into
        Reference Property and to effect any other changes to the terms of the Notes required under this Indenture in connection therewith;

     

    (d)          to add guarantees with respect to the Notes;

     

    (e)          to secure the Notes;

     

    (f)          to add to the covenants or Events of Default for the benefit of the
        Holders or surrender any right or power conferred upon the Company;

     

    (g)          to make any other change that does not
        adversely affect the rights of any Holder;

     

    (h)          to comply with any requirements of the Commission in connection with the
        qualification of this Indenture under the Trust Indenture Act;

     

    (i)          to appoint a successor Trustee with respect to the Notes;

     

    (j)          subject to the conditions and limitations set forth in this Indenture, to
        irrevocably elect a Settlement Method or a Specified Dollar Amount or eliminate the Company’s right to elect a Settlement Method; or

     

    (k)          to conform the provisions of this Indenture or the Notes to the provisions
        of the Term Sheet, as set forth in an Officer’s Certificate.

     

    Upon the written request of the Company, the Trustee is hereby authorized to join with the Company in the execution of any such supplemental indenture,
      to make any further appropriate agreements and stipulations that may be therein contained, but the Trustee shall not be obligated to, but may in its discretion, enter into any supplemental indenture that affects the Trustee’s own rights, duties or
      immunities under this Indenture or otherwise.

     

    Any supplemental indenture authorized by the provisions of this Section 10.01 may be executed by the Company and the Trustee without the consent of the
      Holders of any of the Notes at the time outstanding, notwithstanding any of the provisions of Section 10.02.

     

    
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    Section 10.02.  Supplemental Indentures with Consent of Holders.  With the consent (evidenced as provided in
        Article 8) of the Holders of at least a majority of the aggregate principal amount of the Notes then outstanding (determined in accordance with Article 8 and including, without limitation, consents obtained in connection with a purchase of, or
        tender offer or exchange offer for, Notes), the Company, when authorized by the resolutions of the Board of Directors and the Trustee, at the Company’s expense, may from time to time and at any time enter into an indenture or indentures
        supplemental hereto for the purpose of adding any provisions to or changing in any manner or eliminating any of the provisions of this Indenture or any supplemental indenture or of modifying in any manner the rights of the Holders; provided, however, that, without the consent of each Holder of an
        outstanding Note affected, no such supplemental indenture shall:

     

    (a)          reduce the percentage in aggregate principal amount of Notes outstanding
        whose Holders must consent to an amendment to this Indenture or to waive any past Default or Event of Default pursuant to Section 6.09;

     

    (b)          reduce the rate of or extend the stated time for payment of interest on
        any Note;

     

    (c)          reduce the principal of or extend the Maturity Date of any Note;

     

    (d)          except as required pursuant to this Indenture, make any change that
        impairs or adversely affects the conversion rights of any Notes;

     

    (e)          reduce the Fundamental Change Purchase Price of any Note or amend or
        modify in any manner adverse to the Holders the Company’s obligation to make such payments, whether through an amendment or waiver of provisions in the covenants, definitions or otherwise;

     

    (f)          make any Note payable in a currency other than that stated in the Note;

     

    (g)          change the ranking of the Notes in any manner adverse to the Holders;

     

    (h)          impair the right of any Holder to receive payment of principal of and
        interest, including Additional Interest, if any, on such Holder’s Notes on or after the due dates therefor or to institute suit for the enforcement of any payment on or with respect to such Holder’s Note; or

     

    (i)          make any change in this Article 10 that requires each Holder’s consent or
        in the waiver provisions in Section 6.01 or Section 6.09.

     

    Upon the written request of the Company, and upon the filing with the Trustee of evidence of the consent of Holders as aforesaid and subject to Section
      10.05, the Trustee shall join with the Company in the execution of such supplemental indenture unless such supplemental indenture affects the Trustee’s own rights, duties or immunities under this Indenture or otherwise, in which case the Trustee may
      in its discretion, but shall not be obligated to, enter into such supplemental indenture.

     

    Holders do not need under this Section 10.02 to approve the particular form of any proposed supplemental indenture.  It shall be sufficient if such
      Holders approve the substance thereof.  After any such supplemental indenture becomes effective, the Company shall deliver to the Holders a notice briefly describing such supplemental indenture. However, the failure to give such notice to all the
      Holders, or any defect in the notice, will not impair or affect the validity of the supplemental indenture.

     

    
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    Section 10.03.  Effect of Supplemental Indentures.  Upon the execution of any supplemental indenture pursuant to the provisions of this Article
        10, this Indenture shall be and be deemed to be modified and amended in accordance therewith and the respective rights, limitation of rights, obligations, duties and immunities under this Indenture of the Trustee, the Company and the Holders shall
        thereafter be determined, exercised and enforced hereunder subject in all respects to such modifications and amendments and all the terms and conditions of any such supplemental indenture shall be and be deemed to be part of the terms and
        conditions of this Indenture for any and all purposes.

     

    Section 10.04.  Notation on Notes.  Notes authenticated and delivered after the execution of any supplemental indenture pursuant to the
        provisions of this Article 10 may, at the Company’s expense, bear a notation in form approved by the Trustee as to any matter provided for in such supplemental indenture.  If the Company or the Trustee shall so determine, new Notes so modified as
        to conform, in the opinion of the Trustee and the Board of Directors, to any modification of this Indenture contained in any such supplemental indenture may, at the Company’s expense, be prepared and executed by the Company, authenticated by the
        Trustee (or an authenticating agent duly appointed by the Trustee pursuant to Section 17.10) and delivered in exchange for the Notes then outstanding, upon surrender of such Notes then outstanding.

     

    Section 10.05.  Evidence of Compliance of Supplemental Indenture to Be Furnished Trustee.  In addition to the documents required by Section 17.05, the Trustee shall receive an Officer’s Certificate and an Opinion of Counsel as conclusive
        evidence that any supplemental indenture executed pursuant hereto complies with the requirements of this Article 10 and is permitted or authorized by this Indenture, and is the legal, valid and binding obligation of the Company, enforceable against
        the Company in accordance with its terms.

     

    ARTICLE 11

        Consolidation, Merger, Sale, Conveyance and Lease

     

    Section 11.01.  Company May Consolidate, Etc. on Certain Terms.  Subject to the provisions of Section 11.02, the Company shall not consolidate with, merge with or into, or
        sell, convey, transfer or lease its consolidated properties and assets substantially as an entirety to another Person, unless:

     

    (a)          the resulting, surviving or transferee Person
        (the “Successor Company”), if not the Company, shall be a corporation organized and existing under the laws of the United States of America, any State thereof
        or the District of Columbia, and the Successor Company (if not the Company) shall expressly assume, by supplemental indenture all of the obligations of the Company under the Notes and this Indenture; and

     

    (b)          immediately after giving effect to such transaction, no Default or Event
        of Default shall have occurred and be continuing under this Indenture.

     

    
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    For purposes of this Section 11.01, the sale, conveyance, transfer or lease of the properties and assets of one or more Subsidiaries of the Company
      substantially as an entirety to another Person, which properties and assets, if held by the Company instead of such Subsidiaries, would constitute the properties and assets of the Company substantially as an entirety on a consolidated basis, shall be
      deemed to be the sale, conveyance, transfer or lease of the properties and assets of the Company substantially as an entirety to another Person.  For the avoidance of doubt, the Trustee shall have no duty or obligation to determine whether Sections
      11.01(a) and (b) have been satisfied in the event of such consolidation, merger, sale, conveyance, or lease.

     

    Section 11.02.  Successor Corporation to Be Substituted.  In case of any such consolidation, merger, sale, conveyance, transfer or lease and upon the assumption by the
        Successor Company, by supplemental indenture, executed and delivered to the Trustee and satisfactory in form to the Trustee, of the due and punctual payment of the principal of and accrued and unpaid interest on all of the Notes, the due and
        punctual delivery or payment, as the case may be, of any consideration due upon conversion of the Notes and the due and punctual performance of all of the covenants and conditions of this Indenture to be performed by the Company, such Successor
        Company (if not the Company) shall succeed to and be substituted for the Company, with the same effect as if it had been named herein as the party of the first part, except in the case of a lease of the Company’s properties and assets substantially
        as an entirety.  Such Successor Company thereupon may cause to be signed, and may issue either in its own name or in the name of the Company any or all of the Notes issuable hereunder which theretofore shall not have been signed by the Company and
        delivered to the Trustee; and, upon the order of such Successor Company instead of the Company and subject to all the terms, conditions and limitations in this Indenture prescribed, the Trustee shall authenticate and shall deliver, or cause to be
        authenticated and delivered, any Notes that previously shall have been signed and delivered by the Officers of the Company to the Trustee for authentication, and any Notes that such Successor Company thereafter shall cause to be signed and
        delivered to the Trustee for that purpose.  All the Notes so issued shall in all respects have the same legal rank and benefit under this Indenture as the Notes theretofore or thereafter issued in accordance with the terms of this Indenture as
        though all of such Notes had been issued at the date of the execution hereof.  In the event of any such consolidation, merger, sale, conveyance or transfer (but not in the case of a lease), upon compliance with this Article 11 the Person named as
        the “Company” in the first paragraph of this Indenture (or any successor that shall thereafter have become such in the manner prescribed in this Article 11) may be dissolved,
        wound up and liquidated at any time thereafter and, except in the case of a lease, such Person shall be released from its liabilities as obligor and maker of the Notes and from its obligations under this Indenture and the Notes.

     

    In case of any such consolidation, merger, sale, conveyance, transfer or lease, such changes in phraseology and form (but not in substance) may be made
      in the Notes thereafter to be issued as may be appropriate.

     

    ARTICLE 12

        Immunity of Incorporators, Stockholders, Officers and Directors

     

    Section 12.01.  Indenture and Notes Solely Corporate Obligations.  No recourse for the payment of the principal of or accrued and unpaid interest on any Note, nor for any claim based thereon or otherwise in
        respect thereof, and no recourse under or upon any obligation, covenant or agreement of the Company in this Indenture or in any supplemental indenture or in any Note, nor because of the creation of any indebtedness represented thereby, shall be had
        against any incorporator, stockholder, employee, agent, Officer or director or Subsidiary, as such, past, present or future, of the Company or of any successor corporation, either directly or through the Company or any successor corporation,
        whether by virtue of any constitution, statute or rule of law, or by the enforcement of any assessment or penalty or otherwise; it being expressly understood that all such liability is hereby expressly waived and released as a condition of, and as
        a consideration for, the execution of this Indenture and the issue of the Notes.

     

    
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    ARTICLE 13

        Intentionally Omitted

     

    ARTICLE 14

        Conversion of Notes

     

    Section 14.01.  Conversion Privilege.  (a) Subject to and upon compliance with the provisions of this Article 14, each Holder of a Note shall
        have the right, at such Holder’s option, to convert all or any portion (if the portion to be converted is $1,000 principal amount or multiple thereof) of such Note (i) subject to satisfaction of the conditions described in Section 14.01(b), at any
        time prior to the close of business on the Business Day immediately preceding August 1, 2024 under the circumstances and during the periods set forth in Section 14.01(b), and (ii) irrespective of the conditions described in Section 14.01(b), on or
        after August 1, 2024 until the close of business on the second Scheduled Trading Day preceding the Maturity Date, in each case, at an initial conversion rate of 12.0075 shares of Common Stock (as adjusted as provided in Section 14.04 as of any date, the “Conversion Rate”) per $1,000 principal amount of Notes (subject to the
        settlement provisions of Section 14.02, the “Conversion Obligation”).

     

    (b)          (i) Prior to the close of business on the
        Business Day immediately preceding August 1, 2024, a Holder may surrender all or any portion of its Notes for conversion at any time during the five Business Day period immediately after any five consecutive Trading Day period (the “Measurement Period”) in which the Trading Price per $1,000 principal amount of Notes, as determined following a request by a Holder of Notes in accordance with
        this subsection (b)(i), for each Trading Day of the Measurement Period was less than 98% of the product of the Last Reported Sale Price of the Common Stock and the Conversion Rate on each such Trading Day, subject to compliance with the procedures
        and conditions set forth in this subsection (b)(i) concerning the Bid Solicitation Agent’s obligation to make a Trading Price determination.  The Trading Prices shall be determined by the Bid Solicitation Agent pursuant to this subsection (b)(i)
        and the definition of Trading Price set forth in this Indenture.  The Company shall provide written notice to the Bid Solicitation Agent (if other than the Company) of the three independent nationally recognized securities dealers selected by the
        Company pursuant to the definition of Trading Price, along with appropriate contact information for each.  The Bid Solicitation Agent (if other than the Company) shall have no obligation to determine the Trading Price per $1,000 principal amount of
        Notes unless the Company has requested such determination in writing, and the Company shall have no obligation to make such request (or, if the Company is acting as Bid Solicitation Agent, the Company shall have no obligation to determine the
        Trading Price per $1,000 principal amount of Notes) unless a Holder of at least $1,000,000 aggregate principal amount of Notes provides the Company with reasonable evidence that the Trading Price per $1,000 principal amount of Notes would be less
        than 98% of the product of the Last Reported Sale Price of the Common Stock and the Conversion Rate, at which time the Company shall instruct the Bid Solicitation Agent (if other than the Company) in writing to determine, or if the Company is
        acting as Bid Solicitation Agent, the Company shall determine, the Trading Price per $1,000 principal amount of Notes beginning on the next Trading Day and on each successive Trading Day until the Trading Price per Note is greater than or equal to
        98% of the product of the Last Reported Sale Price of the Common Stock and the Conversion Rate.  If (x) the Company is not acting as Bid Solicitation Agent, and the Company does not instruct the Bid Solicitation Agent to determine the Trading Price
        per $1,000 principal amount of Notes when obligated as provided in the preceding sentence, or if the Company instructs the Bid Solicitation Agent to obtain bids and the Bid Solicitation Agent fails to make such determination, or (y) the Company is
        acting as Bid Solicitation Agent and the Company fails to make such determination when obligated as provided in the preceding sentence, then, in either case, the Trading Price per $1,000 principal amount of Notes shall be deemed to be less than 98%
        of the product of the Last Reported Sale Price of the Common Stock and the Conversion Rate on each Trading Day of such failure.  If the Trading Price condition set forth above has been met on any Trading Day, the Company shall so notify the
        Holders, the Trustee and the Conversion Agent (if other than the Trustee) in writing.  If, at any time after the Trading Price condition set forth above has been met on any Trading Day, the Trading Price per $1,000 principal amount of Notes is
        greater than or equal to 98% of the product of the Last Reported Sale Price of the Common Stock and the applicable Conversion Rate for such Trading Day, the Company shall so notify the Holders of the Notes, the Trustee and the Conversion Agent (if
        other than the Trustee) in writing.

     

    
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        (ii)         If, prior to the close of business on the Business Day immediately preceding August 1, 2024, the Company elects to:

         

        

      

    

    
      
        (A)      distribute to all or substantially all holders of its Common Stock rights, options or warrants (other than in connection with a stockholder rights plan) entitling them, for a period of not more than 60 calendar
          days from the declaration date for such distribution, to subscribe for or purchase shares of its Common Stock, at a price per share less than the average of the Last Reported Sale Prices of the Common Stock for the 10 consecutive Trading Day
          period ending on, and including, the Trading Day immediately preceding the declaration date for such distribution; or

      

    

    

    

    
      
        (B)      distribute to all or
          substantially all holders of its Common Stock the Company’s assets, debt securities or rights to purchase securities of the Company, which distribution has a per share value, as determined by the Board of Directors, exceeding 10% of the average
          of the Last Reported Sale Prices of the Common Stock for the 10 consecutive Trading Day period ending on, and including, the Trading Day immediately preceding the declaration date for such distribution,

         

        

        
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    then, in either case, the Company shall notify all Holders of the Notes, the Trustee and the Conversion Agent (if other than the Trustee) in writing at least 35 Scheduled
      Trading Days prior to the Ex-Dividend Date for such distribution.  Once the Company has given such notice, a Holder may surrender all or any portion of its Notes for conversion at any time until the earlier of (1) the close of business on the
      Business Day immediately preceding the Ex-Dividend Date for such issuance or distribution and (2) the Company’s announcement that such issuance or distribution will not take place, in each case, even if the Notes are not otherwise convertible at such
      time.

