Document:

EX-4.2

 Exhibit 4.2 

CLECO CORPORATE HOLDINGS LLC, 

AS ISSUER 
 AND 

WELLS FARGO BANK, N.A., 

AS TRUSTEE 
 THIRD
SUPPLEMENTAL INDENTURE 
 Dated as of May 24, 2016 

 
  

$165,000,000 
 3.25%
Senior Secured Notes due 2023 

 THIS THIRD SUPPLEMENTAL INDENTURE (this “Third Supplemental Indenture”) is made
as of the 24th day of May, 2016, by and between CLECO CORPORATE HOLDINGS LLC, a Louisiana limited liability company, as issuer (the “Company”), and WELLS FARGO BANK, N.A., a national banking association, as trustee (the
“Trustee”): 
 WHEREAS, the Company has heretofore entered into an Indenture, dated as of May 17, 2016 (the
“Original Indenture”), with the Trustee; 
 WHEREAS, the Original Indenture is incorporated herein by this reference and
the Original Indenture, as supplemented, including by this Third Supplemental Indenture, is herein called the “Indenture”; 

WHEREAS, under the Original Indenture, a new series of senior secured notes may at any time be established by the Board of Managers in
accordance with the provisions of the Original Indenture and the terms of such series may be described by a supplemental indenture executed by the Company and the Trustee; 

WHEREAS, the Company proposes to create under the Indenture a new series of senior secured notes which shall contain certain transfer
restrictions as described herein; and 
 WHEREAS, all things necessary to authorize the execution and delivery of this Third Supplemental
Indenture and make it a valid and binding agreement of the Company, in accordance with its terms, have been done. 
 NOW THEREFORE, in
consideration of the agreements and obligations set forth herein and for other good and valuable consideration, the sufficiency of which is hereby acknowledged, the parties hereto hereby agree as follows: 

ARTICLE I 
 3.25% SENIOR
NOTES DUE 2023 
 SECTION 1.01 Establishment. There is hereby established a new series of senior secured notes to be issued
under the Indenture, to be designated as the Company’s 3.25% Senior Secured Notes due 2023 (the “Notes”). 
 There are
to be authenticated and delivered $165,000,000 principal amount of Notes. All Notes shall be issued at the same time in physical, certificated form. No additional Notes with respect to this series may be issued pursuant to Section 3.01 of
the Original Indenture. 
 The form of the Trustee’s Certificate of Authentication for the Notes shall be substantially in the form set
forth in Exhibit B hereto. 
 Each Note shall be dated the date of authentication thereof and shall bear interest from the date of
original issuance thereof or from the most recent Interest Payment Date to which interest has been paid or duly provided for. 

  
 2 

 SECTION 1.02 Definitions. The following defined terms used herein shall, unless
the context otherwise requires, have the meanings specified below. Capitalized terms used herein for which no definition is provided herein shall have the meanings set forth in the Original Indenture. 

“Change of Control” has the meaning specified in Section 1.10(j). 

“Change of Control Date” has the meaning specified in Section 1.10(a). 

“Change of Control Offer” has the meaning specified in Section 1.10(a). 

“Change of Control Purchase Notice” has the meaning specified in Section 1.10(c). 

“Change of Control Purchase Price” has the meaning specified in Section 1.10(a). 

“Change of Control Repurchase Event” has the meaning specified in Section 1.10(j). 

“Company” has the meaning specified in the Preamble hereof. 

“Comparable Treasury Issue” has the meaning specified in Section 1.09. 

“Comparable Treasury Price” has the meaning specified in Section 1.09. 

“Indenture” has the meaning specified in the Recitals hereof. 

“Independent Investment Banker” has the meaning specified in Section 1.09. 

“Interest Payment Date” means May 1 and November 1 of each year, commencing on November 1, 2016. 

“Investment Grade” has the meaning specified in Section 1.10(j). 

“Investors” has the meaning specified in Section 1.10(j). 

“Moody’s” means Moody’s Investors Service, Inc. or its successors. 

“Notes” has the meaning specified in Section 1.01. 

“Operating Agreement” has the meaning specified in Section 1.10(j). 

“Original Indenture” has the meaning specified in the Recitals hereof. 

“Par Call Date” has the meaning specified in Section 1.09(a). 

“Permitted Holders” has the meaning specified in Section 1.10(j). 

  
 3 

 “Purchase Date” has the meaning specified in Section 1.10(a). 

“Rating Agency” has the meaning specified in Section 1.10(j). 

“Ratings Event” has the meaning specified in Section 1.10(j). 

“Reference Treasury Dealer” has the meaning specified in Section 1.09. 

“Reference Treasury Dealer Quotation” has the meaning specified in Section 1.09. 

“Regular Record Date” means, with respect to each Interest Payment Date, the close of business on April 15 or
October 15 immediately preceding such Interest Payment Date. 
 “S&P” means Standard & Poor’s Financial
Services LLC, a subsidiary of The McGraw-Hill Companies, Inc., or its successors. 
 “Stated Maturity” means May 1, 2023.

 “Third Supplemental Indenture” has the meaning specified in the Preamble hereof. 

“Treasury Rate” has the meaning specified in Section 1.09. 

“Trustee” has the meaning specified in the Preamble hereof. 

“Voting Stock” has the meaning specified in Section 1.10(j). 

SECTION 1.03 Payment of Principal and Interest. 

(a) The principal of the Notes shall be due at Stated Maturity. The unpaid and outstanding principal amount of the Notes, and any overdue
installment of interest thereon to the extent permitted by law, shall bear interest at the rate of 3.25% per year until paid or made available for payment, such interest to accrue from the most recent Interest Payment Date to which interest has been
paid or duly provided for or, if no interest has been paid, from the date hereof. Interest shall be paid semi-annually in arrears on each Interest Payment Date, commencing on November 1, 2016, to the Person in whose name the Notes are
registered on the Regular Record Date for such Interest Payment Date; provided that interest payable at the Stated Maturity of principal or on a Redemption Date as provided herein will be paid to the Person to whom principal is
payable. Any such interest that is not so punctually paid or duly provided for will forthwith cease to be payable to the holders on such Regular Record Date and may be paid as provided in Section 3.07 of the Original Indenture. 

(b) Payments of interest on the Notes will include interest accrued to but excluding the respective Interest Payment Dates. Interest
payments for the Notes shall be computed and paid on the basis of a 360-day year consisting of twelve 30-day months. In the event that any date on which interest is payable on the Notes is not a Business Day, then payment of the interest
payable on such date will be made on the next succeeding day that is a 

  
 4 

 
Business Day (and without any interest or other payment in respect of any such delay), except that, if such Business Day is in the next succeeding calendar year, such payment shall be made on the
immediately preceding Business Day, in each case with the same force and effect as if made on the date the payment was originally payable. 

(c) Payment of the principal, premium, if any, and interest due at the Stated Maturity of, or on a Redemption Date for, the Notes shall be
made upon surrender of the Notes at the Corporate Trust Office. The principal of and interest on the Notes shall be paid in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public
and private debts. Payments of interest (including interest on any Interest Payment Date) will be made, subject to such surrender where applicable, at the option of the Company, (i) by check mailed to the address of the Person entitled thereto
as such address shall appear in the Security Register or (ii) by wire transfer at such place and to such account at a banking institution in the United States as may be designated in writing to the Trustee at least fifteen (15) days prior to the
date for payment by the Person entitled thereto. 
 SECTION 1.04 Denominations. The Notes will be issued only in
denominations of $2,000 and integral multiples of $1,000 in excess thereof. 
 SECTION 1.05 Form of Notes. 

(a) Notes initially offered and sold shall be issued in the form of one or more Notes in physical, certificated form in the form of Exhibit A
hereto. 
 SECTION 1.06 Transfer and Exchange. 

(a) Transfer Restrictions. The Notes may not be transferred except in compliance with the applicable legends contained in
Exhibit A unless otherwise determined by the Company in accordance with applicable law. 
 No service charge will be made for any
transfer or exchange of Notes, but the Trustee may require payment of a sum sufficient to cover any tax or other governmental charge that may be imposed in connection therewith. 

The Company shall not be required (i) to issue, transfer or exchange any Notes during a period beginning at the opening of business fifteen
(15) days before the day of the mailing of a notice identifying the Notes to be called for redemption, and ending at the close of business on the day of the mailing, or (ii) to transfer or exchange any Notes theretofore selected for redemption
in whole or in part, except the unredeemed portion of any Note redeemed in part. 
 SECTION 1.07 Legends. 

(a) Except as otherwise determined by the Company in accordance with applicable law, each Note shall bear the applicable legends relating to
restrictions on transfer pursuant to the securities laws in substantially the form set forth on Exhibit A hereto. 
 SECTION 1.08
Satisfaction and Discharge. The Company will not exercise its right under Article Six of the Original Indenture prior to the Stated Maturity. 

  
 5 

 SECTION 1.09 Redemption at the Option of the Company. 

(a) At any time prior to April 1, 2023 (one month prior to the Stated Maturity of the Notes) (the “Par Call Date”), the Notes
shall be redeemable, at the sole option of the Company, in whole at any time or in part from time to time, at a Redemption Price equal to the greater of (i) 100% of the aggregate principal amount of the Notes to be redeemed and (ii) an amount equal
to the sum of the present values of the remaining scheduled payments for principal of and interest on the Notes to be redeemed that would be due if the Notes matured on the Par Call Date, not including any portion of the payments of interest accrued
as of such Redemption Date, discounted to such Redemption Date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate, plus 25 basis points, plus, in the case
of each of (i) and (ii), accrued and unpaid interest on the principal amount of the Notes to be redeemed to, but excluding, such Redemption Date. 

(b) At any time on or after the Par Call Date, the Notes shall be redeemable, at the sole option of the Company, in whole at any time or in
part from time to time, at 100% of the principal amount being redeemed plus accrued and unpaid interest on the principal amount of the Notes to be redeemed to, but excluding, such Redemption Date. 

(c) Notwithstanding Section 4.04(a) of the Original Indenture, notice of redemption shall be given in the manner provided in Section 1.06
of the Original Indenture to the Holders of the Notes to be redeemed not less than three (3) Business Days prior to the Redemption Date. 

(d) Notwithstanding any provision of Article IV of the Original Indenture, any redemption of the Notes and notice thereof, may, in the
Company’s discretion, state that such notice is conditioned upon the the consummation of any refinancing, debt issuance or other capital markets transaction or upon any acquisition, divestiture or change of control transaction. In the
event that such notice of redemption contains such a condition and the stated condition is not met, then: (i) the redemption shall not be made; (ii) notice shall be given on or prior to the Redemption Date by facsimile to the Holders of the Notes
and the Trustee that such condition was not met and such redemption was not required to be made; and (iii) the Paying Agent or Agents for the Notes shall promptly return to the Holders any Notes surrendered for payment upon such redemption. 

“Comparable Treasury Issue” means the United States Treasury security selected by an Independent Investment Banker as having
a maturity comparable to the remaining term of the Notes to be redeemed (assuming for this purpose that the Notes matured on the Stated Maturity) that would be used, at the time of selection and in accordance with customary financial practice, in
pricing new issues of corporate debt securities of comparable maturity to the remaining term of the Notes. 
 “Comparable Treasury
Price” means, with respect to any Redemption Date, (i) the average of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) on the third Business Day preceding such
Redemption Date, as set forth in the daily statistical release (or any successor release) published by the Federal Reserve Bank of New York and designated “Composite 3:30 p.m. Quotations for 

  
 6 

 
U.S. Government Securities” or (ii) if such release (or any successor release) is not published or does not contain such prices on such third Business Day, (A) the average of the Reference
Treasury Dealer Quotations for such Redemption Date, after excluding the highest and lowest of such Reference Treasury Dealer Quotations, or (B) if the Independent Investment Banker obtains fewer than five such Reference Treasury Dealer Quotations,
the average of all such Quotations. 
 “Independent Investment Banker” means each of Mizuho Securities USA Inc., CIBC World
Markets Corp., Credit Agricole Securities (USA) Inc., Scotia Capital (USA) Inc. and SMBC Nikko Securities America, Inc. or their respective successors, or if any such firm is unwilling or unable to serve as such, an independent investment banking
institution of national standing appointed by the Company. 
 “Reference Treasury Dealer” means (a) Mizuho Securities USA
Inc. or its successor, and Scotia Capital (USA) Inc. and its affiliates or successors (b) one primary U.S. Government securities dealer in New York City (a “Primary Treasury Dealer”) selected by CIBC World Markets Corp. or its successor,
(c) one Primary Treasury Dealer selected by Credit Agricole Securities (USA) Inc. or its successor, (d) one Primary Treasury Dealer selected by SMBC Nikko Securities America, Inc. or its successor and (e) one other Primary Treasury Dealer selected
by the Company. 
 “Reference Treasury Dealer Quotation” means, with respect to each Reference Treasury Dealer and any
Redemption Date, the average, as determined by the Independent Investment Banker, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Independent
Investment Banker by such Reference Treasury Dealer at or before 5:00 p.m., New York City time, on the third Business Day preceding such Redemption Date. 

“Treasury Rate” means, with respect to any Redemption Date, the rate per year equal to the semi-annual equivalent yield to
maturity of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for such Redemption Date. 

(c) The Company shall notify the Trustee in writing of the Redemption Price with respect to the foregoing redemption promptly after the
calculation thereof. The Trustee shall not be responsible for calculating said Redemption Price or confirming the accuracy thereof. Notwithstanding Section 4.04 of the Original Indenture, such notice need not set forth the Redemption
Price but only the manner of calculation thereof. 
 SECTION 1.10 Change of Control. 

(a) In the event of any Change of Control Repurchase Event (the effective date of such Change of Control Repurchase Event being the
“Change of Control Date”) each Holder of the Notes will have the right, at such Holder’s option, subject to the terms and conditions herein, to require the Company to repurchase all or any part (equal to $2,000 or an integral
multiple of $1,000 in excess thereof) of such Holder’s Notes (a “Change of Control Offer”) on a date selected by the Company that is no earlier than sixty (60) days nor later than ninety (90) days (the
“Purchase Date”) after the mailing of written notice by the Company, with 

  
 7 

 
a copy to the Trustee, of the occurrence of such Change of Control Repurchase Event, at a repurchase price payable in cash equal to 101% of the principal amount of such Notes plus accrued
interest, if any, thereon to the Purchase Date (the “Change of Control Purchase Price”). The Company will not be required to make a Change of Control Offer upon a Change of Control Repurchase Event if a third party makes the Change
of Control Offer in the manner, at the times and otherwise in compliance with the requirements set forth in the Indenture applicable to a Change of Control Offer made by the Company and purchases all Notes properly tendered and not withdrawn in
accordance with such offer. Notwithstanding anything to the contrary contained herein, a Change of Control Offer may be made in advance of a Change of Control, conditioned upon the occurrence of such Change of Control and without regard to the
occurrence of a Ratings Event, if a definitive agreement is in place for the Change of Control at the time the Change of Control Offer is made; provided any such offer will be deemed to satisfy the Company’s obligation to make a Change
of Control Offer upon the occurrence of any related Change of Control Repurchase Event. 
 (b) Within thirty (30) days after the Change of
Control Date, the Company shall mail to each Holder of a Note a notice, with a copy to the Trustee, regarding the Change of Control Repurchase Event, which notice shall state: 

(i) that a Change of Control Repurchase Event has occurred and that each such Holder has the right to require the Company to
repurchase all or any part of such Holder’s Notes at the Change of Control Purchase Price; 
 (ii) the Change of Control
Purchase Price; 
 (iii) the Purchase Date; 

(iv) that any Note not tendered will continue to accrue interest; 

(v) that, unless the Company defaults in the payment of the Change of Control Purchase Price, all Notes accepted for payment
pursuant to the Change of Control Repurchase Event will cease to accrue interest after the Purchase Date; 
 (vi) that
Holders electing to have any Notes purchased pursuant to a Change of Control Repurchase Event shall be required to surrender the Notes, with the form entitled “Option of Holder to Elect Purchase” on the reverse of the Notes completed, to
the Paying Agent at the address specified in the notice prior to the close of business on the third Business Day preceding the Purchase Date; 

(vii) the procedures to withdraw a Holder’s election to have any Notes repurchased pursuant to the Change of Control
Repurchase Event; and 
 (viii) that Holders whose Notes are being purchased only in part will be issued new Notes equal in
principal amount to the unpurchased portion of the Notes surrendered, which unpurchased portion must be equal to $2,000 in principal amount or an integral multiple of $1,000 in excess of $2,000. 

  
 8 

 (c) To exercise its right to have any Notes repurchased pursuant to a Change of Control
Repurchase Event, a Holder must deliver a written notice (the “Change of Control Purchase Notice”) to the Paying Agent at the Corporate Trust Office or any other office of the Paying Agent maintained for such purposes, not later
than thirty (30) days prior to the Purchase Date. The Change of Control Purchase Notice shall state: 
 (i) the portion
of the principal amount of any Notes to be repurchased, which shall be a minimum of $2,000 and in integral multiples of $1,000 in excess thereof; 

(ii) that such Notes are to be repurchased by the Company pursuant to this Section 1.10; and 

(iii) the certificate number(s) of the Notes to be repurchased. 

(d) The Paying Agent shall promptly mail to each Holder of Notes properly tendered the Change of Control Purchase Price for such Notes, and
the Trustee shall promptly authenticate and mail to each Holder a new Note equal in principal amount to any unpurchased portion of the Notes surrendered, if any; provided that each new Note will be in a principal amount of $2,000 or an
integral multiple of $1,000. The Company shall publicly announce the results of the Change of Control Offer on or as soon as practicable after the Purchase Date. 

(e) Any Change of Control Purchase Notice may be withdrawn by a Holder by a written notice of withdrawal delivered to the Paying Agent not
later than three (3) Business Days prior to the Purchase Date. The notice of withdrawal shall state the principal amount and, if applicable, the certificate number(s) of the Notes as to which the withdrawal notice relates and the principal
amount, if any, that remains subject to a Change of Control Purchase Notice. 
 (f) If the Paying Agent holds money sufficient to pay the
Change of Control Purchase Price of a Note on the Business Day following the Purchase Date for such Note, then, on and after such date, interest on such Note will cease to accrue, whether or not such Note is delivered to the Paying Agent, and all
other rights of the Holder of such Note shall terminate (other than the right to receive the Change of Control Purchase Price upon delivery of such Note). 

(g) The Company shall comply with the requirements of Rule 14e-1 under the Exchange Act and any other securities laws and regulations
thereunder to the extent those laws and regulations are applicable in connection with the repurchase of the Notes as a result of a Change in Control Repurchase Event. To the extent that the provisions of any securities laws or regulations
conflict with the provisions of this Section 1.10, the Company shall comply with the applicable securities laws and regulations and shall not be deemed to have breached its obligations under this Section 1.10 by virtue of such compliance.

 (h) Notwithstanding anything to the contrary in this Section 1.10, the Company shall not be required to make a Change of Control
Offer upon a Change of Control Repurchase Event if (i) a third party makes a Change of Control Offer in the manner, at the times and otherwise in compliance with the requirements set forth herein applicable to a Change of Control Offer made by the
Company and purchases all Notes properly tendered and not 

  
 9 

 
withdrawn in accordance with such Change of Control Offer, or (ii) notice of redemption has been given pursuant to Section 1.09 unless and until there is a default in payment of the
applicable Redemption Price. 
 (i) Notwithstanding anything to the contrary in this Section 1.10, no Note may be repurchased by the
Company as a result of a Change of Control Repurchase Event if there shall have occurred and be continuing an Event of Default (other than a default in the payment of the Change of Control Purchase Price with respect to the Notes). 

(j) The following terms shall have the following meanings in this Section 1.10: 

“Change of Control” means the occurrence of any of the following events: 

(i) any “person” or “group” (as such terms are used in Sections 13(d) and 14(d) of the Exchange Act or
any successor provisions to either of the foregoing), other than the Permitted Holders, becomes the “beneficial owners” (as used in Rules 13d-3 and 13d-5 under the Exchange Act, except that a person or group will be deemed to have
“beneficial ownership” of all shares that any such person or group has the right to acquire, whether such right is exercisable immediately or only after the passage of time), directly or indirectly, of a majority of the total voting power
of the Voting Stock of the Company, whether as a result of the issuance of securities of the Company, any merger, consolidation, liquidation or dissolution of the Company or otherwise; 

(ii) the sale, transfer, assignment, lease, conveyance or other disposition, directly or indirectly, of all or substantially
all the assets of the Company and its subsidiaries, considered as a whole (other than a disposition of such assets as an entirety or virtually as an entirety to a wholly-owned subsidiary) to any person other than the Permitted Holders shall have
occurred, or the Company merges, consolidates or amalgamates with or into any other person or any other person merges, consolidates or amalgamates with or into the Company, in any such event pursuant to a transaction in which the outstanding Voting
Stock of the Company is reclassified into or exchanged for cash, securities or other property, other than any such transaction where (x) the outstanding Voting Stock of the Company is reclassified into or exchanged for other Voting Stock of the
Company or for Voting Stock of the surviving corporation and (y) the holders of the Voting Stock of the Company immediately prior to such transaction own, directly or indirectly, a majority of the Voting Stock of the Company or the surviving
corporation immediately after such transaction; 
 (iii) during any period, individuals who at the beginning of such period
constituted the Board of Managers (for so long as the Operating Agreement of the Company, adopted April 13, 2016 (as amended from time to time, the “Operating Agreement”) is in effect, together with any replacement or new managers
appointed to such Board of Managers in accordance with the terms of the Operating Agreement, and to the extent the terms of the Operating Agreement are no longer in effect, together with any new managers whose election or appointment by such Board
of Managers or whose nomination for election by the members of the Company was approved by a vote of a 

  
 10 

 
majority of the managers then still in office who were either managers at the beginning of such period or whose election or nomination for election was previously so approved) cease for any
reason to constitute a majority of the Board of Managers then in office; or 
 (iv) the Company’s members shall have
approved any plan of liquidation or dissolution of the Company. 
 “Change of Control Repurchase Event” means the
occurrence of both a Change of Control and a Ratings Event. 
 “Investment Grade” means BBB- or higher by S&P and Baa3
or higher by Moody’s, or the equivalent of such ratings by S&P or Moody’s or, if either S&P or Moody’s shall not make a rating on the Notes publicly available, another Rating Agency. 

“Investors” means MIP Cleco Partners L.P. (f/k/a Como B L.P.), bcIMC Como Investment Limited Partnership and John Hancock
Life Insurance Company (U.S.A.), and each of their respective Affiliates. 
 “Permitted Holders” means each of the
Investors and members of management of the Company (or its direct or indirect parent) who are holders of Voting Stock of the Company (or any of its direct or indirect parent companies) on the issue date of the Notes and any “group” (as
such term is used in Section 13(d) and 14(d) of the Exchange Act or any successor provision) of which any of the foregoing are members; provided that, in the case of such group and without giving effect to the existence of such group or
any other group, such Investors and members of management, collectively, have beneficial ownership of a majority of the total voting power of the Voting Stock of the Company. 

“Rating Agency” means each of S&P and Moody’s or, if S&P or Moody’s or both shall not make a rating on the
Notes publicly available, a nationally recognized statistical rating organization or organizations, as the case may be, selected by the Company (as certified by a resolution of the Board of Managers), which shall be substituted for S&P or
Moody’s, or both, as the case may be. 
 “Ratings Event” means a decrease in the ratings of the Notes by one or more
gradations (including gradations within categories as well as between rating categories) by each of the Rating Agencies on any date from the date of the public notice of an arrangement that could result in a Change of Control until the end of the
30-day period following public notice of the occurrence of the Change of Control (which 30-day period shall be extended so long as the rating of the Notes is under publicly announced consideration for possible downgrade by either of the Rating
Agencies and the other Rating Agency has either downgraded, or publicly announced that it is considering downgrading, the Notes). Notwithstanding the foregoing, if the rating of the Notes by each of the Rating Agencies is Investment Grade, then
“Ratings Event” means a decrease in the ratings of the Notes by one or more gradations (including gradations within categories as well as between rating categories) by each of the Rating Agencies such that the rating of the Notes by
each of the Rating Agencies falls below Investment Grade on any date from the date of the public notice of an arrangement that could result in a Change of Control until the end of the 30-day period following public notice of the occurrence of the
Change of 

  
 11 

 
Control (which 30-day period shall be extended so long as the rating of the Notes is under publicly announced consideration for possible downgrade by either of the Rating Agencies and the other
Rating Agency has either downgraded, or publicly announced that it is considering downgrading, the Notes). 
 “Voting
Stock” means securities of any class or classes the holders of which are ordinarily, in the absence of contingencies, entitled to vote for corporate directors or managers (or persons performing similar functions). 

SECTION 1.11 Rule 144A Reporting Requirement. Upon request therefor, the Company shall provide to prospective Holders of the
Notes, all information required to be delivered pursuant to Rule 144A(d)(4) under the Securities Act so long as any Note that remains Outstanding is a “restricted security” with the meaning of Rule 144(a)(3) under the Securities Act. 

ARTICLE II 

MISCELLANEOUS PROVISIONS 

SECTION 2.01 Recitals by the Company. The recitals in this Third Supplemental Indenture are made by the Company only and not
by the Trustee, and the Trustee assumes no responsibility for their correctness. The Trustee makes no representations as to the validity or sufficiency of this Third Supplemental Indenture or of the Notes. The Trustee shall not be
accountable for the use or application by the Company of the Notes or the proceeds thereof. All of the provisions contained in the Original Indenture in respect of the rights, privileges, immunities, powers and duties of the Trustee shall be
applicable in respect of the Notes and of this Third Supplemental Indenture as fully and with like effect as if set forth herein in full. 

SECTION 2.02 Ratification and Incorporation of Original Indenture. As supplemented hereby, the Original Indenture is in all
respects ratified and confirmed, and the Original Indenture and this Third Supplemental Indenture shall be read, taken and construed as one and the same instrument. 

SECTION 2.03 Executed in Counterparts. This Third Supplemental Indenture may be simultaneously executed in several
counterparts, each of which shall be deemed to be an original, and such counterparts shall together constitute but one and the same instrument. The exchange of copies of this Third Supplemental Indenture and of signature pages by facsimile or
PDF transmission shall constitute effective execution and delivery of this Third Supplemental Indenture as to the parties hereto and may be used in lieu of the Third Supplemental 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 2.04 New York Law to
Govern. This Third Supplemental Indenture and each Note shall be governed by and construed in accordance with the laws of the State of New York. 

  
 12 

 SECTION 2.05 Valid and Binding Obligation. This Third Supplemental Indenture, upon
execution and delivery by the parties hereto, constitutes a valid and binding obligation of the Company or the Trustee, as applicable, enforceable against the Company or the Trustee, as applicable, in accordance with its terms, except to the extent
the enforcement thereof may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws affecting enforcement of creditors’ rights generally and except as enforcement thereof is subject to general principles of equity
and except as rights to indemnification may be limited by applicable law. 
 [Signature page immediately follows] 

  
 13 

 IN WITNESS WHEREOF, each party hereto has caused this instrument to be signed in its name and
behalf by its duly authorized officers, all as of the day and year first above written. 
  

			
	 CLECO CORPORATE HOLDINGS LLC,

	 as Issuer

		
	 By:
	 	 /s/ Terry L. Taylor

		 	Name: Terry L. Taylor
		 	Title: Chief Financial Officer
	
	 WELLS FARGO BANK, N.A.,

	 as Trustee

		
	 By:
	 	 /s/ Patrick Giordano

		 	Name: Patrick Giordano
		 	Title: Vice President

 [Signature Page to Third Supplemental Indenture] 

 Table of Contents 

Page 
 ARTICLE I 

3.25% SENIOR NOTES DUE 2023 
  

									
	 SECTION 1.01
	 		 	 Establishment
	  	 	2	  
	 SECTION 1.02
	 		 	 Definitions
	  	 	3	  
	 SECTION 1.03
	 		 	 Payment of Principal and Interest
	  	 	4	  
	 SECTION 1.04
	 		 	 Denominations
	  	 	5	  
	 SECTION 1.05
	 		 	 Form of Notes
	  	 	5	  
	 SECTION 1.06
	 		 	 Transfer and Exchange
	  	 	5	  
	 SECTION 1.07
	 		 	 Legends
	  	 	5	  
	 SECTION 1.08
	 		 	 Defeasance
	  	 	6	  
	 SECTION 1.09
	 		 	 Redemption at the Option of the Company
	  	 	6	  
	 SECTION 1.10
	 		 	 Change of Control
	  	 	7	  
	 SECTION 1.11
	 		 	 Rule 144A Reporting Requirement
	  	 	12	  

 ARTICLE II 

MISCELLANEOUS PROVISIONS 
  

									
	 SECTION 2.01
	 		 	 Recitals by the Company
	  	 	12	  
	 SECTION 2.02
	 		 	 Ratification and Incorporation of Original Indenture
	  	 	12	  
	 SECTION 2.03
	 		 	 Executed in Counterparts
	  	 	12	  
	 SECTION 2.04
	 		 	 New York Law to Govern
	  	 	12	  
	 SECTION 2.05
	 		 	 Valid and Binding Obligation
	  	 	13	  
		
	EXHIBIT A Form of Note	  	 	A-1	  
	EXHIBIT B Form of Certificate of Authentication	  	 	B-1	  

 EXHIBIT A 

FORM OF NOTE 
 THE NOTE (OR ITS
PREDECESSOR) EVIDENCED HEREBY WAS ORIGINALLY ISSUED IN A TRANSACTION EXEMPT FROM REGISTRATION UNDER SECTION 5 OF THE UNITED STATES SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND THE NOTE EVIDENCED HEREBY MAY NOT BE
OFFERED, SOLD OR OTHERWISE TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION THEREFROM. THE HOLDER OF THE NOTE EVIDENCED HEREBY AGREES FOR THE BENEFIT OF CLECO CORPORATE HOLDINGS LLC (THE “COMPANY”) THAT (A) SUCH
NOTE MAY BE RESOLD, PLEDGED OR OTHERWISE TRANSFERRED, ONLY (1)(a) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT PROVIDED BY RULE 144 THEREUNDER (IF APPLICABLE) OR (b) IN ACCORDANCE WITH ANOTHER EXEMPTION FROM THE REGISTRATION
REQUIREMENTS OF THE SECURITIES ACT (AND BASED UPON AN OPINION OF COUNSEL ACCEPTABLE TO THE TRUSTEE IF THE TRUSTEE SO REQUESTS), (2) TO THE COMPANY OR (3) PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT AND, IN EACH CASE, IN ACCORDANCE WITH ANY
APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES OR ANY OTHER APPLICABLE JURISDICTION AND (B) THE HOLDER WILL, AND EACH SUBSEQUENT HOLDER IS REQUIRED TO, NOTIFY ANY PURCHASER OF THE NOTE EVIDENCED HEREBY OF THE RESALE RESTRICTIONS SET
FORTH IN CLAUSE (A) ABOVE. NO REPRESENTATION CAN BE MADE AS TO THE AVAILABILITY OF THE EXEMPTION PROVIDED BY RULE 144 FOR RESALE OF THE NOTE EVIDENCED HEREBY. 

BECAUSE OF THE FOREGOING RESTRICTIONS, PURCHASERS ARE ADVISED TO CONSULT LEGAL COUNSEL PRIOR TO MAKING ANY RESALE, PLEDGE OR TRANSFER THE NOTE EVIDENCED
HEREBY. INVESTORS SHOULD BE AWARE THAT THEY MAY BE REQUIRED TO BEAR THE FINANCIAL RISKS OF THIS INVESTMENT FOR AN INDEFINITE PERIOD OF TIME. 
 BY ITS
ACQUISITION OF THIS NOTE, THE HOLDER THEREOF WILL BE DEEMED TO HAVE REPRESENTED AND WARRANTED THAT EITHER (1) IT IS NOT USING ASSETS OF (I) AN EMPLOYEE BENEFIT PLAN, AS DEFINED IN SECTION 3(3) OF THE U.S. EMPLOYEE RETIREMENT INCOME SECURITY ACT OF
1974, AS AMENDED (“ERISA”), THAT IS SUBJECT TO TITLE I OF ERISA, (II) A PLAN AS DEFINED IN SECTION 4975(e)(1) OF THE U.S. INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE “CODE”), (III) ANY ENTITY DEEMED TO HOLD “PLAN
ASSETS” OF ANY SUCH EMPLOYEE BENEFIT PLAN OR EMPLOYEE BENEFIT PLANS PURSUANT TO SECTION 3(42) OF ERISA BY REASON OF AN EMPLOYEE BENEFIT PLAN’S OR EMPLOYEE BENEFIT PLANS’ INVESTMENT IN SUCH ENTITY OR (IV) A GOVERNMENTAL, CHURCH OR
NON-U.S. PLAN SUBJECT TO FEDERAL, STATE, LOCAL OR NON-U.S. LAWS OR REGULATIONS THAT ARE SUBSTANTIALLY SIMILAR TO THE FIDUCIARY RESPONSIBILITY OR PROHIBITED TRANSACTION PROVISIONS OF SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE (“SIMILAR

  
 A-1 

 
LAW”) OR (2) THE PURCHASE AND HOLDING OF A NOTE THROUGHOUT THE PERIOD THAT IT HOLDS SUCH NOTE IS EXEMPT FROM THE PROHIBITED TRANSACTION PROVISIONS UNDER SECTION 406 OF ERISA AND SECTION 4975
OF THE CODE OR ANY PROVISIONS OF SIMILAR LAW, PURSUANT TO ONE OR MORE EXEMPTIONS.” 