     

    
      
        (iii)        If a transaction or event that constitutes a Fundamental Change or a Make-Whole Fundamental Change occurs prior to the close of business on the Business Day immediately preceding August 1, 2024,
          regardless of whether a Holder has the right to require the Company to purchase the Notes pursuant to Section 15.02, the Notes may be surrendered for conversion at any time from and after the effective date of such Fundamental Change or
          Make-Whole Fundamental Change, as the case may be, until the second Scheduled Trading Day immediately preceding the Fundamental Change Purchase Date corresponding to such Fundamental Change (or, in the case of a Make-Whole Fundamental Change that
          does not constitute a Fundamental Change, until the 35th Trading Day immediately following the Effective Date of such Make-Whole Fundamental Change).  If the Company is party to a combination, merger, binding share exchange or sale or conveyance
          of all or substantially all of its property or assets on a consolidated basis (other than any such transaction that constitutes a Fundamental Change or a Make-Whole Fundamental Change), in each case pursuant to which the Common Stock would be
          converted into cash, securities and/or other property, the Notes may be surrendered for conversion at any time beginning on the effective date of such transaction and ending on the 35th Trading Day following such effective date.  The Company
          shall notify Holders, the Trustee and the Conversion Agent (if other than the Trustee) in writing no later than the Business Day following the effective date of any such transaction.

      

    

    
      
         

          

        (iv)       
          Prior to the close of business on the Business Day immediately preceding August 1, 2024, a Holder may surrender all or any portion of its Notes for conversion during any calendar quarter commencing after the calendar quarter ending on March 31,
          2020 (and only during such calendar quarter), if the Last Reported Sale Price of the Common Stock for at least 20 Trading Days (whether or not consecutive) during the period of 30 consecutive Trading Days ending on the last Trading Day of the
          immediately preceding calendar quarter is greater than or equal to 130% of the Conversion Price on each applicable Trading Day.  The Conversion Agent, on behalf of the Company, shall determine at the beginning of each calendar quarter commencing
          after March 31, 2020 whether the Notes may be surrendered for conversion in accordance with this clause (iv) and shall notify the Company and the Trustee if the Notes become convertible in accordance with this clause (iv).

      

    

     

    

    
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    If the Company announces a transaction that causes the Notes to become convertible pursuant to clause (ii) or (iii), but the transaction is not
      consummated, then the Notes will cease to be convertible pursuant to these provisions on account of such transaction immediately prior to the open of business on the Business Day immediately following the date on which the Company announces that such
      transaction will not occur.  In connection with any conversion upon satisfaction of the above sale price condition, none of the Trustee, Bid Solicitation Agent or the Conversion Agent shall have any obligation to determine the Last Reported Sale
      Price.

     

    Section 14.02.  Conversion
          Procedure; Settlement Upon Conversion.

     

    (a)          Subject to this Section 14.02, Section
        14.03(b) and Section 14.07(a), upon conversion of any Note, the Company shall pay or deliver, as the case may be, to the converting Holder, in respect of each $1,000 principal amount of Notes being converted, cash (“Cash Settlement”), shares of Common Stock, together with cash, if applicable, in lieu of delivering any fractional share of Common Stock in accordance with subsection (j) of this Section
        14.02 (“Physical Settlement”) or a combination of cash and shares of Common Stock, together with cash, if applicable, in lieu of delivering any fractional
        share of Common Stock in accordance with subsection (j) of this Section 14.02 (“Combination Settlement”), at its election, as set forth in this Section 14.02.
        Prior to August 1, 2024, the Company may irrevocably elect, in its sole discretion without the consent of the Holders, Combination Settlement with a Specified Dollar Amount of at least $1,000 (an “Irrevocable Election”) for all conversions subsequent to the date of such election.  If the Company makes such an election in its sole discretion, it shall notify each Holder, the Trustee, the Paying Agent
        (if other than the Trustee) and the Conversion Agent (if other than the Trustee) in writing.  From and after any such Irrevocable Election, the Company will continue to be able to select any Specified Dollar Amount subject to the conditions and
        limitations set forth in this Indenture so long as such Specified Dollar Amount is at least $1,000.

     

    
      
        (i)     All conversions occurring on or
          after August 1, 2024 shall be settled using the same Settlement Method.

      

    

    
      
         

          

        (ii)    Except for any conversions
          occurring on or after August 1, 2024, the Company shall use the same Settlement Method for all conversions occurring on the same Conversion Date, but, unless the Company shall have made an Irrevocable Election, the Company shall not have any
          obligation to use the same Settlement Method with respect to conversions that occur on different Conversion Dates.

      

    

    
      
         

          

        (iii)   If, in respect of any Conversion Date (or on or after August 1, 2024), the Company elects to deliver a notice (the “Settlement Notice”)
          of the relevant Settlement Method in respect of such Conversion Date (or such period, as the case may be), the Company, through the Trustee, shall deliver such Settlement Notice to converting Holders no later than the close of business on the
          Trading Day immediately following the relevant Conversion Date (or, in the case of any conversions occurring on or after August 1, 2024, no later than August 1, 2024).  If the Company does not elect a Settlement Method prior to the deadline set
          forth in the immediately preceding sentence, the Company shall no longer have the right to elect Cash Settlement or Physical Settlement and the Company shall be deemed to have elected Combination Settlement in respect of its Conversion
          Obligation, and the Specified Dollar Amount per $1,000 principal amount of Notes shall be equal to $1,000.  Such Settlement Notice shall specify the relevant Settlement Method and in the case of an election of Combination Settlement, the relevant
          Settlement Notice shall indicate the Specified Dollar Amount.  If the Company delivers a Settlement Notice electing Combination Settlement in respect of its Conversion Obligation but does not indicate a Specified Dollar Amount in such Settlement
          Notice, the Specified Dollar Amount shall be deemed to be $1,000.

      

    

    
      
         

          

        
          57

          
            


        

        (iv)        The cash, shares of Common Stock or combination of cash and shares of Common Stock in respect of any conversion of Notes (the “Settlement
            Amount”) shall be computed as follows:

      

    

    

    

    
      
        (A)         if the Company elects to
          satisfy its Conversion Obligation in respect of such conversion by Physical Settlement, the Company shall deliver to the converting Holder in respect of each $1,000 principal amount of Notes being converted a number of shares of Common Stock
          equal to the Conversion Rate in effect on the Conversion Date;

      

    

    
      
         

          

        (B)         if the Company elects to
          satisfy its Conversion Obligation in respect of such conversion by Cash Settlement, the Company shall pay to the converting Holder in respect of each $1,000 principal amount of Notes being converted cash in an amount equal to the sum of the Daily
          Conversion Values for each of the 30 consecutive Trading Days during the related Observation Period; and

      

    

    
      
         

          

        (C)         if the Company elects (or is
          deemed to have elected) to satisfy its Conversion Obligation in respect of such conversion by Combination Settlement, the Company shall pay or deliver, as the case may be, to the converting Holder in respect of each $1,000 principal amount of
          Notes being converted, a Settlement Amount equal to the sum of the Daily Settlement Amounts for each of the 30 consecutive Trading Days during the related Observation Period.

      

    

    
      
         

          

        (v)         The Daily Settlement Amounts
          (if applicable) and the Daily Conversion Values (if applicable) shall be determined by the Company promptly following the last day of the Observation Period.  Promptly after such determination of the Daily Settlement Amounts or the Daily
          Conversion Values, as the case may be, and the amount of cash payable in lieu of delivering any fractional share, the Company shall notify the Trustee and the Conversion Agent (if other than the Trustee) of the Daily Settlement Amounts or the
          Daily Conversion Values, as the case may be, and the amount of cash payable in lieu of delivering any fractional shares of Common Stock.  The Trustee and the Conversion Agent (if other than the Trustee) shall have no responsibility for any such
          determination.

      

    

     

      

    
      58

      
        


    

    (b)          Subject to Section 14.02(e), before any Holder of a Note shall be entitled to convert a Note as set forth above, such Holder shall provide an irrevocable notice (a “Notice of Conversion”) (i) in the case of a Global Note, by complying with the procedures of the Depositary in effect at that time and, if required, paying all documentary, stamp or similar issue or
        transfer taxes as set forth in Section 14.02(d) and, if required, paying funds equal to interest payable on the next Interest Payment Date to which such Holder is not entitled as set forth in Section 14.02(h) and (ii) in the case of a Physical Note
        (1) completing, manually signing and delivering an irrevocable notice to the Conversion Agent as set forth in the Form of Notice of Conversion (or a facsimile thereof) at the office of the Conversion Agent and stating in writing therein the
        principal amount of Notes to be converted and the name or names (with addresses) in which such Holder wishes the certificate or certificates for any shares of Common Stock to be delivered upon settlement of the Conversion Obligation to be
        registered, (2) surrendering such Notes, duly endorsed to the Company or in blank (and accompanied by appropriate endorsement and transfer documents), at the office of the Conversion Agent, (3) if required, furnishing appropriate endorsements and
        transfer documents, (4) if required, paying all documentary, stamp or similar issue or transfer taxes as set forth in Section 14.02(d) and (e) and (5) if required, paying funds equal to interest payable on the next Interest Payment Date to which
        such Holder is not entitled as set forth in Section 14.02(h).  The Trustee (and if different, the Conversion Agent) shall notify the Company of any conversion pursuant to this Article 14 on the Conversion Date for such conversion.  No Notice of
        Conversion with respect to any Notes may be surrendered by a Holder thereof if such Holder has also delivered a Fundamental Change Purchase Notice to the Company in respect of such Notes and not validly withdrawn such Fundamental Change Purchase
        Notice in accordance with Section 15.03.

     

    If more than one Note shall be surrendered for conversion at one time by the same Holder, the Conversion Obligation with respect to such Notes shall be
      computed on the basis of the aggregate principal amount of the Notes (or specified portions thereof to the extent permitted thereby) so surrendered.

     

    (c)          A Note shall be deemed to have been converted
        immediately prior to the close of business on the date (the “Conversion Date”) that the Holder has complied with the requirements set forth in subsection (b)
        above.  Except as set forth in Section 14.03(b) and Section 14.07(a), the Company shall pay or deliver, as the case may be, the consideration due in respect of the Conversion Obligation on the second Business Day immediately following the relevant
        Conversion Date, if the Company elects Physical Settlement (unless such Conversion Date is on or after the Regular Record Date immediately preceding the Maturity Date, in which case the Company shall deliver the consideration due in respect of such
        Conversion Obligation on the Maturity Date), or on the second Business Day immediately following the last Trading Day of the Observation Period, in the case of any other Settlement Method.  If any shares of Common Stock are due to converting
        Holders, the Company shall issue or cause to be issued, and deliver to the Conversion Agent or to such Holder, or such Holder’s nominee or nominees, certificates or a book-entry transfer through the Depositary for the full number of shares of
        Common Stock to which such Holder shall be entitled in satisfaction of the Company’s Conversion Obligation.

     

    (d)          In case any Note shall be surrendered for
        partial conversion, the Company shall execute and the Trustee shall authenticate and deliver to or upon the written order of the Holder of the Note so surrendered a new Note or Notes in authorized denominations in an aggregate principal amount
        equal to the unconverted portion of the surrendered Note, without payment of any service charge by the converting Holder but, if required by the Company or Trustee, with payment of a sum sufficient to cover any documentary, stamp, or similar issue
        or transfer tax or similar governmental charge required by law or that may be imposed in connection therewith as a result of the name of the Holder of the new Notes issued upon such conversion being different from the name of the Holder of the old
        Notes surrendered for such conversion.

     

    
      59

      
        


    

    (e)          If a Holder
        submits a Note for conversion, the Company shall pay any documentary, stamp or similar issue or transfer tax due on the issue of any shares of Common Stock upon conversion, unless the tax is due because the Holder requests such shares to be issued
        in a name other than the Holder’s name, in which case the Holder shall pay that tax.  The Conversion Agent may refuse to deliver the certificates representing the shares of Common Stock being issued in a name other than the Holder’s name until the
        Trustee receives a sum sufficient to pay any tax that is due by such Holder in accordance with the immediately preceding sentence.

     

    (f)          Except as provided in Section 14.04, no adjustment shall be made for
        dividends on any shares of Common Stock issued upon the conversion of any Note as provided in this Article 14.

     

    (g)          Upon the conversion of an interest in a Global Note, the Trustee, or the
        Custodian at the direction of the Trustee, shall make a notation on such Global Note as to the reduction in the principal amount represented thereby.  The Company shall notify the Trustee in writing of any conversion of Notes effected through any
        Conversion Agent other than the Trustee.

     

    (h)          Upon conversion, a Holder shall not receive
        any separate cash payment for accrued and unpaid interest, if any, except as set forth below.  The Company’s settlement of the full Conversion Obligation shall be deemed to satisfy in full its obligation to pay the principal amount of the Note and
        accrued and unpaid interest, if any, to, but not including, the relevant Conversion Date. As a result, accrued and unpaid interest, if any, to, but not including, the relevant Conversion Date shall be deemed to be paid in full rather than
        cancelled, extinguished or forfeited.  Upon a conversion of Notes into a combination of cash and shares of Common Stock accrued and unpaid interest will be deemed to be paid first out of the cash paid upon such conversion.  Notwithstanding the
        foregoing, if Notes are converted after the close of business on a Regular Record Date, Holders of such Notes as of the close of business on such Regular Record Date will receive the full amount of interest payable on such Notes on the
        corresponding Interest Payment Date notwithstanding the conversion.  Notes surrendered for conversion during the period beginning after the close of business on any Regular Record Date and ending at the open of business on the immediately following
        Interest Payment Date must be accompanied by funds equal to the amount of interest payable on the Notes so converted; provided that no such payment shall be
        required (1) for Notes surrendered for conversion after the close of business on the Regular Record Date immediately preceding the Maturity Date; (2) if the Company has specified a Fundamental Change Purchase Date that is after a Regular Record
        Date and on or prior to the second Scheduled Trading Day following the corresponding Interest Payment Date; or (3) to the extent of any Defaulted Amounts, if any Defaulted Amounts exist at the time of conversion with respect to such Note.
        Therefore, for the avoidance of doubt, all Holders of record at the close of business on the Regular Record Date immediately preceding the Maturity Date and any Fundamental Change Purchase Date described in clause (2) above shall receive the full
        interest payment due on the Maturity Date or other applicable Interest Payment Date regardless of whether their Notes have been converted following such Regular Record Date.

     

    
      60

      
        


    

    (i)          The Person in whose name the certificate
        for any shares of Common Stock delivered upon conversion is registered shall be treated as a stockholder of record as of the close of business on the relevant Conversion Date (if the Company elects to satisfy the related Conversion Obligation by
        Physical Settlement) or the last Trading Day of the relevant Observation Period (if the Company elects to satisfy the related Conversion Obligation by Combination Settlement), as the case may be.  Upon a conversion of Notes, such Person shall no
        longer be a Holder of such Notes surrendered for conversion.

     

    (j)          The Company shall not issue any fractional
        share of Common Stock upon conversion of the Notes and shall instead pay cash in lieu of delivering any fractional share of Common Stock issuable upon conversion based on the Daily VWAP on the relevant Conversion Date (in the case of Physical
        Settlement) or based on the Daily VWAP on the last Trading Day of the relevant Observation Period (in the case of Combination Settlement).  For each Note surrendered for conversion, if the Company has elected Combination Settlement, the full number
        of shares that shall be issued upon conversion thereof shall be computed on the basis of the aggregate Daily Settlement Amounts for the applicable Observation Period and any fractional shares remaining after such computation shall be paid in cash.

     

    Section 14.03.  Increased Conversion Rate Applicable to Certain Notes Surrendered in Connection with Make-Whole
          Fundamental Changes.  (a)  If a Make-Whole Fundamental Change occurs prior to the Maturity Date and a Holder elects to convert its Notes in connection with such Make-Whole Fundamental Change, the Company shall, under the circumstances
        described below, increase the Conversion Rate for the Notes so surrendered for conversion by a number of additional shares of Common Stock (the “Additional Shares”),
        as described below.  A conversion of Notes shall be deemed for these purposes to be “in connection with” such Make-Whole Fundamental Change if the relevant Notice of Conversion is received by the Conversion Agent from, and including, the Effective
        Date of the Make-Whole Fundamental Change up to, and including, the close of business on the Business Day immediately prior to the related Fundamental Change Purchase Date (or, in the case of a Make-Whole Fundamental Change that would have been a
        Fundamental Change but for the proviso in clause (b) of the definition thereof, the 35th Trading Day immediately following the Effective Date of such
        Make-Whole Fundamental Change) (such period, the “Make-Whole Fundamental Change Period”).  The Company shall notify the Holders of Notes and the Trustee of the
        Effective Date of any Make-Whole Fundamental Change no later than five Business Days after such Effective Date.

     

    (b)          Upon surrender
        of Notes for conversion in connection with a Make-Whole Fundamental Change pursuant to Section 14.01(b)(iii), the Company shall, at its option, satisfy the related Conversion Obligation by Physical Settlement, Cash Settlement or Combination
        Settlement in accordance with Section 14.02; provided, however,
        that if, at the effective time of a Make-Whole Fundamental Change described in clause (b) of the definition of Fundamental Change, the Reference Property is composed entirely of cash, for any conversion of Notes following the Effective Date of such
        Make-Whole Fundamental Change, the Conversion Obligation shall be calculated based solely on the Stock Price for the transaction and shall be deemed to be an amount of cash per $1,000 principal amount of converted Notes equal to the Conversion Rate
        (including any adjustment for Additional Shares), multiplied by such Stock Price.  In such event, the Conversion Obligation shall be paid to Holders in cash
        on the second Business Day following the Conversion Date.

     

    
      61

      
        


    

    
    (c)          The number of Additional Shares, if any, by
        which the Conversion Rate shall be increased for conversions during the Make-Whole Fundamental Change Period shall be determined by reference to the table below, based on the date on which the Make-Whole Fundamental Change occurs or becomes
        effective (the “Effective Date”) and the price (the “Stock Price”)
        paid (or deemed to be paid) per share of the Common Stock in the Make-Whole Fundamental Change.  If the holders of the Common Stock receive in exchange for their Common Stock only cash in a Make-Whole Fundamental Change described in clause (b) of
        the definition of Fundamental Change, the Stock Price shall be the cash amount paid per share.  In the case of any other Make-Whole Fundamental Change, the Stock Price shall be the average of the Last Reported Sale Prices of the Common Stock over
        the five Trading Day period ending on, and including, the Trading Day immediately preceding the Effective Date of the Make-Whole Fundamental Change.  The Board of Directors shall make appropriate adjustments to the Stock Price, in its good faith
        determination, to account for any adjustment to the Conversion Rate that becomes effective, or any event requiring an adjustment to the Conversion Rate where the Ex-Dividend Date of the event occurs, during any such five consecutive Trading Day
        period.

     

    (d)          The Stock Prices set forth in the column headings of the table below shall
        be adjusted as of any date on which the Conversion Rate of the Notes is otherwise adjusted.  The adjusted Stock Prices shall equal the Stock Prices applicable immediately prior to such adjustment, multiplied by a fraction, the numerator of which is the Conversion Rate immediately prior to such adjustment giving rise to the Stock Price adjustment and the denominator of which is the Conversion Rate as
        so adjusted.  The number of Additional Shares set forth in the table below shall be adjusted in the same manner and at the same time as the Conversion Rate as set forth in Section 14.04.

     

    (e)          The following table sets forth the number of Additional Shares by which
        the Conversion Rate shall be increased per $1,000 principal amount of Notes pursuant to this Section 14.03 for each Stock Price and Effective Date set forth below:

     

    
      	
              
                Effective Date

              

            	 	
              
                $

              

            	
              
                61.69

              

            	 	 	
              
                $

              

            	
              
                65.00

              

            	 	 	
              
                $

              

            	
              
                70.00

              

            	 	 	
              
                $

              

            	
              
                83.28

              

            	 	 	
              
                $

              

            	
              
                90.00

              

            	 	 	
              
                $

              

            	
              
                100.00

              

            	 	 	
              
                $

              

            	
              
                110.00

              

            	 	 	
              
                $

              

            	
              
                120.00

              

            	 	 	
              
                $

              

            	
              
                140.00

              

            	 	 	
              
                $

              

            	
              
                160.00

              

            	 	 	
              
                $

              

            	
              
                180.00

              

            	 	 	
              
                $

              

            	
              
                200.00

              

            	 
	
              December 19, 2019

            	 	 	
              4.2025

            	 	 	 	
              3.7526

            	 	 	 	
              3.1803

            	 	 	 	
              2.1053

            	 	 	 	
              1.7298

            	 	 	 	
              1.3072

            	 	 	 	
              1.0000

            	 	 	 	
              0.7724

            	 	 	 	
              0.4709

            	 	 	 	
              0.2922

            	 	 	 	
              0.1824

            	 	 	 	
              0.1132

            	 
	
              December 15, 2020

            	 	 	
              4.2025

            	 	 	 	
              3.7526

            	 	 	 	
              3.1680

            	 	 	 	
              2.0393

            	 	 	 	
              1.6509

            	 	 	 	
              1.2195

            	 	 	 	
              0.9114

            	 	 	 	
              0.6874

            	 	 	 	
              0.3989

            	 	 	 	
              0.2348

            	 	 	 	
              0.1382

            	 	 	 	
              0.0801

            	 
	
              December 15, 2021

            	 	 	
              4.2025

            	 	 	 	
              3.7372

            	 	 	 	
              3.0910

            	 	 	 	
              1.9078

            	 	 	 	
              1.5096

            	 	 	 	
              1.0765

            	 	 	 	
              0.7755

            	 	 	 	
              0.5633

            	 	 	 	
              0.3019

            	 	 	 	
              0.1629

            	 	 	 	
              0.0866

            	 	 	 	
              0.0441

            	 
	
              December 15, 2022

            	 	 	
              4.2025

            	 	 	 	
              3.6442

            	 	 	 	
              2.9443

            	 	 	 	
              1.6925

            	 	 	 	
              1.2870

            	 	 	 	
              0.8623

            	 	 	 	
              0.5819

            	 	 	 	
              0.3950

            	 	 	 	
              0.1831

            	 	 	 	
              0.0836

            	 	 	 	
              0.0359

            	 	 	 	
              0.0133

            	 
	
              December 15, 2023

            	 	 	
              4.2025

            	 	 	 	
              3.4688

            	 	 	 	
              2.6730

            	 	 	 	
              1.3098

            	 	 	 	
              0.9062

            	 	 	 	
              0.5223

            	 	 	 	
              0.3013

            	 	 	 	
              0.1740

            	 	 	 	
              0.0566

            	 	 	 	
              0.0161

            	 	 	 	
              0.0027

            	 	 	 	
              0.0000

            	 
	
              December 15, 2024

            	 	 	
              4.2025

            	 	 	 	
              3.3771

            	 	 	 	
              2.2783

            	 	 	 	
              0.0002

            	 	 	 	
              0.0000

            	 	 	 	
              0.0000

            	 	 	 	
              0.0000

            	 	 	 	
              0.0000

            	 	 	 	
              0.0000

            	 	 	 	
              0.0000

            	 	 	 	
              0.0000

            	 	 	 	
              0.0000

            	 


    

       

    
      62

      
        


    

    The exact Stock Prices and Effective Dates may not be set forth in the table above, in which case:

     

    
      
        (i)          if the Stock Price is
          between two Stock Prices in the table above or the Effective Date is between two Effective Dates in the table, the number of Additional Shares shall be determined by a straight-line interpolation between the number of Additional Shares set forth
          for the higher and lower Stock Prices and the earlier and later Effective Dates, as applicable, based on a 365-day year;

      

    

    
       

        (ii)         if the Stock Price is
          greater than $200.00 per share (subject to adjustment in the same manner as the Stock Prices set forth in the column headings of the table above pursuant to subsection (d) above), no Additional Shares shall be added to the Conversion Rate; and

         

        

      

    

    
      
        (iii)        if the Stock Price is less than $61.69 per share (subject to adjustment in the same manner as the Stock Prices set forth in the column headings of the table above pursuant to subsection (d) above), no Additional
          Shares shall be added to the Conversion Rate.

      

    

     

    

    Notwithstanding the foregoing, in no event shall the Conversion Rate exceed 16.2100 per $1,000 principal amount of Notes, subject to adjustment in the same manner as the
      Conversion Rate pursuant to Section 14.04.

     

    (f)          Nothing in this Section 14.03 shall prevent an adjustment to the
        Conversion Rate pursuant to Section 14.04 in respect of a Make-Whole Fundamental Change.

     

    Section 14.04.  Adjustment of Conversion Rate.  The Conversion Rate shall be adjusted from time to time by the Company if any of the following events occur, except that the
        Company shall not make any adjustments to the Conversion Rate if Holders of the Notes participate (as a result of holding the Notes, and contemporaneously with holders of the Common Stock) in any of the transactions described in this Section 14.04
        as if they held a number of shares of Common Stock equal to the Conversion Rate, multiplied by the principal amount (expressed in thousands) of Notes held by
        such Holder, without having to convert their Notes.

     

    (a)          If the Company issues solely shares of Common Stock as a dividend or distribution to all holders of the outstanding Common Stock on all or substantially all of the shares of outstanding Common Stock, or if the Company
        effects a share split or share combination of the Common Stock, the applicable Conversion Rate will be adjusted based on the following formula:

     

    
      

    

     
    where

     

    
      
        	

              	CR0	=

              	the Conversion Rate in effect immediately prior to the open of business on the Ex-Dividend Date for such dividend or
                distribution, or immediately prior to the open of business on the effective date of such share split or share combination, as the case may be;


      

    

     

    
      63

      
        


    

    
      
        	

              	CR’   

              	=

              	the Conversion Rate in effect immediately after the open of business on the Ex-Dividend Date for such dividend or
                distribution, or immediately after the open of business on the effective date of such share split or share combination, as the case may be;


      

    

     

    
      
        	

              	OS0	=

              	the number of shares of Common Stock outstanding immediately prior to the open of business on the Ex-Dividend Date for
                such dividend or distribution, or immediately prior to the open of business on the effective date of such share split or share combination, as the case may be; and


      

    

     

    
      
        	

              	OS’    

              	=

              	the number of shares of Common Stock outstanding immediately after such dividend or distribution, or immediately after
                the effective date of such share split or share combination, as the case may be.


      

    

     

    Any adjustment made under this Section 14.04(a) shall become effective immediately after the open of business on the Ex-Dividend Date for such dividend or distribution, or
      immediately after the open of business on the effective date for such share split or share combination, as applicable.  If any dividend or distribution of the type described in this Section 14.04(a) is declared but not so paid or made, or the
      outstanding shares of Common Stock are not split or combined, as the case may be, the Conversion Rate shall be immediately readjusted, effective as of the date the Board of Directors determines not to pay such dividend or distribution or to effect
      such split or combination, to the Conversion Rate that would then be in effect if such dividend or distribution or share split or share combination had not been declared or announced.

     

    (b)          If an Ex-Dividend Date occurs for a
        distribution to all or substantially all holders of its outstanding Common Stock any rights, options or warrants entitling them for a period of not more than 60 days from the declaration date of such distribution to subscribe for or purchase shares
        of the Common Stock, at a price per share less than the average of the Last Reported Sale Prices of the Common Stock for the 10 consecutive Trading Day period ending on, and including, the Trading Day immediately preceding the declaration date for
        such distribution, the Conversion Rate shall be increased based on the following formula:

     

    

     

    where

     

    
      
        	

              	CR0	=

              	the Conversion Rate in effect immediately prior to the open of business on the Ex-Dividend Date for such distribution;


      

    

     

    
      
        	

              	CR’

              	=

              	the Conversion Rate in effect immediately after the open of business on the Ex-Dividend Date for such distribution;


      

    

     

    
      64

      
        


    

    
      
        	

              	OS0	=

              	the number of shares of the Common Stock that are outstanding immediately prior to the open of business on the Ex-Dividend Date
                for such distribution;


      

    

     

    
      
        	

              	X

              	=

              	the total number of shares of the Common Stock issuable pursuant to such rights, options or warrants; and


      

    

     

    
      
        	

              	Y

              	=

              	the number of shares of the Common Stock equal to the aggregate price payable to exercise such rights, options or warrants,
                divided by the average of the Last Reported Sale Prices of the Common Stock over the 10 consecutive Trading Day period ending on, and including, the Trading Day immediately preceding the Ex-Dividend Date relating to such distribution of
                such rights, options or warrants.


      

    

     

    Any increase made under this Section 14.04(b) shall be made successively whenever any such rights, options or warrants are distributed and shall become effective
      immediately after the open of business on the Ex-Dividend Date for such distribution.  To the extent that shares of the Common Stock are not delivered after the expiration of such rights, options or warrants, the Conversion Rate shall be decreased,
      as of the date of such expiration, to the Conversion Rate that would then be in effect had the increase with respect to the distribution of such rights, options or warrants been made on the basis of delivery of only the number of shares of Common
      Stock actually delivered.  If such rights, options or warrants are not so distributed, the Conversion Rate shall be decreased, as of the date of such expiration, to the Conversion Rate that would then be in effect if such Ex-Dividend Date for such
      distribution had not occurred.

     

    For purposes of this Section 14.04(b) and for the purpose of Section 14.01(b)(ii)(A), in determining whether any rights, options or warrants entitle the
      holders to subscribe for or purchase shares of the Common Stock at less than such average of the Last Reported Sale Prices of the Common Stock for the 10 consecutive Trading Day period ending on, and including, the Trading Day immediately preceding
      the declaration date of such distribution, and in determining the aggregate offering price of such shares of Common Stock, there shall be taken into account any consideration received by the Company for such rights, options or warrants and any amount
      payable on exercise or conversion thereof, the value of such consideration, if other than cash, to be determined by the Board of Directors.