  
 A-2 

 CLECO CORPORATE HOLDINGS LLC 

3.25% Senior Secured Note due 2023 
  

			
	Principal Amount:	  	$165,000,000
		
	Regular Record Date:	  	April 15 or October 15 immediately preceding the Interest Payment Date
		
	Original Issue Date:	  	May 24, 2016
		
	Stated Maturity:	  	May 1, 2023
		
	Interest Payment Dates:	  	May 1 and November 1, beginning on November 1, 2016
		
	Interest Rate:	  	3.25% per annum
		
	Authorized Denominations:	  	$2,000 or any integral multiple of $1,000 in excess thereof

  

			
	No. 1	 	$165,000,000

 Cleco Corporate Holdings LLC, a Louisiana limited liability company (the “Company,” which term
includes any successor corporation under the Indenture referred to on the reverse hereof), for value received, hereby promises to pay to CoBank, ACB, or registered assigns, the principal sum of ONE HUNDRED SIXTY-FIVE MILLION DOLLARS
($165,000,000) on the Stated Maturity shown above (or upon earlier redemption), and to pay interest thereon from the Original Issue Date shown above, or from the most recent Interest Payment Date to which interest has been paid or duly
provided for, semi-annually in arrears on each Interest Payment Date as specified above, commencing on the Interest Payment Date next succeeding the Original Issue Date shown above and on the Stated Maturity (or upon earlier redemption) at the rate
per annum shown above until the principal hereof is paid or made available for payment and on any overdue principal and on any overdue installment of interest. The interest so payable, and punctually paid or duly provided for, on any Interest
Payment Date (other than an Interest Payment Date that is the Stated Maturity or on a Redemption Date) will, as provided in such Indenture, be paid to the Person in whose name this Note (this “Note”) is registered at the close of
business on the Regular Record Date as specified above next preceding such Interest Payment Date; provided that any interest payable at Stated Maturity or on any Redemption Date will be paid to the Person to whom principal is
payable. Except as otherwise provided in the Indenture, any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose
name this Note is registered at the close of business on a Special Record Date for the payment of such defaulted interest to be fixed by the Company, notice whereof shall be given to Holders of Notes of this series not less than 15 days prior to
such Special Record Date, or be paid at any time in any other lawful manner not inconsistent with the requirements of any securities exchange, if any, on which the Notes of this series shall be listed, and upon such notice as may be required by any
such exchange, all as more fully provided in the Indenture. 

  
 A-3 

 Payments of interest on this Note will include interest accrued to but excluding the respective
Interest Payment Dates. Interest payments for this Note shall be computed and paid on the basis of a 360-day year of twelve 30-day months. In the event that any date on which interest is payable on this Note is not a Business Day, then payment of
the interest payable on such date will be made on the next succeeding day that is a Business Day (and without any interest or other payment in respect of any such delay), except that, if such Business Day is in the next succeeding calendar year,
payment shall be made on the immediately preceding Business Day, in each case with the same force and effect as if made on the date the payment was originally payable. A “Business Day” shall mean any day other than a Saturday or a
Sunday or a day on which banks in New York, New York are authorized or obligated by law or executive order to remain closed or a day on which the Trustee’s Corporate Trust Office is closed for business. 

Payment of the principal, premium, if any, and interest due at the Stated Maturity or earlier redemption of this Note shall be made upon
surrender of this Note at the Corporate Trust Office of the Trustee, in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts. Payments of interest (including
interest on any Interest Payment Date) will be made, subject to such surrender where applicable, at the option of the Company, (i) by check mailed to the address of the Person entitled thereto as such address shall appear in the Security Register or
(ii) by wire transfer at such place and to such account at a banking institution in the United States as may be designated in writing to the Trustee at least 15 days prior to the date for payment by the Person entitled thereto; provided that any
payments of interest to CoBank, ACB will be made by wire transfer in accordance with the procedures set forth in this paragraph. 
 The
unpaid principal amount of this Note shall bear interest at the rate per annum set forth above. 
 REFERENCE IS HEREBY MADE TO THE FURTHER
PROVISIONS OF THIS NOTE SET FORTH ON THE REVERSE HEREOF, WHICH FURTHER PROVISIONS SHALL FOR ALL PURPOSES HAVE THE SAME EFFECT AS IF SET FORTH AT THIS PLACE. 

Unless the certificate of authentication hereon has been executed by the Trustee by manual signature, this Note shall not be entitled to any
benefit under the Indenture or be valid or obligatory for any purpose. 

  
 A-4 

 IN WITNESS HEREOF, the Company has caused this instrument to be duly executed. 

 

			
	 CLECO CORPORATE HOLDINGS LLC

		
	 By:
	 	  

		 	 Name:

		 	 Title:

	
	 ATTEST:

		
	 By:
	 	  

		 	 Name:

		 	 Title:

  
 A-5 

 CERTIFICATE OF AUTHENTICATION 

This is one of the Notes referred to in the within-mentioned Indenture: 

 

			
	WELLS FARGO BANK, N.A.,
	as Trustee
		
	By:	 	  

		 	Authorized Signatory
	
	Dated:

  
 A-6 

 (Reverse Side of Note) 

This Note is one of a duly authorized issue of Senior Secured Notes of the Company, issued and issuable in one or more series under an
Indenture, dated as of May 17, 2016, as supplemented, including by the First Supplemental Indenture dated as of May 17, 2016, the Second Supplemental Indenture dated as of May 17, 2016 and the Third Supplemental Indenture dated as of May 24, 2016
(collectively, the “Indenture”), between the Company and Wells Fargo Bank, N.A., to which the Indenture reference is hereby made for a statement of the respective rights, limitation of rights, duties and immunities thereunder of the
Company, the Trustee and the Holders of the Senior Secured Notes issued thereunder and of the terms upon which said Senior Secured Notes are, and are to be, authenticated and delivered. This Note is one of the series designated on the face hereof as
3.25% Senior Secured Notes due 2023 (the “Senior Secured Notes”) in aggregate principal amount of up to $165,000,000. Capitalized terms used herein for which no definition is provided herein shall have the meanings set forth in the
Indenture. 
 The Notes are secured obligations of the Company. The Notes are secured by a pledge of Collateral pursuant to the
Security Documents referred to in the Indenture. 
 The Notes are subject to optional redemption, and may be the subject of a Change of
Control Offer, as further described in the Indenture. 
 If an Event of Default with respect to the Notes of this series shall occur and be
continuing, the principal of the Notes of this series may be declared due and payable in the manner, with the effect and subject to the conditions provided in the Indenture. 

The Indenture permits, with certain exceptions as therein provided, the amendment thereof and the modification of the rights and obligations
of the Company and the rights of the Holders of the Senior Secured Notes of each series to be affected under the Indenture at any time by the Company and the Trustee with the consent of the Holders of not less than a majority in principal amount of
the Outstanding Senior Secured Notes of each series to be affected. The Indenture also contains provisions permitting the Holders of specified percentages in principal amount of the Outstanding Senior Secured Notes of each series, on behalf of
the Holders of all Senior Secured Notes of such series, to waive compliance by the Company with certain provisions of the Indenture and certain past defaults under the Indenture and their consequences. Any such consent or waiver by the Holder
of this Note shall be conclusive and binding upon such Holder and upon all future Holders of this Note and of any Note issued upon the registration of transfer hereof or in exchange hereof or in lieu hereof, whether or not notation of such consent
or waiver is made upon this Note. Without the consent of any Holder, the Company and the Trustee may amend the Indenture or the Notes for the purpose of curing any ambiguity or mistake, or of curing, correcting or supplementing any defective
provision thereof or hereof, or that is not inconsistent with the Indenture and the Notes and will not adversely affect the interests of any Holder in any material respect. 

The Indenture contains certain covenants, including without limitation, covenants with respect to liens and mergers, consolidations and
certain transfers of assets. The Company 

  
 A-7 

 
must furnish to the Trustee annual statements as to the Company’s compliance with such limitations in accordance with the terms of the Indenture. 

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 of and interest on this Note at the times, place and rate, and in the coin or currency, herein prescribed. 

As provided in the Indenture and subject to certain limitations therein set forth, the transfer of this Note is registrable in the Security
Register, upon surrender of this Note for registration of transfer at the office or agency of the Company for such purpose, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Company and the Security
Registrar and duly executed by, the Holder hereof or his attorney duly authorized in writing, and thereupon one or more new Notes of this series, of authorized denominations and of like tenor and for the same aggregate principal amount, will be
issued to the designated transferee or transferees. No service charge shall be made for any such registration of transfer or exchange, but the Company or the Trustee may require payment of a sum sufficient to cover any tax or other governmental
charge payable in connection therewith. 
 Prior to due presentment of this Note for registration of transfer, the Company, the Trustee and
any agent of the Company or the Trustee may treat the Person in whose name this Note is registered as the owner hereof for all purposes, whether or not this Note be overdue, and neither the Company, the Trustee nor any such agent shall be affected
by notice to the contrary. 
 The Senior Secured Notes are issuable only in registered form without coupons in minimum denominations of
$2,000 and integral multiples of $1,000 in excess thereof. As provided in the Indenture and subject to certain limitations therein set forth, Senior Secured Notes are exchangeable for a like aggregate principal amount of Notes of this series of
a different authorized denomination, as requested by the Holder surrendering the same upon surrender of the Senior Secured Note or Notes to be exchanged at the office or agency of the Company. 

This Note shall be governed by, and construed in accordance with, the laws of the State of New York. 

The Trustee will furnish to any Holder upon written request and without charge a copy of the Indenture. Requests may be made to Wells
Fargo Bank, N.A., Attention: Corporate Municipal & Escrow Services. 

  
 A-8 

 EXHIBIT B 

CERTIFICATE OF AUTHENTICATION 

This is one of the Notes referred to in the within-mentioned Indenture: 

 

			
	 WELLS FARGO BANK, N.A.,

	 as Trustee

		
	 By:
	 	  

		 	 Authorized Signatory

	
	 Dated:

 ASSIGNMENT FORM 

To assign this Note, fill in the form below: 

(I) or (we) assign and transfer this Note to:
                                         
                                         
                                  

                        
                                         
               (Insert assignee’ legal name) 
  

 
 (Insert assignee’s Social Security
no. or tax I.D. no.) 
  
  

 
  
  

 
  

 
 (Print or type assignee’s name,
address and zip code) 
 and irrevocably appoint
                                         
                                         
                                         
                          to transfer this Note on the books of the Company. The agent may substitute another to act
for him. 
 Date:
                                         
   
 Your Signature:
                                        
                                         
                   
 (Sign exactly as your
name
appears                                        
    
 on the face of this
Note)                                        
                      
 Signature Guarantee*:
                                         
                   
  

 

	*	Participant in a recognized Signature Guarantee Medallion Program (or other signature guarantor acceptable to the Trustee).EX-4.2

 Exhibit 4.2 
  

 
  

ALLEGHENY TECHNOLOGIES INCORPORATED 

and 
 THE BANK OF NEW YORK MELLON,

 as Trustee 
 FIFTH
SUPPLEMENTAL INDENTURE 
 Dated as of May 24, 2016 

TO THE INDENTURE 
 Dated as of
June 1, 2009 
 Relating to 

$287,500,000 principal amount of 

4.75% Convertible Senior Notes due 2022 
  

 
  

 Table of Contents 

 

							
	 	 	 	  	Page	 
	 ARTICLE I
	 	Definitions	  	 	2	  
			
	 SECTION 1.01.
	 	Capitalized Terms	  	 	2	  
	 SECTION 1.02.
	 	References	  	 	2	  
	 SECTION 1.03.
	 	Definitions	  	 	2	  
			
	 ARTICLE II
	 	General Terms and Conditions of the Notes	  	 	7	  
			
	 SECTION 2.01.
	 	Designation and Principal Amount	  	 	7	  
	 SECTION 2.02.
	 	Maturity	  	 	7	  
	 SECTION 2.03.
	 	No Optional Redemption	  	 	7	  
	 SECTION 2.04.
	 	No Sinking Fund	  	 	8	  
	 SECTION 2.05.
	 	No Defeasance and Covenant Defeasance	  	 	8	  
	 SECTION 2.06.
	 	Limited Satisfaction and Discharge	  	 	8	  
	 SECTION 2.07.
	 	Form and Payment	  	 	8	  
	 SECTION 2.08.
	 	Interest	  	 	8	  
			
	 ARTICLE III
	 	[reserved]	  	 	9	  
			
	 ARTICLE IV
	 	Purchase of Notes at the Option of Holders upon a Fundamental Change	  	 	9	  
			
	 SECTION 4.01.
	 	Purchase of Notes at the Option of Holders upon a Fundamental Change	  	 	9	  
	 SECTION 4.02.
	 	Further Conditions and Procedures for Purchase at the Option of the Holder upon a Fundamental Change	  	 	11	  
			
	 ARTICLE V
	 	Conversion	  	 	13	  
			
	 SECTION 5.01.
	 	Conversion of Notes	  	 	13	  
	 SECTION 5.02.
	 	Adjustments to Conversion Rate	  	 	15	  
	 SECTION 5.03.
	 	Effect of Reclassification, Consolidation, Merger or Sale	  	 	24	  
	 SECTION 5.04.
	 	Adjustment upon Certain Fundamental Changes	  	 	25	  
	 SECTION 5.05.
	 	Stockholder Rights Plan	  	 	26	  
	 SECTION 5.06.
	 	Trustee Adjustment Disclaimer	  	 	27	  
			
	 ARTICLE VI
	 	Events of Default and Remedies	  	 	27	  
			
	 SECTION 6.01.
	 	Additional Events of Default	  	 	27	  
	 SECTION 6.02.
	 	Exception to Remedies	  	 	28	  
	 SECTION 6.03.
	 	Amendment to the Base Indenture	  	 	28	  

  
 i 

							
	 	 	 	  	Page	 
	 ARTICLE VII
	 	Modification and Amendment	  	 	29	  
			
	 SECTION 7.01.
	 	Modification and Amendment	  	 	29	  
			
	 ARTICLE VIII
	 	Miscellaneous	  	 	29	  
			
	 SECTION 8.01.
	 	Ratification of Base Indenture	  	 	29	  
	 SECTION 8.02.
	 	Application of Supplemental Indenture	  	 	29	  
	 SECTION 8.03.
	 	Trust Indenture Act Controls	  	 	30	  
	 SECTION 8.04.
	 	Conflict with Base Indenture	  	 	30	  
	 SECTION 8.05.
	 	Withholding Offset	  	 	30	  
	 SECTION 8.06.
	 	Calculations in Respect of Notes	  	 	30	  
	 SECTION 8.07.
	 	Governing Law	  	 	30	  
	 SECTION 8.08.
	 	Successors	  	 	31	  
	 SECTION 8.09.
	 	Counterparts	  	 	31	  
	 SECTION 8.10.
	 	Appointment of Conversion Agent	  	 	31	  
	 SECTION 8.11.
	 	Trustee Disclaimer	  	 	31	  

  
 ii 

 FIFTH SUPPLEMENTAL INDENTURE 

FIFTH SUPPLEMENTAL INDENTURE, dated as of May 24, 2016 (this “Supplemental Indenture”), to the Indenture (defined below)
between ALLEGHENY TECHNOLOGIES INCORPORATED, a Delaware corporation (the “Company”), and THE BANK OF NEW YORK MELLON, a New York banking corporation, as Trustee under the Indenture (the “Trustee”). 

RECITALS 
 WHEREAS, the Company
has heretofore executed and delivered to the Trustee an Indenture, dated as of June 1, 2009 (the “Base Indenture”), providing for the issuance from time to time of its Securities (as defined in the Base Indenture), to be issued
in one or more series as therein provided; 
 WHEREAS, Sections 2.01, 3.01 and 9.01 of the Base Indenture provide that the Company, when
authorized by an Establishment Action (as defined in the Base Indenture), and the Trustee may, without the consent of the Holders (as defined in the Base Indenture) of Securities, enter into one or more supplemental indentures, in form satisfactory
to the Trustee, to establish the form or terms of Securities of any series permitted by the Base Indenture; 
 WHEREAS, pursuant to the
terms of the Base Indenture, the Company desires to provide for the establishment of a new series of its Securities to be known as its 4.75% Convertible Senior Notes due 2022 (the “Notes”), the form and substance of such Notes and
the terms, provisions and conditions thereof to be set forth as provided in the Base Indenture, as heretofore supplemented, and this Supplemental Indenture (together, the “Indenture”); 

WHEREAS, the Company has duly authorized the creation and issuance of such Notes under the Base Indenture, and has duly authorized the
execution and delivery of this Supplemental Indenture to supplement the Base Indenture and to provide certain additional provisions as hereinafter described; and 

WHEREAS, the Company has requested that the Trustee execute and deliver this Supplemental Indenture, and all requirements necessary to make
this Supplemental Indenture a valid instrument in accordance with its terms, and to make the Notes, when executed by the Company and authenticated and delivered by the Trustee, the valid and legally binding obligations of the Company, and all acts
and things necessary have been done and performed to make this Supplemental Indenture enforceable in accordance with its terms, and the execution and delivery of this Supplemental Indenture has been duly authorized in all respects. 