     

    (c)          If an Ex-Dividend Date occurs for a
        distribution of shares of the Company’s Capital Stock, evidences of its indebtedness, other assets or property or rights, options or warrants to acquire its Capital Stock or other securities, to all or substantially all holders of the outstanding
        Common Stock, excluding (i) dividends or distributions (including share splits) as to which an adjustment was effected pursuant to Section 14.04(a) or Section 14.04(b), (ii) dividends or distributions paid in cash as to which an adjustment was
        effected pursuant to Section 14.04(d), (iii) except as otherwise set forth in Section 14.11 pursuant to which an adjustment is made to the Conversion Rate pursuant to this Section 14.04(c), rights issued pursuant to any stockholder rights plan of
        the Company then in effect, (iv) any dividends and distributions in connection with a reclassification, change, consolidation, merger, conveyance, transfer, sale, lease or other disposition resulting in a change of the consideration constituting
        the Conversion Obligation as set forth in Section 14.07, (v) rights issued pursuant to any Spin-Offs as to which the provisions set forth below in this Section 14.04(c) shall apply (any of such shares of Capital Stock, evidences of indebtedness,
        other assets or property or rights, options or warrants to acquire Capital Stock or other securities of the Company, the “Distributed Property”), then the
        Conversion Rate shall be increased based on the following formula:

     

    
       

      

    

    
      65

      
        


    

    where

     

    
      
        	

              	CR0	=

              	the Conversion Rate in effect immediately prior to the open of business on the Ex-Dividend Date for such distribution;


      

    

     

    
      
        	

              	CR’

              	=

              	the Conversion Rate in effect immediately after the open of business on the Ex-Dividend Date for such distribution;


      

    

     

    
      
        	

              	SP0	=

              	the average of the Last Reported Sale Prices of the Common Stock over the 10 consecutive Trading Day period ending on, and
                including, the Trading Day immediately preceding the Ex-Dividend Date for such distribution; and


      

    

     

    
      
        	

              	FMV

              	=

              	the fair market value (as determined by the Board of Directors) of the Distributed Property distributed with respect to each
                outstanding share of the Common Stock as of the open of business on the Ex-Dividend Date for such distribution.


      

    

     

    Any increase made under the portion of this Section 14.04(c) above shall become effective immediately after the open of business on the Ex-Dividend Date for such
      distribution.  If such distribution is not so paid or made, or if any rights, options or warrants are not exercised before their expiration date, the Conversion Rate shall be decreased, as of the date of such expiration, to the Conversion Rate that
      would then be in effect if such distribution had not been declared or to the extent such rights, options or warrants that are not exercised expire, as applicable.  Notwithstanding the foregoing, if “FMV” (as defined above) is equal to or greater than
      “SP0” (as defined above), in lieu of the foregoing increase, each Holder of a Note shall receive, in respect of each $1,000 principal amount thereof, at the same time and upon the same terms as holders of the Common Stock receive the
      Distributed Property, the amount and kind of Distributed Property such Holder would have received if such Holder owned a number of shares of Common Stock equal to the Conversion Rate in effect on the Ex-Dividend Date for the distribution.  If the
      Board of Directors determines the “FMV” (as defined above) of any distribution for purposes of this Section 14.04(c) by reference to the actual or when-issued trading market for any securities, it shall in doing so consider the prices in such market
      over the same period used in computing the Last Reported Sale Prices of the Common Stock over the 10 consecutive Trading Day period ending on, and including, the Trading Day immediately preceding the Ex-Dividend Date for such distribution.

     

    
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    With respect to an adjustment pursuant to this Section 14.04(c) where there has been an Ex-Dividend Date for a dividend or other distribution on the
      Common Stock of shares of Capital Stock of any class or series, or similar equity interest, of or relating to a Subsidiary or other business unit of the Company, which Capital Stock or similar equity interest will be quoted or listed for trading on a
      U.S. national securities exchange after its distribution (a “Spin-Off”), the Conversion Rate will be increased based on the following formula:

     

    

    where

     

    
      
        	

              	CR0	=

              	the Conversion Rate in effect immediately prior to the open of business on the Ex-Dividend Date for the Spin-Off;


      

    

     

    
      
        	

              	CR’     

              	=

              	the Conversion Rate in effect immediately after the open of business on the Ex-Dividend Date for the Spin-Off;


      

    

     

    
      
        	

              	FMV  

              	=

              	the average of the Last Reported Sale Prices of the Capital Stock or similar equity interest distributed to holders of the Common
                Stock applicable to one share of the Common Stock over the first 10 consecutive Trading Day period immediately following, and including, the Ex-Dividend Date for the Spin-Off; and


      

    

     

    
      
        	

              	MP0	=

              	the average of the Last Reported Sale Prices of the Common Stock over the first 10 consecutive Trading Day period immediately
                following and including the Ex-Dividend Date for the Spin-Off.


      

    

     

    The adjustment to the Conversion Rate under the preceding paragraph shall be determined immediately after the close of business on the tenth Trading Day immediately
      following, and including, the Ex-Dividend Date for the Spin-Off, but will be given effect immediately after the open of business on the Ex-Dividend Date for the Spin-Off.  If the Ex-Dividend Date for the Spin-Off is less than 10 Trading Days prior
      to, and including, the last Trading Day of an Observation Period in respect of any conversion, references in the portion of this Section 14.04(c) related to Spin-Offs to 10 Trading Days shall be deemed replaced, solely in respect of that conversion,
      with such lesser number of Trading Days as have elapsed from, and including, the Ex-Dividend Date for the Spin-Off to, and including, the last Trading Day of such Observation Period.  In respect of any conversion during the 10 Trading Days following
      the Ex-Dividend Date for any Spin-Off, references in the portion of this Section 14.04(c) related to Spin-Offs to 10 Trading Days shall be deemed replaced with such lesser number of Trading Days as have elapsed between the Ex-Dividend Date for such
      Spin-Off and the relevant Conversion Date.  If any dividend or distribution that constitutes a Spin-Off pursuant to this Section 14.04(c) is declared but not so paid or made, the
      Conversion Rate shall be immediately decreased, effective as of the date the Board of Directors determines not to pay such dividend or distribution, to the Conversion Rate that would then have been in effect if such dividend or distribution had not
      been declared or announced.

     

    
      67

      
        


    

    For purposes of this Section 14.04(c) (and subject in all respect to Section 14.11),
      rights, options or warrants distributed by the Company to all holders of its Common Stock entitling them to subscribe for or purchase shares of the Company’s Capital Stock, including Common Stock (either initially or under certain circumstances),
      which rights, options or warrants, until the occurrence of a specified event or events (“Trigger Event”): (i) are deemed to be transferred with such shares of
      the Common Stock; (ii) are not exercisable; and (iii) are also issued in respect of future issuances of the Common Stock, shall be deemed not to have been distributed for purposes of this Section 14.04(c) (and no adjustment to the Conversion Rate
      under this Section 14.04(c) will be required) until the occurrence of the earliest Trigger Event, whereupon such rights, options or warrants shall be deemed to have been
      distributed and an appropriate adjustment (if any is required) to the Conversion Rate shall be made under this Section 14.04(c).  If any such right, option or warrant, including any such existing rights, options or warrants distributed prior to the
      date of this Indenture, are subject to events, upon the occurrence of which such rights, options or warrants become exercisable to purchase different securities, evidences of indebtedness or other assets, then the date of the occurrence of any and
      each such event shall be deemed to be the date of distribution and Ex-Dividend Date with respect to new rights, options or warrants with such rights (in which case the existing rights, options or warrants shall be deemed to terminate and expire on
      such date without exercise by any of the holders thereof).  In addition, in the event of any distribution (or deemed distribution) of rights, options or warrants, or any Trigger Event or other event (of the type described in the immediately preceding
      sentence) with respect thereto that was counted for purposes of calculating a distribution amount for which an adjustment to the Conversion Rate under this Section 14.04(c) was made, (1) in the case of any such rights, options or warrants that shall
      all have been redeemed or purchased without exercise by any holders thereof, upon such final redemption or purchase (x) the Conversion Rate shall be readjusted as if such rights, options or warrants had not been issued and (y) the Conversion Rate
      shall then again be readjusted to give effect to such distribution, deemed distribution or Trigger Event, as the case may be, as though it were a cash distribution, equal to the per share redemption or purchase price received by a holder or holders
      of Common Stock with respect to such rights, options or warrants (assuming such holder had retained such rights, options or warrants), made to all holders of Common Stock as of the date of such redemption or purchase, and (2) in the case of such
      rights, options or warrants that shall have expired or been terminated without exercise by any holders thereof, the Conversion Rate shall be readjusted as if such rights, options and warrants had not been issued.

     

    For purposes of Section 14.04(a), Section 14.04(b) and this Section 14.04(c), any dividend or distribution to which this Section 14.04(c) is applicable that also includes one or both of:

     

    (A)          a dividend or distribution of shares of Common Stock to
        which Section 14.04(a) is applicable (the “Clause A Distribution”); or

     

    (B)          a dividend or distribution of rights, options or
        warrants to which Section 14.04(b) is applicable (the “Clause B Distribution”),

     

    
      68

      
        


    

    then, in either case, (1) such dividend or distribution other than the Clause A Distribution and the Clause B Distribution, shall be deemed to be a dividend or distribution
      to which this Section 14.04(c) is applicable (the “Clause C Distribution”) and any
      Conversion Rate adjustment required by this Section 14.04(c) with respect to such Clause C Distribution shall then be made, and (2) the Clause A Distribution and Clause B Distribution shall be deemed to immediately follow the Clause C Distribution
      and any Conversion Rate adjustment required by Section 14.04(a) and Section 14.04(b) with respect thereto shall then be made, except that, if determined by the Company (I) the “Ex-Dividend Date” of the Clause A Distribution and the Clause B
      Distribution shall be deemed to be the Ex-Dividend Date of the Clause C Distribution and (II) any shares of Common Stock included in the Clause A Distribution or Clause B Distribution shall be deemed not to be “outstanding immediately prior to the
      open of business on the Ex-Dividend Date for such dividend or distribution, or immediately prior to the open of business on the effective date of such share split or share combination, as the case may be” within the meaning of Section 14.04(a) or
      “outstanding immediately prior to the open of business on the Ex-Dividend Date for such distribution” within the meaning of Section 14.04(b).

     

    (d)          If an Ex-Dividend Date occurs for a cash
        dividend or distribution by the Company to all or substantially all holders of the outstanding Common Stock (other than a dividend or distribution in connection with the liquidation, dissolution or winding up of the Company or any dividends or
        distributions in connection with a reclassification, change, consolidation, merger, conveyance, transfer, sale, lease or other disposition resulting in a change in the consideration constituting the Conversion Obligation as set forth in Section
        14.07), the Conversion Rate shall be increased based on the following formula:

     

    

     

    where

     

    
      
        	 	CR0	=

              	the Conversion Rate in effect immediately prior to the open of business on the Ex-Dividend Date for such dividend or distribution;


      

    

     

    
      
        	 	CR’

              	=

              	the Conversion Rate in effect immediately after the open of business on the Ex-Dividend Date for such dividend or distribution;


      

    

     

    
      
        	 	SP0	= 

              	the Last Reported Sale Price of the Common Stock on the Trading Day immediately preceding the Ex-Dividend Date for such dividend
                or distribution; and


      

    

     

    
      
        	 	C

              	=

              	the amount in cash per share the Company distributes to all or substantially all holders of its outstanding Common Stock.


      

    

     

    Any increase pursuant to this Section 14.04(d) shall become effective immediately after the open of
      business on the Ex-Dividend Date for such dividend or distribution.  If such dividend or distribution is not so paid, the Conversion Rate shall be decreased, effective as of the date the Board of Directors determines not to make or pay such dividend
      or distribution, to the Conversion Rate that would then be in effect if such dividend or distribution had not been declared.  Notwithstanding the foregoing, if “C” (as defined above) is equal to or greater than “SP0” (as defined above), in
      lieu of the foregoing increase, each Holder of a Note shall receive, for each $1,000 principal amount of Notes, at the same time and upon the same terms as holders of shares of the Common Stock, the amount of cash that such Holder would have received
      if such Holder owned a number of shares of Common Stock equal to the Conversion Rate on the Ex-Dividend Date for such cash dividend or distribution.

     

    
      69

      
        


    

    (e)          If the Company or any of its Subsidiaries makes a payment in respect of a tender offer or exchange offer for the Common Stock (other than an odd-lot tender offer) and the cash and value of any other consideration included
        in the payment per share of the Common Stock exceeds the Last Reported Sale Price of the Common Stock on the Trading Day next succeeding the last date on which tenders or exchanges may be made pursuant to such tender or exchange offer (the “Expiration Date”), the Conversion Rate shall be increased based on the following formula:

     

    

     

    where

     

    
      
        	

              	CR0	=

              	the Conversion Rate in effect immediately prior to the close of business on the Trading Day next succeeding the Expiration Date;


      

    

     

    
      
        	

              	CR’

              	=

              	the Conversion Rate in effect immediately after the close of business on the Trading Day next succeeding the Expiration Date;


      

    

     

    
      
        	

              	FMV

              	=

              	the aggregate value, on the Expiration Date, of all cash and the fair market value (as determined by the Board of Directors) of
                any other consideration paid or payable for shares validly tendered or exchanged as of the Expiration Date;


      

    

     

    
      
        	

              	OS’    

              	=

              	the number of shares of Common Stock outstanding immediately after the time (the “Expiration Time”) that the tender or exchange offer expires (after giving effect to such tender offer or exchange offer);


      

    

     

    
      
        	

              	OS0	=  

              	the number of shares of Common Stock outstanding immediately prior to the Expiration Time (prior to giving effect to such tender
                offer or exchange offer); and


      

    

     

    
      
        	

              	SP’

              	= 

              	the Last Reported Sale Price of Common Stock on the Trading Day next succeeding the Expiration Date.


      

    

     

    The adjustment to the Conversion Rate under this Section 14.04(e) shall be determined and shall be given
        effect immediately after the close of business on the Trading Day next succeeding the Expiration Date.  If the Company is obligated to purchase shares pursuant to any such tender offer or exchange offer, but the Company is permanently
      prevented by applicable law from effecting any or all or any portion of such purchases or all such purchases are rescinded, the Conversion Rate shall again be adjusted to be the Conversion Rate that would then be in effect if such tender offer or
      exchange offer had not been made or had been made only in respect of the purchases that have been effected.

     

    
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    (f)          Notwithstanding this Section 14.04 or any other provision of this
        Indenture or the Notes, if a Conversion Rate adjustment becomes effective on any Ex-Dividend Date as described in this Section 14.04, and a Holder that has converted its Notes on or after such Ex-Dividend Date and on or prior to the related Record
        Date would be treated as the record holder of the shares of Common Stock as of the related Conversion Date as described under Section 14.02(i) based on an adjusted Conversion Rate for such Ex-Dividend Date, then, notwithstanding the Conversion Rate
        adjustment provisions in this Section 14.04, the Conversion Rate adjustment relating to such Ex-Dividend Date shall not be made for such converting Holder. Instead, such Holder shall be treated as if such Holder were the record owner of the shares
        of Common Stock on an unadjusted basis and participate in the related dividend, distribution or other event giving rise to such adjustment.

     

    (g)          Except as stated herein, the Company shall not adjust the Conversion Rate
        for the issuance of shares of its Common Stock or any securities convertible into or exchangeable for shares of its Common Stock or the right to purchase shares of its Common Stock or such convertible or exchangeable securities.  If the application
        of the foregoing formulas in clauses  (a), (b), (c), (d) and (e) of this Section 14.04 would result in a decrease in the Conversion Rate, no adjustment to the Conversion Rate shall be made (other than as a result of a reverse share split or share
        combination or the reversal of an Increase in the Conversion Rate pursuant to this Section 14.04 where the relevant event did not occur). In no event shall the Company adjust the Conversion Rate to the extent that the adjustment would reduce the
        Conversion Price below the par value per share of the Common Stock.

     

    (h)          In addition to those adjustments required by clauses (a), (b), (c), (d)
        and (e) of this Section 14.04, and to the extent permitted by applicable law and subject to the applicable listing standards of The Nasdaq Global Select Market, the Company from time to time may increase the Conversion Rate by any amount for a
        period of at least 20 Business Days if the Board of Directors determines that such increase would be in the Company’s best interest.  In addition, the Company may (but is not required to) increase the Conversion Rate to avoid or diminish any income
        tax to holders of Common Stock or rights to purchase Common Stock in connection with a dividend or distribution of shares (or rights to acquire shares) or similar event, subject to the applicable listing standards of The Nasdaq Global Select
        Market.  If the Company makes either such determination, it shall be conclusive and the Company shall deliver to each Holder of Notes written notice of the increased Conversion Rate and the period during which it will be in effect  at least 15
        calendar days prior to the date the increased Conversion Rate takes effect (in accordance with applicable law).

     

    (i)          Notwithstanding anything to the contrary in this Article 14, the
        Conversion Rate shall not be adjusted:

     

    
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        (i)          upon the issuance of any
          shares of Common Stock pursuant to any present or future plan providing for the reinvestment of dividends or interest payable on the Company’s securities and the investment of additional optional amounts in shares of Common Stock under any plan;

      

    

    
      
         

          

        (ii)         upon the issuance of any shares of Common Stock or options or rights to purchase those shares pursuant to any present or future employee, director or consultant benefit plan or program of or assumed by the
          Company or any of the Company’s Subsidiaries;

      

    

    
      
         

          

        (iii)        upon the issuance of any
          shares of the Common Stock pursuant to any option, warrant, right or exercisable, exchangeable or convertible security not described in clause (ii) of this subsection and outstanding as of the date the Notes were first issued;

      

    

    
      
         

          

        (iv)        upon the repurchase of shares
          of Common Stock pursuant to an open-market share repurchase program or other buy-back transaction that is not a tender offer or exchange offer of the nature described in Section 14.04(e);

      

    

    
      
         

          

        (v)         solely for a change in the
          par value of the Common Stock; or

      

    

    
      
         

          

        (vi)        for accrued and unpaid
          interest, if any.

      

    

     

      

    (j)          All calculations and other determinations under this Article 14 shall be
        made by the Company and shall be made to the nearest one-ten thousandth (1/10,000th) of a share.

     

    (k)          The Company shall not be required to make an adjustment in the Conversion
        Rate unless the adjustment would require a change of at least 1% in the Conversion Rate. However, the Company shall carry forward any adjustment that is less than 1% of the Conversion Rate, take such carried-forward adjustments into account in any
        subsequent adjustment and make such carried forward adjustments (x) when the aggregate adjustment (taking into account all carried-forward adjustments that have not yet been made) is at least 1% of the applicable Conversion Rate and (y), regardless
        of whether the aggregate adjustment is less than 1%, (i) on the Conversion Date for any Notes (in the case of Physical Settlement) or on each day of the relevant Observation Period (in the case of Cash Settlement or Combination Settlement) or (ii)
        on the date any Fundamental Change occurs or becomes effective or the Effective Date (with respect to any Make-Whole Fundamental Change), unless such adjustment shall have already been made.

     

    (l)           Whenever the Conversion Rate is adjusted as
        herein provided, the Company shall promptly deliver to the Trustee (and the Conversion Agent if not the Trustee) an Officer’s Certificate setting forth the Conversion Rate after such adjustment and setting forth a brief statement of the facts
        requiring such adjustment.  Unless and until a Responsible Officer of the Trustee shall have received such Officer’s Certificate, the Trustee shall not be deemed to have knowledge of any adjustment of the Conversion Rate and may assume without
        inquiry that the last Conversion Rate of which it has knowledge is still in effect.  Promptly after delivery of such certificate, the Company shall prepare a notice of such adjustment of the Conversion Rate setting forth the adjusted Conversion
        Rate and the date on which each adjustment becomes effective and shall deliver such notice of such adjustment of the Conversion Rate to each Holder.  Failure to deliver such notice shall not affect the legality or validity of any such adjustment.

     

    
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    (m)         For purposes of this Section 14.04, the number of shares of Common Stock
        at any time outstanding shall not include shares of Common Stock held in the treasury of the Company so long as the Company does not pay any dividend or make any distribution on shares of Common Stock held in the treasury of the Company, but shall
        include shares of Common Stock issuable in respect of scrip certificates issued in lieu of fractions of shares of Common Stock.

     

    Section 14.05.  Adjustments of Prices.  Whenever any provision of this Indenture requires the Company to calculate the Last Reported Sale Prices, the Daily VWAPs, the Daily
        Conversion Values or the Daily Settlement Amounts over a span of multiple days (including an Observation Period and the period for determining the Stock Price for purposes of a Make-Whole Fundamental Change), the Board of Directors shall make
        appropriate adjustments to each to account for any adjustment to the Conversion Rate that becomes effective, or any event requiring an adjustment to the Conversion Rate where the Ex-Dividend Date, Record Date, effective date, Effective Date or
        expiration date of the event occurs at any time during the period when the Last Reported Sale Prices, the Daily VWAPs, the Daily Conversion Values or the Daily Settlement Amounts are to be calculated.  Such adjustments will be effective as of the
        Ex-Dividend Date, Record Date, effective date, Effective Date or Expiration Date, as the case may be, of the event causing the adjustment to the Conversion Rate.

     

    Section 14.06.  Shares to Be Fully Paid.  The Company shall provide, free from preemptive rights, out of its authorized but unissued shares or shares held in treasury, sufficient shares of Common Stock to provide
        for conversion of the Notes from time to time as such Notes are presented for conversion (assuming that at the time of computation of such number of shares, all such Notes would be converted by a single Holder and that Physical Settlement is
        applicable).

     

    Section 14.07.  Effect of Recapitalizations, Reclassifications and Changes of the Common Stock.

     

    (a)          In the case of:

     

    
      
        (i)          any recapitalization,
          reclassification or change of the Common Stock (other than changes resulting from a subdivision or combination),

      

    

    
      
         

          

        (ii)         any consolidation, merger or
          combination involving the Company,

      

    

    
      
         

          

        (iii)        any sale, lease or other
          transfer to a third party of the consolidated assets of the Company and the Company’s Subsidiaries substantially as an entirety or

      

    

    
      
         

          

        (iv)        any statutory share exchange,

      

    

     

    

    
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    in each case, as a result of which the Common Stock would be converted into, or exchanged for, stock, other securities, other property or assets (including cash or any
      combination thereof) (any such event, a “Merger Event”), then, at and after the effective time of such Merger Event, the right to
      convert each $1,000 principal amount of Notes shall be changed into a right to convert such principal amount of Notes into the kind and amount of shares of stock, other securities or other property or assets (including cash or any combination
      thereof) that a holder of a number of shares of Common Stock equal to the Conversion Rate immediately prior to such Merger Event would have owned or been entitled to receive (without giving effect to statutory dissenters’ appraisal rights) (the “Reference Property,” with each “unit of Reference Property” meaning the kind
      and amount of Reference Property that a holder of one share of Common Stock is entitled to receive) upon such Merger Event and, prior to or at the effective time of such Merger Event, the Company or the successor or purchasing Person, as the case may
      be, shall execute with the Trustee a supplemental indenture permitted under Section 10.01(c) providing for such change in the right to convert each $1,000 principal amount of
      Notes; provided, however, that at and after the effective time of
      the Merger Event (A) the Company shall continue to have the right to determine the form of consideration to be paid or delivered, as the case may be, upon conversion of Notes in accordance with Section 14.02 and (B) (I) any amount payable in cash
      upon conversion of the Notes in accordance with Section 14.02 shall continue to be payable in cash, (II) any shares of Common Stock that the Company would have been required to deliver upon conversion of the Notes in accordance with Section 14.02
      shall instead be deliverable in the amount and type of Reference Property that a holder of that number of shares of Common Stock would have been entitled to receive in such Merger Event and (III) the Daily VWAP shall be calculated based on the value
      of a unit of Reference Property.

     

    If the Merger Event causes the Common Stock to be converted into, or exchanged for, the right to receive more than a single type of consideration
      (determined based in part upon any form of stockholder election), then (i) the Reference Property into which the Notes will be convertible shall be deemed to be the weighted average of the types and amounts of consideration actually received by the
      holders of Common Stock, and (ii) the unit of Reference Property for purposes of the immediately preceding paragraph shall refer to the consideration referred to in clause (i) attributable to one share of Common Stock.  If the holders of the Common
      Stock receive only cash in such Merger Event, then for all conversions for which the relevant Conversion Date occurs after the effective date of such Merger Event (A) the consideration due upon conversion of each $1,000 principal amount of Notes
      shall be solely cash in an amount equal to the Conversion Rate in effect on the Conversion Date (as may be increased by any Additional Shares pursuant to Section 14.03), multiplied by the price paid per share of Common Stock in such Merger Event and (B) the Company shall satisfy the Conversion Obligation by paying cash to converting Holders on the second Business Day immediately following the
      relevant Conversion Date. The Company shall notify Holders, the Trustee and the Conversion Agent (if other than the Trustee) of such weighted average as soon as practicable after such determination is made.

     

    Such supplemental indenture described in the second immediately preceding paragraph shall provide to the extent the Reference Property is comprised, in
      whole or in part, of Common Equity for adjustments that shall be as nearly equivalent as is possible to the adjustments provided for in this Article 14.  If, in the case of any Merger Event, the Reference Property includes shares of stock or other
      securities issued by a Person that is party to such Merger Event other than the successor or purchasing corporation, as the case may be, in such Merger Event, then such supplemental indenture shall also be executed by such other Person and shall
      contain such additional provisions to protect the interests of the Holders of the Notes as the Board of Directors shall reasonably consider necessary by reason of the foregoing, including to the extent required by the Board of Directors and
      practicable the provisions providing for the purchase rights set forth in Article 15.

     

    
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    (b)          In the event the Company shall execute a supplemental indenture pursuant
        to subsection (a) of this Section 14.07, the Company shall promptly file with the Trustee an Officer’s Certificate briefly stating the reasons therefor, the kind or amount of cash, securities or property or asset that will comprise the Reference
        Property after any such Merger Event, any adjustment to be made with respect thereto and that all conditions precedent have been complied with, and shall promptly deliver notice thereof to all Holders.  The Company shall cause notice of the
        execution of such supplemental indenture to be delivered to each Holder (in the case of Physical Notes, such notice to be mailed to each such Holder at its address appearing on the Note Register provided for in this Indenture), within 20 days after
        execution thereof.  Failure to deliver such notice shall not affect the legality or validity of such supplemental indenture.

     

    (c)          The Company shall not become a party to any
        Merger Event unless its terms are consistent with this Section 14.07.  None of the foregoing provisions shall affect the right of a holder of Notes to convert its Notes into cash, shares of Common Stock or a combination of cash and shares of Common
        Stock, as applicable, as set forth in Section 14.01 and Section 14.02 prior to the effective date of such Merger Event.

     

    (d)          The above provisions of this Section shall similarly apply to successive
        Merger Events.

     

    Section 14.08.  Certain Covenants.  (a) The Company covenants that all shares of Common Stock issued upon conversion of Notes will be fully paid and non-assessable by the Company and free from all taxes, liens
        and charges with respect to the issue thereof.

     

    (b)          The Company covenants that, if any shares of Common Stock to be provided
        for the purpose of conversion of Notes hereunder require registration with or approval of any governmental authority under any federal or state law before such shares may be validly issued upon conversion, the Company will, to the extent then
        permitted by the rules and interpretations of the Commission, secure such registration or approval, as the case may be.

     

    (c)          The Company further covenants that if at any time the Common Stock shall
        be listed on any national securities exchange or automated quotation system the Company will list and keep listed, so long as the Common Stock shall be so listed on such exchange or automated quotation system, any Common Stock issuable upon
        conversion of the Notes.

     

    Section 14.09.  Responsibility of Trustee.  The Trustee and any other Conversion Agent shall not at any time be under any duty or responsibility to any Holder to determine the Conversion Rate (or any adjustment thereto) or whether any facts
        exist that may require any adjustment (including any increase) of the Conversion Rate, or with respect to the nature or extent or calculation of any such adjustment when made, or with respect to the method employed, or herein or in any supplemental
        indenture provided to be employed, in making the same.  The Trustee and any other Conversion Agent shall not be accountable with respect to the validity or value (or the kind or amount) of any shares of Common Stock, or of any securities, property
        or cash that may at any time be issued or delivered upon the conversion of any Note; and neither the Trustee nor any other Conversion Agent makes any representation with respect thereto.  Neither the Trustee nor any Conversion Agent shall be
        responsible for any failure of the Company to issue, transfer or deliver any shares of Common Stock or stock certificates or other securities or property or to make or calculate any cash payment upon the surrender of any Note for the purpose of
        conversion or to comply with any of the duties, responsibilities or covenants of the Company contained in this Article.  Without limiting the generality of the foregoing, neither the Trustee nor any Conversion Agent shall be under any
        responsibility to determine the correctness of any provisions contained in any supplemental indenture entered into pursuant to Section 14.07 relating either to the kind or amount of shares of stock or securities or property (including cash)
        receivable by Holders upon the conversion of their Notes after any event referred to in such Section 14.07 or to any adjustment to be made with respect thereto, but, subject to the provisions of Section 7.01, may accept (without any independent
        investigation) as conclusive evidence of the correctness of any such provisions, and shall be protected in relying upon, the Officer’s Certificate (which the Company shall be obligated to file with the Trustee prior to the execution of any such
        supplemental indenture) with respect thereto.  Neither the Trustee nor the Conversion Agent shall be responsible for determining whether any event contemplated by Section 14.01(b) has occurred that makes the Notes eligible for conversion or no
        longer eligible therefor until the Company has delivered to the Trustee and the Conversion Agent the notices referred to in Section 14.01(b) with respect to the commencement or termination of such conversion rights, on which notices the Trustee and
        the Conversion Agent may conclusively rely, and the Company agrees to deliver such notices to the Trustee and the Conversion Agent immediately after the occurrence of any such event or at such other times as shall be provided for in Section
        14.01(b).

     

    
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    Section 14.10.  Notice to Holders Prior to Certain Actions.  In case of any:

     

    (a)          action by the Company or one of its Subsidiaries that would require an
        adjustment in the Conversion Rate pursuant to Section 14.04 or Section 14.11;

     

    (b)          voluntary or involuntary dissolution, liquidation or winding-up of the
        Company;

     

    then, in each case (unless notice of such event is otherwise required pursuant to another provision of this Indenture), the Company shall cause to be filed with the Trustee
      and the Conversion Agent (if other than the Trustee) and to be delivered to each Holder, as promptly as possible but in any event at least 10 days prior to the applicable date hereinafter specified, a notice stating (i) the date on which a record is
      to be taken for the purpose of such action by the Company or one of its Subsidiaries or, if a record is not to be taken, the date as of which the holders of Common Stock of record are to be determined for the purposes of such action by the Company or
      one of its Subsidiaries, or (ii) the date on which such dissolution, liquidation or winding-up is expected to become effective or occur, and the date as of which it is expected that holders of Common Stock of record shall be entitled to exchange
      their Common Stock for securities or other property deliverable upon such dissolution, liquidation or winding-up.  Failure to give such notice, or any defect therein, shall not affect the legality or validity of such action by the Company or one of
      its Subsidiaries, dissolution, liquidation or winding-up.