 W I T N E S S E T H: 

NOW, THEREFORE, for and in consideration of the premises contained herein, each party agrees for the benefit of each other party and for the
equal and ratable benefit of the Holders of the Notes, as follows: 
 ARTICLE I 

Definitions 
 SECTION
1.01. Capitalized Terms. Capitalized terms used but not defined in this Supplemental Indenture shall have the meanings ascribed to them in the Base Indenture. 

SECTION 1.02. References. References in this Supplemental Indenture to article and section numbers shall be deemed to be references to
article and section numbers of this Supplemental Indenture unless otherwise specified. 
 SECTION 1.03. Definitions. For purposes of
this Supplemental Indenture, the following terms have the meanings ascribed to them as follows: 
 “Additional Interest”
means all amounts, if any, payable pursuant to Section 6.02. 
 “Additional Shares” has the meaning provided in
Section 5.04(a). 
 “Adjustment Event” has the meaning provided in Section 5.02(j). 

“Base Indenture” has the meaning provided in the recitals. 

“Beneficial Owner” means any person who is considered a beneficial owner of a security in accordance with Rule 13d-3
promulgated by the SEC under the Exchange Act. 
 “Clearstream” means Clearstream Banking S.A. 

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

“Common Stock” means the Common Stock, par value $0.10 per share, of the Company existing on the Issue Date or any other
shares of capital stock into which such Common Stock shall be reclassified or changed. 
 “Company” has the meaning
provided in the recitals. 
 “Company Notice” has the meaning provided in Section 4.01(b). 

“Company Notice Date” has the meaning provided in Section 4.01(b). 

“Conversion Agent” means the office or agency appointed by the Company where Notes may be presented for conversion. The
Conversion Agent shall initially be the Trustee. 

  
 2 

 “Conversion Date” has the meaning provided in Section 5.01(a). 

“Conversion Price” means, in respect of each $1,000 principal amount of Notes, $1,000 divided by the Conversion Rate, as may
be adjusted from time to time as set forth herein. 
 “Conversion Rate” means, in respect of each $1,000 principal amount of
Notes, initially 69.2042 shares of Common Stock, subject to adjustment as set forth herein. 
 “Depositary” has the meaning
provided in Section 2.07. 
 “Determination Date” has the meaning provided in Section 5.02(j). 

“DTC” has the meaning provided in Section 2.07. 

“Effective Date” has the meaning provided in Section 5.04(c). 

“Euroclear” means Euroclear Bank S.A./N.V., as operator of the Euroclear System. 

“Exchange Act” means the Securities Exchange Act of 1934, as amended from time to time, and any statute successor thereto.

 “Ex-Dividend Date” means the first date on which the 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, the seller of the Common Stock on such exchange or market (in the form of due bills or otherwise)
as determined by such exchange or market. 
 “Fair Market Value” means the amount that a willing buyer would pay a willing
seller in an arm’s length transaction. 
 A “Fundamental Change” shall be deemed to have occurred at the time after
the Notes are originally issued that any of the following occurs: 
 (1) a “person” or
“group” within the meaning of Section 13(d) of the Exchange Act other than the Company, a Subsidiary of the Company or any employee benefit plans of the Company or a Subsidiary of the Company files a Schedule 13D or Schedule TO
(or any successor schedule, form or report) pursuant to the Exchange Act disclosing that such person has become the direct or indirect “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 all shares of the Company’s common equity entitled to vote generally in the election of directors, unless such Beneficial Ownership arises as a result of a revocable proxy delivered in response
to a public proxy or consent solicitation made pursuant to the applicable rules and regulations under the Exchange Act; provided that no person or group shall be deemed to be the Beneficial Owner of any securities tendered pursuant to a
tender or exchange offer made by or on behalf of such person or group until such tendered securities are accepted for purchase or exchange under such offer; 

  
 3 

 (2) 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, other property or assets, (B) any statutory share
exchange, consolidation or merger involving the Company pursuant to which the Common Stock shall be converted into cash, securities or other property 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 the Company’s Subsidiaries, taken as a whole, to any Person other than one or more of the Company’s Subsidiaries, other than any transaction: 

(a) involving a consolidation or merger that does not result in a reclassification, conversion, exchange or cancellation of the
outstanding Common Stock; 
 (b) where the Holders of more than 50% of all classes of the Company’s common equity
immediately prior to such transaction that is a statutory share exchange, consolidation or merger own, directly or indirectly, more than 50% of all classes of common equity of the continuing or surviving entity or transferee or the parent entity
thereof immediately after such transaction and the proportion of the respective ownership of each pre-transaction holder remains substantially the same relative to all other pre-transaction holders; or 

(c) that is effected solely to change the Company’s jurisdiction of incorporation and results in a reclassification,
conversion or exchange of outstanding shares of Common Stock solely into shares of common stock of the surviving entity; 

(3) the Company’s stockholders approve any plan or proposal for the Company’s liquidation or dissolution; or 

(4) the Common Stock (or other capital stock or American Depositary Receipts underlying the Notes pursuant to the terms of the
Indenture) ceases to be listed on the New York Stock Exchange, the Nasdaq Global Select Market or the Nasdaq Global Market (or their respective successors); 

provided, however, that a Fundamental Change as a result of clause (2) above shall not be deemed to have occurred if 90% or more of the
consideration received or to be received by the holders of Common Stock (excluding cash payments for fractional shares and cash payments made pursuant to dissenters’ appraisal rights) in connection with the transaction or transactions
constituting the Fundamental Change consists of shares of common stock or American Depositary Receipts traded on the New York Stock Exchange, the Nasdaq Global Select Market or the Nasdaq Global Market (or their respective successors) or which shall
be so traded when issued or exchanged in connection with such transaction or transactions that would otherwise be a Fundamental Change (these securities being referred to as “Publicly Traded Securities”) and as a result of this
transaction or transactions the Notes become convertible into such consideration, excluding cash payments for fractional shares. 

  
 4 

 “Fundamental Change Purchase Date” has the meaning provided in
Section 4.01(a). 
 “Fundamental Change Purchase Notice” has the meaning provided in Section 4.01(c). 

“Fundamental Change Purchase Price” has the meaning provided in Section 4.01(a). 

“Indenture” has the meaning provided in the recitals. 

“Initial Dividend Threshold” has the meaning provided in Section 5.02(d). 

“Interest Payment Date” has the meaning provided in Section 2.08(a). 

“Issue Date” means May 24, 2016. 

“Last Reported Sale Price” of the Common Stock on any Trading Day means (i) the closing sale price per share (or if no
closing sale price is reported, the average of the bid and ask prices or, if more than one in either case, the average of the average bid and average ask prices) of the Common Stock on that Trading Day as reported in composite transactions for the
principal United States national or regional securities exchange on which the Common Stock is traded, or (ii) if the Common Stock is not listed for trading on a United States national or regional securities exchange on the relevant Trading Day,
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 Trading Day as reported by the OTC Markets Group Inc. or similar organization selected by the Company. If the Common
Stock is not so listed or 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. 
 “Make-Whole Fundamental Change” means any Fundamental Change
(determined after giving effect to any exceptions or exclusions from the definition of “Fundamental Change” but without regard to the exceptions in clause (2) of the definition thereof). 

“Notes” has the meaning provided in the recitals. 

“Officer” means the Chairman of the Board, the Chief Executive Officer, the President, the Chief Financial Officer, any Vice
President, the Treasurer or the Secretary of the Company. 
 “open of business” means 9:00 a.m., New York City time. 

“parent” has the meaning provided in the definition of Subsidiary in this Section 1.03. 

“Paying Agent” has the meaning provided in Section 2.07. 

  
 5 

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

“Publicly Traded Securities” has the meaning provided in the definition of Fundamental Change in this Section 1.03. 

“Record Date” means, with respect to any dividend, distribution or other transaction or event in which the holders of the
Common Stock (or other 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 securityholders 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” has the meaning provided in Section 5.03(a). 

“Regular Record Date” for the payment of interest on the Notes (including Additional Interest, if any), means the
December 15 (whether or not a Business Day) immediately preceding the Interest Payment Date on January 1 and the June 15 (whether or not a Business Day) immediately preceding the Interest Payment Date on July 1. 

“Reorganization Event” has the meaning provided in Section 5.03(a). 

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

“Securities” has the meaning provided in the recitals. 

“Settlement Date” has the meaning provided in Section 5.01(a). 

“Spin-Off” has the meaning provided in Section 5.02(c). 

“Stated Maturity Date” means July 1, 2022. 

“Stock Price” means, with respect to a Fundamental Change, (i) if such Fundamental Change is a transaction described in
clause (2) of the definition thereof and holders of Common Stock receive only cash as a result of such Make-Whole Fundamental Change, the cash amount paid per share of the Common Stock and (ii) in all other cases, 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 Effective Date. 

“Subsidiary” means, with respect to any Person (the “parent”) at any date, any corporation, limited
liability company, partnership, association or other entity owning a majority of the shares of securities or other interests having ordinary voting power for the election of directors or another governing body (other than securities or interests
having such power only by 

  
 6 

 
reason of the happening of a contingency) are at the time beneficially owned directly or indirectly through one or more intermediaries, or both by the parent. 

“Supplemental Indenture” has the meaning provided in the preamble. 

“Trading Day” means a day during which (i) trading in the Common Stock generally occurs on the New York Stock Exchange
or, if the Common Stock is not then listed or admitted to trading on the New York Stock Exchange, on the principal other United States national or regional securities exchange or market on which the Common Stock is then traded, and (ii) a last
reported sale price for the Common Stock is available on such securities exchange or market; provided, however, that if the Common Stock is not so listed or traded, “Trading Day” means a Business Day. 

“Trustee” has the meaning provided in the recitals. 

“Withholding Agent” means the office or agency appointed by the Company to withhold the appropriate amount from any payment,
to which withholding applies, made by the Company to a Holder in respect of the Notes. The Withholding Agent appointed by the Company shall initially be the Trustee. 

“$” means United States dollars. 

ARTICLE II 
 General Terms and
Conditions of the Notes 
 SECTION 2.01. Designation and Principal Amount. The Notes are hereby authorized and are designated
the 4.75% Convertible Senior Notes due 2022, initially limited in aggregate principal amount to $287,500,000. The Notes issued on the date hereof pursuant to the terms of the Indenture shall be in an aggregate principal amount of $250,000,000, which
amount shall be set forth in the Company Order for the authentication and delivery of the Notes pursuant to Section 3.03 of the Base Indenture. In addition, the Company may issue, from time to time in accordance with the provisions of the
Indenture, additional Notes having the same terms and conditions as the Notes issued on the date hereof in all respects (except for the payment of interest accruing prior to the issue date of such additional Notes), so that such additional Notes
shall be consolidated and form a single series with the Notes issued on the date hereof and shall be governed by the terms of the Indenture; provided, however, that any such additional Notes must be part of the same issue as the
previously issued Notes for U.S. Federal income tax purposes. 
 SECTION 2.02. Maturity. The principal amount of the Notes shall be
payable on July 1, 2022. 
 SECTION 2.03. No Optional Redemption. The Notes issued under this Supplemental Indenture shall not
be redeemable at the election of the Company prior to the Stated Maturity Date. 

  
 7 

 SECTION 2.04. No Sinking Fund. No sinking fund will be provided with respect to the
Notes. 
 SECTION 2.05. No Defeasance and Covenant Defeasance. The Notes shall not be subject to Article XIII of the Base Indenture.

 SECTION 2.06. Limited Satisfaction and Discharge. The Notes shall not be subject to Section 4.01(1)(B)of the Base Indenture.

 SECTION 2.07. Form and Payment. The Notes shall be issued in substantially the form set forth on Exhibit A hereto and shall have
the terms set forth in such form and shall initially be Global Securities for purposes of the Base Indenture. The Notes shall be issued in fully registered book-entry form without coupons in denominations of $1,000 and integral multiples of $1,000
in excess thereof. 
 The Depositary in respect of the Notes represented by Global Securities shall be The Depository Trust Company
(“DTC”). The Global Securities representing the Notes shall be deposited with, or on behalf of, the Depositary and shall be registered in the name of its nominee, Cede & Co. Except as otherwise set forth in
Section 3.05 of the Base Indenture, the Global Securities may be transferred, in whole and not in part, only to another nominee of the Depositary or to a successor of the Depositary or its nominee. 

The Trustee shall act as Paying Agent for the Notes. The Company may choose to pay interest by mailing checks or making wire transfers. All
money paid by the Company to any Paying Agent that remains unclaimed at the end of two years after the amount is due to Holders shall be repaid to the Company, subject to any applicable abandoned property laws. After such two-year period, Holders
may look only to the Company for payment and not to the Trustee, any other Paying Agent or anyone else. The Company may also arrange for additional payment offices, and may cancel or change these offices, including any use of the Trustee’s
Corporate Trust Office. The Company may appoint and change the Paying Agent without prior notice to the Holders. 
 SECTION 2.08.
Interest. (a) Interest on the Notes shall accrue at the rate of 4.75% per annum from and including the date specified on the face of such Notes until the principal thereof is paid, deemed paid, or made available for payment. Interest on
the Notes shall be payable semiannually in arrears on January 1 and July 1 (each such date, an “Interest Payment Date”), commencing on January 1, 2017. Interest on the Notes shall be computed on the basis of a 360-day
year comprised of twelve 30-day months. If any Interest Payment Date (other than an Interest Payment Date coinciding with the Stated Maturity Date or earlier required repurchase date upon a Fundamental Change) of a Note falls on a day that is not a
Business Day, such Interest Payment Date shall be postponed to the next succeeding Business Day and no interest (or Additional Interest) on such payment shall accrue for the period from the Interest Payment Date to the next succeeding Business Day.
If the Stated Maturity Date falls on a day that is not a Business Day, any required payments of interest and principal shall be made on the next succeeding Business Day and no interest (or Additional Interest) on such payment shall accrue for the
period from and after the Stated Maturity Date to such next succeeding Business Day. If a Fundamental Change Purchase Date falls on a day that is not a Business Day, the 

  
 8 

 
Company shall purchase the Notes on the next succeeding Business Day and no interest (or Additional Interest) on such Notes shall accrue for the period from and after the earlier Fundamental
Change Purchase Date to such next succeeding Business Day. 
 (b) Holders of Notes at the close of business on a Regular Record Date shall
receive payment of interest (including any Additional Interest) payable on the corresponding Interest Payment Date notwithstanding the conversion of such Notes at any time after the close of business on such Regular Record Date. Notes surrendered
for conversion during the period from the close of business on any Regular Record Date to the open of business on the corresponding Interest Payment Date must be accompanied by funds equal to the amount of interest (including any Additional
Interest) that the Holder is to receive on the Notes so converted on such Interest Payment Date; provided, however, that no such payment need be made (i) for conversions following the Regular Record Date immediately preceding the
Stated Maturity Date; (ii) if the Company has specified a Fundamental Change Purchase Date that is after a Regular Record Date and on or prior to the corresponding Interest Payment Date; or (iii) to the extent of any overdue interest
(including any overdue Additional Interest), if any overdue interest (including any overdue Additional Interest) exists at the time of conversion with respect to such Note. The Company’s delivery to the Holder of the full number of shares of
Common Stock, together with any cash payment for any fractional shares, into which a Note is convertible, shall be deemed to satisfy in full the Company’s obligation to pay (i) the principal amount of the Note and (ii) accrued and
unpaid interest and Additional Interest, if any, to, but not including, the Conversion Date. 
 For the avoidance of doubt, each Holder of
Notes at the close of business on the Regular Record Date immediately preceding the Stated Maturity Date will receive the full payment of Interest (including any Additional Interest) on the Stated Maturity Date regardless of whether all or any of
the Holder’s Notes have been converted following such Regular Record Date. 
 ARTICLE III 

[reserved] 
 ARTICLE IV 

Purchase of Notes at the Option of Holders upon a Fundamental Change 

SECTION 4.01. Purchase of Notes at the Option of Holders upon a Fundamental Change. (a) If a Fundamental Change occurs at any time,
each Holder shall have the right, at such Holder’s option, to require the Company to purchase any or all of the Holder’s Notes, or any portion of the principal amount thereof, that is equal to $1,000 or an integral multiple thereof at a
purchase price equal to 100% of the principal amount of the Notes to be purchased plus accrued and unpaid interest, including Additional Interest, if any, to but excluding the Fundamental Change Purchase Date (the “Fundamental Change
Purchase Price”); provided, however, that if the Fundamental Change Purchase Date occurs after the close of 

  
 9 

 
business on a Regular Record Date and on or prior to the corresponding Interest Payment Date, the Company shall pay accrued and unpaid interest plus Additional Interest, if any, to but excluding
the Fundamental Change Purchase Date to the record Holder on the Regular Record Date corresponding to such Interest Payment Date and the Fundamental Change Purchase Price payable to the Holder who presents the Note for repurchase shall be 100% of
the principal amount of such Note. The Fundamental Change Purchase Date shall be a Business Day specified by the Company that is no earlier than the 20th calendar day and no later than the 35th calendar day following the date of the Company Notice
delivered in connection with such Fundamental Change pursuant to Section 4.01(b) (subject to extension to comply with applicable law, as provided in Section 4.02(d)) (the “Fundamental Change Purchase Date”). Any Notes
purchased by the Company shall be paid for in cash. 
 (b) Notice of Fundamental Change. The Company shall deliver notice of the
occurrence of a Fundamental Change and of the purchase rights arising as a result thereof (each, a “Company Notice”) to the Holders at their addresses shown in the Security Register maintained by the Security Registrar, and to the
Trustee and the Paying Agent, on or before the 20th calendar day after the occurrence of the Fundamental Change (each such date of delivery, a “Company Notice Date”). Each Company Notice shall include a form of Fundamental Change
Purchase Notice to be completed by a Holder and shall state: 
 (i) the events causing the Fundamental Change; 

(ii) the effective date of the Fundamental Change; 

(iii) the last date on which a Holder may exercise its repurchase rights under this Section 4.01; 

(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) the applicable Conversion Rate and, if applicable, any adjustments to the applicable Conversion Rate as a result of such
Fundamental Change; 
 (viii) 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 Supplemental Indenture; and 

(ix) the procedures that a Holder must follow to require the Company to purchase its Notes pursuant to this Section 4.01. 

Simultaneously with providing such Company Notice, the Company shall publish a notice containing the information in such Company Notice in a
newspaper of general 

  
 10 

 
circulation in The City of New York or publish such information on its then existing website or through such other public medium as it may use at that time. 

(c) Exercise of Option. For a Note to be so purchased at the option of the Holder, the Holder must deliver, on or before the Business
Day immediately preceding the Fundamental Change Purchase Date, subject to extension to comply with applicable law, the Notes to be purchased, duly endorsed for transfer, together with a written purchase notice (a “Fundamental Change
Purchase Notice”) in the form entitled “Form of Fundamental Change Purchase Notice” on the reverse side of the Notes duly completed, to the Paying Agent. The Fundamental Change Purchase Notice must include the following
information: 
 (i) if the Notes are certificated, the certificate numbers of the Holder’s Notes to be delivered for
purchase; 
 (ii) the portion of the principal amount of the Holder’s Notes to be purchased, which portion must be
$1,000 or an integral multiple thereof; and 
 (iii) that the Holder’s Notes shall be purchased as of the Fundamental
Change Purchase Date pursuant to the applicable provisions of the Notes and this Supplemental Indenture. 
 (d) Procedures. The
Company shall purchase from a Holder on the Fundamental Change Purchase Date, subject to extension to comply with applicable law, pursuant to this Section 4.01, Notes if the principal amount of such Notes is $1,000 or an integral multiple
thereof if so requested by such Holder. 
 The Company shall require each Paying Agent (other than the Trustee) to agree in writing that the
Paying Agent shall hold in trust for the benefit of Holders or the Trustee all cash held by the Paying Agent for the payment of the Fundamental Change Purchase Price and shall notify the Trustee of any default by the Company in making any such
payment. If the Company or an Affiliate of the Company acts as Paying Agent, it shall segregate the cash held by it as Paying Agent and hold it as a separate trust fund. The Company at any time may require a Paying Agent to deliver all cash held by
it to the Trustee and to account for any funds disbursed by the Paying Agent. Upon doing so, the Paying Agent shall have no further liability for the cash delivered to the Trustee. 

SECTION 4.02. Further Conditions and Procedures for Purchase at the Option of the Holder upon a Fundamental Change. (a) Upon receipt by
the Company of the Fundamental Change Purchase Notice specified in, and the Notes to be purchased as provided in, Section 4.01(c), the Holder of the Notes in respect of which such Fundamental Change Purchase Notice was given shall (unless such
Fundamental Change Purchase Notice is withdrawn as specified in this Section 4.02(a)) thereafter be entitled to receive solely the Fundamental Change Purchase Price with respect to such Notes. Such Fundamental Change Purchase Price shall be
paid by the Paying Agent, solely from funds received from the Company for such purpose, to such Holder promptly following the later of (x) the Fundamental Change Purchase Date with respect to such Notes (provided the conditions in this Article
IV have been satisfied) and (y) the time of delivery or book-entry transfer of such Notes to the Paying Agent 

  
 11 

 
by the Holder thereof in the manner required by Section 4.01. Notes in respect of which a Fundamental Change Purchase Notice has been given by the Holder thereof may not be converted on or
after the date of the delivery of such Fundamental Change Purchase Notice unless such Fundamental Change Purchase Notice has first been validly withdrawn as specified in this Section 4.02(a). Notwithstanding anything herein to the contrary, any
Holder delivering to the Paying Agent the Fundamental Change Purchase Notice contemplated by Section 4.01(c), shall have the right at any time prior to the close of business on the Business Day immediately prior to the Fundamental Change
Purchase Date to withdraw such Fundamental Change Purchase Notice (in whole or in part) by delivery of a written notice of withdrawal to the Paying Agent in accordance with this Section 4.02(a). 

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. 
 On or before 11:00 a.m. (New York City time) on the Fundamental Change Purchase Date, the Company shall deposit with
the Paying Agent (or if the Company or an Affiliate of the Company is acting as the Paying Agent, shall segregate and hold in trust) cash sufficient to pay the aggregate Fundamental Change Purchase Price of the Notes to be purchased pursuant to
Section 4.01. If the Paying Agent holds, in accordance with the terms of this Supplemental Indenture, cash sufficient to pay the Fundamental Change Purchase Price of such Notes on the second Business Day after the Fundamental Change Purchase
Date, then (i) the Notes tendered for purchase and not withdrawn shall cease to be Outstanding, and interest, including Additional Interest, if any, shall cease to accrue on the Fundamental Change Purchase Date (whether or not book-entry
transfer of such Notes is made or whether or not the Note is delivered to the Paying Agent); and (ii) all other rights of the Holders with respect to Notes tendered for purchase shall terminate on the Fundamental Change Purchase Date (other
than the right to receive the Fundamental Change Purchase Price upon delivery or transfer of the Notes). Nothing herein shall preclude any withholding of tax required by law. 

A Fundamental Change Purchase Notice may be withdrawn, in whole or in part, by means of a written notice of withdrawal delivered to the office
of the Paying Agent prior to the close of business on the Business Day immediately prior to the Fundamental Change Purchase Date. The notice of withdrawal shall state: 

(i) the principal amount of the withdrawn Notes; 

(ii) if certificated Notes have been issued, the certificate numbers of the withdrawn Notes, or if not certificated, the notice
must comply with appropriate DTC, Clearstream and/or Euroclear procedures; and 
 (iii) the principal amount, if any, which
remains subject to the Fundamental Change Purchase Notice, which must be $1,000 or an integral multiple thereof. 
 If the Notes are
certificated, the Paying Agent shall promptly return to the respective Holders thereof any Notes with respect to which a Fundamental Change Purchase Notice has been withdrawn in compliance with this Supplemental Indenture. 

  
 12 

 (b) Notes Purchased in Part. Any Notes that are to be purchased only in part shall be
surrendered at the office of the Paying Agent (with, if the Company or the Trustee so requires, due endorsement by, or a written instrument of transfer in form satisfactory to the Company and the Trustee duly executed by, the Holder thereof or such
Holder’s attorney duly authorized in writing) and the Company shall execute and the Trustee or the Authenticating Agent shall authenticate and deliver to the Holder of such Notes, without service charge, a new Note or Notes, of any authorized
denomination as requested by such Holder in aggregate principal amount equal to, and in exchange for, the portion of the principal amount of the Notes so surrendered which is not purchased. 

(c) Compliance with Securities Laws upon Purchase of Notes. In connection with any offer to purchase, or purchase of, Notes under
Section 4.01, the Company shall, to the extent applicable, (a) comply with Rules 13e-4 and 14e-1 (and any successor provisions thereto) under the Exchange Act; (b) file the related Schedule TO (or any successor schedule, form or
report) under the Exchange Act; and (c) otherwise comply with all applicable Federal and state securities laws. To the extent that the provisions of any securities laws or regulations conflict with the provisions of this Supplemental Indenture
as described in this Article IV, compliance by the Company with such laws and regulations shall not in and of itself cause a breach of the Company’s obligations described in this Article IV. 

(d) Repayment to the Company. The Trustee and the Paying Agent shall return to the Company any cash or property that remains unclaimed
at the end of two years after the amount is due to Holders, together with interest that the Trustee or Paying Agent, as the case may be, has expressly agreed in writing to pay, if any, that is held by them for the payment of a Fundamental Change
Purchase Price; provided, however, that to the extent that the aggregate amount of cash or property deposited by the Company pursuant to Section 4.02(b), as applicable, exceeds the aggregate Fundamental Change Purchase Price of
the Notes or portions thereof which the Company is obligated to purchase as of the Fundamental Change Purchase Date, then promptly on and after the second Business Day following the Fundamental Change Purchase Date, the Trustee and the Paying Agent
shall return any such excess to the Company together with interest that the Trustee or Paying Agent, as the case may be, has expressly agreed in writing to pay, if any. 

(e) Officers’ Certificate. At least three Business Days (or such lesser period as agreed to by the Trustee) before the Company
Notice Date, the Company shall deliver an Officers’ Certificate to the Trustee specifying whether the Company desires the Trustee to give the Company Notice required by Section 4.02(a) hereof. 

ARTICLE V 
 Conversion 

SECTION 5.01. Conversion of Notes. Subject to the procedures for conversion set forth in this Article V and at any time prior to the
close of business on the Business Day immediately preceding the Stated Maturity Date of the Notes, a Holder may convert its Notes at their full principal amount, or any portion of their principal amount that is equal to $1,000 or an integral
multiple thereof, into shares of Common Stock at the Conversion 

  
 13 

 
Rate in effect at the time of conversion. No payment or adjustment shall be made for dividends on, or other distributions with respect to, any Common Stock, except as expressly provided in this
Article V. 
 (a) Conversion Procedures. The following procedures shall apply to convert Notes: 

(i) in respect of a beneficial interest in a Global Security, a Beneficial Owner must comply with the procedures of the
Depositary for converting a beneficial interest in a Global Security and, if required pursuant to Section 2.08(b), pay funds equal to interest and Additional Interest, if any, payable on the next Interest Payment Date to which such Beneficial
Owner is not entitled, and if required, pay all taxes or duties, if any; and 
 (ii) in respect of a certificated Note, the
Holder must (A) complete and manually sign the conversion notice on the back of the Note, or a facsimile of the conversion notice; (B) deliver such conversion notice, which is irrevocable, and the Note to the Conversion Agent;
(C) furnish appropriate endorsements and transfer documents as may be required by the Conversion Agent; (D) if required pursuant to Section 5.02(c), pay all transfer or similar taxes; and (E) if required pursuant to
Section 2.08(b), pay funds equal to interest and Additional Interest, if any, payable on the next Interest Payment Date to which such Holder is not entitled. 

The date a Holder complies with the foregoing requirements is the “Conversion Date” hereunder. At the Conversion Date the
rights of the Holders of such converted Notes as Holders shall cease, and, as of the close of business on the Conversion Date, the Person or Persons entitled to receive the shares of Common Stock issuable upon conversion shall be treated for all
purposes as the record holder or holders of such Common Stock as and after such time. The Company shall issue and shall deliver at such office or agency a certificate or certificates for the number of full shares of Common Stock issuable upon
conversion, together with payment in cash in lieu of any fractional shares, as provided in Section 5.01(b), by the third Business Day immediately following the applicable Conversion Date. A Holder may convert a portion of its Notes only if the
principal amount of such portion is $1,000 or an integral multiple thereof. 
 In the case of any Note that is converted in part only, upon
such conversion the Company shall execute and the Trustee shall authenticate and deliver to the Holder thereof, at the expense of the Company, a new Note or Notes of authorized denominations in aggregate principal amount equal to the unconverted
portion of the principal amount of such Note. 
 If a Holder has already delivered a Fundamental Change Purchase Notice in connection with a
Fundamental Change, with respect to a Note, the Holder may not surrender that Note for conversion until the Holder has validly withdrawn the Fundamental Change Purchase Notice in accordance with this Supplemental Indenture. 

If more than one Note shall be surrendered for conversion at one time by the same Holder, the number of full shares of Common Stock issuable
upon conversion thereof shall be computed on the basis of the aggregate principal amount of the Notes (or specified portions thereof) so surrendered. 

  
 14 

 (b) Cash Payments in Lieu of Fractional Shares. The Company shall not issue fractional
shares of Common Stock upon conversion of Notes. Instead the Company shall deliver cash, rounded to the nearest whole cent, for such fractional shares based on the Last Reported Sale Price of the Common Stock on the applicable Conversion Date. 

(c) Taxes on Conversion. If a Holder converts Notes, the Company shall pay any documentary, stamp or similar issue or transfer tax due
on the issuance of shares of Common Stock upon such conversion; provided, however, the Holder shall pay any such tax which is due because the Holder requests the shares of Common Stock to be issued in a name other than the
Holder’s name. 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 Conversion Agent receives a sum sufficient to pay any tax
which shall be due because the shares are to be issued in a name other than the Holder’s name, but the Conversion Agent shall have no duty to determine if any such tax is due. Nothing herein shall preclude any withholding of tax required by
law. 
 (d) Certain Covenants of the Company. (i) The Company shall, prior to issuance of any Notes hereunder, and from time to
time as may be necessary, reserve out of its authorized but unissued Common Stock or shares of Common Stock held in treasury, a sufficient number of shares of Common Stock, free of preemptive rights, to permit the conversion of the Notes, calculated
assuming the maximum number of Additional Shares are issuable upon conversion of the Notes pursuant to Section 5.04. 

(ii) All shares of Common Stock delivered upon conversion of the Notes shall be newly issued shares or treasury shares, shall
be duly and validly issued and fully paid and nonassessable and shall be free from preemptive rights and free of any lien or adverse claim. 

(iii) The Company shall endeavor to comply promptly with all applicable Federal and state securities laws regulating the
issuance and delivery of shares of Common Stock upon the conversion of Notes. 
 (iv) Before taking any action that would
cause an adjustment increasing the Conversion Rate to an amount that would cause the Conversion Price to be reduced below the then par value per share, if any, of the shares of Common Stock issuable upon conversion of the Notes, the Company shall
take all corporate action which may, in the opinion of its counsel, be necessary in order that the Company may validly and legally issue shares of such Common Stock at such adjusted Conversion Rate. 

SECTION 5.02. Adjustments to Conversion Rate. The Conversion Rate shall be adjusted from time to time by the Company as described
below, 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 at the same time as holders of the Common Stock participate) in any of the transactions
described in this Section 5.02 as if such Holders of the Notes held a number of shares of the Common Stock equal to the applicable Conversion Rate, multiplied by the principal amount (expressed in thousands) of Notes held by such Holders,
without having to convert their Notes. 

  
 15 

 (a) If the Company issues shares of Common Stock as a dividend or distribution on shares of
Common Stock, or if the Company effects a share split or share combination, the Conversion Rate shall be adjusted based on the following formula: 
  

 
 

 
 where, 
 CR0 = the conversion rate in effect immediately prior to the close of business on the Record Date for such dividend or distribution or immediately prior to the open of business on the effective date
of such share split or combination, as applicable; 
 CR1 = the conversion rate in
effect immediately after the close of business on such Record Date or immediately after the open of business on such effective date, as applicable; 

OS0 = the number of shares of Common Stock outstanding immediately prior to the close
of business on such Record Date or immediately prior to the open of business on such effective date, as applicable; and 
 OS1 = the number of shares of Common Stock outstanding immediately prior to such Ex-Dividend Date or effective date, as applicable, after giving pro forma effect to such dividend, distribution,
share split or share combination. 
 Any adjustment made under this Section 5.02(a) shall become effective immediately after the close
of business on the Record Date for such dividend or distribution, or immediately after the open of business of the effective date for such share split or share combination, as applicable. The Company shall not pay any dividend or make any
distribution on shares of Common Stock held in treasury by the Company. If any dividend or distribution of the type described in this Section 5.02(a) is declared but not so paid or made, the Conversion Rate shall be immediately readjusted,
effective as of the date the Company’s Board of Directors determines not to pay such dividend or distribution, to the Conversion Rate that would then be in effect if such dividend or distribution had not been declared. 