     

    Section 14.11.  Stockholder Rights Plans.  To the extent that the Company has a stockholder rights plan in effect upon conversion of the Notes, each share of Common Stock, if
        any, issued upon such conversion shall be entitled to receive the appropriate number of rights, if any, and the certificates representing the Common Stock issued upon such conversion shall bear such legends, if any, in each case as may be provided
        by the terms of any such stockholder rights plan, as the same may be amended from time to time. However, if, prior to any conversion of Notes, the rights have separated from the shares of Common Stock in accordance with the provisions of the
        applicable stockholder rights plan so that the Holders would not be entitled to receive any rights in respect of Common Stock, if any, issuable upon conversion of the Notes, the Conversion Rate shall be adjusted at the time of separation as if the
        Company distributed to all or substantially all holders of the Common Stock Distributed Property as provided in Section 14.04(c), subject to readjustment in the event of the expiration, termination or redemption of such rights.

     

    
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    Section 14.12.  Limit on Issuance of Shares of Common Stock Upon Conversion.  Notwithstanding anything to the contrary in this Indenture, if an event occurs that would result in an increase in the Conversion Rate by an amount in excess of
        limitations imposed by any shareholder approval rules or listing standards of any national or regional securities exchange that are applicable to the Company, the Company will, at its option, either obtain stockholder approval of any issuance of
        Common Stock upon conversion of the Notes in excess of such limitations or pay cash in lieu of delivering any shares of Common Stock otherwise deliverable upon conversions in excess of such limitations based on the Daily VWAP (i) on the Conversion
        Date (in the case of Physical Settlement) or (ii) on each Trading Day of the relevant Observation Period (in the case of Combination Settlement) in respect of which, in lieu of delivering shares of Common Stock, the Company pays cash pursuant to
        this Section 14.12.

     

    Section 14.13.  Exchange in Lieu of Conversion.  (a) When a Holder surrenders its Notes for conversion, the Company may, at its election, direct the Conversion Agent to
        surrender, on or prior to the Trading Day following the relevant Conversion Date, such Notes to a financial institution designated by the Company (the “Designated
          Institution”) for exchange in lieu of conversion (an “Exchange Election”).  In order to accept any Notes surrendered for exchange in lieu of
        conversion, the Designated Institution must agree to timely deliver, in exchange for such Notes, the cash, shares of Common Stock or combination thereof that would otherwise be due upon conversion pursuant to Section 14.02 and in respect of which
        the Company has notified converting Holders. If the Company makes an Exchange Election, the Company shall, by the close of business on the Trading Day following the relevant Conversion Date, notify the Holder surrendering Notes for conversion that
        it has made such Exchange Election. In addition, the Company shall concurrently notify the Designated Institution of the settlement method the Company has elected with respect to such conversion and the relevant deadline for payment and/or delivery
        of cash, shares of Common Stock or combination thereof due upon conversion.  Any Notes exchanged by the Designated Institution will remain outstanding.

     

    (b) If the Designated Institution accepts any Notes for exchange, it will pay and/or deliver the cash, shares of Common Stock or combination thereof due
      upon conversion to the Conversion Agent, and the Conversion Agent will pay and/or deliver such cash, shares of common stock or combination thereof to the Holders of such Notes in accordance with the applicable provisions of Section 14.02.

     

    
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    (c) If the Designated Institution agrees to accept any Notes for exchange but does not timely pay and/or deliver the required cash, shares of Common
      Stock or combination thereof due upon conversion to the Conversion Agent, or if the Designated Institution does not accept such Notes for exchange, the Company shall, within the time period specified in Section 14.02(c), pay and/or deliver the
      required cash, shares of Common Stock or combination thereof due upon conversion in accordance with the provisions of Section 14.02 as if the Company had not made an Exchange Election.

     

    (d) For the avoidance of doubt, in no event will the Company’s designation of a Designated Institution pursuant to this Section 14.13 require such
      Designated Institution to accept any Notes for exchange except pursuant to a separate agreement between the Company and such Designated Institution. The Company may, but has no obligation to, enter into such a separate agreement with any Designated
      Institution that provides for compensation to the Designated Institution pursuant to this Section 14.13.

     

    ARTICLE 15

        Purchase of Notes at Option of Holders

     

    Section 15.01.  Intentionally Omitted.

     

    Section 15.02.  Purchase at
          Option of Holders Upon a Fundamental Change.  (a) If a Fundamental Change occurs at any time prior to the Maturity Date, then each Holder shall have the right, at such Holder’s option, to require the Company to purchase for cash all of
        such Holder’s Notes, or any portion thereof that is a multiple of $1,000 principal amount, on the date (the “Fundamental Change Purchase Date”) specified by
        the Company that is not less than 20 calendar days and not more than 35 calendar days after the date of the Fundamental Change Company Notice (as defined below) at a purchase price equal to 100% of the principal amount thereof, together with
        accrued and unpaid interest, if any, thereon to, but excluding, the Fundamental Change Purchase Date (the “Fundamental Change Purchase Price”), unless the
        Fundamental Change Purchase Date is after a Regular Record Date and on or prior to the immediately succeeding Interest Payment Date, in which case interest accrued to the Interest Payment Date will be paid to Holders of the Notes as of the
        immediately preceding Regular Record Date and the Fundamental Change Purchase Price payable to the Holder surrendering the Note for purchase pursuant to this Section 15.02 shall be equal to the principal amount of Notes subject to purchase.

     

    (b)          Purchases of Notes under this Section 15.02 shall be made, at the option
        of the Holder thereof, upon:

     

    
      
        (i)          delivery to the Paying Agent by a Holder of a duly completed notice (the “Fundamental Change Purchase Notice”) in the Form of the
          Fundamental Change Purchase Notice, if the Notes are Physical Notes, or in compliance with the Depositary’s procedures for surrendering interests in Global Notes, if the Notes are Global Notes, in each case prior to the close of business on the
          second Scheduled Trading Day preceding the Fundamental Change Purchase Date; and

      

    

    
      
         

          

        
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        (ii)         delivery of the Notes, if
          the Notes are Physical Notes, to the Paying Agent at any time after delivery of the Fundamental Change Purchase Notice (together with all necessary endorsements for transfer) at the Corporate Trust Office of the Paying Agent, or book-entry
          transfer of the Notes, if the Notes are Global Notes, in compliance with the procedures of the Depositary, in each case such delivery being a condition to receipt by the Holder of the Fundamental Change Purchase Price therefor.

      

    

     

    

    The Fundamental Change Purchase Notice in respect of any Notes to be purchased shall state:

     

    
      
        (i)          in the case of Physical
          Notes, the certificate numbers of the Notes to be delivered for purchase;

      

    

    
      
         

          

        (ii)         the portion of the principal
          amount of Notes to be purchased, which must be $1,000 or a multiple thereof; and

      

    

    
      
         

          

        (iii)        that the Notes are to be
          purchased by the Company pursuant to the applicable provisions of the Notes and this Indenture;

      

    

     

      

    provided, however, that if the Notes are Global Notes, the Fundamental Change Purchase Notice must comply with appropriate Depositary procedures.

     

    Notwithstanding anything herein to the contrary, any Holder delivering to the Paying Agent the Fundamental Change Purchase Notice contemplated by this
      Section 15.02 shall have the right to withdraw, in whole or in part, such Fundamental Change Purchase Notice at any time prior to the close of business on the second Scheduled Trading Day preceding the Fundamental Change Purchase Date by delivery of
      a written notice of withdrawal to the Paying Agent in accordance with Section 15.03.

     

    The Paying Agent shall promptly notify the Company of the receipt by it of any Fundamental Change Purchase Notice or written notice of withdrawal
      thereof.

     

    (c)          On or before the 20th calendar day after the
        occurrence of the effective date of a Fundamental Change, the Company shall provide to all Holders of Notes and the Trustee and the Paying Agent (in the case of a Paying Agent other than the Trustee) a written notice (the “Fundamental Change Company Notice”) of the occurrence of the effective date of the Fundamental Change and of the purchase right at the option of the Holders arising as a result
        thereof.  In the case of Physical Notes, such notice shall be by first class mail or, in the case of Global Notes, in accordance with the applicable procedures of the Depositary.  Contemporaneously with providing such notice, the Company shall
        publish a notice containing the information set forth in the Fundamental Change Company Notice on the Company’s website or through such other public medium as the Company may use at that time.  Each Fundamental Change Company Notice shall specify:

     

    
      
        (i)          the events causing the
          Fundamental Change;

      

    

    
      
         

          

        
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        (ii)         the date the Fundamental
          Change occurred, and whether such Fundamental Change is a Make-Whole Fundamental Change, in which case the Effective Date of such Make-Whole Fundamental Change shall also be specified;

      

    

    
      
         

          

        (iii)        the last date on which a Holder may exercise the purchase right pursuant to this Article 15;

      

    

    
      
         

          

        (iv)        the Fundamental Change
          Purchase Price;

      

    

    
      
         

          

        (v)          the Fundamental Change
          Purchase Date;

      

    

    
      
         

          

        (vi)        the name and address of the
          Paying Agent and the Conversion Agent, if applicable;

      

    

    
      
         

          

        (vii)       if applicable, the Conversion
          Rate and any adjustments to the Conversion Rate made or to be made on account of such Fundamental Change;

      

    

    
      
         

          

        (viii)      if applicable, that the Notes
          with respect to which a Fundamental Change Purchase Notice has been delivered by a Holder may be converted only if the Holder withdraws the Fundamental Change Purchase Notice in accordance with the terms of this Indenture; and

      

    

    
      
         

          

        (ix)        the procedures that Holders
          must follow to require the Company to purchase their Notes.

      

    

     

    

    No failure of the Company to give the foregoing notices and no defect therein shall limit the Holders’ purchase rights or affect the validity of the
      proceedings for the purchase of the Notes pursuant to this Section 15.02.

     

    At the Company’s expense and written request, the Trustee shall give such notice in the Company’s name and at the Company’s expense; provided, however, that, in all cases, the text of such Fundamental
      Change Company Notice shall be prepared by the Company.

     

    (d)          Notwithstanding the foregoing, no Notes may be purchased by the Company on
        any date at the option of the Holders upon a Fundamental Change if the principal amount of the Notes has been accelerated, and such acceleration has not been rescinded, on or prior to such date (except in the case of an acceleration resulting from
        a Default by the Company in the payment of the Fundamental Change Purchase Price with respect to such Notes). The Paying Agent will promptly return to the respective Holders thereof any Physical Notes held by it during the acceleration of the Notes
        (except in the case of an acceleration resulting from a Default by the Company in the payment of the Fundamental Change Purchase Price with respect to such Notes), or any instructions for book-entry transfer of the Notes in compliance with the
        procedures of the Depositary shall be deemed to have been cancelled, and, upon such return or cancellation, as the case may be, the Fundamental Change Purchase Notice with respect thereto shall be deemed to have been withdrawn.

     

    
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    Section 15.03.  Withdrawal of Fundamental Change Purchase Notice.  (a)  A Fundamental Change Purchase Notice may
        be withdrawn (in whole or in part) by means of a written notice of withdrawal delivered to the Corporate Trust Office of the Paying Agent in accordance with this Section 15.03 at any time prior to the close of business on the second Scheduled
        Trading Day immediately preceding the Fundamental Change Purchase Date, specifying:

     

    
      
        (i)          the principal amount of the
          Notes with respect to which such notice of withdrawal is being submitted, which amount must be $1,000 or a multiple thereof,

      

    

    
      
         

          

        (ii)         if Physical Notes have been
          issued, the certificate number of the Note in respect of which such notice of withdrawal is being submitted, and

      

    

    
      
         

          

        (iii)        the principal amount, if
          any, of such Note that remains subject to the original Fundamental Change Purchase Notice, which portion must be in principal amounts of $1,000 or a multiple of $1,000;

      

    

     

      

    provided, however, that if the Notes are Global Notes, the notice must comply with appropriate procedures of the Depositary.

     

    Section 15.04.  Deposit of Fundamental Change Purchase Price.  (a)  The Company will deposit with the Trustee (or other Paying Agent appointed
        by the Company, or if the Company is acting as its own Paying Agent, set aside, segregate and hold in trust as provided in Section 4.04) on or prior to 11:00 a.m., New York City time, on the Fundamental Change Purchase Date, an amount of money
        sufficient to purchase all of the Notes to be purchased at the appropriate Fundamental Change Purchase Price.  Subject to receipt of funds and/or Notes by the Trustee (or other Paying Agent appointed by the Company), payment for Notes surrendered
        for purchase (and not withdrawn prior to the close of business on the second Scheduled Trading Day immediately preceding the Fundamental Change Purchase Date) will be made on the later of (i) the Fundamental Change Purchase Date with respect to
        such Note (provided the Holder has satisfied the conditions in Section 15.02) and (ii) the time of book-entry transfer or the delivery of such Note to the
        Trustee (or other Paying Agent appointed by the Company) by the Holder thereof in the manner required by Section 15.02, as applicable, by mailing checks for the amount payable
        to the Holders of such Notes entitled thereto as they shall appear in the Note Register; provided, however, that payments to the Depositary shall be made by wire transfer of immediately available funds to the account of the Depositary or its nominee.  The Trustee shall, promptly after such payment and upon
        written demand by the Company, return to the Company any funds in excess of the Fundamental Change Purchase Price.

     

    (b)          If by 11:00 a.m. New York City time, on the Fundamental Change Purchase
        Date, the Trustee (or other Paying Agent appointed by the Company) holds money sufficient to make payment on all the Notes or portions thereof that are to be purchased on such Fundamental Change Purchase Date, then, with respect to Notes that have
        been tendered and not validly withdrawn, (i) such Notes will cease to be outstanding, (ii) interest will cease to accrue on such Notes (whether or not book-entry transfer of the Notes has been made or the Notes have been delivered to the Trustee or
        Paying Agent) and (iii) all other rights of the Holders of such Notes will terminate (other than the right to receive the Fundamental Change Purchase Price and, subject to Section 15.02(a), previously accrued and unpaid interest upon delivery or
        transfer of such Notes).

     

    
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    (c)          Upon surrender of a Note that is to be purchased in part pursuant to
        Section 15.02, the Company shall execute and the Trustee shall authenticate and deliver to the Holder a new Note in an authorized denomination equal in principal amount to the unpurchased portion of the Note surrendered.

     

    Section 15.05.  Covenant to Comply with Applicable Laws Upon Purchase of Notes.  In connection with any purchase offer, the Company will, to the extent required:

     

    (a)          comply with the provisions of Rule 13e-4,
        Rule 14e-1 and any other tender offer rules under the Exchange Act that may then be applicable;

     

    (b)          file a Schedule TO or any successor or similar schedule required under the
        Exchange Act; and

     

    (c)          otherwise comply with all applicable federal and state securities laws in
        connection with any offer by the Company to purchase the Notes;

     

    in each case, so as to permit the rights and obligations under this Article 15 to be exercised in the time and in the manner specified in this Article 15.

     

    ARTICLE 16

        No Optional Redemption

     

    Section 16.01.  No Optional Redemption.  The Notes shall not be redeemable by the Company prior to the Maturity Date, and no sinking fund is provided for the Notes. 

     

    ARTICLE 17

        Miscellaneous Provisions

     

    Section 17.01.  Provisions Binding on Company’s Successors.  All the covenants, stipulations, promises and agreements of the Company contained in this Indenture shall bind its successors and assigns whether so
        expressed or not.

     

    Section 17.02.  Official Acts by Successor Corporation.  Any act or proceeding by any provision of this Indenture authorized or required to be done or performed by any board, committee or Officer of the Company shall and may be done and
        performed with like force and effect by the like board, committee or officer of any corporation or other entity that shall at the time be the lawful sole successor of the Company.