(b) If the Company distributes to holders of all or substantially all the Common Stock any rights or warrants entitling them for a period of
not more than 45 calendar days to subscribe for or purchase shares of 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 date of announcement of such distribution, the Conversion Rate shall be adjusted based on the following formula: 
  

 
 

 

  
 16 

 where, 

CR0 = the Conversion Rate in effect immediately prior to the close of business on the
Record Date for such distribution; 
 CR1 = the Conversion Rate in effect immediately
after the close of business on such Record Date; 
 OS0 = the number of shares of
Common Stock outstanding immediately prior to the close of business on such Record Date; 
 X = the total number of shares of Common Stock
issuable pursuant to such rights or warrants; and 
 Y = the number of shares of Common Stock equal to the aggregate price payable to
exercise such rights or warrants divided by the average of the Last Reported Sale Prices of Common Stock over the 10 consecutive Trading-Day period ending on, and including, the Trading Day immediately preceding the date of announcement of the
distribution of such rights or warrants. 
 Any adjustment made under this Section 5.02(b) shall be successively made whenever any such
rights, options or warrants are issued and shall become effective immediately after the close of business on the Record Date for such issuance. The Company shall not issue any such rights, options or warrants in respect of shares of Common Stock
held in treasury by the Company. To the extent that shares of Common Stock are not delivered after the expiration of such rights, options or warrants, the Conversion Rate shall be readjusted to the Conversion Rate that would then be in effect had
the adjustments made upon the issuance 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 issued, the Conversion Rate
shall again be adjusted to be the Conversion Rate that would then be in effect if such Ex-Dividend Date for such issuance had not occurred. 

In determining whether any rights, options or warrants entitle the Holders to subscribe for or purchase shares of Common Stock at less than
such average Last Reported Sale Prices for the 10 consecutive trading-day period ending on, and including the Trading Day immediately preceding the date of announcement for such issuance, 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 Company’s Board of Directors. 
 (c) If the Company distributes shares of its capital stock, evidences of its
indebtedness or other assets or property of the Company or rights or warrants to acquire the Company’s capital stock or other securities to holders of all or substantially all the Common Stock, excluding: 

(i) dividends or distributions and rights or warrants referred to in Section 5.02(a) or (b) above; 

  
 17 

 (ii) dividends or distributions paid exclusively in cash; and 

(iii) as described below in this Section 5.02(c) with respect to Spin-Offs (as defined below), 

then the Conversion Rate shall be adjusted based on the following formula: 
  

 
 

 
 where, 
 CR0 = the Conversion Rate in effect immediately prior to the close of business on the Record Date for such distribution; 

CR1 = the Conversion Rate in effect immediately after the close of business on such
Record Date; 
 SP0 = the average of the Last Reported Sale Prices of 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 Company’s Board of Directors) of the shares of capital stock, evidences of indebtedness,
assets, property, rights or warrants distributed with respect to each outstanding share of Common Stock on the Record Date for such distribution. 

Any adjustment made under this Section 5.02(c) shall become effective immediately after the close of business on the Record Date for such
distribution. If such distribution is not so paid or made, the Conversion Rate shall be decreased to be the Conversion Rate that would then be in effect if such distribution had not been declared. 

If the Company’s Board of Directors determines the Fair Market Value of any distribution for purposes of this Section 5.02(c) by
reference to the actual or when-issued trading market for any securities, it will in doing so consider the prices in such market over the same period used in computing the Last Reported Sale Price 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. 
 Notwithstanding
the foregoing, if the Fair Market Value of any distribution for purposes of this Section 5.02(c) is equal to or greater than the “SP0” (as defined above), in lieu of the
foregoing increase, each Holder shall receive, in respect of each $1,000 principal amount of Notes, at the same time and upon the same terms as holders of the Common Stock, the amount and kind of the Company’s capital stock or other securities
that such Holder would have received if such Holder owned a number of shares of the Common Stock equal to the Conversion Rate in effect on the Record Date for the distribution. 

  
 18 

 With respect to an adjustment pursuant to this Section 5.02(c) where there has been a
payment of a dividend or other distribution on the Common Stock in shares of capital stock of any class or series, or similar equity interest, of or relating to a Subsidiary or other business unit where such capital stock or similar equity interest
is listed or quoted (or will be listed or quoted upon consummation of the dividend or distribution) on a U.S. national or regional securities exchange (a “Spin-Off”), the Conversion Rate shall be increased based on the following
formula: 
  
  
 

 
 where, 
 CR0 = the Conversion Rate in effect immediately prior to the end of the valuation period (as defined below); 

CR1 = the Conversion Rate in effect immediately after the end of the valuation period
(as defined below); 
 FMV0 = the average of the Last Reported Sale Prices of the
capital stock or similar equity interest distributed to holders of Common Stock applicable to one share of Common Stock (determined for purposes of the definition of Last Reported Sale Price as if such capital stock or similar equity interest were
Common Stock) over the first 10 consecutive Trading-Day period beginning on, and including, the Ex-Dividend Date for the Spin- Off (the “Valuation Period”); and 

MP0 = the average of the Last Reported Sale Prices of Common Stock over the Valuation
Period. 
 Such adjustment shall be determined on the last Trading Day of the Valuation Period but will be given effect immediately after
the open of business on the Ex-Dividend Date for the Spin-Off; provided that, if the relevant Conversion Date occurs during the Valuation Period, the reference to “10” in the in the preceding paragraph shall be deemed replaced with
such lesser number of Trading Days as have elapsed between the Ex-Dividend Date for such Spin-Off and such Conversion Date in determining the Conversion Rate. 

(d) If any cash dividend or distribution is made to the holders of all or substantially all of the Common Stock other than a regular, quarterly
cash dividend that does not exceed $0.08 per share (the “Initial Dividend Threshold”), the Conversion Rate shall be adjusted based on the following formula: 
  

 
 

 

  
 19 

 where, 

CR0 = the Conversion Rate in effect immediately prior to the close of business on the
Record Date for such dividend or distribution; 
 CR1 = the Conversion Rate in effect
immediately after the close of business on the Record Date for such dividend or distribution; 
 SP0 = the Last Reported Sale Price of Common Stock on the Trading Day immediately preceding the Ex-Dividend Date for such dividend or distribution; 

T = the Initial Dividend Threshold; provided that if the dividend or distribution is not a regular, quarterly cash dividend, the Initial
Dividend Threshold will be deemed to be zero; and 
 C = the amount in cash per share distributed by the Company to holders of Common Stock.

 The Initial Dividend Threshold shall be concurrently adjusted at any time the Conversion Rate is adjusted in a manner inversely
proportional to adjustments to the Conversion Rate; provided that no adjustment shall be made to the Initial Dividend Threshold for any adjustment made to the Conversion Rate under this Section 5.02(d). 

Such increase shall become effective immediately after the close of business on the Record Date for such dividend or distribution. If such
dividend or distribution is not so paid, the Conversion Rate shall be decreased to be the Conversion Rate that would then be in effect if such dividend or distribution had not been declared. 

Notwithstanding the foregoing, in the event the Company declares or pays more than one dividend during the 90 days preceding the Stated
Maturity Date, no such additional dividend shall constitute a regular quarterly dividend. 
 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 shall receive, for each $1,000 principal amount of Notes, at
the same time and upon the same terms as holders 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 Record Date for such cash
dividend or distribution. 
 (e) If the Company or any of its Subsidiaries makes a payment in respect of a tender or exchange offer for
Common Stock, to the extent that the cash and value of any other consideration included in the payment per share of 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 Conversion Rate shall be increased based on the following formula: 

  
 20 

  
 

 
 where, 
 CR0 = the Conversion Rate in effect immediately prior to the close of business on the 10th Trading Day immediately following, and including, the Trading Day next succeeding the date such tender or
exchange offer expires; 
 CR1 = the Conversion Rate in effect immediately after the
close of business on the 10th Trading Day immediately following, and including, the Trading Day next succeeding the date such tender or exchange offer expires; 

AC = the aggregate value of all cash and any other consideration (as determined by the Company’s Board of Directors) paid or payable for
shares accepted for purchase or exchange in such tender or exchange offer; 
 OS0 =
the number of shares of Common Stock outstanding immediately prior to the date such tender or exchange offer expires (prior to giving effect to the purchase of all shares accepted for purchase or exchange in such tender or exchange offer); 

OS1 = the number of shares of Common Stock outstanding immediately after the date such
tender or exchange offer expires (after giving effect to the reduction of shares accepted for purchase or exchange in such tender or exchange offer); and 

SP1 = the average of the Last Reported Sale Prices of Common Stock over the 10
consecutive Trading-Day period commencing on, and including, the Trading Day next succeeding the date such tender or exchange offer expires. 

Such increase will be determined at the close of business on the 10th Trading Day immediately following, and including, the Trading Day next
succeeding the date such tender or exchange offer expires but will be given effect immediately after the open of business on the Trading Day next succeeding the date such tender or exchange offer expires; provided that, if the relevant Conversion
Date occurs during the 10 Trading Days immediately following, and including, the Trading Day next succeeding the expiration date of any tender or exchange offer, references to “10” or “10th” in the preceding paragraph shall be
deemed replaced with such lesser number of trading days as have elapsed between the expiration date of such tender or exchange offer and such conversion date in determining the Conversion Rate. 

If the Company is obligated to purchase shares pursuant to any such tender or exchange offer, but the Company is permanently prevented by
applicable law from effecting any 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 or exchange offer had not been made. 

Except as stated herein, the Company shall not adjust the Conversion Rate for the issuance of shares of Common Stock or any securities
convertible into or exchangeable for 

  
 21 

 
shares of Common Stock or the right to purchase shares of Common Stock or such convertible or exchangeable securities. 

(f) The Company may (but is not required to) increase the Conversion Rate to avoid or diminish income tax to holders of Common Stock or rights
to purchase shares of Common Stock in connection with a dividend or distribution of shares (or rights to acquire shares) or any similar event treated as such for income tax purposes. 

(g) To the extent permitted by applicable law and the rules of any stock exchange or market upon which the Common Stock is listed or admitted
for trading, the Company may increase the Conversion Rate by any amount for a period of at least 20 days if the Company’s Board of Directors determines that such increase would be in the best interest of the Company, which determination shall
be conclusive. 
 (h) Notwithstanding the foregoing provisions of this Section 5.02, the applicable Conversion Rate will not be
adjusted: 
 (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 securities of the Company 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 shares of Common Stock pursuant to any
present or future employee, director or consultant benefit plan or program of or assumed by the Company or any of its Subsidiaries; 

(iii) upon the issuance of any shares of Common Stock pursuant to any option, warrant, right, or exercisable, exchangeable or
convertible security not described in clause (ii) above and outstanding as of the Issue Date; 
 (iv) for a change in
the par value of the Common Stock; or 
 (v) for accrued and unpaid interest, if any (including Additional Interest, if any).

 (i) All calculations under this Section 5.02 shall be made by the Company and shall be made to the nearest cent or to
the nearest one-ten thousandth (1/10,000) of a share, as the case may be. 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;
provided, however, that the Company shall carry forward any adjustments that are less than 1% of the Conversion Rate that the Company elects not to make and take them into account upon the earlier of (i) any conversion of Notes or
(ii) such time as all adjustments that have not been made prior thereto would have the effect of adjusting the Conversion Rate by at least 1%. Except as provided in this Section 5.02 and Sections 5.03 and 5.04, the Company shall not adjust
the Conversion Rate. 
 (j) Whenever the Conversion Rate is adjusted as provided in this Supplemental Indenture, the Company
shall promptly file with the Trustee and any Conversion Agent 

  
 22 

 
other than the Trustee an Officers’ 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 at the Corporate Trust Office of the Trustee such Officers’ Certificate, the Trustee shall not be deemed to have knowledge of any adjustment of the Conversion Rate and may assume
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 such adjustment becomes effective and shall mail such notice of such adjustment of the Conversion Rate to the Holder of each Note at such Holder’s last address appearing on the Security Register. Failure to deliver such notice
shall not affect the legality or validity of any such adjustment. 
 (k) In any case in which this Section 5.02 provides
that an adjustment shall become effective immediately after (i) an Ex-Dividend Date for an event, (ii) the date fixed for the determination of a share split or combination pursuant to Section 5.02(a), or (iii) the last date on
which tenders or exchanges may be made for any tender or exchange offer pursuant to Section 5.02(e), (each a “Determination Date”), the Company may elect to defer until the occurrence of the applicable Adjustment Event
(x) issuing to the Holder of any Note converted after such Determination Date and before the occurrence of such Adjustment Event, the Additional Shares of Common Stock or other securities issuable upon such conversion by reason of the
adjustment required by such Adjustment Event over and above the Common Stock issuable upon such conversion before giving effect to such adjustment and (y) paying to such Holder any amount in cash in lieu of such Additional Shares of Common
Stock or other securities or in lieu of any fraction pursuant to Section 5.01(b). For purposes of this Section 5.02, the term “Adjustment Event” shall mean: 

(1) in any case referred to in clause (i) above, the occurrence of such event, 

(2) in any case referred to in clause (ii) above, the date any such dividend or distribution is paid or made, and 

(3) in any case referred to in clause (iii) above, the date a sale or exchange of Common Stock pursuant to such tender or
exchange offer is consummated and becomes irrevocable. 
 (l) For purposes of this Section 5.02, the number of shares of
Common Stock at any time outstanding shall not include shares held in the treasury of the Company but shall include shares issuable in respect of scrip certificates issued in lieu of fractions of shares of Common Stock. The Company shall not pay any
dividend or make any distribution on shares of Common Stock held in the treasury of the Company. 
 (m) Whenever any
provision of this Article V requires a calculation of the Last Reported Sale Prices over a span of multiple days (including the “Stock Price” for purposes of a Make-Whole Fundamental Change), the Company shall make appropriate adjustments
(determined in good faith by the Company’s Board of Directors) to account 

  
 23 

 
for any adjustment to the Conversion Rate that becomes effective, or any event requiring an adjustment to the Conversion Rate where the Record Date or the Ex-Dividend Date of the event occurs, at
any time during the period from which the average is to be calculated. Such adjustments shall be effective as of the Effective Date of the adjustment to the Conversion Rate. 

SECTION 5.03. Effect of Reclassification, Consolidation, Merger or Sale. (a) If any of the following events occur: (i) any
recapitalization, reclassification or change of the Common Stock (other than a subdivision or combination); (ii) any consolidation, merger or combination involving the Company; (iii) any sale, lease or other transfer to another Person of
all or substantially all of the Company’s property and assets; or (iv) any statutory share exchange, in each case, as a result of which the Common Stock would be converted into, or exchanged for, stock, other securities or other property
or assets (including cash or any combination thereof) (any such event or transaction, a “Reorganization Event”), then the Company or the successor or purchasing Person, as the case may be, shall execute with the Trustee a
supplemental indenture (which shall comply with the Trust Indenture Act as in force at the date of execution of such supplemental indenture) providing that at the effective time of the Reorganization Event each Note shall be convertible into, with
respect to each $1,000 in principal amount of such Note, 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 Reorganization Event would have owned or been entitled to receive upon such Reorganization Event (the “Reference Property”). For purposes of the foregoing, the type and amount of
consideration that a holder of Common Stock would have been entitled to receive in the case of any such Reorganization Event that causes the Common Stock to be converted into the right to receive more than a single type of consideration (determined
based in part upon any form of stockholder election) shall be deemed to be (i) the weighted average of the types and amounts of consideration received by the holders of Common Stock that affirmatively make such an election or (ii) if no
holders of Common Stock affirmatively make such an election, the types and amounts of consideration actually received by the holders of Common Stock. If the holders of Common Stock receive only cash in such transaction, then for all conversions that
occur after the effective date of such transaction (i) 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 as described in Section 5.04), multiplied by the price paid per share of Common Stock in such transaction and (ii) the Company will satisfy its conversion obligation by paying cash to converting Holders on the third Business Day
immediately following the Conversion Date. The Company will notify Holders, the Trustee and the Conversion Agent (if other than the Trustee) of the weighted average as soon as practicable after such determination is made. 

Such supplemental indenture shall provide for provisions and adjustments which shall be as nearly equivalent as may be practicable to the
provisions and adjustments provided for in this Article V and in Article IV of this Supplemental Indenture and in the definition of “Fundamental Change” herein, as appropriate, as determined in good faith by the Company (which
determination shall be conclusive), to make such provisions apply to such other Person if different from the original issuer of the Notes. If, in the case of any Reorganization Event, the cash, securities or other property receivable thereupon by a
holder of Common Stock includes 

  
 24 

 
cash, securities or other property of a Person other than the successor or purchasing Person, as the case may be, in such Reorganization Event, then such supplemental indenture shall also be
executed by such successor or purchasing Person, as the case may be, and shall contain such additional provisions to protect the interests of the Holders of the Notes as the Company’s Board of Directors shall reasonably consider necessary by
reason of the foregoing. The Company shall not become a party to any transaction unless its terms are consistent with the foregoing. 
 In
connection with any adjustment to the Conversion Rate as described in this clause Section 5.03(e), the Company also will adjust the Initial Dividend Threshold based on the number of shares of Common Stock comprising the Reference Property and
(if applicable) the value of any non-stock consideration comprising the Reference Property. If the Reference Property is comprised solely of non-stock consideration, the Initial Dividend Threshold will be zero. 

(b) The Company shall cause notice of the execution of any supplemental indenture required by this Section 5.03 to be mailed to each
Holder of Notes, at its address appearing on the Security Register, within 20 calendar days after execution thereof. Failure to deliver such notice shall not affect the legality or validity of such supplemental indenture. 

(c) The above provisions of this Section 5.03 shall similarly apply to successive Reorganization Events. 

(d) None of the foregoing provisions shall affect the right of a Holder of Notes to convert the Notes into shares of Common Stock as set forth
in Section 5.02 prior to the effective time of such Reorganization Event. 
 SECTION 5.04. Adjustment upon Certain Fundamental
Changes. (a) If the effective date of a Make-Whole Fundamental Change occurs prior to the Stated Maturity Date and a Holder elects to convert Notes in connection with such Make-Whole Fundamental Change, the Conversion Rate for such Notes so
converted shall be increased by an additional number of shares of Common Stock (the “Additional Shares”) as described below. A conversion of Notes shall be deemed for purposes of this Section 5.04(a) to have occurred in
connection with such Make-Whole Fundamental Change if the relevant notice of conversion of the Notes is received by the Conversion Agent from, and including, the effective date of the Make-Whole Fundamental Change up to, and including, 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 exceptions in clause (2) of the definition thereof, the 35th Trading
Day immediately following the effective date of such Make-Whole Fundamental Change). 
 (b) If the consideration for the Common Stock in any
Fundamental Change described in clause (2) of the definition of Fundamental Change is comprised 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 equal to the applicable Conversion Rate (including any adjustment to the Conversion Rate described in this Section 5.04)
multiplied by such Stock Price. In such event, the conversion obligation shall be determined and paid to 

  
 25 

 
Holders in cash on the third Business Day following the Conversion Date. The Company shall notify Holders of the effective date of any Make-Whole Fundamental Change and issue a press release
announcing such effective date no later than five Business Days after such effective date. 
 (c) The number of Additional Shares by which
the Conversion Rate shall be increased shall be determined by reference to the table attached as Schedule A hereto, based on the date on which the Make-Whole Fundamental Change occurs or becomes effective (the “Effective Date”) and
the Stock Price paid or deemed paid per share of Common Stock in the Fundamental Change. If a Holder elects to convert its Notes prior to the Effective Date of any Make-Whole Fundamental Change, and the Make-Whole Fundamental Change does not occur,
such Holder shall not be entitled to an increased Conversion Rate in connection with such conversion. 
 (d) The Stock Prices set forth in
the column headings of the table in Schedule A hereto and in clauses (ii) and (iii) of the immediately succeeding paragraph shall be adjusted as of any date on which the Conversion Rate of the Notes is adjusted pursuant to
Section 5.02. 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 and the
denominator of which is the Conversion Rate as so adjusted. The number of Additional Shares set forth in such table shall be adjusted in the same manner as the Conversion Rate as set forth in Section 5.02. 

The exact Stock Prices and Effective Dates may not be set forth in the table in Schedule A, in which case the following shall apply: 

(i) if the Stock Price is between two Stock Price amounts in the table or the Effective Date is between two Effective Dates in
the table, the number of Additional Shares by which the Conversion Rate shall be increased shall be determined by a straight-line interpolation between the number of Additional Shares set forth for the higher and lower Stock Price amounts and the
two dates, as applicable, based on a 365-day year; 
 (ii) if the Stock Price is greater than $60.00 per share (subject to
adjustment in the same matter as the Stock Prices set forth in the column headings of the table in Schedule A), no Additional Shares shall be added to the Conversion Rate; and 

(iii) if the Stock Price is less than $11.56 per share (subject to adjustment in the same manner as the Stock Prices set forth
in the column headings of table in Schedule A), no Additional Shares shall be added to the Conversion Rate. 
 Notwithstanding the
foregoing, in no event shall the total number of shares of Common Stock issuable upon conversion exceed 86.5052 per $1,000 principal amount of Notes, subject to adjustments in the same manner as the Conversion Rate under Section 5.02. 

SECTION 5.05. Stockholder Rights Plan. To the extent that the Company has a rights plan in effect upon conversion of the Notes into
Common Stock, Holders that convert their Notes shall receive, in addition to the Common Stock, the rights under the rights plan, unless prior to any conversion, the rights have separated from the Common Stock, in 

  
 26 

 
which case, and only in such case, the Conversion Rate shall be adjusted at the time of separation as if the Company distributed to all holders of Common Stock shares of the Company’s
capital stock evidences of indebtedness or assets as described in Section 5.02(b) above, subject to readjustment in the event of the expiration, termination or redemption of such rights. In lieu of any such adjustment, the Company may amend
such applicable stockholder rights agreement to provide that upon conversion of the Notes the Holders shall receive, in addition to the Common Stock issuable upon such conversion, the rights which would have attached to such Common Stock if the
rights had not become separated from the Common Stock under such applicable stockholder rights agreement. 
 SECTION 5.06. Trustee
Adjustment Disclaimer. The Trustee has no duty to determine when an adjustment under this Article V should be made, how it should be made or what it should be or to otherwise calculate the Conversion Price, and shall be protected in relying upon
an Officers’ Certificate with request to same. The Trustee has no duty to determine whether a supplemental indenture under Section 5.03 need be entered into or whether any provisions of any supplemental indenture are correct. The Trustee
shall not be accountable for and makes no representation as to the validity or value of any securities or assets issued upon conversion of Notes. The Trustee shall not be responsible for the Company’s failure to make any cash payment or to
issue, transfer or deliver any shares of Common Stock or share certificates or other securities or property upon the surrender of any Security for the purpose of conversion or otherwise comply with this Article V. Each Conversion Agent (other than
the Company or an affiliate of the Company) shall have the same protection under this Section 5.06 as the Trustee. 
 ARTICLE VI 

Events of Default and Remedies 

SECTION 6.01. Additional Events of Default. In addition to the Events of Default set forth in Section 5.01 of the Base Indenture,
each of the following shall also constitute Events of Default: 
 (i) a failure by the Company to convert the Notes in
accordance with the provisions of this Supplemental Indenture upon exercise of a Holder’s conversion right which default shall continue for a period of three Business Days after there has been given, by registered or certified mail, to the
Company by the Trustee or by such Holder, a written notice specifying such default or breach and requiring it to be remedied and stating that such notice is a “Notice of Default” under this Supplemental Indenture; 

(ii) a failure by the Company to deliver a Company Notice when due; 

(iii) a failure by the Company to repurchase Notes tendered for repurchase following the occurrence of a Fundamental Change in
accordance with Section 4.01 of this Supplemental Indenture; and 
 (iv) a failure by the Company or any of its
Subsidiaries to pay any indebtedness for borrowed money, within any applicable grace period after final maturity or the 

  
 27 

 
acceleration by the holders thereof, if the total amount of such indebtedness unpaid or accelerated exceeds $50,000,000. 

SECTION 6.02. Exception to Remedies. Notwithstanding anything in this Supplemental Indenture or the Base Indenture to the contrary, to
the extent elected by the Company, the sole remedy for an Event of Default relating to the failure by the Company to comply with the reporting obligations set forth in Section 7.04 of the Base Indenture and for any failure to comply with the
requirements of Section 314(a)(1) of the Trust Indenture Act shall, for the first 120 days after the occurrence of such an Event of Default, consist exclusively of the right of Holders to receive additional interest on the Notes at an annual
rate equal to 0.50% of the principal amount of the Notes (the “Additional Interest”). If the Company so elects, such Additional Interest shall be payable in the same manner and on the same dates as the stated interest payable on the
Notes. The Additional Interest shall accrue on all Outstanding Notes from and including the date on which the Event of Default relating to the failure to comply with the reporting obligations in the Base Indenture or the failure to comply with the
requirements of Section 314(a)(1) of the Trust Indenture Act first occurs to but not including the 120th day thereafter (or such earlier date on which such Event of Default is cured or waived by the Holders of a majority in principal amount of
the Outstanding Notes). On such 120th day (or earlier, if the Event of Default relating to the reporting obligations under the Base Indenture or the failure to comply with the requirements of Section 314(a)(1) of the Trust Indenture Act is
cured or waived by the Holders of a majority in principal amount of the Outstanding Notes prior to such 120th day), such Additional Interest shall cease to accrue and, if the Event of Default relating to reporting obligations or the failure to
comply with Section 314(a)(1) of the Trust Indenture Act has not been cured or waived prior to such 120th day, the Notes shall be subject to acceleration as provided in the Base Indenture. The provisions of this Section 6.02 shall not
affect the rights of Holders of Notes in the event of the occurrence of any other Event of Default. In the event the Company does not elect to pay the Additional Interest upon an Event of Default in accordance with this Section 6.02, the Notes
shall be subject to acceleration as provided in the Base Indenture. In order to elect to pay the Additional Interest on the Notes as the sole remedy during the first 120 days after the occurrence of an Event of Default relating to the failure to
comply with the reporting obligations in Section 7.04 of the Base Indenture or the failure to comply with Section 314(a)(1) of the Trust Indenture Act in accordance with this Section 6.02, the Company must notify all Holders of Notes,
the Trustee and the Paying Agent of such election on or before the close of business on the date on which such Event of Default first occurs, stating (i) the amount of such Additional Interest that is payable and (ii) the date on which
such Additional Interest is payable. 
 SECTION 6.03. Amendment to the Base Indenture. (a) Solely for the purposes of the Notes,
Section 5.13 of the Base Indenture is amended to renumber existing clause (2) in the first sentence thereof as clause (3) and insert immediately preceding thereto the following: 

“(2) in the Company’s obligation to deliver the consideration due upon conversion of any Security in accordance with this Indenture,
or” 
 (b) Solely for the purposes of the Notes, Section 5.08 of the Base Indenture is replaced in its entirety with the following:

  
 28 

 “Notwithstanding the foregoing, a Holder of any Security will have an absolute and
unconditional right (1) to receive payment of the principal of and any premium and, subject to the provisions of the Indenture regarding the payment of default interest, interest on such Security on the Interest Payment Dates; (2) to
receive delivery of the consideration due upon conversion; and (3) to institute suit for the enforcement of such payment or delivery, and such right to receive such payment or delivery on or after such respective dates shall not be impaired or
affected without the consent of such Holder.” 
 ARTICLE VII 

Modification and Amendment 

SECTION 7.01. Modification and Amendment. (a) In addition to the provisions set forth in Section 9.01 and Section 9.02 of
the Base Indenture, the Company and the Trustee may, without the consent of the Holders, enter into one or more supplemental indentures to conform the provisions of the Indenture or the Notes to the Description of the Notes provided in the final
prospectus supplement of the Company for the Notes dated May 18, 2016 and filed with the Commission. 
 (b) In addition to the
provisions set forth in Section 9.01 and Section 9.02 of the Base Indenture, without the consent of each Holder of an Outstanding Note affected thereby, the Company and the Trustee may not: 

(i) make any change that adversely affects the conversion rights of any Note; or 

(ii) reduce the Fundamental Change Purchase Price of any Note or amend or modify in any manner adverse to the holders of Notes
the Company’s obligation to make such payment, whether through an amendment or waiver of provisions in the covenants, definitions or otherwise. 

ARTICLE VIII 
 Miscellaneous

 SECTION 8.01. Ratification of Base Indenture. The Base Indenture, as heretofore supplemented, as supplemented by this
Supplemental Indenture is in all respects ratified and confirmed, and this Supplemental Indenture shall be deemed part of the Base Indenture, as heretofore supplemented, in the manner and to the extent herein and therein provided. 

SECTION 8.02. Application of Supplemental Indenture. The provisions of this Supplemental Indenture shall take effect immediately upon
its execution in accordance with Section 9.04 of the Base Indenture; provided, however, that the provisions set forth in this Supplemental Indenture shall apply only in respect of the Notes issued under this 

  
 29 

 
Supplemental Indenture and not to any past or future series of Securities established under the Base Indenture or any other supplemental indenture. 

SECTION 8.03. Trust Indenture Act Controls. If any provision hereof limits, qualifies or conflicts with the duties imposed by Sections
310 through 317 of the Trust Indenture Act, the imposed duties shall control. 
 SECTION 8.04. Conflict with Base Indenture. To the
extent not expressly amended or modified by this Supplemental Indenture, the Base Indenture, as heretofore supplemented, shall remain in full force and effect. If any provision of this Supplemental Indenture relating to the Notes is inconsistent
with any provision of the Base Indenture, as heretofore supplemented, the provision of this Supplemental Indenture shall control. 
 SECTION
8.05. Withholding Offset. (a) The Company (through the Withholding Agent or otherwise) shall be entitled to reduce or otherwise set-off against any payments made or deemed made by the Company to Holders in respect of the Notes or the Common
Stock for any amounts the Company believes it is required to withhold by law. For the avoidance of doubt, if the Company pays any withholding taxes on behalf of a Holder as a result of an adjustment to the Conversion Rate of the Notes, the Company
may, at its option, set-off such payments against payments to such Holder of cash and Common Stock in respect of the Notes. Any amounts withheld pursuant to this Section 8.06 shall be paid over by the Company (through the Withholding Agent or
otherwise) to the appropriate taxing authority. 
 (b) Prior to or upon the occurrence of any event that results in an actual or deemed
payment by the Company to Holders in respect of the Notes or the Common Stock, the Company (through the Trustee, Paying Agent, Withholding Agent or otherwise) may request a Holder to furnish any appropriate documentation that may be required in
order to determine the Company’s withholding obligations under applicable law (including, without limitation, a United States Internal Revenue Service Form W-9, Form W-8BEN or Form W-8ECI, as appropriate). 

SECTION 8.06. Calculations in Respect of Notes. The Company shall make all calculations called for in respect of the Notes. These
calculations include, but are not limited to, determinations of the Last Reported Sale Price, accrued interest payable on the Notes and the Conversion Rate. The Company shall make all calculations in good faith and, absent manifest error, such
calculations shall be final and binding on the Holders. The Company shall provide a schedule of its calculations to each of the Trustee and the Conversion Agent, and each of the Trustee and Conversion Agent is entitled to rely conclusively upon the
accuracy of such calculations without independent verification. The Trustee shall forward the Company’s calculations to any Holder upon such Holder’s request. 

SECTION 8.07. Governing Law. THIS SUPPLEMENTAL INDENTURE AND THE NOTES SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS
OF THE STATE OF NEW YORK. 

  
 30 

 SECTION 8.08. Successors. All agreements of the Company in the Base Indenture, as
heretofore supplemented, this Supplemental Indenture and the Notes shall bind its successors. 
 SECTION 8.09. Counterparts. This
instrument may be executed in any number of counterparts, each of which so executed shall be deemed to be an original, but all such counterparts shall together constitute but one and the same instrument. 

SECTION 8.10. Appointment of Conversion Agent. The Company hereby appoints the Trustee as Conversion Agent, and the Trustee hereby
accepts such appointment. 
 SECTION 8.11. Trustee Disclaimer. The Trustee makes no representation as to the validity or adequacy of
this Supplemental Indenture or the Notes other than the Trustee’s Certificate of Authentication. The recitals and statements herein and in the Notes are deemed to be those of the Company and not the Trustee. The Trustee shall not be accountable
for the use by the Company of the proceeds of the Notes. 
 [remainder of page intentionally left blank] 

  
 31 

 IN WITNESS WHEREOF, the parties to this Supplemental Indenture have caused it to be duly
executed as of the day and year first above written. 
  