     

    
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    Section 17.03.  Addresses for Notices, Etc.  Any notice or demand that by any provision of this Indenture is required or permitted to be given
        or served by the Trustee or by the Holders on the Company shall be deemed to have been sufficiently given or made, for all purposes if given or served by being deposited postage prepaid by registered or certified mail in a post office letter box,
        telecopied, or electronically provided in PDF format, addressed (until another address is filed by the Company with the Trustee) to Ionis Pharmaceuticals, Inc., 2855
          Gazelle Court, Carlsbad, CA 92010, Attention: General Counsel, facsimile 760-268-4922.  Any notice, direction, request or demand hereunder to or upon the Trustee shall be deemed to have been sufficiently given or made, for all purposes, if
        given or served by being deposited postage prepaid by registered or certified mail in a post office letter box addressed to the Corporate Trust Office or electronically provided in PDF format.  Except as otherwise expressly provided herein, any
        notice or communication to a Holder may be given or served by being deposited in first class mail, postage prepaid, addressed at the Holder’s address as it appears in the Note Register.

     

    Each of the Company, by notice to the Trustee, and the Trustee, by notice to the Company, may designate additional or different addresses for subsequent
      notices or communications.

     

    Any notice or communication sent to a Holder shall be sent electronically in PDF format (in the case of a Global Note) or mailed to it by first class
      mail, postage prepaid, at its address as it appears on the Note Register and shall be sufficiently given to it if so mailed within the time prescribed.

     

    Failure to send a notice or communication to a Holder or any defect in it shall not affect its sufficiency with respect to other Holders.  If a notice or
      communication is sent in the manner provided above, it is duly given, whether or not the addressee receives it.

     

    In case by reason of the suspension of regular mail service or by reason of any other cause it shall be impracticable to give such notice to Holders by
      mail, then such notification as shall be made with the approval of the Trustee shall constitute a sufficient notification for every purpose hereunder.

     

    Section 17.04.  Governing Law.  THIS INDENTURE AND EACH NOTE, AND ANY CLAIM, CONTROVERSY OR DISPUTE ARISING UNDER OR RELATED TO THIS INDENTURE AND EACH NOTE, SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE
        WITH, THE LAWS OF THE STATE OF NEW YORK (WITHOUT REGARD TO THE CONFLICTS OF LAWS PROVISIONS THEREOF).

     

    Section 17.05.  Evidence of Compliance with Conditions Precedent; Certificates and Opinions of Counsel to Trustee.  Upon any application or demand by the Company to the Trustee to take any action under any of the provisions of this Indenture,
        the Company shall, if requested by the Trustee, furnish to the Trustee an Officer’s Certificate stating that all conditions precedent to such action have been satisfied and such action is permitted by the terms of this Indenture; provided, that (x) no Opinion of Counsel shall be required to be delivered in connection with the initial issuance of Notes dated as of the date hereof under the
        Indenture or (y) the exchange of restricted Notes for unrestricted Notes with no restrictive legend and with an unrestricted CUSIP number upon expiration of applicable restrictions on transfer in accordance with Section 2.05(b).

     

    
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    Each Officer’s Certificate or Opinion of Counsel provided for, by or on behalf of the Company in this Indenture and delivered to the Trustee with respect
      to compliance with this Indenture (other than the Officer’s Certificates provided for in Section 4.08) shall include (a) a statement that the Person making such certificate is familiar with the requested action and this Indenture; (b) a brief
      statement as to the nature and scope of the examination or investigation upon which the statement contained in such certificate is based; (c) a statement that, in the judgment of such person, he or she has made such examination or investigation as is
      necessary to enable him or her to express an informed judgment as to whether or not such action is permitted by this Indenture; and (d) a statement as to whether or not, in the judgment of such Person, all conditions precedent to such action have
      been satisfied and such action is permitted by this Indenture.

     

    Notwithstanding anything to the contrary in this Section 17.05, if any provision in this Indenture specifically provides that the Trustee shall or may
      receive an Opinion of Counsel in connection with any action to be taken by the Trustee or the Company hereunder, the Trustee shall be entitled to, or entitled to request, such Opinion of Counsel.

     

    Section 17.06.  Legal Holidays.  In any case where any Interest Payment Date, Fundamental Change Purchase Date, Conversion Date or Maturity Date is not a Business Day, then any action to be taken on such date
        need not be taken on such date, but may be taken on the next succeeding Business Day with the same force and effect as if taken on such date, and no interest shall accrue in respect of the delay.

     

    Section 17.07.  No Security Interest Created.  Nothing in this Indenture or in the Notes, expressed or implied, shall be construed to constitute a security interest under the Uniform Commercial Code or similar
        legislation, as now or hereafter enacted and in effect, in any jurisdiction.

     

    Section 17.08.  Benefits of Indenture.  Nothing in this Indenture or in the Notes, expressed or implied, shall give to any Person, other than the parties hereto, any Paying Agent, any Conversion Agent, any authenticating agent, any Note
        Registrar and their successors hereunder or the Holders, any benefit or any legal or equitable right, remedy or claim under this Indenture.

     

    Section 17.09.  Table of Contents, Headings, Etc.  The table of contents and the titles and headings of the articles and sections of this Indenture have been inserted for convenience of reference only, are not to
        be considered a part hereof, and shall in no way modify or restrict any of the terms or provisions hereof.

     

    
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    Section 17.10.  Authenticating Agent.  The Trustee may appoint an authenticating agent that shall be authorized to
        act on its behalf and subject to its direction in the authentication and delivery of Notes in connection with the original issuance thereof and transfers and exchanges of Notes hereunder, including under Section 2.04, Section 2.05, Section 2.06,
        Section 2.07, Section 10.04 and Section 15.04 as fully to all intents and purposes as though the authenticating agent had been expressly authorized by this Indenture and those Sections to authenticate and deliver Notes.  For all purposes of this
        Indenture, the authentication and delivery of Notes by the authenticating agent shall be deemed to be authentication and delivery of such Notes “by the Trustee” and a certificate of authentication executed on behalf of the Trustee by an
        authenticating agent shall be deemed to satisfy any requirement hereunder or in the Notes for the Trustee’s certificate of authentication.  Such authenticating agent shall at all times be a Person eligible to serve as trustee hereunder pursuant to
        Section 7.08.

     

    Any corporation or other entity into which any authenticating agent may be merged or converted or with which it may be consolidated, or any corporation
      or other entity resulting from any merger, consolidation or conversion to which any authenticating agent shall be a party, or any corporation or other entity succeeding to all or substantially all the corporate trust business of any authenticating
      agent, shall be the successor of the authenticating agent hereunder, if such successor corporation or other entity is otherwise eligible under this Section 17.10, without the execution or filing of any paper or any further act on the part of the
      parties hereto or the authenticating agent or such successor corporation or other entity.

     

    Any authenticating agent may at any time resign by giving written notice of resignation to the Trustee and to the Company.  The Trustee may at any time
      terminate the agency of any authenticating agent by giving written notice of termination to such authenticating agent and to the Company.  Upon receiving such a notice of resignation or upon such a termination, or in case at any time any
      authenticating agent shall cease to be eligible under this Section, the Trustee may appoint a successor authenticating agent (which may be the Trustee), shall give written notice of such appointment to the Company and shall mail notice of such
      appointment to all Holders as the names and addresses of such Holders appear on the Note Register.

     

    The Company agrees to pay to the authenticating agent from time to time reasonable compensation for its services although the Company may terminate the
      authenticating agent, if it determines such agent’s fees to be unreasonable.

     

    The provisions of Section 7.02, Section 7.03, Section 7.04, Section 8.03 and this Section 17.10 shall be applicable to any authenticating agent.

     

    If an authenticating agent is appointed pursuant to this Section 17.10, the Notes may have endorsed thereon, in addition to the Trustee’s certificate of
      authentication, an alternative certificate of authentication in the following form:

     

    __________________________,

      as Authenticating Agent, certifies that this is one of the Notes described

      in the within-named Indenture.

     

    
      	
              By: 

              

            	
               

            	 


       Authorized Signatory

     

    
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    Section 17.11.  Execution in Counterparts.  This Indenture may be executed in any number of counterparts, each of which shall be an original, but such counterparts shall together constitute but one and the same
        instrument.  The exchange of copies of this Indenture and of signature pages by facsimile or PDF transmission shall constitute effective execution and delivery of this Indenture as to the parties hereto and may be used in lieu of the original
        Indenture for all purposes.  Signatures of the parties hereto transmitted by facsimile or PDF shall be deemed to be their original signatures for all purposes.

     

    Section 17.12.  Severability.  In the event any provision of this Indenture or in the Notes shall be invalid, illegal or unenforceable, then (to the extent permitted by law) the validity, legality or
        enforceability of the remaining provisions shall not in any way be affected or impaired.

     

    Section 17.13.  Waiver of Jury Trial.  EACH OF THE COMPANY AND THE TRUSTEE HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING
        ARISING OUT OF OR RELATING TO THIS INDENTURE, THE NOTES OR THE TRANSACTIONS CONTEMPLATED HEREBY.

     

    Section 17.14.  Force Majeure.  In no event shall the Trustee be responsible or liable for any failure or delay in the performance of its obligations hereunder arising out of or caused by, directly or indirectly,
        forces beyond its control, including, without limitation, strikes, work stoppages, accidents, acts of war or terrorism, civil or military disturbances, nuclear or natural catastrophes or acts of God, and interruptions, loss or malfunctions of
        utilities, communications or computer (software and hardware) services; it being understood that the Trustee shall use reasonable efforts that are consistent with accepted practices in the banking industry to resume performance as soon as
        practicable under the circumstances.

     

    Section 17.15.  Calculations.  Except as otherwise provided herein, the Company shall be responsible for making all calculations called for under the Notes.  These calculations include, but are not limited to,
        determinations of the Last Reported Sale Prices of the Common Stock, the Daily VWAPs, the Daily Conversion Values, the Daily Settlement Amounts, accrued interest payable on the Notes and the Conversion Rate of the Notes.  Each of the Trustee and
        Conversion Agent is entitled to rely conclusively upon the accuracy of the Company’s calculations without independent verification.  The Company shall make all these calculations in good faith and, absent manifest error, the Company’s calculations
        shall be final and binding on Holders of Notes.  Other than as set forth with respect to adjustments to the Conversion Rate in Section 14.04(l), the Company shall provide a schedule of its calculations to each of the Trustee and the Conversion
        Agent, and the Trustee will forward the Company’s calculations to any Holder of Notes upon the written request of that Holder at the sole cost and expense of the Company.

     

    Section 17.16.  U.S.A. Patriot Act.  The parties hereto acknowledge that in accordance with Section 326 of the U.S.A. Patriot Act, the Trustee, like all financial institutions and in order to help fight the funding of terrorism and
        money laundering, is required to obtain, verify, and record information that identifies each person or legal entity that establishes a relationship or opens an account with the Trustee.  The parties to this Indenture agree that they will provide
        the Trustee with such information as it may request in order for the Trustee to satisfy the requirements of the U.S.A. Patriot Act.

     

    [Remainder of page intentionally left blank]

     

    

    
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    IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be duly executed as of the date first written above.

     

    	               

          	
            IONIS PHARMACEUTICALS, INC.

          
	 	 

          
	 	
            By:

          	
            /s/Elizabeth L. Hougen

          
	 	
            

            

          	
            Name:  Elizabeth L. Hougen

          
	 	
            

            

          	Title:    SVP & CFO 

          


    

    

    	 	
            U.S. BANK NATIONAL ASSOCIATION, as Trustee

          
	 	 
	 	
            By:

          	
            /s/Karen R. Beard

          
	 	
            

            

          	
            Name:  Karen R. Beard

          
	 	
            

            

          	Title:    Vice President 

          


    

    

    
      [Signature Page to Indenture]

    

    

    

    
      
        


    

    
    EXHIBIT A

     

    [FORM OF FACE OF NOTE]

     

    [INCLUDE FOLLOWING LEGEND IF A GLOBAL NOTE]

     

    [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”), TO THE COMPANY
      OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT HEREUNDER IS MADE TO
      CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO.,
      HAS AN INTEREST HEREIN.]

     

    [INCLUDE FOLLOWING LEGEND IF A RESTRICTED SECURITY]

     

    [THIS SECURITY AND THE COMMON STOCK, IF ANY, ISSUABLE UPON CONVERSION OF THIS SECURITY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
      AMENDED (THE “SECURITIES ACT”), AND MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE WITH THE FOLLOWING SENTENCE. BY ITS ACQUISITION HEREOF OR OF A BENEFICIAL INTEREST HEREIN, THE ACQUIRER:

     

    (1) REPRESENTS THAT IT AND ANY ACCOUNT FOR WHICH IT IS ACTING IS A “QUALIFIED INSTITUTIONAL BUYER” (WITHIN THE MEANING OF RULE 144A UNDER THE SECURITIES
      ACT) AND THAT IT EXERCISES SOLE INVESTMENT DISCRETION WITH RESPECT TO EACH SUCH ACCOUNT, AND

     

    (2) AGREES FOR THE BENEFIT OF IONIS PHARMACEUTICALS, INC. (THE “COMPANY”) THAT IT WILL NOT OFFER, SELL, PLEDGE OR OTHERWISE TRANSFER THIS SECURITY OR ANY
      BENEFICIAL INTEREST HEREIN PRIOR TO THE DATE THAT IS THE LATER OF (X) ONE YEAR AFTER THE LAST ORIGINAL ISSUE DATE HEREOF OR SUCH SHORTER PERIOD OF TIME AS PERMITTED BY RULE 144 UNDER THE SECURITIES ACT OR ANY SUCCESSOR PROVISION THERETO, AND (Y) SUCH
      LATER DATE, IF ANY, AS MAY BE REQUIRED BY APPLICABLE LAW, EXCEPT:

     

    (A) TO THE COMPANY OR ANY SUBSIDIARY THEREOF, OR

     

    (B) PURSUANT TO A REGISTRATION STATEMENT WHICH HAS BECOME EFFECTIVE UNDER THE SECURITIES ACT, OR

     

    
      A-1

      
        


    

    (C) TO A QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, OR

     

    (D) PURSUANT TO AN EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT OR ANY OTHER AVAILABLE EXEMPTION FROM THE REGISTRATION
      REQUIREMENTS OF THE SECURITIES ACT.

     

    PRIOR TO THE REGISTRATION OF ANY TRANSFER IN ACCORDANCE WITH CLAUSE (2)(D) ABOVE, THE COMPANY AND THE TRUSTEE RESERVE THE RIGHT TO REQUIRE THE DELIVERY
      OF SUCH LEGAL OPINIONS, CERTIFICATIONS OR OTHER EVIDENCE AS MAY REASONABLY BE REQUIRED IN ORDER TO DETERMINE THAT THE PROPOSED TRANSFER IS BEING MADE IN COMPLIANCE WITH THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS. NO REPRESENTATION IS
      MADE AS TO THE AVAILABILITY OF ANY EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT.]

     

    
      A-2

      
        


    

    Ionis Pharmaceuticals, Inc.

      

      0.125% Convertible Senior Note due 2024

     
      	
              No. [        ]  

              

            	
              Initially $[      ] 

              

            


    

             

    

    CUSIP No. [•1]

     

    Ionis Pharmaceuticals, Inc., a corporation duly organized and validly existing under the laws of the State of Delaware (the “Company,” which term includes any successor corporation or other entity under the Indenture referred to on the reverse hereof), for value received hereby promises to pay to CEDE &
      CO., or registered assigns, the principal sum as set forth in the “Schedule of Exchanges of Notes” attached hereto, which amount, taken together with the principal amounts of all other outstanding Notes, shall not, unless permitted by the Indenture,
      exceed $548,826,000, in accordance with the rules and procedures of the Depositary, on December 15, 2024, and interest thereon as set forth below.