							
	ALLEGHENY TECHNOLOGIES INCORPORATED
			
		 	By	 	
		 		 	 /s/ Patrick J. DeCourcy

		 		 	Name:	 	Patrick J. DeCourcy
		 		 	Title:	 	Senior Vice President, Finance and Chief Financial Officer
	
	 THE BANK OF NEW YORK MELLON,
 as
Trustee

			
		 	By	 	
		 		 	 /s/ Laurence J. O’Brien

		 		 	Name:	 	Laurence J. O’Brien
		 		 	Title:	 	Vice President

  
 [signature page to
Convertible Supplemental Indenture] 

 Schedule A 

The following table sets forth the hypothetical stock price and the number of Additional Shares to be received per $1,000 principal amount of
Notes: 
 Stock price on fundamental change date 
  

																																													
	 Effective date
	  	$11.56	 	  	$13.00	 	  	$14.45	 	  	$16.00	 	  	$18.00	 	  	$20.00	 	  	$25.00	 	  	$30.00	 	  	$40.00	 	  	$50.00	 	  	$60.00	 
	 May 24, 2016
	  	 	17.3010	  	  	 	15.9350	  	  	 	12.9913	  	  	 	10.6063	  	  	 	8.3202	  	  	 	6.6392	  	  	 	3.9818	  	  	 	2.5044	  	  	 	1.0431	  	  	 	0.4116	  	  	 	0.1205	  
	 July 1, 2017
	  	 	17.3010	  	  	 	14.8850	  	  	 	12.0262	  	  	 	9.7267	  	  	 	7.5443	  	  	 	5.9564	  	  	 	4.8642	  	  	 	2.1428	  	  	 	0.8466	  	  	 	0.3055	  	  	 	0.0703	  
	 July 1, 2018
	  	 	17.3010	  	  	 	13.7413	  	  	 	10.9651	  	  	 	8.7557	  	  	 	6.6851	  	  	 	5.2000	  	  	 	2.9407	  	  	 	1.7500	  	  	 	0.6413	  	  	 	0.2019	  	  	 	0.0269	  
	 July 1, 2019
	  	 	17.3010	  	  	 	12.4338	  	  	 	9.7395	  	  	 	7.6290	  	  	 	5.6865	  	  	 	4.3227	  	  	 	2.3177	  	  	 	1.3115	  	  	 	0.4267	  	  	 	0.1016	  	  	 	0.0000	  
	 July 1, 2020
	  	 	17.3010	  	  	 	10.8572	  	  	 	8.2431	  	  	 	6.2429	  	  	 	4.4579	  	  	 	3.2512	  	  	 	1.5834	  	  	 	0.8189	  	  	 	0.2104	  	  	 	0.0209	  	  	 	0.0000	  
	 July 1, 2021
	  	 	17.3010	  	  	 	8.8020	  	  	 	6.2313	  	  	 	4.3571	  	  	 	2.7999	  	  	 	1.8418	  	  	 	0.7122	  	  	 	0.3000	  	  	 	0.0349	  	  	 	0.0000	  	  	 	0.0000	  
	 July 1, 2022
	  	 	17.3010	  	  	 	7.7189	  	  	 	0.0000	  	  	 	0.0000	  	  	 	0.0000	  	  	 	0.0000	  	  	 	0.0000	  	  	 	0.0000	  	  	 	0.0000	  	  	 	0.0000	  	  	 	0.0000	  

  
 A-1 

 Exhibit A 

[FORM OF NOTE] 
 Face of Security

 UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (THE
“DEPOSITARY”), 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 THE DEPOSITARY (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY), 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 A BENEFICIAL INTEREST HEREIN. 
 THIS NOTE IS A GLOBAL SECURITY WITHIN
THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF THE DEPOSITARY OR A NOMINEE THEREOF. THIS NOTE MAY NOT BE TRANSFERRED TO, OR REGISTERED OR EXCHANGED FOR SECURITIES REGISTERED IN THE NAME OF, ANY PERSON OTHER
THAN THE DEPOSITARY OR A NOMINEE THEREOF AND NO SUCH TRANSFER MAY BE REGISTERED, EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE. EVERY NOTE AUTHENTICATED AND DELIVERED UPON REGISTRATION OF TRANSFER OF, OR IN EXCHANGE FOR OR IN LIEU
OF, THIS SECURITY SHALL BE A GLOBAL SECURITY SUBJECT TO THE FOREGOING, EXCEPT IN SUCH LIMITED CIRCUMSTANCES. 

 ALLEGHENY TECHNOLOGIES INCORPORATED 

4.75% CONVERTIBLE NOTES DUE 2022 
 No.
             
 CUSIP No. 01741R AG7 

ISIN No. US01741RAG74 
 Allegheny
Technologies Incorporated, a corporation duly organized and existing under the laws of Delaware (herein called the “Company”, which term includes any successor Person under the Indenture hereinafter referred to), for value received,
hereby promises to pay to [the order of [            ]] [if Global Securities, CEDE & CO.], or its registered assigns, the principal sum of
$[            ] ([            ] Dollars) on July 1, 2022, and to pay interest thereon from and including May 24, 2016
or from and including the most recent Interest Payment Date to which interest has been paid or duly provided for, semi-annually on January 1 and July 1 in each year, commencing January 1, 2017, at the rate of 4.75% per annum,
until the principal hereof is paid. The interest so payable, and punctually paid or duly provided for, on any Interest Payment Date will, as provided in such Indenture, be paid to the Person in whose name this Security (or one or more Predecessor
Securities) is registered at the close of business on the Regular Record Date for such interest, which shall be on December 15 or June 15 (whether or not a Business Day), as the case may be, next preceding such Interest Payment Date. Any
such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose name this Security (or one or more Predecessor Securities) is
registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to Holders of Securities of this series not less than 10 days prior to such Special
Record Date, or be paid at any time in any other lawful manner not inconsistent with the requirements of any securities exchange on which the Securities of this series may be listed, and upon such notice as may be required by such exchange, all as
more fully provided in said Indenture. 
 Payment of the principal of (and premium, if any) and any such interest on this Security will be
made at the Corporate Trust Office of the Trustee or such other office or agency of the Company as may be designated by it for that purpose in the Borough of Manhattan, The City of New York, in such coin or currency of the United States of America
as at the time of payment is legal tender for payment of public and private debts; provided, however, that at the option of the Company payment of interest may be made by check mailed to the address of the Person entitled thereto as
such address shall appear in the Security Register; provided further, however, that any such payment in respect of a Global Security shall be made by wire transfer of same-day funds to the applicable Depositary. 

Reference is hereby made to the further provisions of this Security set forth on the reverse hereof, which further provisions shall for all
purposes have the same effect as if set forth at this place. 

 Unless the certificate of authentication hereon has been executed by the Trustee referred to on
the reverse hereof by manual signature, this Security shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose. 

  
 [remainder of page
intentionally left blank] 

 IN WITNESS WHEREOF, the Company has caused this Note to be signed manually or by facsimile by its
duly authorized officers. 
  

					
	Date:	  	ALLEGHENY TECHNOLOGIES INCORPORATED
			
		  	    By:	  	  

		  		  	Name:
		  		  	Title:

  

			
	
		
	Attest:	 	 
		 	Name:
		 	Title:

 This is one of the Securities of the series designated therein referred to in the within mentioned Indenture.

  

			
	 THE BANK OF NEW YORK MELLON,
 as
Trustee

		
	By:	 	 
		 	Authorized Signatory

 Reverse of Security 

1. Indenture 
 This Security is one of a
duly authorized issue of securities of the Company (herein called the “Securities”), issued and to be issued in one or more series under an Indenture, dated as of June 1, 2009 (the “Base Indenture”), as
heretofore supplemented, and as supplemented by the Fifth Supplemental Indenture, dated as of May 24, 2016 (the “Fifth Supplemental Indenture”, and together with the Base Indenture as so supplemented, the
“Indenture”), between the Company and The Bank of New York Mellon, a New York banking corporation, as Trustee (herein called the “Trustee”, which term includes any successor trustee under the Indenture), to which
Indenture reference is hereby made for a statement of the respective rights, limitations of rights, duties and immunities thereunder of the Company, the Trustee and the Holders of the Securities and of the terms upon which the Securities are, and
are to be, authenticated and delivered. The terms of the Securities include those stated in the Indenture and those made part of the Indenture by reference to the Trust Indenture Act of 1939. Capitalized terms used but not defined herein shall have
the meanings ascribed thereto in the Indenture. If any provision of this Security is inconsistent with any provision of the Indenture, the provision in the Indenture shall control. This Security is one of the series designated on the face hereof.

 No reference herein to the Indenture and no provision of this Security or of the Indenture shall alter or impair the obligation of the
Company, which is absolute and unconditional, to pay the principal of (and premium, if any) and interest on this Security at the times, place and rate, and in the coin or currency, herein prescribed. 

2. No Optional Redemption; No Sinking Fund; No Defeasance and Covenant Defeasance 

The Securities are not subject to redemption at the election of the Company. The Securities are not subject to a sinking fund or mandatory
redemption. The Securities are not subject to Article XIII of the Base Indenture. 
 3. Purchase of Securities at the Option of Holders upon a
Fundamental Change 
 If a Fundamental Change occurs at any time, subject to the provisions set forth in the Indenture, the Holder of
this Security shall have the right, at such Holder’s option, to require the Company to purchase all of such Security, or any portion of the principal amount thereof, that is equal to $1,000 or an integral multiple thereof, at the Fundamental
Change Purchase Price specified in the Indenture. Article IV of the Fifth Supplemental Indenture sets forth the procedures, obligation, conditions and other terms of such repurchase option upon the occurrence of a Fundamental Change. 

4. Conversion 
 Subject to the procedures
for conversion set forth in Article V of the Fifth Supplemental Indenture and at any time prior to the close of business on the Business Day immediately preceding the Stated Maturity Date of the Securities, a Holder may convert its Securities at
their full principal amount, or any portion of their principal amount that is equal to $1,000 or an 

 
integral multiple thereof, into shares of Common Stock at the Conversion Rate then in effect at the time of conversion. 

5. Amendment; Waiver 
 The Indenture
permits, with certain exceptions as therein provided, the amendment thereof and the modification of the rights and obligations of the Company and the rights of the Holders of the Securities at any time by the Company and the Trustee with the consent
of the Holders of a majority in principal amount of the Securities at the time Outstanding. The Indenture also contains provisions permitting the Holders of specified percentages in principal amount of the Securities at the time Outstanding, on
behalf of the Holders of all Securities, to waive compliance by the Company with certain provisions of the Indenture and certain past defaults under the Indenture and their consequences. Any such consent or waiver by the Holder of this Security
shall be conclusive and binding upon such Holder and upon all future Holders of this Security and of any Security issued upon the registration of transfer hereof or in exchange herefor or in lieu hereof, whether or not notation of such consent or
waiver is made upon this Security. 
 6. Remedies 

As provided in and subject to the provisions of the Indenture, the Holder of this Security shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee or for any other remedy thereunder, unless such Holder shall have previously given the Trustee written notice of a continuing Event of Default with respect to the
Securities, the Holders of not less than 25% in principal amount of the Securities at the time Outstanding shall have made written request to the Trustee to institute proceedings in respect of such Event of Default as Trustee and offered the Trustee
reasonable indemnity and the Trustee shall not have received from the Holders of a majority in principal amount of Securities at the time Outstanding a direction inconsistent with such request, and shall have failed to institute any such proceeding,
for 60 days after receipt of such notice, request and offer of indemnity. The foregoing shall not apply to any suit instituted by the Holder of this Security for the enforcement of any payment of principal hereof or any premium or interest hereon on
or after the respective due dates expressed herein. 
 7. Registered Form; Denominations; Transfer; Exchange 

As provided in the Indenture and subject to certain limitations therein set forth, the transfer of this Security is registrable in the Security
Register, upon surrender of this Security for registration of transfer at the office or agency of the Company in any Place of Payment, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Company and the
Security Registrar duly executed by, the Holder hereof or his attorney duly authorized in writing, and thereupon one or more new Securities of this series and of like tenor, of authorized denominations and for the same aggregate principal amount,
will be issued to the designated transferee or transferees. 
 The Securities are issuable only in registered form without coupons in
denominations of $1,000 and any integral multiple thereof. As provided in the Indenture and subject to certain 

 
limitations therein set forth, Securities are exchangeable for a like aggregate principal amount of Securities and of like tenor of a different authorized denomination, as requested by the Holder
surrendering the same. 
 No service charge shall be made for any such registration of transfer or exchange, but the Company or the Security
Registrar may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith. 
 Prior to
due presentment of this Security for registration of transfer, the Company, the Trustee and any agent of the Company or the Trustee may treat the Person in whose name this Security is registered as the owner hereof for all purposes, whether or not
this Security be overdue, and neither the Company, the Trustee nor any such agent shall be affected by notice to the contrary. 
 8. Limited Satisfaction
and Discharge 
 The Securities are not subject to Section 4.01(1)(B) of the Base Indenture. 

9. Abbreviations 
 Customary abbreviations
may be used in the name of a Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (= tenants by the entireties), JT TEN (= joint tenants with right of survivorship and not as tenants in common), CUST (= Custodian) and U/G/M/A/ (=
Uniform Gifts to Minors Act). 
  

	10.	Governing Law 

 THIS SECURITY SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE
LAWS OF THE STATE OF NEW YORK. 

 ASSIGNMENT FORM 

To assign this Security, fill in the form below and have your signature guaranteed: 

I or we assign and transfer this Security to: 
  

 
 (Print or type name, address and zip
code and social security or tax ID number of assignee) 

and irrevocably appoint                    
                                         
                                         
                                         
                   agent to transfer this Security on the books of the Company. The agent may substitute another to act for him. 

 

					
	Dated:
                                         
   	  	Signed:	  	  

		  		  	(Sign exactly as your name appears on the other side of this Security)
			
		  	Signature	  	Guarantee:
                                         
                                   
		  		  	(Signature must be guaranteed by a participant in a recognized Signature Guarantee Medallion Program or other signature guarantor program reasonably acceptable to the Trustee)

 SCHEDULE OF EXCHANGES OF INTERESTS IN THE GLOBAL SECURITY 

The initial principal amount of this Global Security is $[            ]
([            ] DOLLARS). The following increases or decreases in this Global Security have been made: 
  

									
	 Date of

Exchange
	  	 Amount of decrease

in Principal Amount of
 this
Global Security
	  	 Amount of increase in
Principal Amount of

this Global Security
	  	 Principal Amount of

this Global Security
following such decrease
or increase
	  	
Signature of authorized officer of Trustee
or Securities Custodian

		  		  		  		  	
		  		  		  		  	
		  		  		  		  	
		  		  		  		  	
		  		  		  		  	

 FORM OF FUNDAMENTAL CHANGE PURCHASE NOTICE 

To: Allegheny Technologies Incorporated 
 The undersigned
registered Holder of this Security hereby acknowledges receipt of a notice from Allegheny Technologies Incorporated (the “Company”) as to the occurrence of a Fundamental Change with respect to the Company and requests and instructs
the Company to repurchase this Security, or the portion hereof (which is $1,000 principal amount or an integral multiple thereof) designated below, in accordance with the terms of the Fifth Supplemental Indenture and the Base Indenture referred to
in this Security and directs that the check or wire or other electronic funds transfer of the Company in payment for this Security or the portion thereof and any portion of this Security representing any unrepurchased principal amount hereof be
issued and delivered to the registered Holder hereof unless a different name has been indicated below. If any portion of this Security not repurchased is to be issued in the name of a Person other than the undersigned, the undersigned shall pay all
transfer taxes payable with respect thereto. 
 Principal amount to be converted (if less than all): 

$                         
                              

Certificate number (if Securities in certificated form): 
  

					
	Dated:
                                         
       	  	Signed:                                   
                                         
                     
		  		  	(Sign exactly as your name appears on the other side of this Security)
			
		  	Signature	  	Guarantee:                                    
                                         

		  		  	(Signature must be guaranteed by a participant in a recognized Signature Guarantee Medallion Program or other signature guarantor program reasonably acceptable to the Trustee)

 Fill in if a check is to be issued, or Securities are to be issued, other than to and in the name of registered holder: 

 

					
	  
	 		  	
	(Name)	 		  	
	  
	 		  	
	(Street Address)	 		  	
	  
	 		  	  

	 (City, state and zip code)
 Please print name
and address
	 		  	Social Security or Other Taxpayer Number

 FORM OF CONVERSION NOTICE 

To: Allegheny Technologies Incorporated 
 The undersigned
registered Holder of this Security hereby exercises the option to convert this Security, or portion hereof (which is $1,000 principal amount or an integral multiple thereof) designated below, for shares of the Common Stock of Allegheny Technologies
Incorporated, in accordance with the terms of the Fifth Supplemental Indenture and the Base Indenture referred to in this Security, and directs that the shares issuable and deliverable upon such conversion, cash in lieu of fractional shares and any
portion of this Security representing any unconverted principal amount hereof, be issued and delivered to the registered Holder hereof unless a different name has been indicated below. If shares or any portion of this Security not converted are to
be issued in the name of a Person other than the undersigned, the undersigned shall pay all transfer taxes payable with respect thereto. Any amount required to be paid by the undersigned on account of interest accompanies this Security. The
undersigned acknowledges that the conversion of the specified Securities is subject to the requirements established by the Company in the Fifth Supplemental Indenture and the Base Indenture, as applicable, as well as the procedures of any
Depositary, each as in effect from time to time. 
 This notice shall be deemed to be an irrevocable exercise of the option to convert this Security. 

Principal amount to be converted (if less than all): 

$[                    ] 

 

					
	Dated:
                                         
       	  	Signed:                                   
                                         
                   
		  		  	(Sign exactly as your name appears on the other side of this Security)
			
		  	Signature	  	Guarantee:                                    
                                         

		  		  	(Signature must be guaranteed by a participant in a recognized Signature Guarantee Medallion Program or other signature guarantor program reasonably acceptable to the Trustee)

 Fill in if a check is to be issued, or Securities are to be issued, other than to and in the name of registered holder: 

 

					
	  
	 		  	
	(Name)	 		  	
	  
	 		  	
	(Street Address)	 		  	
	  
	 		  	  

	 (City, state and zip code)
 Please print name
and address
	 		  	Social Security or Other Taxpayer Number

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00258-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00258-of-00352.parquet"}]]