     

    This Note shall bear interest at the rate of 0.125% per year from December 19, 2019, or from the most recent date to which interest had been paid or
      provided for to, but excluding, the next scheduled Interest Payment Date until December 15, 2024.  Accrued interest on this Note shall be computed on the basis of a 360-day year composed of twelve 30-day months and, for partial months, on the basis
      of the number of days actually elapsed in a 30-day month.  Interest is payable semi-annually in arrears on each June 15 and December 15, commencing on June 15, 2020, to Holders of record at the close of business on the preceding June 1 and December 1
      (whether or not such day is a Business Day), respectively.  Additional Interest will be payable as set forth in Section 4.06(d), Section 4.06(e) and Section 6.03 of the within-mentioned Indenture, and any reference to interest on, or in respect of,
      any Note therein shall be deemed to include Additional Interest if, in such context, Additional Interest is, was or would be payable pursuant to any of such Section 4.06(d), Section 4.06(e)or Section 6.03 and any express mention of the payment of
      Additional Interest in any provision therein shall not be construed as excluding Additional Interest in those provisions thereof where such express mention is not made.

     

    Any Defaulted Amounts shall accrue interest per annum at the rate borne by the Notes from, and including, the relevant payment date to, but excluding,
      the date on which such Defaulted Amounts shall have been paid by the Company, at its election, in accordance with Section 2.03(c) of the Indenture.

     

    The Company shall pay, or cause the paying agent to pay, the principal of and interest on this Note, so long as such Note is a Global Note, in
      immediately available funds to the Depositary or its nominee, as the case may be, as the registered Holder of such Note.  As provided in and subject to the provisions of the Indenture, the Company shall pay the principal of any Notes (other than
      Notes that are Global Notes) at the office or agency designated by the Company for that purpose.  The Company has initially designated the Trustee as its Paying Agent and Note Registrar in respect of the Notes and its agency in its Corporate Trust
      Office as a place where Notes may be presented for payment or for registration of transfer.

     

    
      


    
      1 At such time as the Company notifies the Trustee to remove the legend (other than the first paragraph thereof) pursuant to Section 2.05 of
        the Indenture, the CUSIP number for this Note shall be unrestricted CUSIP No. [•].

    

     

    

    
      A-3

      
        


    

    Reference is made to the further provisions of this Note set forth on the reverse hereof, including, without limitation, provisions giving the Holder of
      this Note the right to convert this Note into cash, shares of Common Stock or a combination of cash and shares of Common Stock, as applicable, on the terms and subject to the limitations set forth in the Indenture.  Such further provisions shall for
      all purposes have the same effect as though fully set forth at this place.

     

    This Note, and any claim, controversy or dispute arising under or related to this Note, shall be construed in accordance with and
      governed by the laws of the State of New York (without regard to the conflicts of laws provisions thereof).

     

    In the case of any conflict between this Note and the Indenture, the provisions of the Indenture shall control and govern.

     

    This Note shall not be valid or become obligatory for any purpose until the certificate of authentication hereon shall have been manually signed by the
      Trustee or a duly authorized authenticating agent under the Indenture.

     

    
      [Remainder of page intentionally left blank]

    

     

    

    
      A-4

      
        


    

    IN WITNESS WHEREOF, the Company has caused this Note to be duly executed.

     

    
      	
               

            	
              IONIS PHARMACEUTICALS, INC.

            
	
               

            	 	
               

            
	
               

            	
              By:

            	
               

            
	
               

            	 	
              
                Name: 

              

            
	
               

            	 	
              
                Title: 

              

            


    

     

    

    Dated:

     

    TRUSTEE’S CERTIFICATE OF AUTHENTICATION

      U.S. BANK NATIONAL ASSOCIATION

      as Trustee, certifies that this is one of the Notes described

      in the within-named Indenture.

     

    
      	
              By: 

              

            	
               

            	
               

            
	
               

            	
              Authorized Signatory 

              

            	
               

            


    

      

    
      A-5

      
        


    

    [FORM OF REVERSE OF NOTE]

     

    Ionis Pharmaceuticals, Inc.

      0.125% Convertible Senior Note due 2024

     

    This Note is one of a duly authorized issue of Notes of the Company, designated as its 0.125% Convertible Senior Notes due 2024 (the “Notes”), initially limited to the aggregate principal amount of $548,826,000 all issued or to be issued under and pursuant to an Indenture dated as of December 19,
      2019 (the “Indenture”), between the Company and U.S. Bank National Association (the “Trustee”), to which Indenture and all indentures supplemental thereto reference is hereby made for a description of the rights, limitations of rights, obligations, duties and immunities thereunder of the Trustee, the Company and the
      Holders of the Notes.  Additional Notes may be issued in an unlimited aggregate principal amount, subject to certain conditions specified in the Indenture.

     

    In case an Event of Default, as defined in the Indenture, shall have occurred and be continuing, the principal of, and interest on, all Notes may be
      declared, by either the Trustee or Holders of at least 25% in aggregate principal amount of Notes then outstanding, and upon said declaration shall become, due and payable, in the manner, with the effect and subject to the conditions and certain
      exceptions set forth in the Indenture.

     

    Subject to the terms and conditions of the Indenture, the Company will make all payments and deliveries in respect of the Fundamental Change Purchase
      Price and the principal amount on the Maturity Date, as the case may be, to the Holder who surrenders a Note to a Paying Agent to collect such payments in respect of the Note.  The Company will pay cash amounts in money of the United States of
      America that at the time of payment is legal tender for payment of public and private debts.

     

    The Indenture contains provisions permitting the Company and the Trustee in certain circumstances, without the consent of the Holders of the Notes, and
      in certain other circumstances, with the consent of the Holders of not less than a majority in aggregate principal amount of the Notes at the time outstanding, evidenced as in the Indenture provided, to execute supplemental indentures modifying the
      terms of the Indenture and the Notes as described therein.  It is also provided in the Indenture that, subject to certain exceptions, the Holders of a majority in aggregate principal amount of the Notes at the time outstanding may on behalf of the
      Holders of all of the Notes waive any past Default or Event of Default under the Indenture and its consequences.

     

    No reference herein to the Indenture and no provision of this Note or of the Indenture shall alter or impair the obligation of the Company, which is
      absolute and unconditional, to pay the principal (including the Fundamental Change Purchase Price, if applicable) of and accrued and unpaid interest on this Note at the place, at the respective times, at the rate and in the lawful money herein
      prescribed.

     

    
      A-6

      
        


    

    The Notes are issuable in registered form without coupons in denominations of $1,000 principal amount and multiples thereof.  At the office or agency of
      the Company referred to on the face hereof, and in the manner and subject to the limitations provided in the Indenture, Notes may be exchanged for a like aggregate principal amount of Notes of other authorized denominations, without payment of any
      service charge but, if required by the Company or Trustee, with payment of a sum sufficient to cover any transfer or similar tax that may be imposed in connection therewith as a result of the name of the Holder of the new Notes issued upon such
      exchange of Notes being different from the name of the Holder of the old Notes surrendered for such exchange.

     

    The Notes are not subject to redemption through the operation of any sinking fund or otherwise.

     

    Upon the occurrence of a Fundamental Change, the Holder has the right, at such Holder’s option, to require the Company to purchase for cash all of such
      Holder’s Notes or any portion thereof (in principal amounts of $1,000 or multiples thereof) on the Fundamental Change Purchase Date at a price equal to the Fundamental Change Purchase Price.

     

    Subject to the provisions of the Indenture, the Holder hereof has the right, at its option, during certain periods and upon the occurrence of certain
      conditions specified in the Indenture, prior to the close of business on the second Scheduled Trading Day preceding the Maturity Date, to convert any Notes or portion thereof that is $1,000 or a multiple thereof, into cash, shares of Common Stock or
      a combination of cash and shares of Common Stock, as applicable, at the Conversion Rate specified in the Indenture, as adjusted from time to time as provided in the Indenture.

     

    Terms used in this Note and defined in the Indenture are used herein as therein defined.

     

    
      A-7

      
        


    

    ABBREVIATIONS

     

    The following abbreviations, when used in the inscription of the face of this Note, shall be construed as though they were written out in full according
      to applicable laws or regulations:

     

    TEN COM = as tenants in common

    

    

    UNIF GIFT MIN ACT = Uniform Gifts to Minors Act

    

    

    CUST = Custodian

    

    

    TEN ENT = as tenants by the entireties

    

     JT TEN = joint tenants with right of survivorship and not as tenants in common

        

    

    Additional abbreviations may also be used though not in the above list.

     

    

    
      A-8

      
        


    

    SCHEDULE A

     

    SCHEDULE OF EXCHANGES OF NOTES

      

      Ionis Pharmaceuticals, Inc.

      0.125% Convertible Senior Notes due 2024

     

    The initial principal amount of this Global Note is ___________________ MILLION DOLLARS ($____________).  The following increases or decreases in this
      Global Note have been made:

     

    
      	
              
                Date of exchange

              

            	 	
              
                Amount of 

                decrease in 

                principal amount 

                of this Global Note

              

            	 	
              
                Amount of 

                increase in 

                principal amount 

                of this Global Note

              

            	 	
              
                Principal amount 

                of this Global Note 

                following such 

                decrease or 

                increase

              

            	 	
              
                Signature of 

                

                authorized 

                signatory of 

                Trustee or 

                Custodian

              

            
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 


    

     

    

    
      A-9

      
        


    

    ATTACHMENT 1

     

    [FORM OF NOTICE OF CONVERSION]

     

    To:  Ionis Pharmaceuticals, Inc.

     

    The undersigned registered owner of this Note hereby exercises the option to convert this Note, or the portion hereof (that is $1,000 principal amount or
      a multiple thereof) below designated, into cash, shares of Common Stock or a combination of cash and shares of Common Stock, as applicable, in accordance with the terms of the Indenture referred to in this Note, and directs that any cash payable and
      any shares of Common Stock issuable and deliverable upon such conversion, together with any cash for any fractional share, and any Notes representing any unconverted principal amount hereof, be issued and delivered to the registered Holder hereof
      unless a different name has been indicated below.  If any shares of Common Stock or any portion of this Note not converted are to be issued in the name of a Person other than the undersigned, the undersigned will pay all documentary, stamp or similar
      issue or transfer taxes, if any in accordance with Section 14.02(d) and Section 14.02(e) of the Indenture.  Any amount required to be paid to the undersigned on account of interest accompanies this Note.  Capitalized terms used herein but not defined
      shall have the meanings ascribed to such terms in the Indenture.

     

    
      	
              Dated:   

              

            	
               

            	 	
               

            	 
	
               

            	
               

            	 	
               

            	 
	 	 	 	 	 
	
               

            	
               

            	 	
              Signature(s) 

              

            	 


    

     

    

    
      	
               

            	 
	Signature Guarantee 

            	 


    

    

    

    Signature(s) must be guaranteed

      by an eligible Guarantor Institution

      (banks, stock brokers, savings and

      loan associations and credit unions)

      with membership in an approved

      signature guarantee medallion program

      pursuant to Securities and Exchange

      Commission Rule 17Ad-15 if shares

      of Common Stock are to be issued, or

      Notes are to be delivered, other than

      to and in the name of the registered holder.

     

    
      
        


    

    Fill in for registration of shares if

      to be issued, and Notes if to

      be delivered, other than to and in the

      name of the registered holder:

     

    
      	
               

            	 	
               

            
	
              (Name) 

              

            	 	
               

            
	 	 	 
	 	 	 
	
              (Street Address) 

              

            	 	
               

            
	 	 	 
	 	 	 
	
              (City, State and Zip Code)

              Please print name and address

            	 	 
	 	 	 
	 	 	
              Principal amount to be converted (if less than all):  $______,000

               

              NOTICE:  The above signature(s) of the Holder(s) hereof must correspond with the name as written upon the face of the Note in every particular without alteration
                or enlargement or any change whatever.

               

              _________________________

              Social Security or Other Taxpayer

                Identification Number

            


    

     

    

    
      
        


    

    ATTACHMENT 2

     

    [FORM OF FUNDAMENTAL CHANGE PURCHASE NOTICE]

     

    To:  Ionis Pharmaceuticals, Inc.

     

    The undersigned registered owner of this Note hereby acknowledges receipt of a notice from Ionis Pharmaceuticals, Inc. (the “Company”) as to the occurrence of a Fundamental Change with respect to the Company and specifying the Fundamental Change Purchase Date and requests and instructs the Company to pay to
      the registered holder hereof in accordance with Section 15.02 of the Indenture referred to in this Note (1) the entire principal amount of this Note, or the portion thereof (that is $1,000 principal amount or a multiple thereof) below designated, and
      (2) if such Fundamental Change Purchase Date does not fall during the period after a Regular Record Date and on or prior to the corresponding Interest Payment Date, accrued and unpaid interest, if any, thereon to, but excluding, such Fundamental
      Change Purchase Date.  Capitalized terms used herein but not defined shall have the meanings ascribed to such terms in the Indenture.

     

    In the case of Physical Notes, the certificate numbers of the Notes to be purchased are as set forth below:

     

    
      	
              Dated:   

              

            	
               

            	 	
               

            	 
	
               

            	
               

            	 	
               

            	 
	
               

            	
               

            	 	
              Signature(s) 

              

            	 
	
               

            	
               

            	 	
               

            	 
	 	 	 	 	 
	 	 	 	Social Security or Other Taxpayer

              Identification Number 

            	 
	 	 	 	 	 
	 	 	 	
              Principal amount to be repaid (if less than all):  $______,000

            	 
	 	 	 	 	 
	 	 	 	
              NOTICE:  The above signature(s) of the Holder(s) hereof must correspond with the name as written upon the face of the Note in every particular without alteration
                or enlargement or any change whatever.

            


    

     

    

    

    

    
      
        


    

    ATTACHMENT 3

     

    [FORM OF ASSIGNMENT AND TRANSFER]

     

    For value received ____________________________ hereby sell(s), assign(s) and transfer(s) unto _________________ (Please insert social security or Taxpayer Identification
      Number of assignee) the within Note, and hereby irrevocably constitutes and appoints _____________________ attorney to transfer the said Note on the books of the Company, with full power of substitution in the premises.

     

    In connection with any transfer of the within Note occurring prior to the Resale Restriction Termination Date, as defined in the Indenture governing such Note, the
      undersigned confirms that such Note is being transferred:

     

    ☐          To Ionis Pharmaceuticals, Inc. or a subsidiary thereof; or
     

    ☐          Pursuant to a registration statement that has become or been declared effective under the Securities Act of 1933, as amended; or

     

    ☐          Pursuant to and in compliance with Rule 144A under the Securities Act of 1933, as amended; or

     

    ☐          Pursuant to and in compliance with Rule 144 under the Securities Act of 1933, as amended, or any other available exemption from the registration
        requirements of the Securities Act of 1933, as amended.

     

    
      
        


    

    
      	
              Dated: 

              

            	
               

            	 


      	 	 	 
	 	 	 
	
               

            	
               

            	 
	 	 	 
	
              Signature(s) 

              

            	
               

            	 
	 	 	 
	 	 	 
	Signature Guarantee 

            	 	 


    

     
    Signature(s) must be guaranteed by an

      eligible Guarantor Institution (banks, stock

      brokers, savings and loan associations and

      credit unions) with membership in an approved

      signature guarantee medallion program pursuant

      to Securities and Exchange Commission

      Rule 17Ad-15 if Notes are to be delivered, other

      than to and in the name of the registered holder.

     

    NOTICE:  The signature on the assignment must correspond with the name as written upon the face of the Note in every particular without alteration or enlargement or any
      change whatever.